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  • 1
    ISSN: 0009-2940
    Keywords: Phthalocyanine, soluble ; Cation-induced phthalocyanine aggregates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the octasubstituted phthalocyanine 1, highly soluble in organic solvents, is described. Its aggregation properties in different solvents and in the presence of alkaline, alkaline earth, and ammonium salts are studied.
    Additional Material: 3 Ill.
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  • 2
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of a charge-transfer complex (CTC) between maleic anhydride and tetrahydrofuran both in bulk and in chloroform solution is proved by electronic absorption spectroscopy, and its association constant at 35°C is determined by this technique and by 1H NMR. The effect of irradiation with monochromatic 350 nm light upon the fluorescence spectrum of the CTC excited with this same radiation is studied. Significant changes are noted in the bulk system, but the changes are much smaller in the presence of methyl methacrylate which is simultaneously polymerized. The effect of oxygen on the polymerization is discussed.
    Additional Material: 6 Ill.
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  • 3
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrosilylation reactions of 1-allyloxy-3-phenoxy-2-propanol (3) as model compound were carried out with α-dimethylsilyl-ω-hydrooligosiloxane (7; M̄n = 1200) in the presence of hexachloroplatinic acid. It was found that under stoichiometric conditions only 75--80% of the allyl groups were hydrosilylated, due to some isomerization of the allyl groups into vinyl groups, which do not undergo hydrosilylation. This isomerization could be shown to be sensitive to the type of the allyloxy structure. Thus, for example, allyloxybenzene does not undergo isomerization.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2789-2803 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: All the side-reactions of a hydrosilylating model system (1-allyloxy-3-phenoxy-2-propanol/. . .-Si(CH3)2H in the presence of hexachloroplatinic acid (CPA); R = [CPA]/[SiH] 〉 10-4) are identified by 13C and 1H NMR. In such conditions the vinyl ether isomers and the residual silanes, formed when R 〈 10-4, are changed into several new species. The most important side-reaction consists in a silane-alcohol condensation (secondary alcohol of the model and, to a much lower extent, tertiary alcohol(tert-butyl alcohol) used as solvent of CPA), which leads to silyloxygrafted moieities. Hydrogen formed in this condensation can partially saturate the vinyl ether isomers the remaining fraction of which is cyclized into a 2-ethyl-1,3-dioxolane derivative. All the side-reactions observed in the case of the model system take place when α,β-diallyloligosulfones are polycondensated with α-dimethylsilyl-ω-hydrooligosiloxanes.
    Additional Material: 9 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1691-1703 
    ISSN: 0887-624X
    Keywords: 3-alkoxy-5,7-diiodo-6-fluorones ; visible photoinitiators ; acrylate photopolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several 3-alkoxy-5, 7-diiodo-6-fluorones (λmax ≈ 470 nm) have been synthesized and evaluated as initiators for photopolymerization triggered with the 515.5 nm line of an Ar+ laser. 2-Acyl- and 2-alkyl-4,5,7-triiodo-3-hydroxy-6-fluorones were also tested at 515.5 nm. 9-Cyano-2-Acyl- and 9-cyano-2-alkyl-4,5,7-triiodo-3-hydroxy-6-fluorones were studied and could be excited with the 632 nm line of a He-Ne laser. Dyes with long linear carbon chain alkoxy groups at C-6 showed larger molar extinction coefficients and formed polymers with better mechanical properties than did compounds with shorter carbon chains, or did the corresponding C-6 phenols. The optimum side chain length of the C-6 ether alkyl group is between 4-7 carbon atoms. With longer carbon chain alkoxy groups at C-8, e.g., octyl, the mechanical properties of the formed polymers are inferior to systems formed with the butyl isomer as photoinitiator. In the case of alkoxy groups with branched alkyl groups (e.g., 2-ethylbutyl), the relationship between dye structure and the properties of the polymers formed is less straightforward. Though the dyes react from their triplet state, the fluorescence quantum yields of the dyes and the performance of the dyes as photoinitiators appear directly related. © 1995 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1579-1592 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Differential scanning calorimetry (DSC) has been utilized in several studies on polymerization kinetics, at different heating rates. However, there are several factors affecting the precision of kinetic parameters. In this work, the activation energy of urethane-bond formation between 2,6-tolylene diisocyanate and diethylene glycol is reported, the latter being in excess in order to minimize problems such as thermal transitions and incomplete reaction in the final step. The DSC technique was applied at different heating rates. Both the equal conversion and equal conversion rate options of the method are discussed. The latter appears to be a more adequate option for the system studied here. The results obtained show a good agreement with the model used.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 850-856 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A flocculent strain of Zymomonas mobilis was used for ethanol production from Jerusalem Artichoke juice containing 113-245 g/L sugar in batch fermentation. The kinetic and yields parameters are calculated using a new method based on polynomial equations for the variation of biomass, ethanol, and sugar concentrations with time. The results show that. Z. mobilis can convert rapidly and efficiently Jerusalem Artichoke juice to ethanol. When a sugar concentration of 248 gL was used, 100 g/L ethanol was formed with an ethanol yield based on sugar utilized of 0.47 g/g (92% of theoretical LP).
    Additional Material: 3 Ill.
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  • 8
    ISSN: 0006-3592
    Keywords: enzymatic peptide synthesis ; N-terminal protecting groups ; α-chymotrypsin ; experimental design ; partition constant ; reaction rate ; log P ; molecular refractivity ; response surfaces ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of five different N-terminal protecting groups (For, Ac, Boc, Z, and Fmoc) and reaction conditions (temperature and dimethylformamide content) on the α-chymotrypsin-catalyzed synthesis of the dipeptide derivative X-Phe-Leu-NH2 was studied. Groups such as For, Ac, Boc, and Z always rendered good peptide yields (82% to 85%) at low reaction temperatures and DMF concentrations, which depended on the N-α protection choice. Boc and Z were the most reactive N-α groups and, in addition, the most suitable for peptide synthesis. On the other hand, the use of empirical design methodologies allowed, with minimal experimentation and by multiple regression, to deduce an equation, which correlates the logarithm of the first order kinetic constant (log k') with reaction temperature, DMF concentration, and hydrophobicity (log P values) of the different protecting groups. The predictive value of the equation was tested by comparing the performance of another protective group, such as Aloc, with the performance predicted by said equation. Experimental and calculated k' values were found to be in good agreement.
    Additional Material: 5 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 29 (1987), S. 778-782 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1267-1276 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Reversible competitive inhibitors of the three enzymes β-galactosidase, trypsin, and serum cholinesterase have been covalently attached to nonionic ethoxylated surfactants. The binding of the resulting affinity-derivatized surfactants to the respective enzymes has been quantified by measuring Michaelis-Menten inhibition constants with kinetic assays. The surfactant-inhibitor of serum cholinesterase, octaethylene glycol monohexadecy ether pyridinium (C16E8-PYR), was adsorbed in aqueous solution to an octadecyl-bonded reverse-phase silica packing in a 2 × 0.2 cm stainless steel test column. The ability of the test column to function as a high-performance affinity chromatography (HPAC) column was determined by applying a mixture of bovine serum albumin and cholinesterase (4:1 w/w). Virtually all of the cholinesterase bound and was eluted by applying a gradient in ionic strength. The applied cholinfesterase was recovered with a yield of over 90% and an 11-fold purification. An aliquot of raw horse serum was then purified in the same fashion with a yield of 84% and a 280-fold purification. The surfactant-inhibitor was easily removed from the column with an alcohol wash for sterilization, cleaning, or application of a different affinity ligand. Moreover, the ligand density on the column can be easily manipulated by adsorbing mixtures of derivatized and underivatized surfactants. Leakage of ligands from the support seems to be minimal since the cholinesterase affinity column was operated efficiently after being exposed to 24,000 column volumes of buffer. The application of this technique to high-capacity, high-throughput reversible affinity purifications is limited only by the ability to identify suitable ligands.
    Additional Material: 8 Ill.
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