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  • General Chemistry  (4,740)
  • Inorganic Chemistry  (3,865)
  • Chemical Engineering  (1,794)
  • THERMODYNAMICS AND COMBUSTION  (1,363)
  • Biochemistry and Biotechnology
  • 1970-1974  (12,263)
Collection
Keywords
Publisher
Years
Year
  • 101
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    Full-scale aircraft cabin flammability tests of improved fire-resistant materials (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Full-scale aircraft cabin flammability tests to evaluate the effectiveness of new fire-resistant materials by comparing their burning characteristics with those of older aircraft materials are described. Three tests were conducted and are detailed. Test 1, using pre-1968 materials, was run to correlate the procedures and to compare the results with previous tests by other organizations. Test 2 included newer, improved fire-resistant materials. Test 3 was essentially a duplicate of test 2, but a smokeless fuel was used. Test objectives, methods, materials, and results are presented and discussed. Results indicate that the pre-1968 materials ignited easily, allowed the fire to spread, produced large amounts of smoke and toxic combustion products, and resulted in a flash fire and major fire damage. The newer fire-resistant materials did not allow the fire to spread. Furthermore, they produced less, lower concentrations of toxic combustion products, and lower temperatures. The newer materials did not produce a flash fire.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-58141 , JSC-09060
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    NASA TECHNICAL REPORTS
  • 102
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    High current electrical lead (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An electrical lead has insulators imbedded in an inner conductor rod to form an annulus between the rod and a surrounding outer sheath. This annular space is filled with gas which conducts heat and prevents electrical leakage.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 103
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    Photomultiplier circuit including means for rapidly reducing the sensitivity thereof (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A simple, reliable and inexpensive control circuit is described for rapidly reducing the bias voltage across one or more of the dynode stages of a photomultiplier, to substantially decrease its sensitivity to incoming light at those times where excess light intensity might damage the tube. The control circuit comprises a switching device, such as a silicon controlled rectifier (SCR), coupled between a pair of the electrodes in the tube, preferably the cathode and first dynode, or the first and second dynodes, the switching device operating in response to a trigger pulse applied to its gate to short circuit the two electrodes. To insure the desired reduction in sensitivity, two switching stages, the devices be employed between two of the electrode stages, the devices being operated simultaneously to short circuit both stages.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 104
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    Two-demensional analysis of heat and mass transfer in porous media using the strongly implicit procedure (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Numerical results of the heat and mass transfer in a porous matrix are presented. The coupled, nonlinear partial differential equations describing this physical phenomenon are solved in finite difference form for two dimensions, using a new iterative technique (the strongly implicit procedure). The influence of the external environment conditions (heating and pressure) is shown to produce two-dimensional flow in the porous matrix. Typical fluid and solid temperature distributions in the porous matrix and internal pressure distributions are presented.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TN-D-7608 , JSC-S-382
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  • 105
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    Optical measurement of static temperature and hydroxyl radical profiles in a hydrogen-fueled supersonic combustor (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Profiles of static temperature and hydroxyl radical concentration were measured in a two-dimensional supersonic combustor test section 22.8 cm downstream of hydrogen injection. A high-pressure gas generator supplied vitiated air to the test section at Mach 2.44, atmospheric pressure, and a total temperature of about 2240 K. Room-temperature hydrogen was injected through a 0.40-cm step slot at Mach 1 and matched pressure. The measurements utilized a noninterfering spectral line absorption technique in which narrow ultraviolet emission lines of the hydroxyl electronic transition are absorbed by the broader absorption lines in the combustion gas. Comparison of the measured temperature profiles with theoretical calculations showed good agreement.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-3004 , E-7797
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  • 106
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    Banded transformer cores (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 107
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    Overvoltage protection network (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Electrical equipment to be protected from overvoltage is connected with a possible source of overvoltage via an input conductor. A fuse is connected in series with the input conductor. A spark gap is connected between the input conductor and ground for conducting the overvoltage current to ground and for blowing the fuse to open the circuit to the electrical equipment. A pulse attenuator network is provided between the spark gap and the electrical equipment to be protected for attenuating the pulse of energy passing through the fuse and spark gap prior to blowing of the fuse. The pulse attenuator network includes additional shunt spark gaps, series inductance, and a series connection of a twisted shielded pair of conductors having low-voltage insulation.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 108
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    Heat transfer model for predicting squib ignition times (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A squib ignition model based on transient heat condition from the hot bridgewire to the pyrotechnic is described. No Arrhenius-type chemical reaction is included. Instead, a thermal contact resistance is postulated to exist between the hot bridgewire and the pyrotechnic. Ignition is assumed to occur when a 2.5 micron layer of pyrotechnic next to the bridgewire reaches a characteristic ignition temperature for that pyrotechnic. This model was applied to the JPL squib, which uses a 50 micron (0.002-in.) diameter Tophet A bridgewire to ignite a boron, potassium perchlorate mix. A computer program was utilized that solves the transient heat condition problem with the boundary conditions stipulated by the model. The thermal contact conductance at the interface was determined by trial and error so that the experimentally determined ignition time for one firing condition would be properly predicted by the model. The agreement was quite good for tests run between -129 C and +93.3 C at current levels of 3.5 and 5 A. Axial heat conduction along the bridgewire is shown to be negligible.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-136834 , JPL-TM-33-655
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  • 109
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    High pressure combustion of liquid fuels (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Measurements were made of the burning rates and liquid surface temperatures for a number of alcohol and n-paraffin fuels under natural and forced convection conditions. Porous spheres ranging in size from 0.64-1.9 cm O.D. were emloyed to simulate the fuel droplets. The natural convection cold gas tests considered the combustion in air of methanol, ethanol, propanol-1, n-pentane, n-heptane, and n-decane droplets at pressures up to 78 atmospheres. The pressure levels of the natural convection tests were high enough so that near critical combustion was observed for methanol and ethanol vaporization rates and liquid surface temperature measurements were made of droplets burning in a simulated combustion chamber environment. Ambient oxygen molar concentrations included 13%, 9.5% and pure evaporation. Fuels used in the forced convection atmospheric tests included those listed above for the natural convection tests. The ambient gas temperature ranged from 600 to 1500 K and the Reynolds number varied from 30 to 300. The high pressure forced convection tests employed ethanol and n-heptane as fuels over a pressure range of one to 40 atmospheres. The ambient gas temperature was 1145 K for the two combustion cases and 1255 K for the evaporation case.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134540
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  • 110
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    High isolation RF signal selection switches (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A selection switch with high isolation between RF signal input terminals is achieved with a gated Schmitt trigger circuit feeding into a control NAND gate in each signal switching channel. The control NAND gates of the separate signal channels are coupled to an output terminal by a single NAND gate. The schmitt trigger circuits and all gates are implemented with Schottky transistor-transistor logic circuits having input clamping diodes. Each Schmitt trigger circuit includes two cascaded NAND gates and a feedback isolation Schottky diode between one input terminal connected to receive an RF input and another input terminal connected to receive a feedback signal from the second of the two cascaded NAND gates. Both NAND gates of the Schmitt trigger circuits are enabled by the same switch control signal which enables the control gates.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 111
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    Thermal performance of multilayer insulations (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Experimental and analytical studies were conducted in order to extend previous knowledge of the thermal performance and gas evacuation characteristics of three selected multilayer insulation (MLI) composites. Flat plate calorimeter heat flux measurements were obtained for 20- and 80- shield specimens using three representative layer densities over boundary temperatures ranging from 39 K (70 R) to 389 K (700 R). Laboratory gas evacuation tests were performed on representative specimens of each MLI composite after initially purging them with helium, nitrogen, or argon gases. In these tests, the specimens were maintained at temperatures between 128 K (230 R) and 300 K (540 R). Based on the results of the laboratory-scale tests, a composite MLI system consisting of 112 unperforated, double-aluminized Mylar reflective shields and 113 water preconditioned silk net spacer pairs was fabricated and installed on a 1.22-m-(4-ft-) diameter calorimeter tank.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134477 , LMSC-D349866
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  • 112
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    Measurement of gaseous emissions from a turbofan engine at simulated altitude conditions (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Gaseous emission from a TFE 731-2 turbofan engine were measured over a range of fuel-air ratios from idle to full power at simulated from near sea level to 13,200 m. Carbon monoxide and unburned hydrocarbon emissions were highest at idle and lowest at high power settings; oxides of nitrogen exhibited the reverse trend. Carbon monoxide and unburned hydrocarbon levels decreased with increasing altitude. Oxides of nitrogen emissions were successfully correlated by a parametric group of combustor operating variables.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-3046 , E-7821
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  • 113
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    Low distortion automatic phase control circuit (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A voltage controlled phase shifter is rendered substantially harmonic distortion free over a large dynamic input range by employing two oppositely poled, equally biased varactor diodes as the voltage controlled elements which adjust the phase shift. Control voltages which affect the bias of both diodes equally are used to adjust the phase shift without increasing distortion. A feedback stabilized phase shifter is rendered substantially frequency independent by employing a phase detector to control the phase shift of the voltage controlled phase shifter.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 114
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    Means for accommodating large overstrain in lead wires (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An electrical wire is reported along whose length loops are formed at intervals and retained in a plastic capsule that allows unfolding of the loop when tension is exerted on the opposite ends of the wire. The capsule is formed by encompassing each loop with a sleeve of heat shrinkable synthetic plastic material which overlaps the loop and heat shrinking the overlapping portions. Thus, a length of electrical wire is formed which stores extra lengths of wire in the quantity needed to match the expected stretching of materials or elements such as ropes, cords and the like of high elongation to which the electrical wire may be attached.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 115
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    Experimental investigation at Mach 8 of the effects of projections and cavities on heat transfer to a model of the Viking aeroshell (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental investigation into the aerodynamic heating on a Mars entry vehicle shape with several types of local surface distortion is presented. The configurations tested were 0.033-scale models of a spherically blunted 70 deg half-angle cone with two protuberances of different length, representing the tube leading to the gas chromograph mass spectrometer, and two aeroshell-bioshield attachment points of different size. These models were tested at free-stream Reynolds numbers per meter of 3.7 million and 17 million over an angle-of-attack range from 0 to 18 deg in the Langley Mach 8 variable density hypersonic tunnel. The phase change-coating technique was used to measure heat transfer coefficient. The long protuberance caused more severe interference heating than the short protuberance for the same conditions. When the short projection was located close to the edge of the aeroshell, the interference heating was greater than that on the same projection when located near the vertex. A significant increase in heat transfer coefficient was measured only on the larger aeroshell-bioshield attachment point.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-2941 , L-9244
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  • 116
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    Image tube (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An optical image is projected onto a planar surface of a photocathode that derives an electron beam replica of the image. A target electrode displaced relative to the photocathode so that it does not obstruct the optical image includes a planar surface for receiving and deriving an accurate replica of the electron beam image. The two planar surfaces are parallel. The electron beam image is focused on the target electrode by providing throughout a region that extends between the planar surfaces of the photocathode and receiving electrode, constant homogeneous dc electric and magnetic fields. The electric field extends in a direction perpendicular to the planar surfaces while the magnetic field extends along a straight line that intersects the photocathode and target electrode at an acute angle.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 117
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    Effect of wall to total temperature ratio variation on heat transfer to the leeside of a space shuttle configuration at M equals 10.3 (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental study has been conducted of the influence of wall to total temperature ratio on the heat transfer to the leeside of a 040A space shuttle configuration. The heat transfer tests were made at a Mach number of 10 and a Reynolds number of one million per foot for angles of attack from 0 deg to 30 deg. Range of wall to total temperature ratio was from 0.16 to 0.43. Where the heat transfer was relatively high and the laminar boundary layer attached, the local heat transfer decreased by about 20 percent as the wall to total temperature ratio was increased from the minimum to the maximum test value. On regions of separated flow and vortex reattachment, very low heating rates were measured at some conditions and indicate significant changes are occurring in the leeside flow field. No single trend of heat transfer variation with wall to total temperature ratio could be observed.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134086 , DMS-DR-2047
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  • 118
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    Effects of selected trajectory parameters on weight trends in the shuttle thermal protection system (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An empirical heating model, thermal protection system unit weight correlation, and trajectory analysis were used to develop a computation procedure for studying the sensitivity of thermal protection system weights to variations in pertinent trajectory parameters. The analytical techniques used in developing this computer program are described. Application of the analysis to a Space Shuttle Orbiter configuration was performed to demonstrate gross thermal protection system weight trends with selected entry trajectory parameters.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-58113 , JSC-08585
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  • 119
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    Emissions of nitrogen oxides from an experimental hydrogen-fueled gas turbine combustor (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The effect of operating variables of a hydrogen fueled combustor on exhaust concentrations of total oxides of nitrogen was determined at inlet-air temperature levels up to 810 K, pressure of 414,000N/sa m, and reference velocity of 21.3 m/sec. The combustor, which was originally designed for hydrocarbon fuel produced a NO(x) concentration of 380 ppm with hydrogen at 810 K inlet-air temperature. A reduction in NO(x) of about 30 % was obtained by modification to a lean or rich primary zone. The lowest NO(x) levels obtained with hydrogen were equivalent to those of the reference combustor burning hydrocarbon fuels.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-2997 , E-7745
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  • 120
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    Study of critical defects in ablative heat shield systems for the space shuttle (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Experimental results are presented for a program conducted to determine the effects of fabrication-induced defects on the performance of an ablative heat shield material. Exposures representing a variety of space shuttle orbiter mission environments-humidity acoustics, hot vacuum and cold vacuum-culuminating in entry heating and transonic acoustics, were simulated on large panels containing intentional defects. Nondestructive methods for detecting the defects, were investigated. The baseline materials were two honeycomb-reinforced low density, silicone ablators, MG-36 and SS-41. Principal manufacturing-induced defects displaying a critical potential included: off-curing of the ablator, extreme low density, undercut (or crushed) honeycomb reinforcements, and poor wet-coating of honeycomb.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-2336 , MCR-73-184
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  • 121
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    Heat transfer characteristics of an emergent strand (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A mathematical model was developed to describe the heat transfer characteristics of a hot strand emerging into a surrounding coolant. A stable strand of constant efflux velocity is analyzed, with a constant (average) heat transfer coefficient on the sides and leading surface of the strand. After developing a suitable governing equation to provide an adequate description of the physical system, the dimensionless governing equation is solved with Laplace transform methods. The solution yields the temperature within the strand as a function of axial distance and time. Generalized results for a wide range of parameters are presented, and the relationship of the results and experimental observations is discussed.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TN-D-7584 , JSC-S-362
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  • 122
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    Forced-convection peak heat flux on cylindrical heaters in water and refrigerant 113 (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An investigation was conducted of the peak heat flux on cylindrical heaters in a fluid flowing perpendicular to the major axis of the heater. The test fluids were water and Refrigerant 113. Heaters of 0.049 to 0.181 cm diameter were tested over a fluid velocity range of 10.1 to 81.1 cm/sec. The experimental results were observed to fall within two regions based on the vapor removal geometry: jets or sheets. Mathematical models for each region successfully correlated the data for both fluids.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TN-D-7553 , E-7659
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  • 123
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    Thermodynamic properties of UF6 at high temperatures (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The equilibrium composition and the thermodynamic properties of the mixture resulting from the decomposition of uranium hexafluoride is calculated for temperatures ranging from 600 K to 4000 K at pressures from 0.01 atmospheres to 10 atmospheres.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-2373
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  • 124
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    Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning ASTM jet-A fuel (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An annular gas turbine combustor was tested with heated ASTM Jet-A fuel to determine the effect of increased fuel temperature on the formation of oxides of nitrogen. Fuel temperature ranged from ambient to 700 K. The NOx emission index increased at a rate of 6 percent per 100 K increase in fuel temperature.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-2931 , E-7634
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  • 125
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    Zero-gravity venting of three refrigerants (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental investigation of venting cylindrical containers partially filled with initially saturated liquids under zero-gravity conditions was conducted in the NASA Lewis Research Center 5-second zero-gravity facility. The effect of interfacial mass transfer on the ullage pressure response during venting was analytically determined, based on a conduction analysis applied to an infinitely planer (flat) liquid-vapor interface. This pressure response was compared with both the experimental results and an adiabatic decompression computation.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TN-D-7480 , E-7509
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  • 126
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    Phase protection system for ac power lines (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The system described provides protection for phase sensitive loads from being or remaining connected to ac power lines whenever a phase reversal occurs. It comprises a solid state phase detection circuit, a dc power relay circuit, an ac-to-dc converter for energizing the relay circuit, and a bistable four terminal transducer coupled between the phase detection circuit and the power relay circuit, for controlling both circuits.
    Keywords: THERMODYNAMICS AND COMBUSTION
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  • 127
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    Conformal mapping technique for two-dimensional porous media and jet impingement heat transfer (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-07-27
    Description: Transpiration cooling and liquid metals both provide highly effective heat transfer. Using Darcy's law in porous media and the inviscid approximation for liquid metals, the local fluid velocity in these flows equals the gradient of a potential. The energy equation and flow region are simplified when transformed into potential plane coordinates. In these coordinates, the present problems are reduced to heat conduction solutions which are mapped into the physical geometry. Results are obtained for a porous region with simultaneously prescribed surface temperature and heat flux, heat transfer in a two-dimensional porous bed, and heat transfer for two liquid metal slot jets impinging on a heated plate.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: International Heat Transfer Conference; Sept. 3-7, 1974; Tokyo; Japan
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  • 128
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    Thermal-Structural Evaluation of TD Ni-20Cr Thermal Protection System Panels (1974)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: The results of a thermal-structural test program to verify the performance of a metallic/radiative Thermal Protection System (TPS) under reentry conditions are presented. This TPS panel is suitable for multiple reentry, high L/D space vehicles, such as the NASA space shuttle, having surface temperatures up to 1200 C (2200 F). The TPS panel tested consists of a corrugation-stiffened, beaded-skin TD Ni-20Cr metallic heat shield backed by a flexible fibrous quartz and radiative shield insulative system. Test conditions simulated the critical heating and aerodynamic pressure environments expected during 100 repeated missions of a reentry vehicle. Temperatures were measured during each reentry cycle; heat-shield flatness surveys to measure permanent set of the metallic components were made every 10 cycles. The TPS panel, in spite of localized surface failures, performed its designated function.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-132487
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  • 129
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    Heat Transfer and Thermodynamics: a Compilation (1974)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: A compilation is presented for the dissemination of information on technological developments which have potential utility outside the aerospace and nuclear communities. Studies include theories and mechanical considerations in the transfer of heat and the thermodynamic properties of matter and the causes and effects of certain interactions.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-SP-5959(01)
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  • 130
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    Stagnation and downstream viscous shock-layer solutions with radiation and coupled ablation injection (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: This paper describes a rigorous viscous shock-layer analysis for investigating high energy equilibrium flow fields about blunt axisymmetric bodies. The analysis includes radiation transfer, mass injection, diffusion, and viscous effects. Radiation transfer is calculated with a nongray radiation model that accounts for line and continuum radiation. The analysis can treat all levels of blowing for both stagnation and downstream flow. Results are presented for selected earth entry conditions that demonstrate the essential features of this analysis. Particular emphasis is given to the effects of mass injection on stagnation and downstream flow. Results for both specified and coupled ablation injection are presented.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-73 , Aerospace Sciences Meeting; Jan 30, 1974 - Feb 01, 1974; Washington, DC
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  • 131
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    Energy transfer in volume-reflecting heat shields (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An approximate analytic solution is provided for the unsteady radiative heating of a highly scattering medium under constant heat flux boundary conditions. The accuracy of the method in representing the reflectance, radiative flux, and radiative flux divergence of the materials was also explored, as was the influence of anistropic scattering on these parameters.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-140690
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  • 132
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    The effect of ablation injection on radiative and convective heating (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: A viscous shock-layer analysis is for calculating high energy equilibrium flow fields about blunt axisymmetric bodies is applied to the problem of massive ablation injection with radiation transport. A nongray radiation model is used that accounts for both line and continuum radiation. The solution method is direct and provides both stagnation and downstream solutions. Results for shock heated air show that phenolic-nylon injection is substantially more effective in reducing the wall radiant flux than air injection. Also, for large included body angles, the wall radiative flux and the coupled phenolic-nylon injection rate do not continue to decrease with increasing distance downstream.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-71976 , Anniv. Meeting of the Soc. of Eng. Sci.; Jan 01, 1973
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  • 133
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    Outer planet probe entry thermal protection. I Aerothermodynamic environment (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Solutions are presented for the aerothermal heating environments about blunt probes of various shape entering the candidate atmospheres of Saturn and Uranus. The analysis makes use of a series of interacting codes to predict pressures, cold wall radiative fluxes, cold wall convective fluxes, and corresponding corrections for the radiative and convective fluxes. The solutions show that ablation will either enhance or reduce the radiative flux to the surface depending on the ablation gas composition and ablation rate. Other conclusions suggested by the solutions are discussed.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-700 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 134
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    Heat transfer in turbulent flows under mild and strong adverse pressure gradient conditions for an arbitrary variation of the wall temperature (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: Heat Transfer and Fluid Mechanics Institute; Jun 12, 1974 - Jun 14, 1974; Corvallis, OR
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  • 135
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    The role of thermal contact resistance in pyrotechnic ignition (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: This paper describes a pyrotechnic ignition model based on transient heat conduction from a heated bridgewire to a pyrotechnic that is placed in contact with it. The boundary condition used at the interface was a thermal contact conductance estimated at 31,200 W per sq m-K between the wire and the pyrotechnic. Ignition was assumed to occur when a 2.5-micron layer of pyrotechnic next to the bridgewire reached a critical ignition temperature. The times to ignition predicted by this model for constant current firings were in good agreement with experimentally observed times to fire at 3.5- and 5-ampere current levels and ambient temperatures from 144 K to 366 K.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-694 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 136
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    Evaporation in space manufacturing (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: 'Normal evaporation' equations for predicting the compositional changes with time and temperature have been developed and correlated with actual experimental data. An evaporative congruent temperature is defined and used to explain, predict, or plan space experiments on anomalous constitutional melting (on cooling) or solidification (on heating). Uneven evaporation causes reactive jetting forces capable of initiating new convection currents, nongravitational accelerations, surface vibrations, or other disturbances. Applications of evaporation to space manufacturing are described concerning evaporative purification, surface cooling, specimen selection, particles splitting, freezing data interpretation, material loss and dimensional control, and surface contamination or compositional changes.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-667 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 137
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    Non-equilibrium stagnation region aerodynamic heating of hypersonic glide vehicles (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: A simple method of predicting aerodynamic heating and corresponding radiation equilibrium surface temperature-time histories for critical locations on space shuttle orbiter-type vehicles is presented. The method is based on a generalization of correlation equations developed earlier by Rosner for predicting the energy transfer and radiation equilibrium temperatures of surfaces with arbitrary catalytic activity and total hemispheric emittance. Recently obtained experimental data for O and N atom recombination probabilities on candidate material surfaces above 1000 K are used to assess nonequilibrium effects for a range of nose radii and a specific space shuttle re-entry trajectory. It is concluded that low catalytic activity will be especially important in locations of large effective nose radii by both increasing oxidation-resistant coating lifetime and reducing energy transfer into the vehicle.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-755 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 138
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    External field effects on solidification - Macroscopic and microscopic models (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Comparison of theoretical effects of magnetic and gravitational fields on melts of metals and semiconductors provides two kinds of insight into space processing materials problems. First, the task of comparing effects of the two fields yields mathematical models which may be used to estimate material properties and responses to processing under various field conditions. Then, by using these models, microgravity effects can be inferred from magnetic field data already obtained in laboratories on earth. Magnetohydrodynamics (static and oscillating fields) and the Free Volume Model are used to study macroscopic effects, and Sekerka's interface stability theory is used to show how external fields can affect microsegregation. It is demonstrated that the mathematical formalism is essentially the same for describing macroscopic effects of both microgravity and magnetic fields.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-665 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 139
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    Radiative heat transfer in coupled Mie and Rayleigh atmosphere (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Expressions describing radiative heat transfer in a coupled Mie and Rayleigh scattering atmosphere have been obtained by employing the modified two-stream approximation. The effect of tropospheric aerosols on the albedo as well as on heating rates in the wavelength region from 0.3 to 2.0 microns is studied. The present study indicates that the distinction between cooling or warming of the earth-atmosphere system for a realistic aerosol model proposed by McClatchey will depend on the surface reflectivity being smaller or larger than approximately 0.37. The effect of aerosols on the heating rate close to the surface has the same order of magnitude as atmospheric water vapor.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-652 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 140
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    Solidification of NaCl-NaF eutectic in space (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, have been produced in space and on earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-646 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 141
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    Radial and directional solidification of metallic systems in space (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Investigation of the solidification behavior of spherical specimens of Ni-12 wt % Sn and Ni-1 wt % Ag that froze radially from the surface toward the center and cylindrical specimens of Al-33 wt % Cu eutectic that froze directionally under appropriately selected conditions of thermal gradient at the solid-liquid interface and growth rate. Possible effects of vacuum and low gravity conditions, under which the spherical specimens were processed, on observed nucleation and growth phenomena are discussed. A genetic explanation is given of observed microstructures, and the distributions of alloying elements is discussed. In directionally solidified eutectic specimens a comparison is made between statistically evaluated growth defects in Skylab and in ground specimens.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-645 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 142
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    Two-phase choked flow of subcooled nitrogen through a slit (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Two-phase choked flow rate and pressure distribution data are reported for subcooled nitrogen flowing through a slit. The slit was a narrow rectangular passage of equal length and width. The inlet stagnation pressure ranged from slightly above saturation to twice the thermodynamic critical pressure. Four stagnation isotherms were investigated, covering a range which spanned the critical temperature. The results suggested a uniform two-phase flow pattern with vaporization occurring at or near the exit in most cases. The results compared favorably with the theory of Henry (1970) for nonequilibrium subcooled two-phase choked flow in long tubes.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: Southeastern Seminar on Thermal Science; Apr 11, 1974 - Apr 12, 1974; New Orleans, LA
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  • 143
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    Heat transfer and film cooling following normal injection through a round hole (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: ASME PAPER 74-GT-6 , Gas Turbine Conference and Products Show; Mar 30, 1974 - Apr 04, 1974; Zurich; Switzerland
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  • 144
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    Ablative thermal protection for space tug multipass, aerobraking entry (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Analytical studies had found the employment of an aerobraking trajectory for return of a reusable Space Tug from geosynchronous missions to be feasible and practical. To establish the minimum-weight ablative dome heat shield, trajectories involving 2 and 30 perigee passes were investigated both analytically and by plasma arc testing. Silicone-base ablators with densities of 15, 30, and 50 lb/cu ft were selected for evaluation. All models withstood the multipass exposures without deleterius surface recession or char erosion. Dome heat shield weights based on optimum ablative compositions indicated that ablators are a highly efficient thermal protection system for these missions.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-400 , Structures, Structural Dynamics and Materials Conference; Apr 17, 1974 - Apr 19, 1974; Las Vegas, NV; US
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  • 145
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    Comparison of approximate and numerical analyses of nonlinear combustion instability (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: At the present time, there are three general analytical techniques available to study problems of unsteady motions in rocket motors: linear stability analysis; approximate nonlinear analysis, founded on examining the behavior of coupled normal modes; and numerical calculations based on the conservation equations for one-dimensional flows. The last two yield the linear results as a limit. It is the main purpose of this paper to check the accuracy of the approximate analysis against the numerical analysis for some special cases. The results provide some justification for using the approximate analysis to study three-dimensional problems.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-201 , Aerospace Sciences Meeting; Jan 30, 1974 - Feb 01, 1974; Washington, DC
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  • 146
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    Natural convection in low-g environments (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The present state of knowledge in the area of low-g natural convection is reviewed, taking into account a number of experiments conducted during the Apollo 14, 16, and 17 space flights. Convections due to steady low-g accelerations are considered. Steady g-levels result from spacecraft rotation, gravity gradients, solar wind, and solar pressure. Varying g-levels are produced by engine burns, attitude control maneuvers, and onboard vibrations from machinery or astronaut movement. Thermoacoustic convection in a low-g environment is discussed together with g-jitter convection, surface tension-driven convection, electrohydrodynamics under low-g conditions, phase change convection, and approaches for the control and the utilization of convection in space.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-156 , Aerospace Sciences Meeting; Jan 30, 1974 - Feb 01, 1974; Washington, DC
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  • 147
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    Analysis of the effects of baffles on combustion instability (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: An analytical model has been developed for predicting the effects of baffles on combustion instability. This model has been developed by coupling an acoustic analysis of the wave motion within baffled chambers with a model for the oscillatory combustion response of a propellant droplet developed by Heidmann. A computer program was developed for numerical solution of the resultant coupled equations. Diagnostic calculations were made to determine the reasons for the improper prediction. These calculations showed that the chosen method of representing the combustion response was a very poor approximation. At the end of the program, attempts were made to minimize this effect but the model still improperly predicts the stability trends. Therefore, it is recommended that additional analysis be done with an improved approximation.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134614 , R-9480
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  • 148
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    Two phase detonation studies (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134623 , UM-026030-5-F
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  • 149
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    An investigation of the open-loop amplification of a Reynolds number dependent process by wave distortion (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The response of a constant-temperature hot-wire anemometer to sinusoidal and distorted sinusoidal acoustic oscillations is examined. The output of the anemometer is dependent upon the Reynolds number of the flow over the wire. The response is a measure of the interaction between the anemometer output and the acoustic pressure in the neighborhood of the wire. It is an open-loop prediction of the characteristics of actual closed-loop operation of a system. If the open-loop response is large enough, unstable closed-loop operation is predicted. The study was motivated by a need to investigate the stability limits of liquid-propellant rockets when perturbed by pressure oscillations. The sinusoidal and distorted sinusoidal acoustic oscillations used for this study are the same as those characteristic of unstable rocket combustion. Qualitatively, the results are similar--the response of the system to pure sinusoidal acoustic vibration of the fluid surrounding the wire is small, even when the magnitude of the acoustic pressure is quite large; but the response can be increased by as much as an order of magnitude with respect to the sinusoidal case by the addition of distortion. The amplitude and phase of the distortion component, relative to the fundamental component, are the dominant factors in the increase in the response.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-134620
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  • 150
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    Investigation of arterial gas occlusions (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: The effect of noncondensable gases on high-performance arterial heat pipes was investigated both analytically and experimentally. Models have been generated which characterize the dissolution of gases in condensate, and the diffusional loss of dissolved gases from condensate in arterial flow. These processes, and others, were used to postulate stability criteria for arterial heat pipes under isothermal and non-isothermal condensate flow conditions. A rigorous second-order gas-loaded heat pipe model, incorporating axial conduction and one-dimensional vapor transport, was produced and used for thermal and gas studies. A Freon-22 (CHCIF2) heat pipe was used with helium and xenon to validate modeling. With helium, experimental data compared well with theory. Unusual gas-control effects with xenon were attributed to high solubility.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-114731 , MDC-G4437
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  • 151
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    Outer planet probe entry thermal protection. II - Heat shielding requirements (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Solutions are presented for the material thermal response for heat shields of blunt probes entering Saturn and Uranus. Both monolithic and sandwich concepts were considered having exposed charring ablative or reflective materials. The solutions show that (1) Teflon heat shields are sized by mass loss considerations, other materials (unless entering the Uranus cold-dense atmosphere) by heat soak considerations, (2) steeper entries require less heat shield mass, (3) sizing requirements vary little about the bodies for heat soak dominated materials, and (4) carbon-phenolic appears superior overall, but silica is superior for the steeper entries and the high helium content atmospheres.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-701 , Thermophysics and Heat Transfer Conference; Jul 15, 1974 - Jul 17, 1974; Boston, MA
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  • 152
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    Thermoacoustic convection of fluids in low gravity (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The heat flow in a confined perfect gas in low gravity is investigated, including the effects of conduction and thermal convection. Buoyancy-driven flow is neglected, due to the low-gravity environment, but the effect of thermoacoustic motion due to fluid compressibility is included. One-dimensional mathematical models are constructed from the conservation equations for a compressible, viscous, heat-conducting fluid. A conservative, time-dependent finite-difference method is used to generate numerical solutions on a digital computer. Problems for flat plates and cylindrical segments are solved for specified thermal boundary conditions. Numerical results are given which indicate that thermoacoustic convection can significantly increase the transient heat flow over conduction model predictions for cases where a confined gas is rapidly heated.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA PAPER 74-76 , Aerospace Sciences Meeting; Jan 30, 1974 - Feb 01, 1974; Washington, DC
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  • 153
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    Effects of equivalence ratio and dwell time on exhaust emissions from an experimental premixing prevaporizing burner (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: A flame-tube study was performed to determine the effects of equivalence ratio and residence time on exhaust emissions with premixed, prevaporized propane fuel. Nitrogen oxides emissions as low as .3 g NO2/kg fuel were measured with greater than 99% combustion efficiency at 800 K inlet temperature and an equivalence ratio of .4. For a constant combustion efficiency, lower nitrogen oxides emissions were obtained by burning very lean with relatively long residence times than by using somewhat higher equivalence ratios with shorter times.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-TM-X-71592 , Ann. Intern. Gas Turbine Conf.; Mar 02, 1975 - Mar 06, 1975; Houston, TX; United States
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  • 154
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    Energy transfer in volume-reflecting heat shields (1974)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: An approximate analysis of radiative transfer in highly scattering materials was developed based on the Kubelka-Munk differential equations--a set of two differential equations representing the spatial rate of change of radiative half-fluxes within the scattering media. These approximate solutions of the Kubelka-Munk equations together with analytic solutions for the steady state temperature distribution for two types of boundary conditions are given. These solutions show the influence of back surface reflectance, scattering power, incident radiative flux parameter and boundary conductive flux parameter on overall reflectance and temperature distributions. This radiation field analysis, adapted to spherical geometry, was applied to the evaluation of the thermal performance of teflon and fritted quartz as heat protection materials for entry into the atmosphere of Jupiter.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: NASA-CR-139659
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  • 155
    Electronic Resource
    Electronic Resource
    Photoelektronenspektren und Moleküleigenschaften, XXVI. Die Delokalisation von Schwefel-Elektronenpaaren in Alkylsulfiden und -disulfiden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 68-77 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectra and Molecular Properties, XXVI. The Delocalisation of Sulfur Electron Pairs in Sulfides and DisulfidesThe photoelectron (PE) spectra of sulfides R—S—R (R=H, CH3, C2H5, n- und i-C3H7, n- and tert-C4H9) and disulfides R—S—S—R (R=H, CH3, C2H5, n- and i-C3H7, tert-C4H9, —[CH2]4—) are comparatively discussed. For sulfides the first ionization energy, which decreases as expected with increasing degree of alkylation, can also be obtained from the charge transfer excitation energies of their σ-complexes with tetracyanoethylene (TCNE). Disulfides show a splitting of the first PE-band in a clear dependence on the dihedral angle of the sulfur electron pairs. All observations can be rationalised within MO models as interactions of the sulfur electron pairs with the σ-skeleton and/or with each other.
    Notes: Die Photoelektronen(PE)-Spektren von Sulfiden R—S—R (R=H, CH3, C2H5, n- und i-C3H7, n- und tert-C4H9) und Disulfiden R—S—S—R (R=H, CH3, C2H5, n- und i-C3H7, tert-C4H9, —[CH2]4—) werden vergleichend diskutiert. Bei den Sulfiden R—S—R kann die mit steigendem Alkylierungsgrad erwartungsgemäß abnehmende erste Ionisierungsenergie auch aus den Charge-transfer-Anregungsenergien ihrer σ-Komplexe mit Tetracyanäthylen (TCNE) abgelesen werden. Bei Disulfiden R—S—S—S—R wird eine Aufspaltung der ersten PE-Bande in deutlicher Abhängigkeit vom Diederwinkel zwischen den Schwefel-Elektronen-paaren beobachtet. Die Befunde lassen sich mit MO-Modellen als Wechselwirkungen der Schwefel-Elektronenpaare mit dem σ-Gerüst und/oder untereinander verstehen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070109
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  • 156
    Electronic Resource
    Electronic Resource
    Ylid-Komplexe von Nickel-alkylen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 93-101 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nickelalkyl Ylid ComplexesFrom reactions of [(CH3)3P]3 Ni(CH3)2 and [(CH3)3P]2Ni(CH3)Cl with the ylid (CH3)3PCH2, molecular (1) an ionic complexes (2) are obtained, containing three covalent Ni—C-σ-bonds of square planar nickel atoms. These bonds are strongly stabilized by the proximity of the ylid onium center. Excess ylid converts 2 into a binuclear complex 3, where the metal atoms are bridged by dimethylphosphonium-bismethylid units, with formation of [(CH3)4P]Cl as a byproduct. An isoelectronic dimethylphosphinate complex, 4, containing a similar eight-membered ring structure, has also been prepared.
    Notes: Durch die Reaktion von Dimethyltris(trimethylphosphin)nickel und Methylbis(trimethyl-phosphin)nickel-chlorid mit Trimethylmethylenphosphoran werden molekulare (1) bzw. ionische (2) Ylid-Komplexe erhalten, in denen das quadratisch-planar konfigurierte Nickel-atom jeweils drei kovalente Ni—C-σ-Bindungen ausbildet. Diese Bindungen werden durch das Onium-Zentrum der Ylide erheblich stabilisiert. 2 liefert mit überschüssigem Ylid unter Abspaltung von [(CH3)4P]Cl einen zweikernigen Komplex 3, dessen Metallatome durch Dimethylphosphonium-bis-methylid-Brücken verbunden sind. Hierzu existiert ein isoelektronischer Dimethylphosphinat-Komplex 4, der ebenfalls Achtringstruktur besitzt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070111
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  • 157
    Electronic Resource
    Electronic Resource
    Reaktionen carbonyl-stabilisierter Sulfonium-ylide des 1,3-Dithiolans mit Acylierungsmitteln und aktivierten Acetylenen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 123-127 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of carbonyl-stabilized Sulfonium-ylides of 1,3-Dithiolane with Acylating Reagents and Activated AcetylenesIn aqueous sodium hydroxide monophenacyl-1,3-dithiolanium bromides 3 form carbonylstabilized 1,3-dithiolanium-1-phenacylides 4. These yield with acylation reagents and activated acetylenes new resonance-stabilized sulfonium-ylides 6, 8, 10.
    Notes: Monophenacyl-1,3-dithiolanium-bromide 3 bilden in wäßriger Natronaluge carbonyl-stabilisierte 1,3-Dithiolanium-1-phenacylide 4. Diese reagieren mit Acylierungsmitteln und aktivierten Acetylenen zu neuen mesomeriestabilisierten Sulfonium-yliden 6, 8, 10.
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    Über Aminosäuren und Peptide, IX. Über Pyruvoylaminosäuren (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 145-151 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, IX. On Pyruvoyl Amino AcidsAmino acid derivatives were tranformed to Pyruvoyl amino acid derivatives by use of pyruvoyl chlorid, p-nitrophenyl pyruvate, hydroxymaleic anhydride and the DCC-procedure. The application range of the different acylations is discussed. A convenient method for the preparation of pyruvoyl chloride is given.
    Notes: Aminosäurederivate werden mit Brenztraubensäurechlorid, Brenztraubensäure-p-nitrophenylester, Hydroxymaleinsäureanhydrid und mit Hilfe des DCC-Verfahrens zu Pyruvoylaminosäurederivaten umgesetzt. Die Anwendungsbreite der verschiedenen Acylierungen wird verglichen. Ein Weg zur praktischen Herstellung von Brenztraubensäurechlorid wird ausgearbeitet.
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    URL: http://dx.doi.org/10.1002/cber.19741070118
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    Kristall- und Molekülstruktur von Hexakis(phenylthio)äthan (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 253-262 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structure of Hexakis(phenylthio)ethaneThe structure of hexakis(phenylthio)ethane has been determined by single crystal X-ray diffraction. The phase determination was carried out by means of the Symbolic Addition Method. The structure has been refined with 1780 observed reflections to an R-value of 10.9%. The pseudo bodycentered unit cell contains two molecules, which are situated at the center at 0, 0, 0 and 1/2, 1/2, 1/2, respectively. The bodycentering is almost perfect for the six sulfur atoms, but does not involve the central ethane bonding, which implies that the sulfur atoms, that are connected by the centering, are bonded to different carbon atoms. The six sulfur atoms are staggered around the ethane C—C bond. The S—C—S angles of 113° are larger than the ideal tetrahedrane angles by the same amount by which the S—C—C angles of 105° are smaller. The ethane C—C distances are 1.59 and 1.56 Å respectively.
    Notes: Die Struktur des Hexakis(phenylthio)äthans wurde mit Röntgenmethoden bestimmt. Die Phasenbestimmung wurde mit der symbolischen Additionsmethode durchgeführt. Die Struktur wurde unter Benutzung von 1780 beobachteten Reflexen bis auf einen R-Wert von 10.9% verfeinert. Die pseudoinnenzentrierte Elementarzelle enthält zwei Moleküle, die um die Symmetriezentren in 0, 0, 0 bzw. 1/2, 1/2, 1/2 gelagert sind. Die Innenzentrierung ist nahezu genau für die sechs Schwefelatome, aber gilt nicht für die zentrale Äthanbindung, was zur Folge hat, daß die durch Zentrierung verbundenen Schwefelatome an verschiedene Kohlenstoffatome gebunden sind. Die sechs Schwefelatome sind gestaffelt um die Äthan-C—C-Bindung angeordnet. Die S—C—S-Winkel sind mit 113° etwas größer, die S—C—C-Winkel mit 105° um denselben Betrag kleiner als der Tetraederwinkel. Die Äthan-C—C-Abstände betragen 1.59 bzw. 1.56 Å.
    Additional Material: 5 Ill.
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    Benzothiazol-N-oxide, II. Über eine neue Synthese substituierter 2-Benzothiazolone (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 305-316 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzothiazole N-Oxides, II. New Synthesis of Substituted 2-BenzothiazolonesIn the presence of phosphoryl chloride, 2-carbamoylbenzothiazole N-oxides undergo a new intramolecular redox reaction to give 2-benzothiazolones. In two cases investigated, also 2-ethoxycarbonylbenzothiazole N-oxides undergo this rearrangement. The spectroscopic data are discussed.
    Notes: 2-Carbamoylbenzothiazol-N-oxide gehen in Gegenwart von Phosphoroxychlorid eine neuartige intramolekulare Redoxreaktion unter Bildung von 2-Benzothiazolonen ein. In zwei untersuchten Fällen unterliegen unterliegen auch 2-Äthoxycarbonylbenzothiazol-N-oxide dieser Umlagerung. Spektroskopische Daten werden diskutiert.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070136
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    Aromatische Sulfenylchloride, IX. Herstellung, Oxidation und spektroskopische Untersuchung von 1-substituierten (5-Tetrazolyl)aryldisulfiden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 299-304 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Sulfenyl Chlorides, IX. Preparation, Oxidation, and Spectroscopic Investigation of 1-Substituted 5-Tetrazolyl Aryl Disulfides1-Substituted 5-tetrazolyl mesityl disulfides were synthesized which on oxidation with hydrogen peroxide gave disulfide S2, S2-dioxides (thiolsulfonates). The structure of these as well as that of the 1-substituted 5-tetrazolyl p-tolyl disulfide S2, S2-dioxides synthesized earlier was elucidated by means of their i. r. and n. m. r. spectra. The supposed structures have been established by synthesis.
    Notes: Es wurden 1-substituierte (5-Tetrazolyl)mesityldisulfide hergestellt, welche zu Disulfid-S2, S2-dioxiden (Thiosulfonate) oxidiert wurden. Deren Struktur und die der früher hergestellten 1-substituierten (5-Tetrazolyl)p-tolyldisulfid-S2, S2-dioxide wurde anhand ihrer IR- und NMR-Spektren wahrscheinlich gemacht. Die angenommenen Strukturen wurden durch Synthese bewiesen.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070135
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    Lithio-1,3,5-trithiane Erzeugung, Umsetzung mit Elektrophilen und Verwendung als nucleophile Acylierungsmittel (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 367-379 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lithio-1,3,5-trithianes Generation in Solution, Reactions with Electrophiles, and Use in Nucleophilic Acylation1,3,5-Trithiane and 2-mono- as well as 2,4,6-trisubstituted trithianes are shown to be metallated by n-butyllithium in THF. Reaction of the lithio derivatives thus obtained with electrophiles leads to more highly substituted trithianes which in some cases can be isolated in a pure form. The n.m.r. spectra of the products at room temperature are described. Mercury(II)-assisted solvolysis of alkyltrithianes „liberates“ the most highly substituted carbon with formation of carbonyl compounds or their O-acetals. This completes a sequence of reactions which suggests use of lithiotrithianes as reagents for nucleophilic acylation. Advantages and disadvantages of this procedure compared to the dithiane method are discussed.
    Notes: 1,3,5-Trithian selbst sowie 2-mono- und 2,4,6- trisubstituierte Trithiane lassen sich mit n-Butyllithium in Tetrahydrofuran metallieren. Umsetzung der Lithiumderivate mit Elektrophilen führt zu höher substituierten Trithianen, die teilweise in reiner Form isoliert werden können. Die NMR-Spektren der erhaltenen Produkte bei Raumtemperatur werden beschrieben. Quecksilber(II)-assistierte Solvolyse von alkylierten Trithianen führt zu Carbonyl-verbindungen oder deren O-Acetalen unter „Herauslösung“ des höchstsubstituierten C-Atoms, was die Verwendung von Lithiotrithianen als nucleophile Acylierungsmittel ermöglicht. Vor- und Nachteile gegenüber der Dithian-Methode werden diskutiert.
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    URL: http://dx.doi.org/10.1002/cber.19741070202
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    Über die Abhängigkeit der Bindungslängen in einigen N,O-Dibenzoylhydroxylaminen von der Verdrillung der Carboxyl- und Hydroxamsäuregruppen gegen die Benzolkerne Die Kristallstrukturen von N,O-Dibenzoyl-(C14H11NO3), N,O-Bis(2- chlorbenzoyl)-(C14H9Cl2NO3), N-Benzoyl-O-p-toluoyl- (C15H13NO3) und N-Benzoyl-O-o-toluoylhydroxylamin (C15H13NO3) (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 398-413 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Dependence of the Bond-length in some N,O-Dibenzoylhydroxylamines on the Torsion of the Carboxylic and Hydroxamic Groups against the Benzene Nuclei. The Crystal Structures of N,O-Dibenzoyl-(C14H11NO3), N,O-Bis(2-chlorobenzoyl)-(C14H9Cl2NO3), N-BenzoylO-p-toluoyl- (C15H13NO3), and N-Benzoyl-O-o-toluoylhydroxylamines (C15H13NO3)The crystal structures of four N,O- dibenzoylhydroxylamines - 1: N,O-dibenzoylhydroxylamine (C14H11NO3), 2: N,O- bis(2-chlorobenzoyl)hydroxylamine (C14H9Cl2NO3), 3: N-Benzoyl-O-p toluoylhydroxylamine (C15H13NO3), 4: N-benzoyl-O-o- toluoylhydroxylamine (C15H13NO3) - have been determined by X-ray techniques, using direct methods for phase determination. The torsion angles ϕ of the C—C- bonds between the phenyl groups and the hydroxamic acid groups or the carboxylic groups, respectively, have been calculated. The values of the intramolecular distances of these bonds, plotted versus cos2 ϕ, can be approximated by a straight line. Extrapolating to ϕ = 90°, the pure sp2-sp2-C—C-single-bond is found to be 1.513 Å.
    Notes: Die Kristallstrukturen von vier N,O- Dibenzoylhydroxylaminen - 1: N,O-Dibenzoylhydroxylamin (C14H11NO3), 2: N,O -Bis(2-chlorbenzoyl)hyroxylamin (C14H9Cl2NO3), 3: N-Benzoyl-O-p-toluoylhydroxylamin (C15H13NO3), 4: N- Benzoyl-O-o-toluoylhydroxylamin (C15H13NO3) - wurden röntgenographisch unter Anwendung direkter Methoden zur Lösung des Phasenproblems bestimmt. Die C—C- Bindungslängen zwischen den Phenylgruppen einerseits und den Hydroxamsäure- bzw. Carboxylatgruppen andererseits lassen sich als Funktion der Verdrillungswinkel ϕ dieser Bindung durch eine Gerade darstellen, wenn man die Bindungslängen gegen cos2 ϕ aufträgt. Der reine sp2-sp2-C—C- Einfachbindungsabstand (ϕ = 90°) ist danach 1.513 Å.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19741070205
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    Eine neue Synthese für Tetracyclo[3.3.0.02,8.04,6]octan-3-one durch intramolekulare [2π + 2 σ]-Thermocycloaddition (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 680-685 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Synthesis of Tetracyclo[3.3.0.02.8.04.6]octan-3-ones by Intramolecular Thermal [2π + 2σ]-CycloadditionThe synthesis of the tetracyclooctanone 19 by thermolysis of the tricyclic acetal 15 and subsequent removal of the acetal group is described. Thus, a third synthetic access to this system is now available. The reaction involves the cycloaddition of a thermally ring-opened cyclopropane to a double bond.
    Notes: Die Synthese des Tetracyclooctanons 19 durch Thermolyse des tricyclischen Acetals 15 und anschließende Entacetalisierung wird beschrieben. Damit bietet sich ein dritter synthetischer Zugang zu diesem System an. Die Reaktion beinhaltet die Cycloaddition eines thermisch ringgeöffneten Cyclopropans an eine Doppelbindung.
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    URL: http://dx.doi.org/10.1002/cber.19741070240
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    Notiz zur Alkylierung des Dithizons (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 717-720 
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    ISSN: 0009-2940
    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/cber.19741070247
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    Notiz zur thermischen Valenzisomerisierung des Norpinens (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 731-734 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070251
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    Pteridine, LX. Synthese und Oxidationsverhalten von 7,8-Dihydroxanthopterinen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 785-795 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, LX. Synthesis and Autoxidation of 7, 8-DihydroxanthopterinsThe synthesis of 7,8-dihydroxanthopterin (18) and of various N- and C-methyl derivatives (19-27, 30) is described. Their pKa values and u.v. spectra have been determined and the behaviour during autoxidation has been investigated. The monoanions are subject to autoxidation which is catalysed strongly by ammonia and primary amines. A mechanism for the autoxidation is discussed in which the existence of various intermediates is based on the oxidative behaviour of differently blocked N- und C-methyl derivatives.
    Notes: Die Synthese des 7,8-Dihydroxanthopterins (18) und verschiedener N- und C-Methyl-Derivate (19-27, 30) wird beschrieben. Ihre pKa-Werte und UV-Spektren werden bestimmt und ihr Autoxidationsverhalten untersucht. Die Monoanionen unterliegen der Autoxidation, welche durch Ammoniak und primäre Amine stark katalysiert wird. Ein Mechanismus wird diskutiert und verschiedene Zwischenprodukte anhand von blockierten N- und C-Methyl-Derivaten wahrscheinlich gemacht.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19741070305
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    Die Kristall- und Molekülstruktur des 6,6-Bis(dimethylamino)fulvens (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 832-837 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structure of 6,6-Bis(dimethylamino)fulvene6,6-Bis(dimethylamino)fulvene crystallizes in the space group Pn21a, the lattice constants being ao = 13.344 Å, bo = 7.844 Å and co = 9.438 Å. The structure has been solved by superposition and by direct methods in the space group Pnma. The structure was refined by block-diagonal-least-squares to R = 0.037.
    Notes: Das 6,6-Bis(dimethylamino)fulven kristallisiert in der Raumgruppe Pn21a mit den Gitter-konstanten ao = 13.344 Å, bo = 7.844 Å und co = 9.438 Å. Die Struktur wurde durch Superposition und anschließende Resymmetrisierung der Patterson-Funktion und mit direkten Methoden in der zentrosymmetrischen Obergruppe Pnma gelöst.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19741070309
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    Brom-Lithium-Austausch an Vinyl- und Aryl-bromiden mit tert-Butyllithium Zur Ringerweiterung über Dibromcarbenaddukte (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 847-853 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bromine/Lithium Exchange in Vinyl and Aryl Bromides with tert-Butyl Lithium. On the Ring Enlargement via Dibromocarbene AdductsTwofold molar excess of tert-butyl lithium replaces vinylic and arylic bromine by lithium. The tert-butyl bromide formed is dehydrohalogenated rapidly to isobutene by tert-butyl lithium even at very low temperatures. Transformation of 1-bromo-1-cyclooctene and - cyclononene via the lithium derivatives to vinyl thioethers 1d, e, and i in high yields opens up a simple alternative route from olefin dibromocarbene adducts to ring enlarged ketones. The bromobenzenes 2a and 3a reveal that the Br/Li-exchange described here is not accompanied by arine formation; it is feasible even in the presence of sensitive benzylic CH2-groups as present in 3.
    Notes: Vinylisch und an Aromaten gebundenes Brom läßt sich quantitativ mit zweifachem molarem Überschuß an tert-Butyllithium gegen Lithium austauschen. Das entstehende tert-Butylbromid wird selbst bei tiefen Temperaturen von tert-Butyllithium rasch zu Isobuten dehydrohalogeniert. Die Überführung von 1-Brom-1-cycloocten und -1-cycloneone in Vinylthioäther 1d, e und i über die Lithiumderivate ist in hoher Ausbeute möglich und eröffnet einen einfachen Weg von Dibromcarbenaddukten an Olefine zu ringerweiterten Ketonen. Am Beispiel der Brombenzole 2a und 3a wird gezeigt, daß der hier beschriebene Br/Li-Austausch nicht von Arin-Bildung begleitet und auch in Gegenwart der empfindlichen benzylischen CH2-Gruppe von 3 durchführbar ist.
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    Über N-Vinylimidazolcarbonsäureester (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 892-897 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-VinylimidazolecarboxylatesN-Vinylation of imidazolecarboxylates with vinyl acetate leads to the formation of the N-vinylimidazoles 3a, 3b, 6, 8a, 8b und 9a. The structures are determined by mass and n.m.r. spectra. 3a, 6, 8a are polymerizable.
    Notes: Durch N-Vinylierung von Imidazolcarbonsäureestern mit Vinylacetat werden die N-Vinylimidazole 3a, 3b, 6, 8a, 8b und 9a, erhalten. Die Strukturen werden mit Hilfe von NMR-und Massen-Spektren gesichert. 3a, 6, 8a und 8bsing polymerisationsfähig.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070316
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    Heterocyclisierungen, XIII. Neue polycyclische Pyrimidine mit Brückenkop-Stickstoff (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 929-936 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclizations, XIII. New Polycyclic Pyrimidines with Bridge-Head NitrogenThe base-catalized condensation of 2,3,3-trimethyl-3H-benz[f]indole (9) with dielectrophilic iso(thio)cyanates to polycyclic pyrimidines with bridge-head nitrogen (11, 15, 16) in most cases involves preliminary formation of 1: 2 adducts followed by elimination of diacylamides. Contrary to this the less nucleophilic 2,3,3-trimethyl-3H-pyrrolo [2,3-b]pyridine (20) affords the analogue pyrimidines by intermediacy of 1:1 adducts and elimination of water or ethanol solely.
    Notes: Die basenkatalysierte Kondensation von 2,3,3-Trimethyl-3H-benz[f] indol (9) mit dielektrophilen Iso(thio)cyanaten zu polycyclischen Pyrimidinen mit Brückenkopf-Stickstoff (11, 15, 16) verläft meist über die Bildung von 1:2-Addukten als Zwischenstufe und Eliminierung von Diacylamiden. Dagegen liefert das weniger nucleophile 2,3,3-Trimethyl-3 H-pyrrolo[2.3-b]-pyridin (20) analoge Systeme (22, 23) ausschließlich über 1: 1-Addukte und Eliminierung von Wasser bzw. Äthanol.
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    URL: http://dx.doi.org/10.1002/cber.19741070321
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    Alkaloide aus Rhamnaceen, XVIII. Amphiin-F, -G und -H, weitere Peptidalkaloide aus Ziziphus amphibia A. Cheval (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 686-697 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkaloids from Rhamnaceae, XVIII. Amphibine-F, -G and -H, further Peptide Alkaloids from Ziziphus amphibia A. Cheval.From the complex mixture of crude alkaloids from Ziziphus amphibia A. Cheval., in addition to the already described Amphibines-A, -B, -C, -D and -E, three further peptide alkaloids Amphibine-F, -G and -H have been isolated and their structures elucidated (1-3). Amphibine-F and -G (1, 2) belong to the class of cyclic peptide alkaloides having a fourteen-membered ring system made up from trans-3-hydroxyproline, p-hydroxystyrylamine and an α-aminoacid. Amphibine-H (3) has a thirteen-membered ring system formed from 5-hydroxy-2-methoxystyrylamine and the aminoacids trans-3-hydroxyproline and phenylalanine.
    Notes: Aus dem komplexen Rohbasengemisch von Ziziphus amphibia A. Cheval. wurden neben den bereits beschriebenen Amphibinen-A, -B, -C, -D und -E drei weitere Peptidalkaloide Amphibin-F, -G und -H isoliert und in der Struktur geklärt (1-3). Die Amphibine-F und -G (1, 2) zählen zu den Cyclopeptidalkaloiden mit 14 gliedrigem Ringsystem aus trans-3-Hydroxyprolin, p-Hydroxystyrylamin und einer α-Aminosäure. Das Amphibin-H (3) weist ein 13 gliedriges Ringsystem auf, das aus den Aminosäuren trans-3-Hydroxyprolin und Phenylatanin sowie aus 5-Hydroxy-2-methoxystyrylamin gebildet wird5).
    Additional Material: 3 Ill.
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    Über die Darstellung neuer Chlorformamidine (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 698-705 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Preparation of New ChloroformamidinesAction of phosphine/carbon tetrachloride or dichlorotriphenylphosphorane on N,N,N′-trisubstituted ureas leads to the formation of even such chloroformamidines which are not or only difficultly obtainable by the conventional methods. The spectroscopic and analytic data of the new compounds are given.
    Notes: Durch Einwirkung von Phosphin/Tetrachlorkohlenstoff oder von Dichlortriphenylphos-phoran auf N,N,N′-trisubstituierte Harnstoffe können auch solche Chlorformamidine dargestellt werden, die nach den bisherigen Methoden nicht oder nur schwer zugänglich sind. Die spektroskopischen und analytischen Daten der neuen Verbindungen sind angegeben.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070242
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    Notiz über eine verbesserte Methode zur spezifischen Freisetzung oder Acylierung primärer Hydroxylgruppen ausgehend von pertrimethylsilylierten Polyolen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 721-724 
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    ISSN: 0009-2940
    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/cber.19741070248
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  • 175
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    Notiz zur transanularen n/π-Wechselwirkung in 2,5-Dihydrofuran (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 725-726 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19741070249
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  • 176
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    Heterosubstituierte Fulvene, VIII. Indeno[2,1-c]-1,2-dithiole, eine Gruppe neuer Pseudoazulene (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 739-744 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Fulvenes, VIII. Indeno[2,1-c]-1,2-dithioles, a Group of New PseudoazulenesAcylation of 2-pyrrolidinoindene (4) with carboxylic acid chlorides and subsequent hydrolysis leads to the 1-acyl-2-indanones 6, which have been condensed with diacetyl disulfide in aequous perchloric acid/acetic acid to afford the 8H-indeno[2,1-c]-1,2-dithiolium-perchlorates 7. These are deprotonated with N-ethyldiisopropylamine to yield the indeno[2,1-c]-1,2-dithioles 10, a group of new pseudoazulenes.
    Notes: Acylierung von 2-Pyrrolidinoinden (4) mit Carbonsäurechloriden und nachfolgende Verseifung liefert die 1-Acyl-2-indanone 6, die mit Diacetyldisulfid in wäßriger Perchlorsäure, Eisessig zu den 8H-Indeno[2,1-c]-1,2-dithiolium-perchloraten 7 kondensieren. Letztere lassen sich durch N-Äthyldiisopropylamin zu den Indeno[2,1-c]-1,2-dithiolen 10, einer Gruppe neuer Pseudoazulene, deprotonieren.
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    Stereochemie und reaktives Verhalten tetrahalogenierter 2,3-Diazabicyclo[3.2.0]hept-2-ene und Bicyclo[2.1.0]pentane (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 759-770 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry and Reactivity of Tetrahalogenated 2,3-Diazabicyclo[3.2.0]hept-2-enes and Bicyclo [2.1.0] pentanesThe addition of diazoalkanes to tetrahalogenated cyclobutenes 1-3 leads to 6,6,7,7-tetrahalo-2,3-diazabicyclo[3.2.0]hept-2-enes 4-8, the structure and stereochemistry of which are determined by means of n. m. r. spectroscopy. Thermal decomposition of 4, 5, and 8 in boiling toluene affords the tetrahalobicyclo[2.1.0]pentanes 9, 10, and 12 in good yields. Under the same conditions 7 decomposes in a stereospecific manner to form 11 and small amounts of 13. Sodium methoxide converts 9-11 into the cyclobutenes 14 and 15. Under the influence of sulfuric acid 10 forms the cyclobutenedione 16 or a mixture of cyclopentenones 18, 19 depending on the reaction conditions.
    Notes: Addition von Diazoalkanen an die tetrahalogenierten Cyclobutene 1-3, führt zu 6,6,7,7-Tetrahalogeno-2,3-diazabicyclo[3.2.0]hept-2-enen 4-8, deren Konstitution und Stereochemie auf NMR-spektroskopischem Weg ermittelt wurde. Durch thermische Zersetzung der Bicyclen 4,5 und 8 in siedendem Toluol erhält man in guten Ausbeuten Tetrahalogenobicyclo-[2.1.0]pentane 9,10 und 12. Unter gleichen Bedingungen entstehen aus 7 in stereospezifischer Reaktion 11 sowie geringe Mengen des Cyclobutens 13. Mittels Natriummethylat werden die Bicyclen 9-11 zu den Cyclobutenen 14, 15 abgebaut; unter dem Einfluß von konz. Schwefelsäure entsteht aus 10 je nach Reaktionsbedingungen das Cyclobutendion 16 bzw. ein Gemisch der Cyclopentenone 18 und 19.
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    Ein Eintopfverfahren zur Überführung von Aldehyden in Nitrile (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1221-1227 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conversion of Aldehydes into Nitriles without Isolation of IntermediatesAldehydes are converted into nitriles without isolation of the intermediates by treating their oximes with carbodiimides in the presence of copper(II)ions and triethylamine. The entire process requires 3 hours at room temperature; it is unsuccessful if the oxime does not form or is consumed by competition reactions.
    Notes: Aldehyde können ohne Isolierung von Zwischenprodukten in Nitrile übergeführt werden, indem ihre Oxime in Gegenwart von Kupfer(II)-Ionen und Triäthylamin mit Hilfe von Carbodiimiden dehydratisiert werden. Der gesamte Prozeß erfordert bei Raumtemperatur durchweg 3 Stunden. Das Verfahren versagt, wenn die Oximbildung gestört ist oder das Oxim Konkurrenzreaktionen eingeht.
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    URL: http://dx.doi.org/10.1002/cber.19741070418
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    Synthese und Reaktivität von Silicium-Übergangsmetallkomplexen, V. Die modifizierte Alkalisalz-Eliminierungsmethode  -  ein genereller Weg zu Komplexen mit Silicium-Übergangsmetall-Struktureinheiten (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 979-995 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactivity of Silicon Transition Metal Complexes, V. The Modified Alkali Salt Elimination Method  -  a General Procedure for the Synthesis of Silicon Transition Metal CompoundsThe heterogeneous reaction of the sodium carbonylmetallates Na[Fe(CO)2π-C5H5], Na[M(CO)3π-C5H5] (M=Mo, W), and Na[Mn(CO)5] with various halo- and organohalosilanes leads to the formation of the corresponding silyl complexes. The new compounds are characterized by spectroscopy and the chemical properties are described. The results of a decomposition study of the trimethylsilyl-VIB transition metal complexes are discussed in connection with former synthetic experiments. Exchange reactions of these species with heterosiloxanes can be used for a qualitative estimation of relative metal-metalloid bond reactivity.
    Notes: Die Umsetzung der komplexen Metallate Na[Fe(CO)2π-C5H5], Na[M(CO)3π-C5H5] (M=Mo, W) und Na[Mn(CO)5] mit verschiedenen Halogen- und Organohalogensilanen führt in heterogener Reaktion zu den Silylkomplexen dieser Metalle. Die neuen Verbindungen werden spektroskopisch charakterisiert und ihre chemischen Eigenschaften beschrieben. Die Ergebnisse einer Zerfallsstudie der Trimethylsilyl-VIB-Übergangsmetallkomplexe werden im Zusammenhang mit früheren Syntheseversuchen diskutiert. Der Verlauf von Austauschreaktionen der gleichen Verbindungen mit Heterosiloxanen (Ge, Sn) ermöglicht eine qualitative Abschätzung der Reaktivität der Metall- Metalloideinheit.
    Additional Material: 7 Tab.
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    Untersuchungen an 4-Pyronen, 51 Aminoalkylierung von Chromonen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1057-1065 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on 4-Pyrones, 51. Aminoalkylation of ChromonesThe aminoalkylation of 2-methylchromones (1b, e and 2b, c) leads to the formation of benzopyrano[3.2-c]pyridinium chlorides (9a-d and 11a-e).
    Notes: Die Aminoalkylierung von 2-Methylchromonen (1b, e sowie 2b, c) führt zu Benzopyrano-[3.2-c]pyridinium-chloriden (9a-d sowie 11a-e).
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070334
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    Berichtigung (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1069-1069 
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    ISSN: 0009-2940
    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/cber.19741070336
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    Massenspektrometrische Untersuchung von Amiden, VII Intramolekulare Wechselwirkungen bifunktioneller Gruppen bei der elektronenstoßinduzierten Fragmentierung von Piperididen und Piperideiden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1081-1091 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometric Investigation of Amides, VII. Intramolecular Interactions of Bifunctional Groups in the electron Impact Induced Fragmentation of Piperidides and PiperideidesThe activation energy ∊ for the electron impact induced splitting of the N-carbonyl bond in bifunctional amides is estimated. A clear correlation is shown of ∊ with the ring size of the transition state and the nucleofuge or nucleophilic properties of the nitrogen groups. Furtheron by means of [D]-labelled model compounds selective hydrogen migrations have been established.
    Notes: Die Aktivierungsenergie ∊ für die elektronenstoßinduzierte Spaltung der N-Carbonylbindung bifunktioneller Amide wird bestimmt. Es ergibt sich ein klarer Zusammenhang von ∊ mit der Ringgröße des Übergangszustandes und den nucleofugen bzw. nucleophilen Eigenschaften der Stickstoffgruppen. Ferner werden mit Hilfe [D]-markierter Modellverbindungen selektive Wasserstoffübertragungen nachgewiesen.
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    URL: http://dx.doi.org/10.1002/cber.19741070403
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    Über die Natur des Benzonorbornen-2-yl-Kations, II. Solvolyse von Isopropyliden-substituierten Benzonorbornen-2-yl-Estern (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1126-1135 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Nature of Benzonorbornen-2-yl Cations, II. Solvolysis of Isopropylidene-substituted benzonorbornen-2yl EstersThe 2-epimeric at C-7 and C-3 substituted benzonorbornenols 4a, 6a, 7a and 8a are synthesized. The rate of solvolysis of the tosylates 4b and 6b is measured in acetic acid, that of the 3,5-dinitrobenzoates 7b and 8b in 90% dioxane. The solvolysis products are determined in 80% acetone puffered with 2,6-lutidine. The epimeric 7-isopropylidene derivatives 4b and 6b solvolyse by a different mechanism; the exo derivative 4b reacts exclusively with assistance of the benzene ring, the endo compound by participation of the homoallylic double bond. The epimeric 3-isopropylidene derivatives 7b and 8b solvolyse to a common intermediate allylic ion 10. The kexo/kendo ratio is reduced to 9 due to the presence of this neighbouring group, which is a measure of the steric factor in the secondary benzonorbornen-2-yl system.
    Notes: Die epimeren Benzonorborneole 4a und 6a sowie 7a und 8a werden synthetisiert. Die Solvolysegeschwindigkeit der Tosylate 4b und 6b wird in Eisessig, die der 3,5-Dinitrobenzoate 7b und 8b in 90 proz. Dioxan gemessen. Die Reaktionsprodukte werden in 80 proz., mit 2,6-Lutidin gepuffertem Aceton bestimmt. Die epimeren 7-Isopropyliden-Verbindungen 4b und 6b solvolysieren nach einem unterschiedlichen Mechanismus; die exo-Verbindung 4b reagiert ausschließlich mit Beteiligung des Aromaten, die endo-Verbindung 6b mit der der Isopropyliden-Doppelbindung. Die epimeren 3-Isopropyliden-Verbindungen 7b und 8b solvolysieren zu einem gemeinsamen Allyl-Ion 10 als produktbestimmende Zwischenstufe. Das Verhältnis kexo/kendo wird durch diese Nachbargruppe auf 9 herabgesetzt, welches ein Maß für den sterischen Anteil des sekundären Benzonorbornen-2-yl-Systems ist.
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    Übergangsmetall-Carben-Komplexe, LXXII. Spaltung der Doppelbindung von 1-Vinyl-2-pyrrolidon und β-substituierten 1-Vinylpyrrolidonen bei der Umsetzung mit Pentacarbonyl(methoxyphenylcarben)chrom(0) (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1156-1161 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbene Complexes, LXXII. Cleavage of the Double Bond of 1-vinyl-2-pyrrolidone and β-Substituted 1-Vinylpyrrolidones by Reaction with Pentacarbonyl(methoxyphenylcarbene)chromium(0)Pentacarbonyl(methoxyphenylcarbene)chromium(0) reacts with 1-vinyl-2-pyrrolidone to form α-methoxystyrene by transfer of a methylene group to the carbene moiety. The origin of the transfered methylene group is proved by using methylsubstituted 1-vinylpyrrolidones. The reaction products are identified by their i.r., 1H n.m.r., and mass spectra. As reaction mechanism a cyclic transition state is proposed, which explains the breaking and following formation of a double bond analogously to the heterolytic fragmentation according to Grob.
    Notes: Bei der Umsetzung von Pentacarbonyl(methoxyphenylcarben)chrom(0) mit 1-Vinyl-2-pyrrolidon entsteht durch Übertragung einer Methylengruppe auf den Carben-Rest α-Meth-oxystyrol. Durch Einsetzen methylsubstituierter 1-Vinylpyrrolidone wird die Herkunft der übertragenen Methylengruppe bewiesen. Die Produkte werden anhand ihrer IR-, 1H-NMR- und Massenspektren identifiziert. Als Reaktionsmechanismus wird ein cyclischer Übergangszustand vorgeschlagen, der - in Analogie zur heterolytischen Fragmentierung nach Grob - die Spaltung und Neuknüpfung einer Doppelbindung erklärt.
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    Photochemische Reaktionen, XXIII. Über Photocyclisierungen von 9-Benzylidenxanthenen und 9-Benzylidenthioxanthenen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1207-1212 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Reactions, XXIII. The Photocyclisation of 9-Benzylidenexanthenes and 9-BenzylidenethioxanthenesDehydrocyclisations of the 9-benzylidenexanthenes in u.v. or sunlight (6a-6d→7a-7d) were realized. 6 may be considered as derived from stilbene, and 7 as derived from phenanthrene. Therefore the photoprocess 6→7 is analogue to the photoprocess cis-stilbene → phenanthrene.
    Notes: Dehydrocyclisierungen der Benzylidenxanthene im UV-oder Sonnenlicht (6a-6b→7a-7d) wurden durchgeführt. Da 6 als substituierte cis-Stilbene und 7 als substituierte Phenanthrene aufgefaßt werden können, liegen Analogiereaktionen zu dem Photoprozeß cis-Stilben → Phenanthren vor.
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    URL: http://dx.doi.org/10.1002/cber.19741070416
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    Darstellung und dynamisches Verhalten von Mono- cyclopentadienylarsinen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1228-1234 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Dynamic Behaviour of Mono-cyclopentadienylarsinesMono-cyclopentadienylarsines (3a-e) are synthesized by the reaction of cyclopentadienyl-trimethylsilane (1) or cyclopentadienyllithium (5) with the halogenoarsines 2a-e. They are very sensitive against air and moisture and thermally unstable. The cp-ligands are σ-bonded; the molecules have a fluxional structure. The rapidity of the degenerate metallotropic rearrangements is influenced by the other ligands on the arsenic atom.
    Notes: Mono-cyclopentadienylarsine (3a-e) werden durch Umsetzung von Cyclopentadienyl-trimethylsilan (1) oder Cyclopentadienyllithium (5) mit den Halogenarsinen 2a-e dargestellt. Sie sind äußerst luft- und feuchtigkeitsempfindlich und thermisch instabil. Es liegen σ-gebundene Cp-Liganden und Moleküle mit fluktuierender Struktur vor. Die Geschwindigkeit der entarteten metallotropen Umlagerungen wird durch die anderen Liganden am Arsenatom beeinflußt.
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    URL: http://dx.doi.org/10.1002/cber.19741070419
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    Enhydrazine, 9. 1-Alkyl-3-hydroxypyrazole aus Hydrazonen oder Hydrazinen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1318-1328 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enehydrazines, 9. 1-Alkyl-3-hydroxypyrazoles from Hydrazones or HydrazinesReaction of dimethyl acetylendicarboxylate with hydrazinen oder Alkyl hydrazonen gives the methyl 1-alkyl-3-hydroxy-5-pyrazolecarboxylats 9 and 13a-e, subsequent saponification and decarboxylation gives the 1-alkyl-3-hydroxypyrazoles 11 and 15a-e. The cyclization of 13f to lactone 19a is a structure proff. Starting from benzaldehyde hydrazones, 2-pyrazoline-4,5-dicarboxylic esters are the main products.
    Notes: Durch Umsetzung von Acetylendicarbonsäure- dimethylester mit Hydrazinen oder Alkyl-hydrazonen erhält man die 1-Alkyl-3-hydroxy-5-pyrazolcarbonsäure-methylester 9 und 13a-e, durch Verseifung und Decarboxylierung hieraus die 1-Alkyl-3-hydroxypyrazole 11 und 15a-e. Die Cyclisierung von 13f zum Lacton 19a ist strukturbeweisend. Bei Verwendung von Benzaldehyd-hydrazonen entstehen hauptsächlich 2-Pyrazolin-4,5- dicarbonsäureester.
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    Elektrophile Addition von Dischwefeldichlorid an Alkine, 3. Umsetzung asymmetrisch substituierter Alkine mit Dischwefeldichlorid (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1334-1343 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrophilic Addition of Disulfur Dichloride to Alkynes, 3. Reaction of Asymmetric of Asymmetric Substituted Alkynes with Disulfur DichlorideDisulfur dichloride adds to the triple bond of asymmetric substituted alkynes to afford vinyl sulfides, which are constitution isomers. Substituents R with a negative I-effect yield „Markownikof“ products whereas a positive I-effect leads to the formation of „anti-Markownikoff“ products. The addition is always trans. The obtained sulfides are oxidized with H2O2 in glacial acetic acid to yield the corresponding sulfones.
    Notes: Die bei der elektrophilen Addition von Dischwefeldichlorid an asymmetrische Alkine gebildeten Vinylsulfide sind Konstitutions -Isomere. Substituenten R mit negativem Induktionseffekt führen zu „Markownikoff“-Produkten, während ein positiver I-Effekt „anti-Markownikoff“-Orientierungen liefert. In allen Fällen erfolgt eine trans-Addition. Die erhaltenen Sulfide werden nach der Oxidation mit Wasserstoffperoxid/Eisessig als Sulfone isoliert.
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    Oxidative Additionsreaktionen von Nitroalkanen an Tetrakis(triphenylphosphin)platin(0) (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1371-1379 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Addition Reactions of Nitroalkanes to Tetrakis(triphenylphoshine)platinum(0)The oxidative addition of nitromethane to Pt(PPh3)4 in polar protic solution provides a convenient and safe method for the preparation of trans-(Ph3P) 2Pt(CNO)2 Pt(CNO2)(3). From Pt(PPh3)4 and nitromethane or 2-nitropropane cis-(Ph3P) 2Pt(NO2)2 (2) is obtained. The reactions of Pd(PPh3)4 or Rh(PPh3)2CO)Cl with CH3NO2 or some of its derivatives afford isocyanato compounds. Formaidoxime hydrochloride reacts with Pt(PPh3)4 to give trans-(Ph3P)2Pt-(CN)Cl (4).
    Notes: Die oxidative Addition von Nitromethan an Pt(PPH3)4 in polarem, protischem Medium liefert gefahrlos und in guter Ausbeute trans-(Ph 3P)2Pt(CNO)2 (3). Aus Pt(PPh3)4 und Nitromethan bzw. 2-Nitropropan wird cis-(Ph3P)2Pt(NO2)2 (2) erhalten. Die Umsetzungen von Pd(PPh 3)4 oder Rh(PPh3)2(CO)Cl mit Nitromethan oder Methylnitrolsäure führen zu Isocyanatoverbindungen. Formaldoxim-hydrochlorid reagiert mit Pt(PPh 3)4 zu trans-(Ph3P)2Pt(CN)Cl (4).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070434
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    Botrydial, ein Sesquiterpen-Antibiotikum aus der Nährlösung des Pilzes Botrytis cinerea (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1720-1730 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Botrydial, a Sesquiterpene Antibiotic from the Culture Solution of the Fungus Botrytis cinereaThe antibiotic botrydial (3) and its dihydro derivative (1) were isolated from the culture solution of the fungus Botrytis cinerea. Their structural formulas were elucidated by means of a series of chemical transformations together with the application of spectroscopic methods, especially a detailed analysis of the n.m.r. spectra. The basic skeleton of botrydial is a bicyclic, non-isoprenoid sesquiterpene system.
    Notes: Aus der Nährlösung des Pilzes Botrytis cinerea wurden das antibiotisch wirksame Botrydial (3) und sein Dihydroderivat (1) isoliert. Durch eine Folge chemischer Umwandlungen, verbunden mit der Anwendung spektroskopischer Methoden, insbesondere einer detaillierten Analyse der NMR-Spektren, wurden ihre Konstitutionsformeln abgeleitet. Botrydial liegt ein bicyclisch nicht-isoprenoides Sesquiterpenskelett zugrunde.
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    Natürlich vorkommende Terpen-Derivate, XXXIV. Notiz über die Synthese des Furanoeremophilans (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1767-1768 
    Details
    ISSN: 0009-2940
    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/cber.19741070535
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    Natürlich vorkommende Terpen-Derivate, XXXVI. Synthese von 8-Hydroxybrickellol und Dehydronerol-isovalerat (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1773-1776 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occuring Terpene Derivatives, XXXVI. Synthesis of 8-Hydroxybrickellol and Dehydronerol isovalerateThe sesquiterpene 7 named 8-hydroxybrickellol as well as the isovalerate of dehydronerol (14) have been synthesized.
    Notes: Das 8-Hydroxybrickellol benannte Sesquiterpen 7 sowie der Isovaleriansäureester des Dehydronerols (14) werden synthetisch dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070602
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    Die Reaktionen von Phosphor-yliden mit überschüssigem Alkohol und mit Alkanthiol (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1420-1427 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reactions of Phosphorus Ylids with Excess Alkohol and AlkanethiolThe alkoxytetraalkylphosphoranes of the formula R4POR′, obtained from equimolar amounts of ylid and alkohol, which contain pentacoordinate phosphorus atoms, are converted into ionic products (1 - 7) by addition of excess alkohol. In these compounds phosphonium cations R4P⊕ are accompanied by hydrogen-bonded hydrogenalkoholate anions of the types [R′O…H…OR′]⊖, [H2(OR′)3]⊖, and [H3(OR′)4]⊖. This structure is proposed on the basis of n.m.r., i.r., and Raman-spectroscopic data. With ylids and alkanethiols only salt-like products R4P⊕RS⊖ are formed.
    Notes: Die aus äquimolaren Mengen von Yliden und Alkoholen zugänglichen, kovalent gebauten Alkoxytetraalkylphosphorane R4POR′ mit pentakoordinierten Phosphoratomen werden durch Addition von überschüssigem Alkohol in die Produkte 1 - 7 verwandelt, in welchen Phosphonium-Kationen R4P⊕ den wasserstoffbrückenverknüpften Hydrogenalkoholat-Anionen vom Typ [R′O…H…OR′]⊖, [H2(OR′)3]⊖ und [H3(OR′)4]⊖ gegenüberstehen. Der Strukturvorschlag stützt sich auf NMR-, IR- und Raman-spektroskopische Untersuchungen. Aus Yliden und Alkanthiolen entstehen nur die salzartigen Phosphonium-alkanthiolate R4 P⊕RS⊖.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070503
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    Umlagerungen 3-substituierter Norbornandiazonium-Ionen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1472-1482 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements of 3-Substituted Norbornanediazonium Ions3-Oxonorbornane-2-endo-diazonium ions (1), generated by acid-catalyzed decomposition of 3-diazonorcamphor (5) in alcoholic solutions, produce derivatives of endo-bicyclo[2.2.1]heptane 3 and bicyclo [3.1.1]heptane derivatives 4, varying with the nucleophilicity of the solvent. This suggests the 7-bridged ion 2 as intermediate, which plays also an important part in the deamination of 3,3-dimethoxynorcamphor tosylhydrazone (16) in alkaline solutions as shown by the formation of 3 and 4. In the alkaline deamination of 3,3- dimethoxy-5-norbornen-2-on tosylhydrazone (32) in methanol the homoallylic ion 34 is dominating.
    Notes: 3-Oxonorbornan-2-endo-diazonium-Ionen (1), erzeugt durch sauer katalysierte Zersetzung von 3-Diazonorcampher (5) in alkoholischen Lösungen, ergaben endo-Bicyclo[2.2.1]heptan-3 und Bicyclo[3.1.1]heptan-Derivate 4, deren Menge von der Nucleophilie des eingesetzten Lösungsmittels abhängig ist. Dies läßt das 7-verbrückte Ion 2 als Zwischenstufe vermuten, welches auch bei der Desaminierung des 3,3-Dimethoxynorcampher-tosylhydrazons (16) in alkalischen Lösungen eine entscheidende Rolle spielt, wie die Bildung der Produkte 3 und 4 beweist. Bei der alkalischen Desaminierung des 3,3-Dimethoxy-5-norbornen-2-on-tosylhydrazons (32) in Methanol ist jedoch die Homoallylumlagerung zum Kation 34 produkt-bestimmend.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19741070507
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    Derivate des Guanidins mit N—S- und N—P-Bindungen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1536-1544 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Derivatives of Guanidines Containing Phosphorus and SulfurN-Chloroguanidines 1 react with tervalent phosphorous compounds or with sulfides to yield N-guanylphosphine imidium (3) or sulfimidium salts (9). Dehydrohalogenation gives the respective N-guanyl phosphine imides and sulfimides. The structure and reactions of these compounds are discussed.
    Notes: Die Umsetzung von N-Chlorguanidinen 1 mit tervalenten Phosphorverbindungen sowie Sulfiden führt zu N-Guanylphosphinimidium- (3) bzw. -sulfimidium-Salzen (9). Durch Dehydrohalogenierung werden die entsprechenden Phosphinimide und Sulfimide erhalten. Die Eigenschaften dieser Verbindungen - insbesondere die Struktur-und Bindungsverhältnisse-sowie ihre Reaktionen werden untersucht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070514
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    Konformationsanalyse, III. exo-Anomerer Effekt und Circulardichroismus von Glycopyranosylaziden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1568-1578 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational Analysis, III. exo-Anomeric Effect and Circular Dichroism of Glycopyranosyl AzidesTetra-O-acetyl-aldopentopyranoses and penta-O-acetyl-aldohexopyranoses react readily with trimethylsilyl azide in the presence of BF3 or SnCl4 to afford the corresponding glycosyl azides 1a - 11 (table 1). Only the anomeric glycosyl azide having the azido group „trans“ to the 2-acetoxy group is obtained in each case. The polarization of the Cl—Nx and Nx—Nz bonds in glycosyl azides is such that in both cases the dipole is directed toward Nx. It can be deduced that glycosyl azides, like methyl glycopyranosides, should exhibit an exo-anomeric effect which strongly favors the conformers 9 and 12. The application of the azide-octant rule predicts a negative Cotton effect for the α-D-glycosyl azide 12 and a positive effect for the β-D-glycosyl azide 9. Circular dichroism measurements are in good agreement with these predictions, indicating the operation of an exo-anomeric effect in the glycosyl azides.
    Notes: Tetra-O-acetyl-pentopyranosen und Penta-O-acetyl-hexopyranosen setzen sich mit Trimethylsilylazid bei Gegenwart von BF3 oder SnCl4 leicht zu den entsprechenden Glycosylaziden 1a bis 11 um (Tab. 1). Es entsteht stets nur das anomere Glycosylazid, in dem die Azidogruppe und 2-OAc „trans“ zueinander angeordnet sind. In Glycosylaziden sind die Bindungen Cl—Nx und Nx—Nz in der Weise polarisiert, daß der Dipol in beiden Fällen zum Nx weist. Hieraus wird abgeleitet, daß bei Glycosylaziden wie bei Methylglycosiden ein exo-anomerer Effekt wirksam sein sollte, der die Konformeren 9 und 12 stark bevorzugt. Die Anwendung der Azid-Oktantenregel sagt für das α-D-Glycosylazid 12 einen negativen, für das β-D-Glycosylazid 9 einen positiven Cotton-Effekt voraus. Messungen des Circular-dichroismus stimmen mit diesen Voraussagen gut überein, was für einen exo-anomeren Effekt bei Glycosylaziden spricht.
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    URL: http://dx.doi.org/10.1002/cber.19741070517
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    Thermisch induzierte Reaktionen von Imidazolderivaten, IV. Die Kinetik der thermischen Umlagerung von 2,4,4-Thriaryl-5-mathylthio-4H-imidazolen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1645-1648 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermally Induced Reactions of Imidazole Derivatives, IV. Kinetics of the Thermal Rearrangement of 2,4,4-Triaryl-5-methylthio-4H-imidazolesThe thermal rearrangements of the title compounds 1a - d into the 2,4,5-triarylimidazoles 2 in different solvents and at different temperatures are first order reactions. No linear relation exists between the effect of the p-substituents of the migrating aryl groups on the reaction rates and their Hammett-Brown σ+ values. The solvent has practically no effect on the rearrangement rate of 1c. The activation parameters of the rearrangement 1c → 2c are given.
    Notes: Die thermische Umlagerung der Titelsubstanzen 1a - d in die 2,4,5-Triarylimidazole 2 in verschiedenen Lösungsmitteln und bei verschiedenen Temperaturen folgt einem Geschwindigkeitsgesetz 1. Ordnung. Der Einfluß des p-Substituenten der wandernden Arylgruppe ändert sich nicht linear mit den Hammett-Brownschen σ+-Werten. Das Lösungsmittel hat praktisch keinen Einfluß auf die Umlagerungsgeschwindigkeit von 1c. Die Aktivierungsparameter der Umlagerung 1c → 2c werden angegeben.
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    URL: http://dx.doi.org/10.1002/cber.19741070522
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    Vinyl-Kationen, 15. Darstellung und Solvolyse der stereoisomeren 1-Brommethylen-2-methylcyclopropane (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1676-1683 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinyl Cations, 15. Preparation and Solvolysis of the Stereoisomeric 1-Bromomethylene-2-methylcyclopropanesThe stereoisomeric 1-bromomethylene-2-methylcyclopropanes (6Z and 6E) are synthesized and their solvolysis rates and products in ethanol/Water mixtures are determined. 6Z and 6E solvolyse at approximately the same rates. Both isomers yield only the rearranged products 12, 14, 16 and 18, which are formed from both isomers in the same ratio. The products as well as the kinetic data are explained by assuming the formation of the stabilized cyclopropylidenemethyl cation 7.
    Notes: Die stereoisomeren 1-Brommethylen-2-methylcyclopropane (6Z und 6E) wurden dargestellt und die Solvolysegeschwindigkeiten sowie die Produkte in Äthanol/Wasser-Gemischen bestimmt. 6Z und 6E solvolysieren dabei etwa mit gleicher Geschwindigkeit. Aus beiden Isomeren entstehen ausschließlich die umgelagerten Produkte 12, 14, 16 und 18 im gleichen Mengenverhältnis. Produktanalyse und Kinetik werden mit der Bildung des stabilisierten Cyclopropylidenmethylkations 7 erklärt.
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    URL: http://dx.doi.org/10.1002/cber.19741070526
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    Dispiro[2.0.2.4] deca-7,9-dien und Vergleichsverbindungen: Darstellung, UV-, NMR- und Photoelektronen-spektroskopische Untersuchungen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1684-1701 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dispiro[2.0.2.4]deca-7,9-diene and Related Model Compounds: Synthesis, U.V, N.M.R, and Photoelectron-Spectroscopic InvestigationsDispiro[2.0.2.4]deca-7,9-diene (4) and spiro[2.5]octa-4,6-diene (5 can be obtained from the corresponding monoolefins 6 and 10, respectively, by bromine addition and subsequent dehydrobromination. The u. v. spectra of 5 and 4 with λmax = 269 nm (log ε = 3.4) and 284 nm (3.7), respectively, show bathochromic shifts of their longest wavelength bands as compared to 1,3-cyclohexadiene. An analysis of the 1H n. m. r. chemical shifts and H, H-coupling constants for the olefinic protons in 4 indicates that there is no cyclic electron delocalization in this ring system. The six-membered ring in 4 is only slightly flatter than the one in 1,3- cyclohexadiene. The photoelectron spectroscopic data of 4, 5, spiro[2.5]octane (13), spiro[2.5]oct-4-ene (15), dispiro[2.0.2.4]decane (14), and dispiro[2.0.2.4]dec-7-ene (16) demonstrate the effect of the interaction between π-orbitals and cyclopropyl Walsh-orbitals; an assignment for the first bands in the p. e. spectra of these compounds is proposed.
    Notes: Dispiro[2.0.2.4] deca-7,9-dien (4) und Spiro[2.5]octa-4,6-dien (5) lassen sich aus den entsprechenden Monoolefinen 6 bzw. 10 durch Bromierung und anschließende Dehydrobromierung gewinnen. Die UV-Absorptionen von 5 und 4 mit λmax = 269 nm (log ε = 3.4) bzw. 284 nm (3.7) sind bathochrom verschoben gegenüber denjenigen des 1,3-Cyclohexadiens. Aus einer Analyse der Chemischen Verschiebungen und H,H-Kopplungskonstanten der olefinischen Protonen im 1H-NMR-Spektrum von 4 ist zu schließen, daß 4 kein cyclisch delokalisiertes Elektronensystem enthält. Der Sechsring in 4 ist nur wenig stärker eingeebnet als derjenige im 1,3-Cyclohexadien. Anhand der Photoelektronen-Spektren von 4, 5 sowie Spiro[2.5]octan (13), Spiro[2.5]oct-4-en (15), Dispiro[2.0.2.4]decan (14) und Dispiro[2.0.2.4]dec-7-en (16) wird der Effekt der Wechselwirkung zwischen π-Orbitalen und Cyclopropyl-Walsh-Orbitalen aufgezeigt; für die jeweils ersten Banden in den PE-Spektren dieser Verbindungen wird eine Zuordnung vorgeschlagen.
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    URL: http://dx.doi.org/10.1002/cber.19741070527
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    Asymmetrische Hydrierungen mit 1,4-Bis(dimethylamino)- (2S,3S)-und -(2R,3R)-butan-2,3 -diol(DBD)/Lithiumaluminiumhydrid (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1748-1763 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Hydrogenation with 1,4-Bis(dimethylamino)-(2S,3S)- and -(2R,3R)-butane-2,3-dio(DBD)/Lithium Aluminium HydrideThe diaminodiol 6 (DBD) mentioned inthe in the title is readily available in two steps from commercial diethyl tartrate. It reacts with lithium aluminium hydride (LAH) or deuteride to give chirally modified 1:1-complexes which reduce aldehydes, ketones, and ozonides to optically active carbinols in optical yields of up to 75%. Since both enantiomers of DBD are to accessible, both dextro- and levo-rotatory products may be prepared at will. DBD is easily separated from products and recovered without loss of activity. The (-)- DBD-LAH-complex reduces both dialkyl and aryl alkyl ketones to give samples enantiomerically enriched with carbinols of (S)- configuration, while the (+)-DBD-complex acts the other way around. This result is independent of the mode of preparation of the complex, of the ratio of reducing reagent over substrate, of addition of alcohols or water, of reaction temperature, or solvent. The effects of some of these influences upon the optical yields are large. Optimum conditions are given; the efficiency of the DBD-LAH-complex is compared with similar chirally modified LAH derivatives already known. A mechanism explaining the stereochemical results is proposed.
    Notes: Das aus Weinsäureester in zwei Stufen leicht zugängliche, im Titel genannte Diaminodiol 6 (DBD) setzt sich mit Lithiumaluminiumhydrid (LAH) und -deuterid zu chiral modifizierten 1: 1-Komplexen um. Diese reduzieren Aldehyde, Ketone und Ozonide zu opt. aktiven Carbinolen in optischen Ausbeuten bis zu 75%. Da beide Enantiomeren von DBD zugänglich sind, lassen sich gezielt (+)- oder (-)-drehende Produkte darstellen. DBD ist von den Produkten bequem abtrennbar und ohne opt. Verluste zurückgewinnbar. Mit (-)-DBD-LAH- Komplex entstehen Dialkyl- und Alkyl-aryl- carbinole mit (S)-, aus dem enantiomeren Komplex mit (R)-Konfiguration des Überschußenantiomeren. Dies ist völlig unabhängig von Darstellungsmodus des Komplexes, molarem Verhältnis von Reduktionsmittel und Substrat, Zusätzen von Alkoholen oder Wasser, Reaktionstemperatur oder -lösungsmittel. Die Einflüsse dieser Faktoren auf die opt. Ausbeuten, für die optimale Bedingungen angegeben werden, sind indessen zum Teil groß. Vergleiche mit bekannten Komplexen aus LAH und anderen chiralen Liganden werden gezogen. Es wird ein Vorschlag zur Erklärung der stereochemischen Befunde gemacht.
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    URL: http://dx.doi.org/10.1002/cber.19741070533
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