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  • Inorganic Chemistry  (639)
  • Seismology
  • Industrial Chemistry
  • 1985-1989  (823)
  • 1950-1954
  • 1988  (823)
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  • 1985-1989  (823)
  • 1950-1954
Year
  • 1
    Electronic Resource
    Electronic Resource
    Effect of ethane addition on propane pyrolysis (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 243-248 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pyrolysis of propane/argon mixture in the presence of trace quantities (0.1% and 0.9%) of ethane was investigated at reflected shock wave temperatures between 1200 and 2000K. Traces of ethane accelerated propane decomposition at high temperature. However, increase in the quantity of ethane added to propane/argon mixture did not result in the same increase of its accelerating influence. Ethylene, methane and acetylene were the main hydrocarbon reaction products, with small quantities of propylene and ethane detected only at lower temperatures. Below 1500K, addition of ethane slightly enhanced the yields of ethylene and methane at the expense of propylene and ethane respectively. The selectivity for acetylene increased with increasing temperature and with the decline of those for the other products. For none of the products, did the presence of ethane alter the relationship between product formation rates and temperature. The influence of ethane addition on propane pyrolysis at high temperatures was explained in terms of increased radical concentrations, especially hydrogen atoms and vinyl radicals, formed at high conversions. These accounted for the rapid acceleration of propane decomposition and the high yield of acetylene at high temperatures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110132
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  • 2
    Electronic Resource
    Electronic Resource
    Volumetric mass transfer coefficient in stirred reactors (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 249-251 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown that the volumetric mass transfer coefficients, presented recently by Schmitz et al. [1] for viscous solutions of carboxymethyl cellulose (CMC) in aqueous sodium sulphite, are considerably underestimated as a result of unjustified neglect of the oxygen back pressure during oxygen absorption. Schmitz et. al. [1] found a decrease in the exponent n in the relationship between the oxygen mass transfer coefficient, kla, and the power dissipated per unit volume of the liquid phase, e (kla ∝ en), and ascribed it to viscosity effects. However, no such decrease is observed, provided that the actual oxygen back pressure is taken into account.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110133
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  • 3
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    The role of energy dissipation in contacting and mixing devicesPresented in memory of Professor Otto Nagel, at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 276-287 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The aim of the present paper is the discussion of the relevance of power dissipation as a criterion for the understanding and prediction of transfer and mixing efficiencies in contactors and chemical reactors. After reviewing the approach of Le Goff to the energetic efficiency of exchangers, based on the deviations from Chilton-Colburn analogy, the following processes are studied: mass transfer between a flowing fluid and a reactive solid surface, transfer to a fixed object in a stirred vessel, macro- and micromixing of miscible fluids, and mass transfer in fluid-fluid contractors (especially gas-liquid reactors). It is concluded from the various examples that a direct relationship between the dissipated power and intensity of transfer or mixing can be established only under the two following conditions: local values must be considered at the point where the actual transfer and mixing occur, and not average values over the whole device, and power dissipation must be coupled to transfer or mixing and appear physically as the driving force of the process.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110137
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  • 4
    Electronic Resource
    Electronic Resource
    Development of design charts for fixed-bed adsorptionPaper presented by W. Otten at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 289-297 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model of the dynamic behaviour of non-isothermal fixed-bed adsorbers has been developed which takes into account the various mass and heat transfer resistances. Comparison of experimental and simulated results confirms that the model can predict the adsorption and desorption breakthrough curves of an adiabatically operated column, using only equilibrium data and tortuosity factors obtained from single pellet experiments. A simplified model with a reduced number of parameters was derived by investigation of the dimensionless transfer parameters under industrial conditions. It becomes evident that the main transfer mechanisms are convective heat and mass transfer in the bulk flow and diffusion within the pores of the particle. Dimensionless effluent concentration is expresses in terms of dimensionless time, a transport parameter, a non-isothermal parameter, the adsorption equilibrium and the inlet and initial concentrations and temperatures in the simplified model. For a chosen system of adsorbate and adsorbent, design charts can be developed by computer simulation, to determine graphically the breakthrough time as a function of significant process parameters, i.e. the dimensionless transfer parameter and the feed concentration.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110138
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  • 5
    Electronic Resource
    Electronic Resource
    The significance of fly ash in wet-dry scrubbing of SO2 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 298-305 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A bench scale flue gas desulphurization spray dry scrubbing unit was employed to study the effect of fly ash on the removal of SO2. The equipment consisted of a spray dryer with and ultrasonic nozzle for atomization and a pulse jet baghouse. The flue gas rate was 1500 lN/h (dry gas). Four fly ashes, originating from different countries were investigated. The alkalinity and reactivity of the fly ashes were determined in a pH-stat equipment. Pure fly ash removed SO2 in both the spray dryer and in the baghouse. An increase of humidity divided the fly ashes into two groups. The high calcium fly ash gave a considerably higher SO2 removal than the medium and low calcium fly ashes which showed similar SO2 removals. Fly ash did not enhance the removal of SO2 when added to a lime slurry because lime suppresses the dissolution of the alkali in the fly ashes. The pressure drop build-up in the fabric filter showed a strong dependence on material properties.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110139
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  • 6
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    Thermal radiation of gas/solid mixturesPaper presented by Th. Elsner at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 237-243 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal radiation of gas/solid mixtures in high-temperature heat exchangers is of considerable importance for the design of heat exchange surfaces. Therefore, an experimental plant was constructed to measure solid particle emissivities, since there is a lack of relevant data in the existing literature. A theoretical equation was derived to describe the solid particle emissivity as a function of layer thickness, specific solid surface area, solid loading and absorption and scatter coefficients. Measurements were carried out for fluidized bed ash and quartz sand. The emissivities of these particle fractions increase with increasing layer thickness, slid loading, specific solid surface area and temperature. The description of these data by the derived model equation is very satisfactory. No dependence on wavelength was observed. The ash components do exert some influence which, for the present, cannot be described exactly.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110131
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  • 7
    Electronic Resource
    Electronic Resource
    Parametric sensitivity of the ignition process to mass transfer in adiabatic tubular reactors with exothermic heterogeneous reactions (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 251-258 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The alternative effects of reaction kinetics, mass, heat and momentum transport on mass conversion by chemical reactions are examined theoretically for a reacot tube with laminar flow. The reaction enthalpy is considered. A heterogeneous reaction between several gaseous components takes place at the inner surface of this reactor tube. Strongly exothermic reactions lead to self-acceleration of the reaction, unless reaction enthalpy is removed through the tube wall. Under certain conditions, there will be a sudden change from mass transfer controlled by the reaction to that controlled by diffusion. This phenomenon is known as ignition of the reaction. The effect of ignition and its sensitivity to reaction enthalpy, thermal conductivity and diffusivity of the fluid as well as activation energy of the first order heterogeneous wall reaction are investigated by a numerical solution of the transport equations. Axial conduction of heat and mass is neglected both in the fluid and in the tube wall. Non-stoichiometric wall reactions of first order, with temperature dependent reaction rates and equilibrium constants, are considered. The results are presented in graphical form, as plots of the local mass flux at the reacting wall as functions of the dimensionless tube length.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110134
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  • 8
    Electronic Resource
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    Scale-up of mechanically agitated extraction columnsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 259-263 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The deterioration of mass transfer efficiency of an extraction column with increasing column diameter is the result of developing residence time distributions. These effects can be described by one-dimensional dispersion model. However, it must be verified whether the requirements for its application are fulfilled in the different types of agitated extraction columns. For the columns for which the dispersion model can be applied, a relationship will be derived between the necessary increase of column height with column diameter. This is based on the equations for calculation of the dispersion coefficient of the continuous phase. If the dispersion model cannot be applied to given a type of column, an investigation will be made on the possible modifications of operation or changes in construction, in order to permit a scale-up procedures as proposed here.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110135
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  • 9
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    Chemical engineering aspects of precipitation from solutionPaper presented by A. Mersmann at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to october 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 264-276 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Precipitation is a rapid solidification. As a rule, it applies to substances which are sparingly soluble and is coupled with a chemical reaction or with a salting out process. The chemical engineer has to ensure that the product obtained has a constant and preferably coarse size distribution. This contribution compares the literature data on crystallization of soluble and sparingly soluble substances; it can be shown that, during precipitation processes, nuclei are formed, most probably by a primary mechanism. Analysis of the processes occurring during precipitation, such as chemical reaction, mixing and crystallization, leads to recommendations for the operation of precipitation processes.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110136
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  • 10
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    Mass transfer behaviour of gas-liquid jet loop reactorsPaper presented by M. Geisendörfer at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987.Dedicated to Professor Dr. Horst Langemann on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 306-311 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A special type of jet loop reactor (JLR), designed for continuous operation and short residence times was investigated with regard to its mass transfer behaviour, described by the volumetric mass transfer coefficient kLa. The jet stream and superficial gas velocities are varied in two JLRs of different sizes, equipped with different nozzles. Fully desalinated water, 0.08 molar NaCI solution and solutions of different concentration of carboxymethyl cellulose (CMC) are used as the liquid phase. A steady-state physical method is employed to determine kLa: air oxygen is purged from the liquid phase by gaseous nitrogen. The measurements show that the reactor is characterized by high power density and high mass transfer performance. No limit of mass transfer capacity was observed in the chosen ranges of volumetric gas and liquid flow rates, i.e. at a given jet stream velocity, the relationship between kLa and the superficial gas velocity is nearly linear. The investigations show that the mass transfer contributed by the jet stream largely depends on liquid phase composition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110140
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  • 11
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    Mass transfer in centrifugal extractorsPaper presented by F. Otillinger at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 312-320 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents the methods of measuring the mass transfer in centrifugal extractors and of determining it during the individual life stages of a fluid element of the dispersed liquid, i.e. drop formation, motion, coalescence and stay in the stationary layer of the dispersed phase. The experimental mass transfer coefficients of the dispersed and continuous phases are compared with well-known theoretical models developed for extraction columns in gravitational field. Due to the fast motion and coalescence of the fluid particles at high centrifugal field intensities, mass transfer in centrifugal extractors takes place during short contact times. Nevertheless, this contribution shows that mass transfer in a centrifugal field can be calculated with selected theoretical models of the gravitational field. The investigations on mass transfer are completed by a classification of the strongly deformed fluid particles in centrifugal field into regimes of circulating and oscillating drops. In addition, data on the performance of centrifugal extractors, undergoing several exchange steps, are given.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110141
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  • 12
    Electronic Resource
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    Subcooled boiling heat transfer to R 12 in an annular vertical channel (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 320-327 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Detailed knowledge of the physical phenomena involved in subcooled boiling is of great importance for the design of liquid-cooled heat generating systems with high heat fluxes. Experimental heat transfer data were obtained for forced convective boiling of dichloro-difluoroethane (R 12). The flow is circulated upwards through a concentric annular vertical channel. The inner and outer diameters of the annulus are 0.016 m and 0.03 m respectively. The reduced pressures studied were 0.24 ≤ p/pcrit ≤ 0.8, inlet subcooling varied from 10 to 75 K and mass fluxes from 500 to 3000 kg/m2s, which corresponds to Re numbers from 30000 to 300000. The experiments, described in this study, demonstrate that liquid fluorocarbons show certain unusual boiling characteristics in the subcooled flow, such as hysteresis of the boiling curve. These characteristics are attributed to the properties of the fluid, mainly the Pr number and the very low surface tension. The pronounced boiling curve hysteresis can be explained by the fact that large nucleation sites may have been flooded prior to incipient boiling. A dimensionless regression formula is presented which predicts the onset of subcooled boiling as a function of reduced pressure (p/pcrit), Boiling-(Bo), Reynolds-(Re), and a modified Jacob number (Ja), over the whole range of parameters studied, with a good accuracy, including water data from literature.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110142
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  • 13
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    Modelling of multiphase detonations with drop disintegration - description of thermal detonations (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 327-334 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model is presented which consists of steady-state and transient codes for the description of reacting multiphase flow fields, including hydrodynamic fragmentation of liquid drops in relative flows. An application of this model for the description of large scale melt-coolant interactions (thermal detonations) is described. A simulation of two-phase chemical detonations, especially those with hydrodynamic disintegration of liquid fuel drops in the reaction zone, is possible, in principle, within the framework of the modeling.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110143
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  • 14
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    Characteristics of solid suspensions in a bubble column without and with draft tubePaper presented by J. Heck at the “Jahrestreffen der Verfahrensingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 335-340 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to investigate the suspension behaviour of solid particles in bubble columns without and with draft tube, minimum gas velocities for generating and maintaining complete solid suspension were determined. Experiments were carried out in a bubble column with a diameter of 200 mm and a height of 2 500 mm. The bubble column could be equipped with a draft tube with a diameter of 120 mm and a length of 1 500 mm. The state of suspension was determined by measuring the hydrostatic pressure as a result of suspended solid particles with an inductive pressure gauge. Solid content εs, solid density ϱs, particle size dp, particle shape, particle size distribution, and solid wettability were varied. Furthermore measurements of integral gas holdup were carried out.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110144
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  • 15
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    Modelling of activated carbon desorption by a circulated inert gasPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 352-358 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adsorption solvent recovery process, known as Recursorb which involves desorption and cooling steps by a circulated inert gas, is analyzed in detail on the basis of equilibrium theory. Employing the method of characteristics, the model is solved for each step of the overall process. The estimations confirm that the process performance with respect to final gas purity, activated carbon useful capacity and operation times depends on condenser and heater temperatures. Simple expressions are derived for the calculation of adsorption, desorption and cooling times.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110146
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  • 16
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    Modelling of a pressure swing adsorption process for oxygen enrichment with carbon molecular sievePaper presented by E. Richter at the “Jahrestreffen der Verfahrens Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 341-351 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Adsorptive separation of oxygen from nitrogen and argon is carried out during the desorption steps of a pressure swing adsorption (PSA) process which uses carbon molecular sieves developed by Bergbau-Forschung GmbH. The adsorption isotherms of the three main components of air are very similar. On account of the pore size distribution of CMSN2, the diffusion coefficient of oxygen is more than eight times those of nitrogen and argon so that air separation occurs by adsorption kinetics. Experimental results for the individual steps and cyclic operation of the PSA process are presented and compared with the predictions of an isothermal plug-flow model. Adsorption rate is represented by a linear driving force equation. If the diffusion coefficients are adapted separately to every step, a good agreement is observed between the model calculations and experimental results.
    Additional Material: 22 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110145
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  • 17
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    The importance of corrosion prevention for the safety of chemical plants (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 359-365 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One of the most important tasks to eliminate dangers in chemical plants is the prevention of corrosion. This implies the provision of safe enclosures and reaction spaces for the substances to be processed. The present contribution deals with the procedure in the selection of materials for equipment exposed to corrosion and stresses the difficulties connected with the elimination of local corrosion. The relevance of prevention of crack forming corrosion processes is emphasized. Problems to be solved in order to obtain results from investigations, suitable for a safe application of a materials under practical conditions, are indicated.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110147
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  • 18
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    Theoretical and experimental study of sedimentation in vertical flow tanks (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 95-104 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Settling characteristics of four different suspensions were measured by batch settling tests (glass spheres in glycerol-water mixtures and CaCO3) and by continuous settling test in a bench-scale vertical flow tank (activated sludge and kaolin in water), including the measurement of solids concentrations inside the tank. The characteristics could be described by different correlation functions which now include all the information about the settling behaviour of ideal suspensions. Continuous settling experiments in a bench-scale vertical flow tank were carried out with the same four material systems. These results correspond with sufficient accuracy to those from the theory of limiting flux if the settling characteristics determined earlier are considered.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110114
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  • 19
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    Effect of combustion air preheating on NOx emissions from gas burners in high-temperature industrial applicationsPresented by M. Flamme at the “Jahrestreffen der verfahrens-ingenieure”, strasbourg, september 17 to 19, 1986. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 104-112 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NOx emissions from different commercial gas burners for metal heat treatment applications were measured for a research project of the Gaswärme-Institut. The burners, rated at up to 50 kW, were installed for the tests in a laboratory combustion chamber operated at temperatures of up to 1400°C. The air for combustion was preheated to maximum temperature of 600°C. Following the tests, the potentials of different NOx control techniques were investigated. Methods explored included staged combustion air injection, staged fuel injection and fuel gas injection into the flue for NOx reduction. The results showed that it is feasible to reduce the NOx content of flue gases by as much as 90%.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110115
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  • 20
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    Thermal deactivation of heterogeneous catalyst, part 1. The theta-rule - a critical review (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 113-119 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal deactivation can be described either by deactivation kinetics or by the isokinetic effect. The latter expression is used synonymously with the “compensation effect” and the “Theta-Rule”. An examination of the original literature shows that only the compensation effect is applicable to thermal deactivation but not the Theta-Rule. The introduction of the preparation temperature as a parameter of the compensation effect results in a “modified Theta-Rule”, which describes the experimental data and is proposed for the non-separable kinetics. The consequence of the observed deviations from the validity range of the Theta-Rule is that the activation energy cannot be used as a universal activity criterion.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110116
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  • 21
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    Kinetic analysis of the oxidation of isobutyraldehyde in liquid phase (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 120-126 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of non-catalytic as well as catalytic oxidation of Isobutyraldehyde has been investigated. Reaction rate equations for the formation of the main product isobutyric acid and of the side products acetone, CO and CO2 were derived. Kinetic parameters, namely the order of reaction, preexponential factor and activation energy were estimated by non-linear regression. The influence of selectivity and activity of the different type of catalysts employed was investigated quantitatively.
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    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110101
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    Thermal deactivation of heterogeneous catalysts. Part 2: The compensation effect and the Catalytic Paradox (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 228-236 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interpretation of the term “compensation” obscures a logical contradiction, the catalytic paradox, which is caused by inconsistent validity ranges of the Arrhenius parameters, the pre-exponential factor and the activation energy. For this reason, a theory which contains the Arrhenius parameters cannot be established for the entire system (whole temperature range) on the basis of classical logic. Only the subsystems can be consistent and complete. One subsystem is the range of the topocatalytic concept which is relevant for thermal deactivation, thermal bistability and for all reactions with surface dependence of activity. The other is the range of the energetic concept which is preferred in fundamental research. In order to complete the subsystems, new consistent symbols are introduced. The change of particle size caused by thermal deactivation can result in four possible particle size effects, two of which have been discussed in the literature.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110130
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    Engineering aspects and applications of crossflow microfiltration (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 17-25 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crossflow microfiltration (CMF) is a pressure driven membrane process for the separation of suspended microparticles, bacteria and emulsion droplets. The fluid to be filtered flows in parallel to the membrane surface and restricts the formation of a filter cake. This contribution explains the basic process characteristics and the combination of the crossflow technique with other membrane cleaning methods (periodic backflushing, chemical cleaning). Special attention is paid to the influence of different process parameters on the flux through the membrane. The principle of plant design and different operation modes are described. Engineering aspects such as hydrodynamics, energy requirement and selection of construction materials are discussed in some detail.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110104
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  • 25
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    Mass transfer contributions of solid particles to gas permeation in viscous laminar tube flow (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 25-31 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: While two- and multiphase flows find more and more application in chemical engineering practice, and the demand for theoretical information about mass and heat transfer processes in such systems is increasing, such data or at least experimental results which could be generalized are still lacking. The following pages are concerned with mass transfer in laminar suspension tube flows normal to the main direction of flow due to the individual motions of small, inert spherical particles. On the basis of a large number of experimental data, an interpretation is attempted of the role of nearly neutrally-buoyant particles in mass transfer enhancement, and a model for a semi-empirical description is suggested. The experimental arrangement uses the mass transfer of carbon dioxide in laminar flow of salt water during the process of gas permeation through a permeable membrane tube wall.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110105
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    Effect of chlorine on the selectivity of a fischer-tropsch catalyst composed of iron/vanadium oxidesDedicated to Professor Dr. Karl Schügerl on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 32-39 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fischer-Tropsch catalysts (Fe/V oxides with ZnO and K2CO3 as promoters) were exposed to CHCl3, thereby producing surface and bulk chlorides. The effect of this exposure on activity and selectivity was studied in a continuous recycle reactor at a total pressure of 10 bar (CO/H2 in most experiments: ca 1:1) in a temperature range between 200 and 343°C. CHCl3 was introduced in amounts of up to 1 × 10-2 mol chlorine per g catalyst. The catalyst samples were characterized by internal surface area, pore-size distribution and adsorption capacities for CO, H2 and C2H4. Prior to synthesis, the catalysts were reduced by H2. Catalyst exposure to CHCl3 resulted in a decrease of activity and considerable changes in product distribution. Hydrogenation and isomerization of 1-olefins were partly suppressed; the chain length of the products was slightly increased. Deactivation of the catalysts due to chlorine addition was partly reversible during operation, while olefin formation was not significantly altered with time-on-stream. The effect of chlorine on activity and selectivity is explained by dissociation of CO as the chain initiating step and CO insertion into a carbon/metal bond as a possible chain propagation step. Since adsorption capacity for H2 decreases on the addition of chlorine, this may also contribute to lower activity and change in selectivity, compared to the unexposed catalyst.
    Additional Material: 7 Ill.
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    Attrition and secondary nucleation in crystallizers (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 80-88 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mean crystal size of coarse crystalline products is determined by secondary nucleation and crystal growth. Secondary unclei are mainly produced by contacts of crystals with parts of the crystallizer or with other crystals. As a consequence, attrition effects are very important. In this paper, a model is proposed in order to calculate the attrition rate of crystals, depending on the physical properties of the crystalline product, the geometry of the crystallizer and on the operating conditions such as the stirrer speed or the suspension density. The effective rate of secondary nucleation can be expressed in terms of the attrition rate by introducing effective values for number and size of attrition particles. Finally, a scale-up criterion based on this model is derived. This criterion allows to predict effective rates of secondary nucleation and mean crystal sizes if data obtained in a laboratory crystallizer are available.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110112
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    The stability of crude oil residues and factors affecting their decomposition during mild thermal treatment (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 89-94 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A number of topped crude oil residues were subjected to mild thermal cracking in the temperature range between 613 and 673K at N2 pressure of one atmosphere. It was found that the thermal stability of the six topped crude oils decreased in the order Brent 〈 Piper 〈 Auk 〈 Saudi Arabian 〈 Romashkinskaya 〈 Tia Juana Pesado. This was measured in terms of light end production (C1-C5 hydrocarbons). The asphaltene, sulphur and metal (nickel and vanadium) contents were also determined. The production of light ends, exemplified by methane, was found to be related to the metal asphaltene content of the crude oils, but the sulphur content exerted a moderating influence upon the extent of cracking. Hence, metal asphaltenes, probably as metal porphyrins, catalyse cracking but the presence of sulphur reduces that catalytic activity and can inhibit cracking. If cracking of long chain hydrocarbons is to be minimized, metal asphaltenes should be removed (preferably) or reduced in concentration or poisoned, in order to decrease their catalytic activity.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110113
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    Heat transfer between particle beds and submerged surfacesPaper presented by O. Molerus at the “Jahrestreffen der Verfahrens-Ingenierue”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 126-138 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Theoretical modelling of heat transfer to particle beds comprises two sequential steps: transfer from the heating surface to contacting particles followed by transfer to the interior of the bed. Two different limiting case can be formulated for the second step: unmixed and homogeneously mixed bed. In the case, heat is transferred gradually via a repeated sequence of heat transfer in the gap between adjacent particles and conduction in the particulate material. In the second case, heat is transferred to the interior of the bed by mixing of particles which have previously attained the temperature of the heating surface. On the other hand, the mixing motion maintains a homogeneous lower temperature throughout the bed. Theory predicts a significant and easily measurable difference in the behaviour of heat transfer coefficients for the two regimes at long contact times t: unmixed beds ∝ \documentclass{article}\pagestyle{empty}\begin{document}$$ \sqrt t $$\end{document} and homogeneously mixed beds ∝ 1/t. For short times t, both regimes show the same behaviour, namely of t.From a theoretical standpoint, it makes sense to differentiate further between the behaviour patterns of unmixed beds: at long times t, instantaneous heat transfer coefficients are independent of heat transfer form the heating surface to adjacent particles. Comparison with experimental result from literature shows that the derived models, which are consistent, are suitable for describing the heat transfer from submerged surfaces to unmixed and mixed beds of particles.
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    URL: http://dx.doi.org/10.1002/ceat.270110118
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    Measurement of temperature fields in mixing vessels using optical topographyPaper presented by W. Ostendorf at the “Jahrsterffen der Verfahrens- Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 148-155 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental investigation of stirring processes require the measurement of temperature changes and concentration profiles in all the zones of the mixing volume. The conversion of simultaneous chemical reactions during the mixing process depends on the local temperature and concentration. The time-dependent temperature and concentration fields can be recorded for the entire mixing volume with the use of optical tomography and correlated with time. This technique offers the possibility of continuous measurement of temperature and concentration changes during the mixing process throughout the measurement volume. In the described investigations, optical tomography is used to examine the transport and equalization processes during mixing in stirred vessels.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110120
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    Relationship between residence time, fluid dynamics and efficiency in countercurrent flow equipmentPaper presented at AIChE Annual Meeting 1986, Miami Beach, Florida, USA (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 139-148 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The suitability of any item of equipment for a given thermal separation process cannot always be judged solely in the light of efficient and loading range data. In vacuum rectification, involving a large number of theoretical stages, the vapour pressure drop per transfer unit exerts a considerable effect on the energy consumption and thus largely governs the choice of column fittings. Furthermore, the pressure drop per transfer unit determines the temperature at the bottom of a rectification column and, hence, the suitability of the equipment for the separation of heat-sensitive products. It is also an important criterion for compressor requirements in absorption processes. Another factor of considerable importance in separating heat-sensitive mixtures by distillation is the time during which the product, particularly the liquid phase, is exposed to a given temperature in the column. Therefore, a standardized liquid residence time has been adopted to evaluate the systems in their entirely. This residence time depends on the hydrodynamic conditions in the column and is thus closely related to pressure drop and efficiency. Further important factors, which may decide the selection of column internals, are the specific volume and mass of the column. Based on theoretical considerations, a flow model is derived for describing the main loading range of countercurrent packed columns; the relationships between the above mentioned parameters are presented.
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    URL: http://dx.doi.org/10.1002/ceat.270110119
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    Absorption of SO2 by aqueous NaOH solutions in the presence of a surfactant (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 156-162 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the influence of liquid flow rate, NaOH concentration, column length and presence of 5 × 10-3 wt-% of the surfactant SLS on the rate of absorption of pure SO2 by aqueous NaOH solution in a sphere-and-cylinder column. The presence of sodium lauryl sulphate (SLS) prevented axial turbulence which increased mass transfer in longer columns and was almost independent of the flow rate. The enhancement factor due to the reaction between SO2 and NaOH with respect to the process of physical absorption was analyzed for the systems with excess OH- in the outflow. The results obtained in the presence of a surfactant are satisfactorily explained by film theory with a single reaction plane model. Those obtained in the absence of surfactant are best described by a two-plane model using renewal theory.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110121
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    Influence of mechanical stress on the growth of Rhizopus nigricans in stirred bioreactorsPaper presented at the “Jahrestreffen der Verfahrensigenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 178-187 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This investigation was undertaken in order to examine the factors affecting mechanical damage to micro-organisms in stirred bioreactors. Growth of the mould Rhizopus nigricans was studied in stirred bioreactors at different geometrical and operating parameters. Since experimental results cannot be described by conventional key parameters, a new concept has been suggested. It is based on the analogy to processes of mechanical disintegration. It is shown that the same key parameter, i.e. the ratio of power input to flow rate, can be used for a satisfactory correlation of experimental data on mechanical damage to micro-organisms, which is an important step in the recovery of intracellular products in biotechnology.
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    URL: http://dx.doi.org/10.1002/ceat.270110124
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    Scale-up of bioreactors for fermentation of mammalian cell cultures with special reference to oxygen supply and microcarrier mixingPaper presentet by J. Vorlop at the “Jahrestreffen der Verfahrensingenieure”, September 17 to 19, 1986 in Strasbourg (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 171-178 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The increasing demand for products from mammalian cells has prompted the authors to develop a new type of bioreactor. Its significant features include the supply of oxygen, homogeneous distribution of microcarrier suspensions and process control. Media with high protein contents, required for mammalian cell cultures tend to generate foam. This causes the flotation of solid particles. The reactor was equipped with a system of porous hydrophobic Accurel hollow fibre membranes in order to prevent the formation of bubbles. The membrane is coiled in the form of a basket, or fixed on several carriers. If the liquid pressure is higher than that of the gas phase inside the membrane, a bubble - free oxygen supply to the culture broth can be achieved. The problem of axial mixing of microcarier suspensions was solved by the use of a spiral agitator, attached underneath the aeration system at the bottom of the reactor. The combined aeration and mixing system, which is driven by an eccentric motor, undergoes a tumbling motion. Sufficiently homogeneous suspensions are produced in this system at low membrane velocities, i.e. in presence of low shear forces.
    Additional Material: 14 Ill.
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    A model-based control system for a distillation columnPaper presented by F. F. Rhiel at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 188-194 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A control concept which includes an adaptive multivariable control algorithm and an observer model has been put into practice in the operation of a distillation column which separates water from a solvent. The model yields predictions of solvent concentration in the waste water which forms the top product. Early detection of disturbances permits an adjustment of the process in time. This has resulted in an exceptionally smooth operation of the column, with a drastic reduction in solvent concentration fluctuations, observed with conventional control technology. Since the only measurements required are pressure, temperature and the rate of flow, this control system is largely free from disturbances. In addition to considerably reducing the burden on operating personnel, use of this control system has lowered the costs of waste water treatment, solvent losses, analysis expenditure and energy consumption.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110125
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    A new fluid dynamic model for mixing of newtonian and power-law liquids in the transient regimeModified version of a paper presented at the “GVC Working Party on Mixing”, Trier, 4./5. May 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 162-170 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the description of mixing processes influenced by viscosity in pseudoplastic (power-law) fluids, a definition of representative viscosity is normally used which takes into account the variable flow behaviour of the stirred material as a result of different shear stresses. In this context, the Metzner and Otto concept, which postulates that a representative shear rate is proportional to stirring speed, has become widely know, although the power calculation is inaccurate, particularly in the transient regime between the laminar and turbulent flow. A new model of fluid dynamics in the mixing vessel is presented, based on the increase of the mean flow velocity standardized with the stirrer's tip velocity in the transition regime. It provides a physical explanation for the above deviations. A suitable definition of representative viscosity substantially improves the accuracy of calculations of the stirring power in power-law fluids.
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    Consistent scale-up procedure for the power consumption in agitated non-newtonian fluids (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 199-205 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown how a consistent scale-up rule for the power consumption in agitated non-Newtonian liquids can be obtained. The new approach is based on the concept of including the real liquid in a set of liquids with similar rheological properties and of using, in a small scale laboratory system, a suitable member of that set instead of the original liquid. Considerations of similarity lead to simple unique selection rules for the actual test liquid and for the stirrer speed in the laboratory experiment as well as to a prediction of the power requirement in the real system. The theory is tested experimentally by means of different aqueous polyacrylamide solutions. The results are compared with predictions, according to Metzner and Otto as well as Rieger and Novák.
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    URL: http://dx.doi.org/10.1002/ceat.270110127
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    Axial pressure profile in circulating fluidized beds (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 11-17 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Design and operation of a circulating fluidized bed requires the knowledge of fluid mechanics. According to heat and mass transfer as well as chemical reactions, the effect of the set superficial gas velocity on the axial pressure profile is of particular interest. The axial pressure profile was measured for a variety of solids, as a function of the superficial gas velocity, in a cylindrical circulating fluidized bed with an inner diameter of 0.19 m and an overall height of 11.5 m. Depending on the solids content and superficial gas velocity, two or one sections can be observed in the plant where the pressure gradient is constant. A pressure profile with one pressure gradient exists only at high gas velocities, so long as the acceleration pressure drop immediately above the gas distributor is negligible. Comparison of measured pressure drops in circulating fluidized beds with those measured in vertical pneumatic conveying led to a state diagram for vertical gas-solid flows. The operation behaviour of different types of circulating fluidized bed plants can be explained with the aid of this diagram.
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    Derivation, selection, evaluation and use of asymptotes (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 63-72 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Asymptotes are known to be useful, but their potential in interpreting and correlating chemical and physical behaviour is seldom exploited fully. The derivation and selection of asymptotes for particular as well as limiting cases is described. The evaluation of the range of validity and applicability, if any, of asymptotes is also considered. Asymptotes are shown to be uniquely useful in the identification of groupings of variables which minimize parameteric variations, as upper and lower bounds, as trial functions in the method of weighted residuals, and most especially as components of correlating equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110110
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    Experimental results from a plate-column wet scrubber with gas-atomized sprayPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 73-79 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A pilot wet scrubber was examined experimentally. It is constructed like a plate column. Its plates are designed to set the gas into a whirling motion with tangential velocities of up to 25 m/s and to ensure a uniform distribution of the liquid throughout the gas flow. Particles suspended in the waste gas are collected by gas-atomized droplets to yield cut diameters between one and two microns. Energy consumption is lower than in the case of other scrubbers. The scrubbing mechanisms are analyzed by examining the measured pressure drops. Finally, methods of determining the collection efficiency are discussed and an empirical approach to its calculation is presented.
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    URL: http://dx.doi.org/10.1002/ceat.270110111
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    Decoking of fixed-bed catalytic reactorsDedicated to Prof. Dr. Hanns Hofmann at the ocassion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 367-375 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model for the description of the non-steady state process of decoking of a fixed bed catalytic reactor is presented. The relevant dimensionless groups are identified and their influence on the process discussed. Appropriate relationships are given for the estimation of the maximum temperature in the bed. Methods of monitoring the process and of controlling it in the case of unknown or variable coke contents are explained.
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    URL: http://dx.doi.org/10.1002/ceat.270110148
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    Model discrimination and parameter estimation in the kinetic study of methanol synthesisDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 375-383 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The new model discrimination method is based on the correlation coefficient test of experimental data sets for different reactions, without requiring a prior parameter estimation. The new parameter estimation method reduces by n the number of dimensions to be tested, compared to the classical method where n is the number of independent reactions in the system. This has reduced the computation time for most complex reactions to a level, comparable to that needed for single reactions. The example used is the kinetic study of methanol synthesis in which the formation rates of methanol, methane, ethanol and ethane are considered. Two adequately accurate models were obtained from an extensive range of plausible models by using the new model discrimination and parameter estimation method with a relatively small computation effort.
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    Evaporation and pervaporation of a binary mixture from an inert carrier liquidDedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 384-391 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bench-Scale experiments were carried out with the ternary mixture 2-propanol/water/glycerol. In a cylindrical vessel, the stirred and thermostated liquid was exposed to a preheated and either dry or humidified air stream. The mixture was evaporated either from a free surface or from the surface of a porous plate. On evaporating the mixture from a porous plate into a dry air stream, the less volatile component water escapes preferentially; in the case of evaporation from a free surface, water is retained in the mixture. In the former case, selectivity is liquid diffusion controlled, in the latter, the gas-side mass transfer and the thermodynamic equilibrium are the controlling mechanisms. On reducing the gas flow rate, the more volatile alcohol evaporates preferentially in both cases; the selectivity is controlled only by thermodynamic equilibrium. Humidification of the air stream with water vapour causes preferential evaporation of the alcohol at an increased rate. Furthermore, instabilities in the liquid boundary layer due to density gradients and surface tension effects may affect the selectivity of evaporation. Experimental results show that the selectivity of evaporation can be manipulated by choosing appropriate evaporation conditions. The theory, which applies the generalized Stefan-Maxwell equations to diffusion in the liquid, can describe these effects.
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    A new regenerable process for the recovery of SO2Dedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 402-407 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Increasing demand for regenerable processes with SO2 recovery is to be expected. Advantages and limitations of the earlier developed citrate and adipate absorption/ steam stripping process are compared with those of the Wellman-Lord (sulphite) process. On the basis of comprehensive laboratory studies, a new process is proposed which supplements the citrate and adipate process. In this new process, the absorbent is a concentrated sodium phosphate buffer and the loaded buffer is regenerated by evaporation. The main buffer component is Na2HPO4, but NaH2PO4 is added in order to obtain a more complete stripping of SO2 during regeneration. The new process promises excellent absorption properties for SO2 with extremely low oxidation losses, regeneration with few incrustation problems and appreciable energy savings.
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    Remarks upon the modelling of heterogeneous catalytic reactors - the single fluid-solid casesDedicated to Professor Hanns Hofmann on the occasion of his 65the birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 425-431 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To our benefit, the modelling of fluid-solid catalyzed reaction-reactor systems has long been the keen concern of Hanns Paul Hofmann. In the light of his instruction we remark upon key aspects of modelling for the (a) fixed bed (b) fluid bed and (c) moving bed/transport line reactors. There emerges from such analyses a properly renewed awareness of the need for a more sophisticated respect for reliable physical-chemical data. As Hanns has taught us, our models are no btter than our data.
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    Two-phase flow in porous mediaThe Orginal, shorter form of this paper was presented by the author, as an invited speaker, at the Second Conferance of “Chemical Reaction Engineering” of the Engineering Foundation, March 8 to 13, 1987, Santa Barbara, California.Dedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 407-424 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two-phase flow in porous media depends on many factors, such as displacement vs steady two-phase flow, saturation, wettability conditions, wetting fluid vs non-wetting fluid is displacing, the capillary number, interfacial tension, viscosity ratio, pressure gradient, uniformly wetted vs mixed-wet pore surface, uniform vs distributed pore throats, small vs large pores, well-connected pores vs pores connected by small throats, etc. These parameters determine how the two fluids are distributed in the pores, e.g. whether they flow in seperate channels or side-by-side in the same channels, either with both fluids being continous or only one fluid being continous and the other discontinuous. In displacement, the capillary number and the viscosity ratio determine whether the displacement front is sharp, or if there is either capillary or viscous fingering.
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    Organosolv delignification of southern pine - an alternative pulping process (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 195-199 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aqueous ethylenediamine-ethanol-anthraquinone (EDA-EtOH-AQ) pulping of Southern Yellow Pine was studied for lignin removal and pulp yield. Temperature, time and ethylenediamine concentration in the solvent solution were studied and equations for lignin content and lignin-free yield were developed. Lignin content is decreased by an increase of temperature, time or EDA concentration. Lignin-free yield of pulp decreased with an increase in temperature or time, but increased with increasing EDA concentration. Overall, the solvent is selective, that is, large quantities of lignin are removed while the retention of cellulose remains high.
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    Bubble column research in Japan (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 205-212 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many experimental studies on the bubble column have been reported by Japanese researchers since around 1960. They include studies of bubble behaviour, bubble size distribution, transition from the homogeneous bubbly flow regime to the heterogeneous liquid circulation regime, liquid velocity distribution, longitudinal liquid mixing, hydrodynamic modelling, the gas holdup, and the volumetric coefficient of gas-liquid mass tranfer kLa. Studies covered various modified bubble columns, such as the airlift reactor with an external or internal loop, the packed bubble column, and others. Performance of three-phase bubble columns, which deal with suspensions or emulsions, and their use as bioreactors or chemical reactors were also studied.
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    Application of modern packings in thermal separation processesPaper presented by R. Villet at ACHEMA ′85. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 213-227 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the performance of modern dumped and structured packings for application in the field of thermal separation processes. The evaluation of the results is based on extensive experimental investigations of rectification, absorption, and desorption systems. The following are indicated: the efficiency in terms of the number of theoretical stages per unit height or in terms of the height of transfer unit or volumetric mass transfer coefficient, the pressure drop per unit height as well as per theoretical stage or per gas phase transfer unit, and the liquid hold-up, whereby either the gas capacity factor or the liquid load was adopted as influencing parameter, and finally the maximum gas capacity factor as a function of the flow parameter. The results are presented in diagrams and tables.
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    Interfacial areas and gas hold-ups at elevated pressures in a mechanically agitated gas-liquid reactor (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 1-10 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Interfacial areas and gas hold-ups were determined at pressures of up to 1.7 MPa in a glass vessel, 88 mm in diameter and of standard geometry. Superficial gas velocities between 0.25 and 2.0 cm/s were used and the stirring speed varied between 4 and 30 rps. The interfacial areas were determined by the chemical method, using the model reaction between CO2 and aqueous diethanolamine (DEA). Hold-ups were determined by observation of differences in height. In contrast to literature indications, the gas hold-up was found to be independent of reactor pressure. This is also true for the interfacial area.
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    The influence of stress and attrition on crystal size distributionPaper presented at the Annual Meeting of German Chemical Engineers 1986, September 17 to 19, in Strasbourg.Dedicated to Prof. Dr.-Ing. Rolf Lacmann on the occasion of his 60th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 40-49 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An important parameter influencing the crystal size distribution in mass crystallization from solution is the mechanical stress exerted on crystals in the crystallizer. This contribution presents the study of the influence of mechanical stress and attrition of the system potassium nitrate-water in an FC-crystallizer and in various draft-tube crystallizers, fitted with different types of impellers. The intensity of stress is a newly defined variable which is used to describe the level of stress in crystallizers. The reduction of crystal size by attrition is described by the linear attrition rate. The influence of impeller design and crystal hold-up on crystal size distribution and scale-up rules is discussed.
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    Effect of enzyme inhibition on the performance of packed-bed biological reactor - a theoretical study (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 50-56 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance characteristic of a packed bed reactor has been analyzed by considering diffusional resistance of the biofilm. Model equations were solved by the method of orthogonal collocation for various classical enzyme inhibition kinetics, including partially non-competitive, partially competitive, partially uncompetitive, partially mixed and fully mixed. For all considered modes of inhibition, an increase in the inlet substrate concentration decreases the steady state conversion in the reactor. However, an increase in the Peclet number has been found to improve the conversion. The effects of various other process variables of physical importance were also investigated parametrically.
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    A robust pole-placement self-tuning controller for chemical process control: Theoretical studies and simulation (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 57-62 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A single variable pole-placement self-tuning controller (PPSTC) is used to simulate examples typical of chemical processes; i.e., open-loop stable, unstable, and unstable non-minimum phase systems with unknown varying process dead time. The PPSTC is shown to be effective in each case. Set-point tracking and rejection of randomly occurring deterministic disturbances for all three types of processes are achieved. Simultaneous estimation of process parameters and process time delay is realized by using a recursive extended least squares method.
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    Kinetic investigation of methacrylic acid synthesis on hetropoly-compoundsDedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 392-402 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of heterogeneously catalyzed methacrylic acid synthesis from isobutyric acid has been investigated. Initial catalyst screening pointed to 10-molybdo-2-vanado-phosphoric acid and its Cs-salts as the most promising catalysts. A model describing the reaction behaviour of all the different hetropoly-compounds used in this work was developed. A relationship was found between model parameters and composition of different catalysts. First insight was gained into the catalyst deactivation phenomena. Deactivation appears to be caused mainly by loss of molybdenum with simultaneous collapse of the Keggin structure.
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    A new appraisal of mass transfer processes in zeolites by transient methodsDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 432-438 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Transient diffusion of inert gases into Zeolon 900 H, a zeolite of the mordenite type, was studied by the chromatographic method. Experiments were performed with argon and helium either as tracer or as carrier gas. The diffusion of argon was also studied in a carrier gas containing methanol at a low temperature (75°C, no reaction) and at higher temperatures (up to 130°C) when some dehydration of methanol to dimethyl ether takes place. The adsorption isotherm of argon is linear. In the absence of methanol, its penetration into microcrystals of zeolite is equally well represented either by an effective diffusion coefficient D′μ = 7.4 × 10-8exp(-2873/T)m2s-1 or by a mass transfer coefficient at the crystallite surface keμ = 1.9 × 10-4 exp(-1324/T) ms-1. A small amount of methanol in the carrier gas considerably slows down the transfer of argon (by a factor of 40 for D′μ and 550 for keμ) showing the “blocking” effect of adsorbed methanol. In addition, transient adsorption can no longer be accounted for by a single transfer time. The size distribution of microcrystals, determined from Scanning Electron Microscope photographs leads to a Transfer Time Distribution which account well for experimental breakthrough curves without any parameter fitting. This interpretation is supported by experiments under reaction conditions where transport of argon within crystallites increases faster with temperature than in the absence of reaction due to the transformation of methanol into dimethyl ether, which is less adsorbed and thus provides lesser hindrance to argon diffusion.
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    Less known behaviour of gas-solid reactions: The expanding core model in catalytic and non-catalytic systemsDedicated to Profeesor Dr. Hanns Hofmann on the Occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 438-447 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas-solid reactions cover a wide spectrum of industrial products. Over the years, many conceptual models have been developed to describe the progress of a gas-solid reaction starting outside the solid particle as well as that occurring throughout the particle. But the behaviour of a reaction, initiated inside the pellet, is less known. In this paper, a brief outline is given of this relatively rare but important mode of gas-solid reaction. The causes of this relatively less known behaviour and characteristic features of five typical systems displaying it are discussed.
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    Zur Element-Stickstoff-Doppelbindung in Kationen cyclischer Bis(amino)-phospha-, -arsa-, -stiba- und -bismutane (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 73-88 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Element-Nitrogen Double Bond in Cations of Cyclic Bis(amino)phospha-, -arsa-, -stiba-, and bismuthinesBis(amino)sila-phospha, -arsa-, -stiba-, and bismaetidines which bear a positive charge and incorporate a formally two valent element of group V are obtained from the corresponding bis(amino)elementchlorides by transfer of the chloride anion to the Lewis acids AlCl3, GaCl3, and InCl3. X-ray structure analyses on the compounds Me2Si(NtBu)2P+AlCl4- (2a), Me2Si(NtBu)2Sb+AlCl4- (2c), and Me2Si(NtBu)2Bi+AlCl4 -(2d) reveal that the electron lack at the element(V) can be compensated by two different bonding mechanisms. In the case of the phosphorus derivative 2a the electronic balance is accomplished by intramolecular backbonding from the neighbouring nitrogen atoms (mean N-P+ = 163.3 pm). In the antimony and bismuth derivatives (2c and 2d) the chlorine atoms of the AlCl4 anions coordinate to the unsaturated element(V) in an intermolecular manner (mean: Sb·Cl = 305, Bi⃛Cl = 309 pm). The N—Si—N group which is identical in all molecules, may be used as a probe for the electronic balance within the ring systems. The bond lengths and angles vary dramatically with respect to the electron acceptor properties of the element to which the group is bonded. 2a forms orthorhombic crystals, space group Pnma, Z = 8 (a = 3023.7(9), b = 1001.0(3), c = 1414.6(5) pm), and 2c and 2d are isotypic, again orthorhombic, space group Pbca with Z = 8 (2c a = 2030.8(8), b = 1193.1(4), c = 1777.1(6) pm; 2d: a = 2025.9(8), b = 1198.0(4), c = 1761.3(6) pm).
    Notes: Bis(amino)silaphospha-, -arsa-, -stiba- und bismaetidine mit positiver Ladung und einem formal nur zweibindigen Element der 5. Hauptgruppe können aus den entsprechenden Bis(amino)elementchloriden durch Übertragung des Chloridions auf eine Lewis-Säure wie AlCl3, GaCl3 order InCl3 erhalten werden. Röntgenstrukturanalysen an den Verbindungen Me2Si(NtBu)2P+AlCl4- (2a), Me2Si(NtBu)2Sb+AlCl4- (2c) und Me2Si(NtBu)2Bi+AlCl4- (2d) zeigen, daß die Elektronenarmut am Element(V) durch zwei unterschiedliche Bindungsarten kompensiert wird: Im Falle des Phosphorderivates 2a geschieht der elektronische Ausgleich intramolekular durch die benachbarten Stickstoffatome (Mittelwert N-P+ = 163,3 pm), während in dem Antimon-(2c) und Bismut-Derivat (2d) die Chlorsubstituenten der AlCl4-Anionen intermolekular das Element(V) absättigen (Mittelwerte: Cl⃛Sb = 305, Cl⃛Bi = 309 pm). Die N—Si—N-Gruppierung, die in allen Molekülen als identischer Teil vorhanden ist, kann als Sonde für die Elektronenverteilung im Ring benutzt werden. Die Abstände und Winkel innerhalb dieser Gruppe variieren stark mit der Elektronenakzeptorfähigkeit des Elementes, an das sie gebunden ist. 2a kristallisiert orthorhombisch, Raumgruppe Pnma, Z = 8 (a = 3023,7(9), b = 1001,0(3), c = 1414,6(5) pm) und 2c und 2d sind isotyp, ebenfalls orthorhombisch, Raumgruppe Pbca mit Z = 8 (2c a = 2030,8(8), b = 1193,1(4), c = 1777,1(6) pm; 2d: a = 2025,9(8), b = 1198,0(4), c = 1761,3(6) pm).
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    Struktur und magnetische Eigenschaften von Cs2Mn3S4 und Cs2Co3S4Professor Albrecht Rabenau zum 65. Geburtstage am 17. November 1987 gewidmet (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 95-105 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure and Magnetic Properties of Cs2Mn3S4 and Cs2Co3S4The atomic arrangements of the isotypic compounds Cs2Mn3S4 and Cs2Co3S4 were determined by X-ray investigations on single crystals (space group Ibam, Z = 4). To interprete the magnetic properties of Cs2Mn3S4 mixed crystals of the series Cs2(MnxZn1-x)3S4 have been examined. Additionally neutron diffraction experiments were carried out and yielded the spin structures of Cs2Mn3S4 and Cs2Co3S4 (Shubnikov space group Ibam'). The deviations of the magnetic moments from those expected for high-spin d5 ions are explained by means of crystal field calculations.
    Notes: Der Aufbau der isotypen Verbindungen Cs2Mn3S4 und Cs2Co3S4 wurde an Einkristallen bestimmt (Raumgruppe Ibam, Z = 4). Zur Deutung der magnetischen Eigenschaften des Cs2Mn3S4 wurde die Mischkristallreihe Cs2(MnxZn1-x)3S4 untersucht. Neutronenbeugungsuntersuchungen ermöglichten darüber hinaus die Bestimmung der - antiferromagnetischen - Spinstrukturen von Cs2Mn3S4 und Cs2Co3S4 (Shubnikov-Raumgruppe Ibam'). Die Abweichungen der gemessenen magnetischen Momente von den zu erwartenden High-Spin-Werten lassen sich mit Kristallfeldberechnungen in Einklang bringen.
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    Peroxofluorokomplexe der Übergangsmetalle. VIII. Kristallstruktur von K2Ti(O2)F4 · 1/2 H2O. Strukturchemischer Vergleich und spektroskopische Daten der Verbindungen K2Ti(O2)F4 · xH2O (mit x = 1, 1/2, 0) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 135-142 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Peroxofluoro Complexes. VIII. Crystal Structure of K2Ti(O2)F4. · 1/2H2O. Structural Comparison and Spectroscopic Data of the Compounds K2Ti(O)2F4 · xH2O (x = 1, 1/2, 0)The yellow hemihydrat K2Ti(O2)F4 · 1/2 H2O crystallizes monoclinic (space group C2/c, a = 1680.5(6), b = 653.2(1), c = 1224.3(4) pm, β = 115.8(1)°, Z = 8, Rw = 0.038 for 1113 independent reflections). It contains isolated, dinuclear, di(μ-fluoro)-bridged [Ti2(O2)2F8]4- anions, as known by orange coloured K2Ti(O2)F4 · H2O [1]. They are arranged in layers which are parallel to the (100) plane, whereas they are linked by hydrogen bonds forming infinite chains in K2Ti(O2)F4 · 1/2 H2O. Anhydrous K2Ti(O2)F4 - even yellow - crystallizes monoclinic with a = 828.9(2), b = 1107.6(2), c = 1303.9(3) pm, β = 92.29(2)°. I.r. and Raman spectra of all compounds are listed and interpreted. On the basis of the UV spectra the different colours of some titaniumperoxofluoro compounds are discussed in relation to the titanium-peroxid bonding.
    Notes: Das gelbe Hemihydrat K2Ti(O2)F4 · 1/2H2O kristallisiert monoklin (Raumgruppe C2/c, a = 1680,5(6), b = 653,2(1), c = 1224,3(4) pm, β = 115,8(1)°, Z = 8, Rw = 0,038 für 1113 unabhängige Reflexe). Es enthält isolierte, zweikernige, di(μ-fluoro)-verbrückte [Ti2(O2)2F8]4--Anionen, wie sie vom orangefarbenen K2Ti(O2)F4 · H2O her schon bekannt sind [1]. Während sie dort jedoch über Wasserstoffbrücken zu Ketten verknüpft sind, sind sie im K2Ti(O2)F4 · 1/2 H2O in Schichten parallel zur (100) Ebene angeordnet. Das ebenfalls gelbe wasserfreie K2Ti(O2)F4 kristallisiert monoklin mit den Gitterkonstanten a = 828,9(2), b = 1107,6(2), c = 1303,9(3) pm, β = 92,29(2)°.IR- und Raman-Spektren aller drei Verbindungen K2Ti(O2)F4 · xH2O (x = 0, 1/2, 1) werden aufgeführt und interpretiert. Auf der Grundlage der UV-Spektren werden die unterschiedlichen Farben verschiedener Titanperoxofluoroverbindungen im Zusammenhang mit ihren Bindungsverhältnissen diskutiert.
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    Thiolyse von Malondinitril (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 149-153 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiolysis of Malonic DinitrileIn dependence of the test conditions the thiolysis of malonic dinitrile (NC)2CH2 with H2S yields dithiomalonic diamide (H2N - CS -)2CH2 or α-cyanothioacetamide H2N - CS - CH2 - CN, which have been studied by means of diverse spectroscopic methods.Both compounds do not react with carbon disulfide to form the corresponding dithiocarbamate neither in the presence of help-bases. Also no reaction happens with alkyl esters of chlorodithioformic acid.
    Notes: Je nach den Versuchsbedingungen führt die Thiolyse von Malondinitril (NC)2CH2 mit H2S zum Dithiomalondiamid (H2N - CS -)2CH2 oder zum α-Cyanothioacetamid H2N - CS - CH2 - CN, die mit verschiedenen spektroskopischen Methoden untersucht wurden.Beide Verbindungen reagieren nicht mit Kohlenstoffdisulfid zum entsprechenden Dithiocarbamat, auch nicht in Gegenwart von Hilfsbasen. Mit Chlorodithioameisensäurealkylestern findet ebenfalls keine Umsetzung statt.
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    Thermische Zersetzung von K2Ti(O2)F4 · H2O unter hohem Druck Hochdrucksynthese von K2TiOF4 · H2O und K2TiOF4 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 143-148 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal Decomposition of K2Ti(O2)F4 · H2O by High Pressure. High Pressure Synthesis of K2TiOF4 · H2O and K2TiOF4Heating K2Ti(O2)F4 · H2O and applicating high pressure (1 - 4 GPa) we obtained two hitherto unknown and otherwise not accessible compounds.K2TiOF4 · H2O cristallizes orthorhombic with the “Tl2AlF5-type” (a = 936,2(3); b = 825,1(3); c = 775,9(3) pm, dc = 2,62 g cm-3, dm = 2,57 g cm-3). The crystal structure shows infinite chains of [TiF4O2/2]2- octahedra, linked by trans-bridging O atoms.K2TiOF4 cristallizes orthorhombic with the K2FeF5-type (a = 2025,3(2); b = 736,6(1); c = 1295,1(1) pm, dc = 3,00 g cm-3, dm = 2,97 g cm-3). The crystal structure shows infinite chains of [TiOF3F2/2]2- octahedra, linked by cis-bridging F-atoms.Vibrational spectra of both compounds as well as the different thermal behaviour of K2Ti(O2)F4 · H2O under normal and high pressure are discussed.
    Notes: Beim Erhitzen von K2Ti(O2)F4 · H2O unter hohem Druck (1 - 4 GPa) entstehen zwei bisher nicht bekannte und auf anderem Wege nicht zugängliche Verbindungen.K2TiOF4 · H2O kristallisiert orthorhombisch im “Tl2AlF5-Typ” mit a = 936,2(3); b = 825,1(3); c = 775,9(3) pm, drö = 2,62 g cm-3, dpyk = 2,57 g cm-3. Die Struktur enthält lineare Ketten von über O-Atome trans-verknüpften [TiF4O2/2]2--Oktaedern.K2TiOF4 kristallisiert orthorhombisch im K2FeF5-Typ mit a = 2025,3(2); b = 736,6(1); c = 1295,1(1) pm, drö = 3,00 g cm-3, dpyk = 2,97 g cm-3. In dieser Struktur liegen gewellte Ketten von über F-Atome cis-verknüpften [TiOF3F2/2]2--Oktaedern vor.Die Schwingungsspektren beider Verbindungen sowie das unterschiedliche thermische Verhalten von K2Ti(O2)F4 · H2O bei Normaldruck und unter hohem Druck werden diskutiert.
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    Beiträge zur Chemie der Schwefel-Halogenide. 20. Di(methylthio)methyl- und Di(phenylthio)methylsulfonium-hexafluoroarsenat und -hexachloroantimonat (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 154-162 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Sulfur Halides. 20. Di(methylthio)methyl- and Di(phenylthio)methylsulfonium Hexafluoroarsenate and HexachloroantimonatePreparation and spectroscopic characterization of di(methylthio)methyl- and di(phenylthio)methylsulfonium salts CH3S(SCH3)2+A- and CH3S(SC6H5)2+A- (A- = AsF6-, SbCl6-) is reported. Complementary the crystal structure of di(methylthio)methylsulfonium hexafluoroarsenate has been determined.
    Notes: Es wird über die Darstellung und spektroskopische Charakterisierung der Di(methylthio)methyl- und Di(phenylthio)methylsulfonium-Salze CH3S(SCH3)2+A- und CH3S(SC6H5)2+A- (A- = AsF6-, SbCl6-) berichtet. Ergänzend wird die Kristallstruktur von Di(methylthio)methylsulfoniumhexafluoroarsenat mitgeteilt.
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    Trifluormethyl-difluor und -dibromsulfonium(IV)-metallate(V) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 163-170 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trifluoromethyl-difluoro and -dibromosulfonium (IV)-metallates(V)The preparation and spectroscopical characterisation of CF3SBr2+MF6- is reported. Additional the complete spectroscopic data of CF3SF2+MF6- (M = As, Sb) are submitted.
    Notes: Es wird über die Darstellung und spektroskopische Charakterisierung von CF3SBr2+MF6- berichtet. Ergänzend werden fehlende spektroskopische Daten von CF3SF2+MF6- (M = As, Sb) mitgeteilt.
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    Interaction between Xenon Di- and Tetrafluoride with Alkali Metal Fluorides (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 171-181 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über die Umsetzung der Di- und Tetrafluoride des Xenons mit Fluoriden der AlkalimetalleDie Umsetzung von XeF2 und XeF4 mit Verbindungen des Typs MF (M = Na, K, Rb, Cs) wird untersucht. Es bilden sich dabei Hexafluoroxenate(IV) mit der Summenformel M2XeF6, die das oktaedrische Anion XeF62- enthalten. Cs2XeF6 und Rb2XeF6 bilden monokline Kristalle (a0 = 853,7(5); b0 = 669,6(2); c0 = 843,6(5) pm; β = 121,7(1)° für Cs2XeF6 und a0 = 812,6(4); b0 = 631,9(2); c0 = 795,6(4) pm; β = 121,5(1)° für Rb2XeF6). K2XeF6: tetragonal mit a0 = 868,8(2); c0 = 747,8(2) pm; Na2XeF6: hexagonal mit a0 = 642,1(3); c0 = 844,8(5) pm. Es wird gezeigt, daß sich die Verbindungen M2XeF6 inkongruent in wasserfreiem HF lösen, wobei sich unter anderem das Solvolyseprodukt XeF4 bildet. Es wird nachgewiesen, daß die Thermolyse von M2XeIVF6 und M2XeVIF8 unter ähnlichen Bedingungen abläuft.
    Notes: Interaction of XeF2 or XeF4 with MF (M = Na, K, Rb, Cs) has been studied. Hexafluoroxenates(IV) M2XeF6 containing the octahedral XeF62- anion (in accordance with spectroscopy data) were formed in the reaction. Cs2XeF6 and Rb2XeF6 form monoclynic crystals (a0 = 853.7(5); b0 = 669.6(2); c0 = 843.6(5) pm; β = 121.7(1)° and a0 = 812.6(4); b0 = 631.9(2); c0 = 795.6(4) pm; β = 121.5(1)°, respectively). K2XeF6 has a tetragonal lattice (a0 = 868.8(2); c0 = 747.8(2) pm), while Na2XeF6 has a hexagonal one (a0 = 642.1(3); c0 = 844.8(5) pm). M2XeF6 is shown to dissolve in unhydrous HF incongruently, one of the solvolitic products being XeF4. Thermolysis of M2XeIVF6 and M2XeVIF8 were shown to proceed under similar temperatures.
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    Acid-Base Properties of Xenon Di- and Tetrafluoride in High Temperature Reactions (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 182-190 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über die Säure-Base-Eigenschaften des Di- und Tetrafluorxenons in Reaktionen bei erhöhten TemperaturenEs wurde die Reaktion von Xenondifluorid und Xenontetrafluorid mit Fluorkomplex-Verbindungen verschiedener Übergangsmetalle bei erhöhter Temperatur untersucht. Unter diesen Bedingungen wurde die Bildung von Anionenkomplexen M2XeIVF6 festgestellt. Es wurde gezeigt, daß XeF4 unabhängig davon, ob es direkt in die Reaktion eingeführt wird oder dort aus XeF2 entsteht, zwei typische Eigenschaften aufweist: die eines Oxydationsmittels (〉 300°C) und einer Säure (zwischen 150°C und 300°C). Das Reaktionsverhalten des XeF4 hängt ferner von den Eigenschaften des Reaktionspartners ab. Die Eigenschaften der Xenonfluoride als Lewis-Säuren folgen der Reihe: XeF6 ≈ XeF4 ≫ XeF2.
    Notes: Reaction of xenon di- and tetrafluoride with different transition element fluorocomplexes at high temperatures has been studied. The formation of XeIV anionic complexes M2XeF6 has been found. XeF4 is shown to reveal two kinds of properties: oxidative (higher than 300°C) and acidic (between 150-300°C), independently whether it was initially introduced into the system or arised in it from XeF2. The reaction path of xenon tetrafluoride is shown to depend upon the other reagent properties. The conclusion is made that Lewis acidic properties of xenon fluorides decrease as follows: XeF6 ≈ XeF4 ≫ XeF2.
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    Die hydrothermale Kristallisation des Magadiits. 1. Die Kristallisationskinetik - Möglichkeiten ihrer Beschreibbarkeit (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 191-200 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Hydrothermal Magadiite Crystallisation. 1. The Kinetic of the Crystallisation - Possibilities of their DescriptionThe topic of this paper is the synthesis of the sodium-silicate hydrate (Na—SH) magadiite within reaction mixtures of the ternary system Na2O · SiO2 · H2O. The crystallisation kinetics are studied and characterized by means of physical and chemical methods. As a result of this investigations a schematic model representation of the magadiit crystallisation is given.
    Notes: Gegenstand der Arbeit ist die Synthese des Natriumsilikathydrates (Na—SH) Magadiit im ternären System Na2O · SiO2 · H2O. Die Kinetik der Kristallisation wird verfolgt und durch physikalische und chemische Methoden charakterisiert. Auf Basis dieser Ergebnisse wird eine Modellvorstellung für die Kristallisation des Magadiits entwickelt und angegeben.
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    Zur Darstellung und Struktur von M1—LnTa3O9 (Ln = Pr, Nd) = röntgenographische und elektronenmikroskopische Untersuchungen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 559 (1988), S. 208-208 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/zaac.19885590125
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    Zur Synthese von permethylierten α,ω-Bis(cyclopentasilanyl)-silanenProfessor Ulrich Wannagat zum 65. Geburtstage am 31. Mai 1988 gewidmet (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 27-34 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Synthesis of Permethylated α,ω-Bis(cyclopentasilanyl)silanesMembers of the hitherto unkown class of α,ω-Bis(cyclopentasilanyl)silanes (Si5Me9)—(SiMe2)n—(Si5Me9) with n = 2-5 were synthesized and characterized by spectroscopic methods. Mass spectroscopic fragmentation shows a weakening of the central SiSi-bonds similar to other oligosilanes.
    Notes: Vertreter der bisher noch nicht beschriebenen Klasse der α,ω-Bis(cyclopentasilanyl)silane (Si5Me9)—(SiMe2)n—(Si5Me9) mit n = 2-5 wurden synthetisiert und spektroskopisch charakterisiert. Aus dem massenspektroskopischen Zerfall kann geschlossen werden, daß, ähnlich wie bei anderen Oligosilanen, auch hier eine Schwächung der zentralen SiSi-Bindung eintritt.
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    Zur Struktur und Reaktivität von stannylierten Propylaminen und -sulfiden. Kristall- und Molekülstruktur von Bis(3-dimethylchlorostannylpropyl)sulfid S(CH2CH2CH2SnMe2Cl)2 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 110-118 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure and Reactivity of Stannylated Propyl Amines and Propyl Sulfides. Crystal and Molecular Structure of Bis(3-chlorodimethylstannylpropyl)sulfide S(CH2CH2CH2SnMe2Cl)2The synthesis and reactivity of stannylated propyl amines and propyl sulfides, respectively, E(CH2CH2CH2SnMe3)2 (1, E = NMe; 2 E = S) and N(CH2CH2CH2SnMe3)3 3 are reported. 1 and 3 react with dimethyl dichlorostannane under thermal cyclisation to 1,5-dimethyl-5-chloro-1aza-5-stannabicyclo[3.3.01,5]octane Me(Cl)Sn(CH2CH2CH2)2NMe 4 and 5-chloro-1-aza-5-stannatricyclo[3.3.3.01,5]-undecane ClSn(CH2CH2CH2)3N 5, respectively. The reaction of 2 with dimethyl dichlorostannane leads to the formation of bis(3-chloro-dimethylstannylpropyl)sulfide S(CH2CH2CH2SnMe2Cl)2 6, whereas the treatment of 2 with tin tetrachloride yields the bis(3-di-chloro-methylstannylpropyl)sulfide S(CH2CH2CH2SnMeCl2)2 7. The 1H, 13C, and 119Sn NMR data are discussed. 6 crystallizes in the ortho-rhombic space group Pna21 with the unit cell parameters a = 2275.0(1), b = 733.6(2), c = 1062.0(4) pm, V = 1.77273 nm3, Z = 4. The structure was refined to a final R value of 0.041. Both tin atoms adopt distorted trigonal bipyramidal configurations as a result of intramolecular interactions with the bridging sulphur. The sulphur and the chlorine atoms occupy the apical positions. The Sn—S distances amount to 309.7(4) and 311.8(4) pm.
    Notes: Es wird über die Darstellung und Reaktivität der stannylierten Propylamine bzw. -sulfide E(CH2CH2CH2SnMe3)2 (1, E = NMe; 2, E = S) und N(CH2CH2CH2SnMe3)3 3 berichtet. 1 und 3 reagieren mit Dimethyldichlorstannan unter thermischer Cyclisierung zum 1,5-Dimethyl-5-chloro-1aza-5-stannabicyclo[3.3.01,5]-octan Me(Cl)Sn(CH2CH2CH2)2NMe 4bzw. 5-Chloro-1-aza-5-stannatricyclo[3.3.3.01,5]undecan ClSn(CH2CH2CH2)3N 5. Die Umsetzung von 2 mit Die Umsetzung von 2 mit Dimethyldichlorstannan führt dagegen zum Bis(3-chlorodimethyl-stannylpropyl)sulfid S(CH2CH2CH2SnMe2Cl)2 6, wogegen mit Zinntetrachlorid das Bis(3-dichlormethylstannylpropyl)-sulfid S(CH2CH2CH2SnMeCl2)2 7 resultiert. Die 1H-, 13C- und 119Sn-NMR-Daten werden diskutiert. 6 kristallisiert in der orthorhombischen Raumgruppe Pna21 mit den Gitterkonstanten a = 2275,0(1), b = 733,6(2), c = 1062,0(4) pm, V = 1,77273 nm3, Z = 4. Die Struktur wurde bis zu einem R-Wert von 0,041 verfeinert. Die Zinnatome sind durch intramolekulare Wechselwirkungen mit dem verbrückenden Schwefel jeweils verzerrt trigonal-bipyramidal konfiguriert, der Schwefel und die Chloratome besetzen die apicalen Positionen. Die Sn—S-Abstände betragen 309,7(4) und 311,8(4) pm.
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    Nickelacyclen als isolobale C8-Ringe: Die Struktur von [(CH3CN)NiP(C6H11)3]4 und der Vergleich mit anderen Azaolefinkomplexen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 119-127 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Nickel Compounds as Isolobale C8-Rings: The Structure of [(CH3CN)NiP(C6H11)3]4 and the Comparison with Other Azaolefine ComplexesThe crystal structure of [(CH3CN)NiP(C6H11)3]4 has been determined on a single crystal by X-ray structure analysis. The compound is tetrameric with a eight-membered ring, which included four nickel atoms and four nitrogen atoms. The conformation of this ring system is comparable with 1.3.5.7-cyclooctatetraene. The application of the Isolobalprinciple to this and other nickelacycles enables to compare the stereochemistry of wellknown eigth-membered rings of hydrocarbons.
    Notes: Die Kristallstruktur von [(CH3CN)NiP(C6H11)3]4 wurde durch Röntgeneinkristallstrukturanalyse bestimmt. Die Verbindung liegt tetramer vor und bildet aus vier Nickelatomen und vier Stickstoffatomen einen Achterring. Die Konformation dieses Achterrings ist der des 1,3,5,7-Cyclooctatetraens sehr ähnlich. Durch Anwendung des Isolobalprinzips auf diese und andere Nickelacyclen kann die Stereochemie dieser Verbindungen mit den Strukturen bekannter Achtringe von Kohlenwasserstoffen verglichen werden.
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    Zum Chemischen Transport der Titansilicide mit Chlor und lod (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 128-140 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Chemical Transport of Titanium Silicides with Chlorine and IodineCrystals of Ti5Si3, TiSi and TiSi2 were grown by C.T.R. with halogens as transport medium. Using chlorine as transport agent a transport from hot to cold has been observed in each case. Using iodine as transport agent a transport from cold to hot was found at low pressures. The reasons of this behaviour are interpreted by a thermodynamical transport model. However, the transport of Ti5Si3 is combined with the deposition of Ti2Si3 is combined with the deposition of Ti2O3, which is formed in a reaction with the silica glass of the container. Some estimations have been carried out to this compound.
    Notes: Durch chemische Transportreaktionen mit Halogenen als Transportmittel wurden Kristalle der Phasen Ti5Si3, TiSi und TiSi2 erhalten. Dabei erfolgt mit Chlor als Transportmittel in jedem Falle ein Transport von heiß nach kalt. Mit Iod als Transportmittel ergibt sich bei kleinen Drücken ein Transport von kalt nach heiß. Die Ursachen diese Verhaltens werden mit Hilfe eines thermodynamischen Transportmodells erklärt. Ti5Si3 wird jedoch immer neben Ti2O3 erhalten, welches durch Reaktion mit dem Behältermaterial SiO2 gebildet wird. Hierzu werden weitere Abschätzungen vorgenommen.
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    Oxidationsreaktionen der Additionsprodukte von CF3l, Te(CF3)2 und Sb(CF3)3 an Cyclohexen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 141-146 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidation Reactions of the Addition Products of CF3I, Te(CF3)2, and Sb(CF3)3 to CyclohexeneCF3I, Te(CF3)2, and Sb(CF3)3 add to cyclohexen in good to very good yields to form CF3C6H10I, CF3C6H10TeCF3, and CF3C6H10Sb(CF3)2, respectively, which can be oxidized to the corresponding organo iodine, tellurium, and antimony dihalides. The preparations, properties, and 19F NMR spectra of the new compounds are described.
    Notes: CF3I, Te(CF3)2 und Sb(CF3)3 addieren in guten bis sehr guten Ausbeuten an Cyclohexen unter Bildung von CF3C6H10I, CF3C6H10TeCF3 bzw. CF3C6H10Sb(CF3)2, die zu den entsprechenden Organo-iod-, -tellur- bzw. -antimondihalogeniden oxidiert werden können. Die Darstellungen, Eigenschaften und 19F-NMR-Spektren der neuen Verbindungen werden beschrieben.
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    Röntgenuntersuchung von Einkristallen ternärer Lanthanoid-Vanadium(III)-Oxide LnVO3 (Ln = Gd, Dy, Er) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 153-157 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: X-Ray Structure Analysis of Single Crystals of Ternary Rare Earth Vanadium(III) Oxides LnVO3 (Ln = Gd, Dy, Er)X-ray structure investigations were performed on single crystals of LnVO3 (Ln = Gd, Dy, and Er), grown by flux electrolysis. The three compounds are isotypic, they crystallize in an orthorhombic distorted perovskite structure.
    Notes: An Einkristallen von LnVO3 (Ln = Gd, Dy und Er), die durch Schmelzflußelektrolyse gezüchtet wurden, erfolgten Röntgenstrukturuntersuchungen. Die drei Verbindungen sind isotyp, sie kristallisieren in einer orthorhombisch verzerrten Perowskitstruktur.
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    Perfluoralkyltellur-Verbindungen: Untersuchungen zur Bildung von [(CF3)2TeX]+-Kationen und [(CF3)2TeX2+n]n--Anionen (X = F, Cl, Br) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 147-152 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Perfluoroalkyl Tellurium Compounds: Investigations of the Preparation of [(CF3)2TeX]+ Cations and [(CF3)2TeX2+n]n- Anions (X = F, Cl, Br)The reactions of (CF3)2TeF2 with BF3, AsF5 and SbF5 yield the new complex compounds [(CF3)2TeF][BF4] and [(CF3)2TeF][EF6], respectively, while during the reactions of (CF3)2TeX2 (X = Cl, Br) with halide acceptors only decompositions take place. (CF3)2TeX2 form with MX (X = F, Cl; M = K, Rb, Cs, Me4N, Ag) the isolable salts of the composition M[(CF3)2TeX3]. M[(CF3)2TeBr3] is only detected in solution besides decomposition products. No evidence for the formation of hexa-coordinated tellurates(IV) M2[(CF3)2TeX4] is found.
    Notes: (CF3)2TeF2 reagiert mit BF3, AsF5 und SbF5 zu [(CF3)2TeF][BF4] bzw. [(CF3)2TeF][EF6], während die Reaktionen von (CF3)2TeX2 (X = Cl, Br) mit Halogenidionen-Akzeptoren nur Zersetzungsprodukte liefern. Aus den Umsetzungen von (CF3)2TeX2 mit MX (X = F, Cl; M = K, Rb, Cs, Me4N, Ag) werden die Salze der Zusammensetzung M[(CF3)2TeX3] isoliert, M[(CF3)2TeBr3] wird nur in Lösung neben Zersetzungsprodukten erhalten. Die Bildung hexakoordinierter Tellurate M2[(CF3)2TeX4] kann in keinem Fall nachgewiesen werden.
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    Festkörperreaktionen in Katalysatoren und Katalysatorkomponenten. XV. Zum Reduktionsverhalten von Sulfat-lonen in γ-Al2O3 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 158-162 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solid State Reactions in Catalysts and Components of Catalysts. XV. On the Reduction Behaviour of Sulfate Ions in γ-Al2O3Different sulphuric acid modified alumina samples were used as model systems for sulfided and regenerated Al2O3 carrier catalysts. From investigations of temperature programmed reduction can be concluded that sulphur is reduced by hydrogen to sulfide state at temperatures between 500 and 750°C. The greater part will desorbed as H2S but a smaller one remains adsorbed on the alumina surface.
    Notes: Als Modellsysteme für sulfidierte und oxydativ regenerierte Al2O3-Trägerkatalysatoren wurde Aluminiumoxid auf unterschiedliche Weise mit Schwefelsäure modifiziert. Aus den Untersuchungen zur temperaturprogrammierten Reduktion geht hervor, daß der Schwefel bei Temperaturen zwischen 500 und 750°C durch Wasserstoff bis zum Sulfid reduziert und zum größten Teil als H2S desorbiert wird, in geringem Ausmaß aber auch an der Al2O3-Oberfläche adsorbiert verbleibt.
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    Neue Titanocen-Derivate mit Thiokresolatliganden (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 163-168 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Titanocene Derivatives with Thiocresolate LigandsOn reaction of titanocene dichloride (Cp2TiCl2; Cp = η5-C5H5) with NaSC6H4CH3-o or LiSC6H4CH3-p in toluene/benzene or in pure benzene at room temperature, one chloride ligand is substituted to give Cp2TiCl(SC6H4CH3-o) (I) or Cp2TiCl(SC6H4CH3-p) (II) respectively. Analogously, from Cp2Ti(Cl)CH3 Cp2TiCH3(SC6H4CH3-o) (III) or Cp2TiCH3(SC6H4CH3-p) (IV) is formed. By, substitution of both chloride ligands, the bis(thiocresolato) complexes Cp2Ti(SC6H4CH3-o)2 (V) Cp2Ti(SC6H4CH3-m)2 (VI) and Cp2Ti(SC6H4CH3-p)2 (VII) could be prepared from the corresponding thiocresols in ether using triethylamine as supporting base. The substances were characterized by i.r., 1H n.m.r., and mass spectra.
    Notes: Titanocen-dichlorid (Cp2TiCl2; Cp = η5-C5H5) reagiert mit NaSC6H4CH3-o oder LiSC6H4CH3-p in Toluol/Benzol oder reinem Benzol bei Raumtemperatur unter Substitution eines Chlorid-Liganden zu Cp2TiCl(SC6H4CH3-o) (I) bzw. Cp2TiCl(SC6H4CH3-p) (II). In analoger Reaktionsführung bildet sich aus Cp2Ti(Cl)CH3 Cp2TiCH3(SC6H4CH3-o) (III) bzw. Cp2TiCH3(SC6H4CH3-p) (IV). Die unter Substitution beider Chlorid-Liganden erhaltenen Bis(thiokresolato)-Komplexe Cp2Ti(SC6H4CH3-o)2 (V), Cp2Ti(SC6H4CH3-m)2 (VI) und Cp2Ti(SC6H4CH3-p)2 (VII) konnten aus den entsprechenden Thiokresolen mit Triethylamin als Hilfsbase in Ether dargestellt werden. Alle Substanzen wurden IR-, 1H-NMR- sowie massenspektrometrisch charakterisiert.
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    Direktsynthese von orthometallierten Ketonen des Typs RCO(o-C6H4)Mn(CO)4-n Ln(R = Alkyl- und Arylrest, n = 0,1,2, L = Ligand). (Zur Kristallstruktur von C6H5CO(o-C6H4)Mn(CO)3AS(C6H5)3) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 191-192 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/zaac.19885600123
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    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885610101
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    Die Kristallstruktur von Magnesiumhexaaqua-bis(hexamethylen-tetramin-1-ium)-hexacyanoferrat(II) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 185-190 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure of Magnesiumhexaaqua-bis(hexamethylenetetramine-1-ium)-hexacyanoferrate(II)Single crystals of [Mg(H2O)6](C6H13N4)2[Fe(CN)6] were obtained from diffusion of a methanolic solution of hexamethylenetetramine into an aqueous solution of a mixture of MgCl2 and H4[Fe(CN)6] were obtained from diffusion of a methanolic solution of hexamethylenetetramine into an aqueous solution of a mixture of MgCl2 and H4[Fe(CN)6]. Characterization of the product was performed by CHN-analysis, electron microscopy, infrared spectra, and X-ray methods. The compound is orthorhombic, a = 1386.3(4), b = 1386.3(4), c = 1385.6(4) pm, space group Pbca, the structure wa refined to an unweighted R = 6.7% (1255 intensities). According to the infrared spectra and the X-ray refinement intensive hydrogen bonds are present.
    Notes: Einkristalle von [Mg(H2O)6](C6H13N4)2[Fe(CN)6] wurden durch Diffusion einer methanolischen Lösung von Hexamethylentetramin (HMT) in eine wäßrige Lösung von MgCl2 und H4[Fe(CN)6] erhalten. Die Charakterisierung des Produktes erfolgte mittels CHN-Analyse, Rasterelektronenmikroskopie, Infrarotspektroskopie und Röntgenmethoden. Eine Einkristallstrukturanalyse ergab die orthorhombische Raumgruppe Pbca, die Verfeinerung konvergierte bei einem ungewichteten R-Wert von 6,7% für 1255 Reflexe. Die Ergebnisse der Kristallstrukturanalyse wie auch die Infrarotspektren zeigen die besondere Bedeutung von Wasserstoffbindungen auf.
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    14/15N-NMR und 11B-NMR-Daten von Trifluormethylthioaminoboranen mit natürlicher Isotopenhäufigkeit (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 560 (1988), S. 169-184 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 14/15N N.M.R. and 11B N.M.R. Data of Trifluoromethylthioamino-boranes with Natural Isotope Abundance (Part 2)14/15N as well as 11B-NMR data for trifluoromethylthioabminoboranes of the types XnB[N(SCF3)2], with X = F, Cl, Br, N3, or NHSCF3, n = 0, 1 or 2, and Cl3-nB(NHSCF3)n with n = 1, 2 or 3, as well as for the amine-borne Me3NBCl2N(SCF3)2 and the cyclic borazene (CF3SNHBNH)3 are reported.These data are used, together with a qualitative analysis of the bonding situation based on observed rotational barriers and known structures, to analyse for B ← N back donation in these compounds. Relatively small variations in δ14/15N compared to those observed for alkylaminoboranes as well as large variations in δ11B are suggestive of small contributions only from back bonding. In addition the „halogene like“ nature of the (CF3S)2N group is confirmed. For the series X2BN(SCF3)2 (X = F, Cl, Br on N3), XB[N(SCF3)2]2 (X = Cl, Br, N3 or N(SCF3)2) and Cln-3B(NHSCF3)n (n = 1, 2 or 3) a linear relationship for δ11B and δ14/15N is observed.It is furtheron demonstrated that hitherto known δ14/15N/11B correlations are valid only in case of strong B ← N back donation.
    Notes: Die 14/15N- sowie 11B-NMR-Daten von Trifluormethylthioaminoboranen des Typs XnB[N(SCF3)2]3-n (X = F, Cl, Br, N3, NHSCF3; n = 0-2) und Cl3-nB(NHSCF3)n (n = 1 bis 3), sowie von einem Amin-Boran Me3N · BX2Y (X = Cl, Y = N(SCF3)2) und Cycloborazin [CF3SNHBNH]3 werden mitgeteilt. Mit Hilfe dieser Daten und einer qualitativen Analyse der Bindungsverhältnisse anhand beobachteter Rotationsbarrieren und bekannter Strukturen wird die B←N-Rückbindung in diesen Verbindungen analysiert. Die im Vergleich zu Alkylaminoboranen geringen Änderungen in δ14/15N sowie die großen Änderungen in δ11B werden auf geringe Rückbindungsbeiträge zurückgeführt. Darüber hinaus wird dadurch die „Halogenähnlichkeit“ des (CF3S)2N-Restes bestätigt. Für die Reihen X2BN(SCF3)2 (X = F, Cl, Br, N3), XB[N(SCF3)2]2 (X = Cl, Br, N3, N(SCF3)2) und Cln-3B(NHSCF3)n (n = 1-3) ergibt sich für δ11B und δ14/15N eine lineare Beziehung. Es wird weiterhin gezeigt, daß bisher bekannte δ14/15N/11B-Korrelationen für den Fall starker B←N-Rückbindung gelten.
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    Neue Oxometallate der Formel BaBeLa2O5, SrBeNd2O5 und SrBeSm2O5 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 7-11 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Oxocompounds of the Formula BaBeLa2O5, SrBeNd2O5, and SrBeSm2O5.The hitherto unknown compounds (A) BaBeLa2O5, (B) SrBeNd2O5, and (C) SrBeSm2O5 were prepared by high temperature reactions. Single crystal work lead to monoclinic symmetry for (A) (space group P21/c a = 7.5109(11), b = 6.7875(35), c = 9.8945(35) Å, β = 90.56 (2)°, Z = 4). (B) und (C) crystallize with orthorhombic symmetry (space group Pnma, (B): a = 9.5780(32), b = 7.2527(45), c = 6.5829(20) Å, Z = 4, (C): a = 9.5039(9), b = 7.1885(8), c = 6.5223(8) Å, Z = 4). The statistical occupation of the Kagomé-network by M2+ and Ln3+ is discussed. It is shown that compounds of the formula SrBeLn2O5 form this structure type until Ln = Gd.
    Notes: Neu dargestellt wurden die Verbindungen (A) BaBeLa2O5, (B) SrBeNd2O5 und (C) SrBeSm2O5. (A) kristallisiert monoklin (Raumgruppe P21/c mit a = 7,5109(11), b = 6,7875(35), c = 9,8945(35) Å, β = 90,56°(2), Z = 4). (B) und (C) gehören zur Raumgruppe Pnma [(B): a = 9,5780(32), b = 7,2527(45), c = 6,5829(20) Å, Z = 4, (C): a = 9,5039(9), b = 7,1885(8), c = 6,5223(8) Å, Z = 4]. Die statistische Besetzung des Kagomé-Gerüsts mit M2+ und Ln3+ wird diskutiert und die Existenzgrenze der Reihe SrBeLn2O5 aufgezeigt.
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    Zur Kenntnis des Systems CsF/CuF2: Cs4Cu3F10Professor Heinrich Nöth zum 60. Geburtstage am 20. Juni 1988 gewidmet (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 12-24 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the System CsF/CuF2: Cs4Cu3F10.By annealing of CsF and CuF2 under dried Ar [closed Au-tube, 630°C, 190 d] we received single crystals of hitherto unknown Cs4Cu3F10. They are nearly colorless, a blue tint is barely perceptible. The new fluoride crystallizes in the triclinic system (P1) with: a = 850.5(3) pm, b = 774.0(3) pm, c = 626.8(3) pm, α = 113.92(4)°, β = 111.84(4)°, γ = 103.12(4)° and Z = 1. Characteristical are units of three face shared octahedrons [Cu3F12]. The distances d(Cu—F) are ranging from 186.5 to 225.1 pm.The Madelung Part of Lattice Energie, MAPLE, is calculated and discussed, just so Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR.
    Notes: Erstmals konnten Einkristalle von Cs4Cu3F10 durch Tempern [geschlossenes Au-Rohr, 630°C, 190 d, alles unter Ar] von CsF und CuF2 erhalten werden. Sie sind fast farblos, ein Stich ins Blaue ist kaum merklich. Das neue Fluorocuprat(II) kristallisiert triklin (P1) mit: a = 850,5(3) pm, b = 774,0(3) pm, c = 626,8(3) pm, α = 113,92(4)°, β = 111,84(4)° und γ = 103,12(4)°, Z = 1. In charakteristischen [Cu3F12]-Einheiten sind drei Oktaeder flächenverknüpft. Die Abstände d(Cu—F) variieren von 186,5 bis 225,1 pm.Der Madelunganteil der Gitterenergie, MAPLE, wird (wie auch Effective Koordinationszahlen, ECoN, diese über Mittlere Fiktive Ionenradien, MEFIR) berechnet und diskutiert.
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    Struktur-Reaktivitäts-Beziehungen bei Koordinativ-ungesättigten Chelatkomplexen. IX. Vergleichende synthetische Untersuchungen zur axialen Ligation von tricyclischen und makrocyclischen Eisenkomplexen Schiffscher Basen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 25-37 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Reactivity Correlations in Coordinatively Unsaturated Metal Chelate Complexes. IX. Comparative Investigations on the Axial Ligation of Tricyclic and Macrocyclic Iron Chelate Complexes of Schiff BasesThe addition of axial bases at the iron chelates 1a and 2b has been compared by isolation of stable adducts with methanol, pyridine, and imidazole. 1a forms octahedral high-spin adducts whereas 2b gives mainly pentacoordinated intermediate-spin and octahedral low-spin derivatives. The iodo-iron(III) derivatives are high-spin too in the case 1a and intermediate-spin in the case 2b. The carbonyl substituted macrocycles 2 are closer related to iron porphyrines than the analogous chelates 3 and 4.
    Notes: Die Addition axialer Basen an die Eisenchelate 1a und 2b wurde durch Isolierung stabiler Addukte mit Methanol, Pyridin und Imidazol verglichen. 1a bildet oktaedrische high-spin-Addukte, während 2b hauptsächlich pentakoordinierte intermediate-spin-und oktaedrische low-spin-Derivate ergibt. Auch die Iodoeisen(III)-Derivate sind bei 1a high-spin- und bei 2b intermediate-spin-Komplexe. Die carbonylsubstituierten Makrocyclen 2 sind den Eisenporphyrinen enger verwandt als die analogen Chelate 3 und 4.
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    Darstellung neuer, unsymmetrisch substituierter N-(2-Aminophenyl)azomethine von β-Ketoaldehyden durch Template-Kondensation mit Nickel(II) als potentielle Vorstufen unsymmetrisch substituierter makrocyclischer Komplexe (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 38-48 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of New Unsymmetrically Substituted N-(2-Aminophenyl)-azomethines of β-Ketoaldehydes via Template Condensation with Nickel(II) as Potential Precursors of Unsymmetrically Substituted Macrocyclic ComplexesThe synthesis of new unsymmetrically substituted nickel(II) complexes of type 4 is described. These complexes arises via template condensation of the unsymmetrically substituted tridentate amino-azomethines 3, whereas only the amino group of the less reactive and the carbonyl group of the more reactive aminoazomethine react with each other. Diamagnetic square-planar nickel(II) complexes with a [N3O] donor set and an uncoordinated amino group are formed. The complexes are precursors of carbonyl-substituted macrocyclic chelates. Further condensations of the amino group with e. g. dialdehydes or diketons are possible. All the new complexes are characterized by visible and 1H and 13C n.m.r. spectra as well. The influence of several peripheral substituents on the distribution of the electron density of the ligand is investigated. Strong O…H bonds forms a 6-membered ring between the uncoordinated amino group, the coordinated carbonyl group and the substituents at the R3 position.
    Notes: Die Synthese neuer unsymmetrisch substituierter Nickel(II)-Komplexe des Typs 4 wird beschrieben. Die Komplexe entstehen durch Template-Kondensation der unterschiedlich substituierten dreizähnigen Aminoazomethine 3, wobei nur die Aminogruppe des weniger reaktiven und die Carbonylgruppe des reaktiveren Aminoazomethins miteinander reagieren. Es entstehen diamagnetische planare Nickel(II)-Komplexe mit [N3O]-Koordination und einer freien Aminogruppe. Die Komplexe stellen Vorstufen für carbonylsubstituierte makrocyclische Chelate dar. Die freie Aminogruppe ist weiteren Kondensationsreaktionen, z. B. mit Dialdehyden oder Diketonen, zugänglich. Alle neuen Komplexe werden durch sichtbare sowie 1H- und 13C-NMR-Spektren ausführlich charakterisiert. Der Einfluß der verschiedenen peripheren Substituenten auf die Verteilung der Elektronendichte im Liganden wird untersucht. Zwischen der freien Aminogruppe des Liganden, der koordinierten Carbonylgruppe und dem Substituenten R3 bildet sich über starke H-Brücken ein Sechsring aus.
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    Oxidative Addition von Hexafluoraceton an 1-Chlor-, 1-(2,2,2-Trifluorethoxy)- und 1-[2,2,2-Trifluor-1-(trifluormethyl)ethoxy]-phosphorinan (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 49-56 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Addition of Hexafluoroacetone at 1-Chloro-, 1-(2,2,2-Trifluoroethoxy)- and 1-[2,2,2-Trifluoro-1-(trifluoromethyl)ethoxy]phosphorinaneHexafluoroacetone adds oxidatively to 1-chlorophosphorinane (1) forming the 1,3,4λ5σ5-dioxaphospholane 2 which reacts with antimony pentachloride to give the phosphonium salt 3 showing a ring rearrangement. The hydrolysis of 2 furnishes the phosphinate 4 under splitting off hexafluoroacetone. Following a different reaction pathway 1 and hexafluoroacetone yield also 1-chloro-1-oxo-λ5σ4-phosphorinane (5a) and 1-chloro-1-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]-λ5σ4-phosphorinane (6). From the phosphinites 7 and 8 the 1,2λ5σ5-oxaphosphetanes 9, 10a and 10b are obtained, in which the four membered ring is annellated at the phosphorinane ring. Substituent permutation processes are not observed in 9, 10a and 10b.
    Notes: Hexafluoraceton addiert sich oxidativ an 1-Chlorphosphorinan (1) zu dem 1,3,4λ5σ5-Dioxaphospholan 2, das mit Antimonpentachlorid unter Ringumlagerung das Phosphoniumsalz 3 ergibt. Die Hydrolyse von 2 liefert das Phosphinat 4, wobei Hexafluoraceton abgespalten wird. Auf einem anderen Reaktionsweg bildet sich aus 1 und Hexafluoraceton auch 1-Chlor-1-oxo-λ5σ4-phosphorinan (5a) sowie 1-Chlor-1-[2,2,2-trifluor-1-(trifluormethyl)-ethyliden]-λ5σ-phosphorinan (6). Die Phosphinite 7 und 8 setzen sich zu 1,2λ5σ5-oxaphosphetanen 9, 10a und 10b um, in denen der Vierring an den Phosphorinanring anelliert ist. Substituenten-Umordnungsprozesse sind an 9, 10a und 10b nicht zu beobachten.
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    Komplexe mit aromatischen Carbonsäuren. III Darstellung und Kristallstruktur von Na2Zn2[C6H3(COO)3]2· 11H2OProfessor Heinrich Nöth zum 60. Geburtstage am 20. Juni 1988 gewidmet (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 57-65 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes with Aromatic Carboxylic Acids. III. Preparation and Cystal Structure of Na2Zn2[C6H3(COO)3]2· 11H2OSingle crystals of Na2Zn2[C6H3(COO)3]2· 11 H2O were grown in an aqueous silica gel. Zn2+ is coordinated in a distorted trigonally bipyramidal fashion. Na+ is coordinated octahedrally. The [C6H3(COO)3]3- ions are almost planar. Double-chains consisting of Zn2+, Na+, and [C6H3(COO)3]3- ions are the main feature of the crystal structure. These double-chains are interlinked by further Na+ ions to form infinite layers. Intermolecular hydrogen bonds of partly high strength are established within one layer and between adjacent layers.
    Notes: Einkristalle von Na2Zn2[C6H3(COO)3]2· 11H2O wurden durch Kristallisation in wässerigem Kieselgel dargestellt. Zn2+ ist verzerrt trigonal bipyramidal, Na+ hingegen oktaedrisch koordiniert. Das[C6H3(COO)3]3- Ion ist weitgehend planar. Das wesentliche Strukturmerkmal sind Doppelketten, welche aus [C6H3(COO)3]3--Ionen und Zn2+ sowie Na+ gebildet werden. Diese Doppelketten sind durch weitere Na+-Ionen zu unendlichen Schichten verknüpft. Intermolekulare, z. T. sehr starke, Wasserstoffbrückenbindungen wirken sowohl innerhalb der Schichten als auch zwischen benachbarten Schichten.
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    Imidodiphosphorsäuretetraphenylester als Ligand in Fluorokomplexen. 1. Fluorokomplexe des Titans (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 167-172 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetraphenyl Imidodiphosphate as Ligand in Fluoro Complexes. 1. Fluoro Complexes of TitaniumIn acetonitrile TiF4 reacts with tetraphenyl imidodiphosphate forming two tetrafluoro (I, II) and three trifluoro complexes (III, IV, V) as well as one difluorotitanium complex (VI). The difluoro complex VI is exclusively formed by sing an excess of the ligand. VI was isolated and analytically characterized. The constitution and configuration of the complexes are concluded from 19F and 31P n.m.r. data. The tetraphenyl imidodiphosphate is only bidentately bonded, i.e. as chelate or bridging ligand; in the substitution complexes III-VI it is coordinated as anion.
    Notes: TiF4 bildet mit Imidodiphosphorsäuretetraphenylester in CH3CN zwei Tetrafluoro- (I, II) und drei Trifluorokomplexe (III, IV, V) sowie einen Difluorotitan-Komplex (VI). Mit Ligandenüberschuß entsteht ausschließlich der Difluorokomplex, der isoliert und elementar-analytisch charakterisiert wurde. Die Konstitutions- und Konfigurationsaussagen zu den übrigen Komplexen basieren auf 19F- und 31P-NMR-Untersuchungen. Der Imidodiphosphorsäureestr ist in den Komplexen stets zweizähnig als Chelat- oder Brückenligand gebunden; in den Substitutions-komplexen III-VI ist er in seiner anionischen Form enthalten.
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    Zur Reaktion von Diphenylfluorphosphan mit Aldehyden Kristallstruktur von Diphenylphosphinigsäure-[α-(difluorodiphenyl-λ5-phosphanyl)]piperonylester (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 173-179 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Diphenylfluorophosphane with Aldehydes. Crystal Structure of [α-(Difluorodiphenyl-λ5-phosphanyl)] Piperonyl DiphenylphosphiniteDiphenylfluorophosphane, Ph2PF, reacts with aldehydes forming phosphinito phosphoranes, Ph2F2P—CHR—O—PPh2. [α-(Difluorodiphenyl-λ5-phosphanyl)] piperonyl diphenyl-phosphinite, obtained by the reaction of Ph2PF with piperonal, crystallizes in the triclinic space group P1 with a = 969.3 pm, b = 2360 pm, c = 607,3 pm, α = 88.33°, β = 102.79°, γ = 92.40° and Z = 2.
    Notes: Diphenylfluorphosphan, Ph2PF, reagiert mit Aldehyden unter Bildung von Phosphinitophosphoranen, Ph2F2P—CHR—O—PPh2. Der mit Piperonal erhaltene Diphenyl-phosphinigsäure-[α-(difluorodiphenyl-λ5-phosphanyl)]piperonylestr kristallisiert in der triklinen Raumgruppe P1 mit a = 969,3 pm, b = 2360 pm, c = 607,3 pm, α = 88,33°, β = 102,79°, γ = 92,40° und Z = 2.
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    Crystal chemistry of MX · MgX2 · 6H2O type compounds (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 180-184 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zur Kristallchemie der Verbindungen des Typs MX · MgX2 · 6H2OVon den Verbindungen des Typs MX · MgX2 · 6 H2O wurden unter Variation der M+- und X--Ionen die Doppelsalzhexahydrate CsCl · MgCl2 · 6 H2O, Li(H2O)Cl · MgCl2 · 6 H2O, NH4Br · MgBr2 · 6 H2O, RbBr · MgBr2 · 6 H2O. CsBr · MgBr2 · 6 H2O, KI · MgI2 · 6 H2O, NH4I · MgI2 · 6 H2O und RbI · MgI2 · 6 H2O synthetisiert. Durch röntgenographische Untersuchungen an Pulverpräparaten wurden die Gitterparameter und die Raumgruppe bestimmt. Aus den Ergebnissen wurde die Zuordnung zu Strukturtypen vorgenommen. Danach besteht die Struktur aus einer Verknüpfung aller (M+)X6--Oktaeder untereinander über gemeinsame Ecken zu perowskitanalogen Baueinheiten, in deren Hohlräumen die Mg(H2O)62+-Oktaeder angeordnet sind. Ein “Toleranzfaktor” t von 1,045 bis 1,061, berechnet aus den Radienverhältnissen, stellt ein Charakteristikum für die obere Existenzgrenze dieser Struktur dar. Carnallit besitzt einen höheren Wert und deshalb eine andere Struktur.
    Notes: The following MX · MgX2 · 6H2O compounds (double salt hexahydrates) were synthesized by variation of the M+ and X- ions: CsCl · MgCl2 · 6 H2O, Li(H2O)Cl · MgCl2 · 6H2O, NH4Br · MgBr2 · 6 H2O, RbBr · MgBr2 · 6 H2O, CsBr. MgBr2 · 6 H2O, KI · MgI2 · 6 H2O, NH4I. Mgl2 · 6 H2O and RbI · MgI2 · 6H2O. By X-ray analysis of powder samples the lattice parameters and the space group were determined. On the basis of the results thus obtained, an identification with structural types was carried out. In accordance with the findings, the structure is made up of (M+)X6-octahedra which are linked into perovskite type units by sharing vertices. Their interstices are occupied by the Mg(H2O)62+ octahedra. A “tolerance factor” t which has been calculated on the basis of the proportion of radii and which attains values between 1.045 and 1.061 is a criterion for the upper limit of the area of existence of this structure. Carnallite has a higher to value and, therefore, a different structure.
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    Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen. XXXV. Reduktion von Blockstrukturen im Elektronenmikroskop - in situ-Beobachtung einer topotaktischen Reaktion im System Nb2O5/WO3 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 192-192 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/zaac.19885630124
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    Untersuchungen zum chemischen Transport der Vanadiumoxide V2O5, V3O7 und V6O13 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 192-192 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/zaac.19885630125
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    EPR-Spektren von löslichen Alkylammoniumfluorofer(III) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 185-191 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: EPR Spectra of Soluble Alkylammonium Fluoroferrates(III)The existence of (FeF6)3- has been proved in methanolic solution of alkylammonium fluoroferrates (III) with excess of fluorides. Information about structures of the investigated polycrystalline compounds (NH3CH3)FeF4, (NH3CH3)2FeF5, and (NH3CH3)3FeF6 has been obtained by fitting experimental EPR curves with the help of model functions.
    Notes: In methanolischer Lösung von Alkylammoniumfluoroferraten(III) wird das Vorliegen von (FeF6)3-bei Fluoridüberschuß nachgewiesen. Für die untersuchten polykristallinen Verbindungen (NH3CH3)FeF4, (NH3CH2)2FeF5 und (NH3CH3)3FeF6 werden durch Anpassung von Modellfunktionen an die experimentellen EPR-Spektren Strukturaussagen abgeleitet.
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    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988) 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885640101
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    Zur Verbindungsbildung MO: M2O3. Zur Kenntnis von BaCr2O4 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 26-30 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About a Compound Formation MO:M2O3. X. On BaCr2O4For the first time single crystals of BaCr2O4 were prepared as a high temperature compound of the SrCr2O4-type. It crystallizes with orthorhomibic symmetry, space group D2h13 - Pmmn, a = 12,286; b = 5,921; c = 5,146 Å Z = 4. The crystal structure are described and the relationship to the metastable compounds α-CaCr2O4 and SrCr2O4 are discussed.
    Notes: BaCr2O4 wurde erstmals einkristallin als Hochtemperaturverbindung vom SrCr2O4-Typ dargestellt. Es kristallisiert orthorhombisch, Raumgruppe D2h13 - Pmmn mit a = 12,286; b = 5,921; c = 5,146 Å Z = 4. Die Struktur wird beschrieben und das Verhalten gegenüber den entropiestabilisierten metastabilen Verbindungen α-CaCr2O4 diskutiert.
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    Darstellung und elektronenmikroskopische Untersuchung von monoklinem (Zn, Nb)12O29 und (Mg,Nb)12O29 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 7-16 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Electronmicroscopical Investigation of Monoclinic (Zn,Nb)12O29 and (Mg,Nb)12O29Different chlorinating transport agents were tried for the chemical transport of Zn2/3Nb11 1/3O29 and Mg2/3Nb11 1/3O29. With NH4Cl we succeeded in getting solid solutions of M2/3Nb11 1/3O29 (M = Zn or Mg) and Nb12O29. Only Mg2/3Nb11 1/3O29 could be deposited as a pure phase using HgCl2 as transport agent. The investigation of the transport products with a transmission electron microscope confirmed the expected structure of edge sharing [3×4] blocks like Nb12O29. Nevertheless many different defective crystal areas were observed.
    Notes: Verschiedene chlorierende Transportmittel wurden für den chemischen Transport von Zn2/3Nb11 1/3O29 und Mg2/3Nb11 1/3O29 erprobt. Mit NH4Cl gelang es, Mischkristalle von M2/3Nb11 1/3O29 (mit M = Zn oder Mg) und Nb12O29 zu erhalten. Phasenrein ließ sich nur Mg2/3Nb11 1/3O29 mit dem Transportmittel HgCl2 abscheiden. Die Untersuchung der Transportprodukte mit dem Transmissionselektronenmikroskop bestätigte den Aufbau aus kantenverknüpften [3×4]-Blöcken wie bei Nb12O29. In vielen Kristallbereichen wurde allerdings eine unterschiedliche Fehlordnung beobachtet.
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    Zur Kristallchemie der Oxotantalate M4Ta2O9. III. Beiträge zur Kristallchemie von Zn4-xMgxTa2O9 und Zn2,1Mg0,9Ta2O8 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 31-36 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Chemistry of Oxotantalates M4Ta2O9. III. A Contribution on the Crystal Chemistry of Zn4-xMgxTa2O9 and Zn2.1Mg0.9Ta2O8X-ray powder and single crystal investigations of the Zn4-xMgxTa2O9 system show the instability of the Zn4Ta2O9-type against the substitution of Mg2+ ions. In all cases of substitution, oxides of the formula Zn4-xMgxTa2O9 crystallizes with a corund related structure. The metal positions (M2+) are occupied statistically by Zn2+. Compounds of the type Zn3-xMgxTa2O8 have the structure of Zn3Nb2O8. One of the point positions is occupied by Mg2+ and Zn2+. The existence of The existence of the different structure types and the polyhedra deformation are discussed in respect to the Mg2+ contents in Zn3-xMgxTa2O8.
    Notes: Untersuchungen mit Röntgenpulver- und Einkristalltechnik im System Zn4-xMgxTa2O9 zeigen, daß beim Einbau von Mg2+ der Zn4Ta2O9-Typ verlassen wird. Alle Misch kristalle kristallisieren im aufgefüllten Korundtyp. Zn2+ und Mg2+ besetzen im Metallteilgitter die vorhandenen Positionen statistisch. Verbindungen vom Typ Zn3-xMgxTa2O8 kristallisieren nicht im Zn3Ta2O8-Typ, sondern wie Zn3Nb2O8. Eine Metallpunktlage ist mit Mg2+ und Zn2+ besetzt. Die Existenz der verschiedenen Strukturtypen und die Polyederdeformation werden im Hinblick auf den Ersatz von Zn2+ gegen Mg2+ diskutiert.
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    Hexafluorotitan(IV)-Säure: Untersuchungen zur Bildung und Struktur kristalliner Hydrate (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 17-25 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hexafluorotitanic(IV) Acid: Studies on Formation and Structure of Crystalline HydratesThe system hexafluorotitanic(IV) acid  -  water was investigated y low-temperature difference thermal analysis (DTA) and temperature-dependent X-ray powder diffraction in the water-rich range of 80-100 mol% H2O. A quasi-binary behavior was found, and the melting diagram was constructed. It shows the existence of three crystalline hydrates H2TiF6 · nH2O with n = 4, 6, and (probably) 10. The tetrahydrate and the hexahydrate melt congruently at -12 and 0°C, respectively; the most water-rich hydrate decomposes in the sub-solidus range at -79°C into solid hexahydrate and ice. The tetrahydrate exhibits a phase transition in the solid state at -57°C. Single crystals were grown of the hexahydrate and a trihydrate, too, and were used for complete structure determination of these compounds from X-ray data. The ionic formulae of the oxonium salts are (H5O2)2TiF6 · 2 H2O and (H3O)(H5O2)TiF6, respectively. The structures are governed by extensive hydrogen bonding. The hexahydrate is isotypic to H2SiF6 · 6 H2O.
    Notes: Das System Hexafluorotitan(IV)-säure-Wasser wurde mit Tieftemperatur Differenzthermoanalyse (DTA) und temperaturabhängiger Röntgenpulverbeugung im wasserreichen Bereich von 80 bis 100 Mol-% H2O untersucht. Es wurde quasibinäres Verhalten festgestellt und das Schmelzdiagramm konstruiert. Dieses zeigt die Existenz von drei kristallinen Hydraten H2TiF6. nH2O mit n = 4,6 und (wahrscheinlich) 10. Das Tetrahydrat und das Hexahydrat schmelzen kongruent bei -12 und 0°C; das wasserreichste Hydrat zerfällt im Subsolidusbereich bei -79°C in festes Hexahydrat und Eis. Das Tetrahydrat durchläuft im festen Zustand eine Phasenumwandlung bei-57°C. Einkristalle werden vom Hexahydrat und auch von einem Trihydrat erhalten und dienten zur vollständigen Strukturbestimmung dieser Verbindungen aus Röntgenbeugungsdaten. Die ionischen Formeln der Oxoniumsalze lauten (H5O2)2TiF6 · 2 H2O bzw. (H3O)(H5O2)TiF6. Die Strukturen sind durch zahlreiche Wasserstoffbrücken geprägt. Das Hexahydrat ist isotyp zu H2SiF6 · 6 H2O.
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    Neue Oxoplumbate(II) mit lnselstruktur: Rb4[PbO3] und Cs4[PbO3] (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 45-60 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel Oxoplumbates(II) with Isolated Anion Structure: Rb4[PbO3] and Cs4 [PbO3]For the first time Rb4[PbO3] have been prepared as single crystals. The structure determination (four-circle diffractometer data) [Rb4[PbO3]: 1818 I0 (hkl), MoKα, R = 6.49%, Rw = 6.83%, space group Pbca (a = 681.2(1), b = 1178.7(1), c = 1979,9(1) pm), Z = 8; Cs4[PbO3]: 3663 Io (hkl), AgKα, R = 11.35%, Rw = 9.82%, space group P21 (a = 1188.1(2), b = 734.4(1), c = 1176.2(2) pm, β = 111.52(2)°), Z = 4] proves in both cases the expected “isolated” [PbO3] groups. Comparing the oxides the arrangements of these groups shows surprising differences (see text). The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, have been calculated.
    Notes: Erstmals dargestellt wurden Rb4[PbO3] und Cs4[PbO3] in Form von Einkristallen. Nach der Strukturbestimmung mit Vierkreisdiffraktometerdaten [Rb4[PbO3]: 1818 I0 (hkl), Mokα, R = 6,49%, Rw = 6,83%, Raumgruppe Pbca (a = 681,2(1), b = 1178,7(1), c = 1979,9(1) pm), Z = 8; Cs4[PbO3]: 3663 Io (hkl), AgKα, R = 11,35%, Rw = 9,82%, Raumgruppe P21 (a = 1188,1(2), b = 734,4(1), c = 1176,2(2) pm, β = 111,52(2)°), Z = 4] liegen bei beiden Oxiden „isolierte“ [PbO3]-Gruppen von, deren Anordnung zueinander sich jedoch grundsätzlich unterscheidet, (Einzelheiten vgl. Text). Der Madelunganteil der Gitterenergie, MAPLE, und Effektive Koordinationszahlen, ECoN, werden angegeben.
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    Formation of a continuous series of solid solutions in the System TiTe3O8—ZrTe3O8 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 115-120 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bildung einer kontinuierlichen Reihe fester Lösungen im System TiTe3O8—ZrTe3O8Über den gesamten Zusammensetzungsbereich im System TiTe3O8—ZrTe3O8 werden bei niedrigen Temperaturen feste Lösungen aus amorphem Material gebildet, das durch gleichzeitige Hydrolyse von Titan-iso-propoxid, Zirkon-n-butoxid und Tellurtetrachlorid erhalten wurde. Diese kontinuierliche Reihe fester Lösungen ist gekennzeichnet durch eine kubische Einheitszelle mit a linear ansteigend vom 1,096 bis 1,131 nm, wenn Ti durch Zr ersetzt wird. Bei allen Verhältnissen Ti:Zr enthält die Struktur TeO4-Gruppen.
    Notes: Over the entire range of compositions in the system TiTe3O8—ZrTe3O8, solid solutions are formed at low temperatures from amorphous materials prepared by the simultaneous hydrolysis of titanium isopropoxide, zirconium n-butoxide, and tellurium tetrachloride. A continuous series of solid solutions is indexed in a cubic with a increasing linearly from 1.096 to 1.131 nm as Ti is substituted by Zr. At all Ti:Zr ratios the structures contain TeO4 groups.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885640115
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    Der chemische Transport von Niob(V)-oxid und von Lithiumniobat mit Schwefel (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 564 (1988), S. 127-128 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemical Transport of Niobium(V) Oxide and of Lithium Niobate with SulphurNiobium(V) oxide is transported by means of sulphur (calculated for 10 bar at 1223 K) from 1273 → 1173 K. The same applies for niobate. Similar experiments of lithium oxide lead to turbidity of the quartz ampoule.
    Notes: Niob(V)-oxid wird mit Schwefel (berechnet für 10 bar S2 bei 1223 K) von der heißen Zone (1273 K) zur kälteren Zone (1173 K) transportiert. Dasselbe gilt für Lithiumniobat. Gleiche Versuche mit Lithiumoxid führten zur Trübung der Quarzampulle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885640117
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