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  • Articles: DFG German National Licenses  (6)
  • 1975-1979  (3)
  • 1970-1974  (3)
  • Chemistry  (6)
  • 1
    Electronic Resource
    Electronic Resource
    The mass spectral fragmentation of partially ethylated alditol acetates, a derivative used in determining the glycosly linkage composition of polysaccharidesSupported in part by AEC Contract No. AT(11-1)-1426.Abbreviations: PEGS = poly-(ethylene glycol succinate); PEGA = poly-(ethylene glycol adipate). (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 263-268 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral data for the primary fragmentation of partially ethylated alditol acetates have been tabulated in order to allow easy reference for the identification of these polysaccharide derivatives. Sodium borodeuteride is used in all the aldose to alditol reductions, since the presence of a single deuterium label on C-1 greatly increases the information available in the mass spectrum and allows some identifications to be made which would not otherwise be possible. The primary fragmentations of these derivatives are analogous to those of the partially methylated alditol acetates, with each fragment shifted to a higher m/e value by fourteen mass units for each ether linkage contained in the fragment. The secondary fragmentation is also very similar, being characterized by the loss of acetic acid or ketene, or, less frequently, by the loss of ethanol or acetaldehyde. Coupled with the chromatographic retention time data for the partially ethylated alditol acetates tabulated elsewhere, the unambiguous mass spectral identification makes this derivative an excellent choice as a complementary derivative to the partially methylated alditol acetates for polysaccharide analysis. The utility of the partially ethylated alditol as a routine analytical derivative is further enhanced by the almost identical procedures required for synthesis of the ethyl and methyl derivatives. Through the combined use of these derivatives, most of the possible linkage isomers of the seven common aldoses of plant cell wall polysaccharides can be resolved, identified and quantitated.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010410
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of viscous heating on the observed temperature dependence of mechanochemical reactions (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1701-1720 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The temperature dependence of mechanochemical reactions of high polymers is investigated in light of viscous dissipation in the flow field. The viscosity of the polymer melt is assumed to depend exponentially upon temperature, and the power-law model is used to describe the shear stress-shear rate relationship. Using equations previously reported in in the literature for the temperature profile generated in capillary flow, evidence that such an experimental system operates under decidedly nonisothermal conditions is presented. These equations, together with the classical Arrhenius equation for the temperature dependence of chemical reactions, predict that the average reaction rate in a capillary decreases, passes through a minimum, and increases as the capillary wall temperature is increased. Good agreement exists between the temperature at the minimum rate found in this work and that found experimentally for polystyrene, natural rubber, and polyisobutylene.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160709
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Single drop breakup in developing turbulent pipe flow (1970)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 16 (1970), S. 254-260 
    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: An experimental study was made on the breakup of a single drop in two phase liquid-liquid developing turbulent pipe flow. The predominant breakup mechanism was controlled by dynamic pressure forces, and the drop breakup was characterized by one or two smaller drops breaking off a larger drop.The effect on the increase in interfacial area and the resulting size distribution of the fragmented drops of drop velocity, interfacial tension, initial drop size, and the distance down the pipe was studied. Regression analysis was used to determine the significant effects. Most of these regression equations had significant cubic and two-factor interactions, which is indicative of the complexity of drop breakup.The size distribution of the fragmented drops can be approximated by a normal distribution. However, the steady state distribution was not fully developed in the work here.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690160218
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Aqueous gel permeation chromatography: The effect of solvent ionic strengthPart XI of a series on Characterization and Properties of Macromolecules. (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 419-427 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Porous glass packing materials have been used for gel permeation chromatography using an aqueous phosphate buffer. Elution volumes were determined for polystyrene sulfonates, dextrans, and small neutral and charged molecules at three different ionic strengths, viz., 0.01M, 0.1M, and 1.0M phosphate, pH 7.0. The pore diameters of the glasses studied were 75, 240, 700, and 2000 Å. Elution volumes of nonionic species were unaffected by changing the solvent ionic strength. Elution volumes of charged species were markedly affected by the ionic strength of the solvent. This was attributed to a combination of decreased polymer dimensions and decreased ionic exclusion with increasing buffer concentration. The use of low ionic strength solvents may be exploited to tailor the separating range for polyelectrolytes with porous glass packings. This is particularly useful in the low molecular weight range where the lowest pore size available is 75 Å.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230211
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    The conformational transition in poly(methacrylic acid) and butyl vinyl ether/maleic anhydride copolymers studied by 1H NMR linewidth measurements (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 885-893 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Messungen der Linienbreite in den 1H NMR-Spektren von D2O Lösungen von Polymethacrylsäure (PMA) und von hydrolysiertem Butylvinyläther/Maleinsäureanhydrid Copolymer zeigen eine scharfe Abnahme der Linienbreite der Seitenkettenresonanzsignale bei einem Neutralisationsgrad α ≈ 0,2. Dies ist der Bereich, in dem schon früher potentiometrische Titrationen einen Konformationsübergang aufzeigten. Ein solcher Wechsel tritt weder bei der Polyacrylsäure noch beim Methylvinyläther/Maleinsäureanhydrid Copolymer auf. Die Art des Konformationsübergangs wird auf der Grundlage der Rotationsfreiheit der Seitenketten um die Hauptkette diskutiert.
    Notes: Linewidth measurements on the 1H NMR spectra of D2O solutions of poly(methacrylic acid), (PMA), and the hydrolyzed form of butyl vinyl ether/maleic anhydride copolymer show a sharp decrease in the linewidths of side chain resonances at a degree of neutralization α ≈ 0,2. This is the region in which potentiometric titrations previously have shown a conformational transition to occur. Such a change does not occur in poly(acrylic acid) on the one hand and methyl vinyl ether/maleic anhydride copolymer on the other. The nature of the transition is discussed in terms of the freedom of rotation of the side chains about the main chain.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021770325
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Mannich Reaction of 2,5-Xylenol, Morpholine and Formaldehyde (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 54-56 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mannich-Reaktion von 2,5-Xylenol, Morpholin und FormaldehydDie Reaktion von 2,5-Xylenol mit Morpholin und Formaldehyd in Isopropylalkohol ergibt in 65 proz. Ausbeute eine Mischung der p- und o-substituierten Mannich-Derivate 1 und 3 zusammen mit einer kleinen Menge der o,p-disubstituierten Mannich-Verbindung 2.
    Notes: Reaction of 2,5-xylenol with morpholine and formaldehyde in 2-propanol affords in 65% yield a mixture of the p- and o-substituted Mannich derivatives 1 and 3 together with a minor amount of the o,p-disubstituted Mannich compound 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780106
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    Paper (German National Licenses)
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