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
    ESR study of reactions of cellulose initiated by the ceric ion methodPaper presented in part at the IUPAC International Symposium on Macromolecular Chemistry, Tokyo and Kyoto, Japan, September 28-October 4, 1966. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1591-1606 
    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 ESR spectra of microcrystalline cellulose and purified cotton cellulose reacted with ceric ammonium nitrate in nitric acid were determined. The effects of the concentration of ceric ion, atmosphere, temperature, and graft copolymerization with acrylonitrile on the rates of formation and decay of radicals in the cellulose molecule were determined under both static and dynamic conditions. Under static conditions, after the desired conditions of reaction, the samples were frozen at -100 or -160°C., and then the concentration of free radicals was determined. Under dynamic conditions ceric ion solution was continuously flowed through the celluloses while these determinations were being made at 25°C. In the presence of oxygen the rate of decay of free radicals was decreased. On initiation of copolymerization reactions with acrylonitrile, there was an increase in radical concentration, then a decrease. Apparently, during graft copolymerization the radical site initially on the cellulose molecule was retained on the end of the growing polymer chain. Then additional ceric ion coordinated with the hydroxyl groups of the cellulose, leading to the formation of additional radical sites. An Arrhenius interpretation of the effect of temperature on the formation of these additional radical sites gave apparent activation energies for radical formation on cotton cellulose as 34 kcal./mole and on microcrystalline cellulose as 29 kcal./mole.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1966.070101015
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    ESR study of post-irradiation reactions of cellulose and acrylonitrile (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 1139-1153 
    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: An ESR study of the free-radical mechanisms of the post-irradiation reactions of cotton cellulose with acrylonitrile is reported. The effects of atmosphere, moisture content, and solutions of acrylonitrile on the yield and stability of free-radical sites in irradiated cellulose were determined. On interaction of γ-radiation from a 60Co source with cotton cellulose, long-lived free-radical sites were found within the molecular lattice. Short-lived free-radical sites were apparently also formed on chain cleavage, gave strong singlet spectra, and were readily accessible to interaction with water. Other free-radical sites were formed within regions of the cellulosic fiber which were inaccessible to moisture or aqueous solutions even after contact times as long as three days. It was suggested that long-lived free-radical sites in cellulose I (containing regain moisture) resulted from dehydrogenation at C5, and in cellulose II (containing regain moisture) resulted from dehydrogenation at C5 and dehydrogenation of the OH group or dehydroxylation at C6. When irradiated cellulose was contacted with a solution of acrylonitrile (15%) in 75% aqueous zinc chloride, the initial rate of decrease in spin concentration was higher than the rate of decrease as the time of contact increased. The ESR spectrum of the reacted cellulose, observed at -100°C., as compared with the spectrum for the irradiated cellulose, had decreased in signal strength with increase in time of contact and changed from a three-line spectrum to an ill-defined spectrum. The free radical being observed was probably due to unreacted sites in the cellulose. The extent of the graft copolymerization reaction was directly related to the initial spin concentration in the irradiated cellulose.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110712
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Kinetic studies of gluconic acid fermentations (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 7 (1965), S. 229-243 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of the gluconic acid fermentation have been studied at pH 5.8 Pseudomonas ovalis B-1486 was used as the fermenting organism. D-Gluconolactone was found as an intermediate in the fermentation and accumulated at times in large amounts. When this occurred, hydrolysis of the lactone was found to be the rate limiting reaction. This can be, under certain conditions, a poor fermentation in which to study oxygen transfer limiting conditions. Further, it is impossible to relate batch and continuous kinetic data for this fermentation unless the lactone hydrolysis reaction is taken into account.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260070204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    ESR spectra of copper complexes of cellulose (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 249-265 
    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 ESR spectra of complexes of fibrous cotton cellulose and cupriammonia dihydroxide or cupriethylene diamine dihydroxide under various experimental conditions were determined. The spectra of both complexes with cotton cellulose were almost identical at -100 and 25°C. The spectrum of the complex of cupriethylene diamine dihydroxide with cellulose was stable to temperatures as high as 100°C. The sum of the linewidths of the hyperfine components of the spectra for each complex was about 180 gauss. Cotton fibers were combed and aligned with their axes (lengths) parallel to the magnetic field (B∥); after formation of either of the complexes with cellulose a minumum of hyperfine structure of components centered at H∥ was observed. A maximum of hyperfine structure of these components was observed when the complexed fibers were aligned with their axes perpendicular to the magnetic field (B⊥). The opposite was true of components centered at H⊥. For a complex of cupriethylene diamine dihydroxide and cellulose at 25°C. and at high pH the g∥ was 2.2127 and the g∥ was 2.0476. It was suggested that the alignment of most of the complex was its axis of symmetry at a maximum angle to the axes of the cotton fiber, when the axes of the fibers were in the parallel alignment with the magnetic field. At high pH these observations were even more marked. When ramie was used with cupriethylene diamine dihydroxide at high pH, the contribution of components centered at H∥ to the spectra was zero. Spectra for the copper compounds alone and complexed with cellobiose are also reported.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie der Bor-Azide. VI. Zur Kenntnis von Dimethylborazid und seinen AminatenProfessor E. Wiberg zum 65. Geburtstage am 3. Juni 1966 gewidmet (1966)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 345 (1966), S. 79-86 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimethylboron azide can be prepared from dimethylboron bromide and tri-n-butylsilyl azide as an explosive liquid, b. p. 54°C/720 mm. A temperature-dependent association equilibrium is found for the substance by 1H- and 11B - NMR spectroscopy. The IR vibrations in the range 33-4000 cm-1 are consistent with a Cs-type structure. Some amino complexes of dimethylboron azide are described. On heating the pyridine complex up to 210-220°C, more than 30 compounds are formed the most important of which is hexamethyl borazine, which is found in a yield of 21%.
    Notes: Dimethylborazid entsteht aus Dimethylborbromid und Tri-n-butylsilylazid als explosive Flüssigkeit, Sdp. 54°C/720 Torr. Aus den 1H- und 11B - NMR-Signalen der Substanz geht hervor, daß sie einem temperaturabhängigen Assoziationsgleichgewicht unterliegt. Die im Bereich 33-4000 cm-1 gemessenen IR-Banden lassen sich einem Strukturmodell der Punktgruppe Cs zuordnen. Einige Aminate von Dimethylborazid werden beschrieben. Beim Zerfall von Dimethylborazid-Pyridin bei 210-220°C entstehen mehr als 30 Verbindungen, darunter in 21proz. Ausbeute als Hauptprodukt Hexamethylborazol.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19663450110
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Steady flow viscosity of aqueous hydroxyethyl cellulose solutions (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 411-413 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030143
    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...