ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Desaminierungsreaktionen, 44. Zerfall von 1-Alkylcyclopropandiazonium-Ionen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3672-3693 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 44. Decomposition of 1-Alkylcyclopropanediazonium Ions1-Methyl- (17), 1,2-dimethyl- (41, 44), 1-propyl- (64), 1-(1-methylethyl)cyclopropanediazonium ions (80), and [1,1′-bicyclopropyl]-1-diazonium ions (93) have been generated by alkaline cleavage of the analogous nitrosocarbamates in methanol. Cyclopropyl-allyl transformation and nucleophilic displacement were the only reactions of 17, 41, 44, and 93 while elimination and 1,2-shifts of an α-hydrogen compete increasingly with 64 and 80. The stereochemistry of ring cleavage and nucleophilic displacement has been explored, using 2-D labels in the case of 17 and 93. Cyclopropanediazonium ions (1) and 41 react stereospecifically, 17 and 44 are moderately stereoselective (ca. 85:15), and 93 is entirely unselective. The data indicate a gradual changeover from concerted to stepwise mechanisms. Appreciable stabilization of the positive charge is required to reach the SN1 extreme.
    Notes: 1-Methyl- (17), 1,2-Dimethyl- (41, 44), 1-Propyl- (64), 1-(1-Methylethyl)cyclopropandiazonium-Ionen (80) und [1,1′-Bicyclopropyl]-1-diazonium-Ionen (93) wurden durch alkalische Spaltung der entsprechenden Nitrosocarbamate in Methanol erzeugt. Cyclopropyl-Allyl-Umlagerung und nucleophile Substitution sind die alleinigen Reaktionen von 17, 41, 44 und 93, während bei 64 und 80 Eliminierung und 1,2-Verschiebung eines α-Wasserstoffs zunehmend konkurrieren. Die Stereochemie von Ringöffnung und nucleophiler Substitution wurde untersucht, im Fall von 17 und 93 mit Hilfe von 2-D-Markierung. Cyclopropandiazonium-Ionen (1) und 41 reagieren stereospezifisch, 17 und 44 stereoselektiv (ca. 85:15) und 93 völlig unselektiv. Die Ergebnisse sprechen für einen allmählichen Übergang von konzertierten zu schrittweisen Reaktionsabläufen. Um das SN1-Extrem zu erreichen, ist eine erhebliche Stabilisierung der positiven Ladung erforderlich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Detailed kinetics of titanium nitride synthesis (1995)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 377-388 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A thermogravimetric analyzer is used to study the synthesis of TiN from Ti powder over a wide range of temperature, conversion and heating rate, and for two Ti precursor powders with different morphologies. Conversions to TiN up to 99% are obtained with negligible oxygen contamination. Nonisothermal initial rate and isothermal data are used in a nonlinear least-squares minimization to determine the most appropriate rate law. The logarithmic rate law offers an excellent agreement between the experimental and calculated conversions to TiN and can predict afterburning, which is an important experimentally observed phenomenon. Due to the form of the logarithmic rate law, the observed activation energy is a function of effective particle size, extent of conversion, and temperature even when the intrinsic activation energy remains constant. This aspect explains discrepancies among activation energies obtained in previous studies. The frequently used sedimentation particle size is a poor measure of the powder reactivity. The BET surface area indicates the powder reactivity much better.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690410219
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Noncatalytic gas-solid reactions and mechanical stress generation (1995)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 1235-1250 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reaction rate in gas-solid systems can be affected by mechanical stresses that arise as the reaction proceeds. Stresses develop due to differences between precursor and product molar volumes and thermal expansion coefficients. Experimental evidence on the interaction of reaction rate and mechanical stress for the Ti/N2 and Ti/O2 systems is provided. A detailed and consistent mathematical model is developed for the reaction taking place at the constrained precursor/product interface. An elastic formulation for the stresses is adopted, and stress generation due to mismatches in linear thermal expansion coefficients and equivalent volume (Pilling-Bedworth ratio) for the precursor and product are considered. The effect of surface energy, which becomes significant for particle sizes below 1 μm, is also included in the model. Both experimentally and theoretically, conditions exist where the mechanical stresses exceed the strength of the material, leading to mechanical breakdown of the product layer, thus causing a discontinuity in the observed reaction rate. The entire processing history, including the reaction, temperature, and pressure profiles, plays an important role in determining the overall reaction kinetics of the powder.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690410519
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Reaction rate modeling in noncatalytic gas-solid systems: Species transport and mechanical stress (1995)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 2614-2624 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A detailed model to describe the overall reaction rate of the oxidation of titanium is developed. The mathematical model consists of two facets, the first of which involves a detailed description of species transport that accounts for the formation of charged species. This is augmented by a description of the occurrence of mechanical stress due to a Pilling - Bedworth ratio that differs significantly from I as well as differences between precursor and product thermal expansion coefficients. A self imposed electric field is formed across the oxide layer due to different mobilities of the species considered. This field opposes the transport of electrons and enhances the transport of anion vacancies, thus increasing the overall reaction rate compared to a pure diffusion process, while also ensuring that electrical charge is conserved. Large growth stresses result from the unmatched precursor and product volumes, significantly affecting the overall process. These results show that the incorporation of a consistent treatment of mechanical stress forms a necessay part of any accurate description of the overall behavior of a reacting particle.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690411210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Untersuchungen über das Komplexchemische Verhalten des Berylliums. III (1926)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 152 (1926), S. 347-356 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19261520135
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Chemische Konstitution der natürlichen Eisenoxydhydrate (1928)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 169 (1928), S. 57-80 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19281690106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Untersuchungen über das komplexchemische Verhalten des Berylliums. V (1927)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 163 (1927), S. 31-39 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19271630103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Matrix-assisted laser desorption/ionization mass spectrometry of synthetic polymers. 3. Analysis of condensation polymers (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 95-111 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die matrixunterstützte Laser-Desorptions/Ionisations-Massenspektrometrie ist eine leistungsfähige Methode zur Analyse von Kondensationspolymeren. Obwohl diese Produkte eher niedermolekular sind, weisen sie eine komplexe chemische Struktur auf. Phenol-Novolake und -Resole können bezüglich des Polymerisations grades und des Typs und der Anzahl der funktionellen Gruppen analysiert werden. Modifizierte Phenolharze, wie epoxidierte Novolake, können identifiziert und der Epoxidierungsgrad bestimmt werden. Für Polycarbonate und Polyester wird gezeigt, daß in Abhängigkeit vom Reaktandenverhältnis lineare Oligomere mit unterschiedlichen Endgruppen und cyclische Oligomere gebildet werden.
    Notes: Matrix-assisted laser desorption/ionization mass spectrometry is shown to be a suitable method for the analysis of condensation polymers. Although these products are rather low in molar mass, they exhibit a complex chemical structure. Phenolic novolacs and resols can be analysed with respect to the degree of polymerization and the type and number of functional groups. Modified phenolic resins, such as epoxidized novolacs, can be identified and the degree of epoxidation can be determined. It is shown for polycarbonates and polyesters that depending on the reactant ratio linear oligomers with different endgroups and cyclic oligomers are formed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052410108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Polyacetylenverbindungen, CXXVII. Die Polyine der Gattung Carlina L. (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1507-1514 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Untersuchung der Inhaltsstoffe verschiedener Vertreter der Gattung Carlina L. zeigt, daß diese Gattung neben bereits bekannten Verbindungen mehrere neue Substanzen (10, 15, 16, 20) enthält, die in ihrer Struktur geklärt werden konnten. Biogenetisch sind alle Verbindungen recht eng miteinander verwandt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000516
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Polyacetylenverbindungen, CXXIX. Über die ersten pflanzlichen Polyinglykoside (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1915-1926 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus den Wurzeln verschiedener Vertreter des Tribus Cynareae werden mehrere sehr polare Polyine isoliert und deren Strukturen geklärt. In allen Fällen handelt es sich um C17-Alkohole, die mit l-Rhamnose bzw. ihren Acetaten glykosidisch verknüpft sind (8, 9). Auch das Aglykon kommt in kleiner Menge natürlich vor. Die oberirdischen Teile von Serratula gmelini Ldb. enthalten ein Gemisch von C15—C18-Aldehyden (neu 23 und 25) mit verschiedenen chromophoren Systemen, die die nahe Verwandtschaft mit der Gattung Centaurea erkennen lassen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000620
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...