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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of azido-polymers of butadiene (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 1505-1516 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Iodine azide adds to cyclohexene in acetonitrile or 4:1 methylene chloride/acetonitrile to give trans-1-azido-2-iodocyclohexane. In methylene chloride this reaction gives a mixture of the cis-and trans-iodoazides owing to competing radical addition. Iodine azide adds to 1-hexene in acetonitrile by an ionic mechanism to give a 3:1 mixture of the 2-azido-1-azido- and 1-azido-2-iodohexanes. Dehydroiodination of the model iodoazides proceeds smoothly with potassium t-butoxide in diethyl ether or THF in the presence of 5 mol % 18-crown-6 at room temperature, giving in the previous example a mixture of 2-azido- and trans-1-azidohexenes. Polybutadiene, carboxyterminated poly(acrylonitrile-co-butadiene), and hydroxy-terminated polybutadiene gave iodoazide derivatives with up to 96% of the theoretical maximum nitrogen content and strong azide IR absorption. High azidoiodination gave polymer with N3/I ratios slightly higher than unity while low percent azidoiodination led to polymer with N3/I ratios of as low as 2:3. All of the nitrogen introduced was in the form of azide function. Dehydroiodination gave polymers with vinyl azide functionality and caused loss of some of the azide groups. All the azidoiodinated polymers decomposed between 120 and 160°C. The dehydroiodinated materials were less stable, decomposing between 100 and 150°C. The temperature of initial decomposition decreased as azide content increased. Polymers with 〉55-60% of the theoretical maximum azide content were shock sensitive.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200612
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  • 2
    Electronic Resource
    Electronic Resource
    Pyrolysis of polyacetylene (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2159-2167 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal degradation of polyacetylene has been studied by pyrolysis gas chromatography mass spectrometry (PGC-MS). The most abundant product is benzene, but significant quantities of other products are also produced. In decreasing order of yield, these are methane, ethylene, propylene, ethane, butadiene, toluene, and xylenes. A simple mechanism capable of accounting for most of the observed products is random chain scission followed by electron-proton exchanges and in some cases ring closure. The total material balance between proton-rich and proton-depleted products is within 10%.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200819
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  • 3
    Electronic Resource
    Electronic Resource
    Magnesium-chloride-supported high-mileage catalysts for olefin polymerization. III. Electron paramagnetic resonance studies (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2461-2476 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron paramagnetic resonance (EPR) was used to study a MgCl2-supported, high-mileage olefin polymerization catalyst. Anhydrous Toho MgCl2 was the starting material. Treatment with HCl at an elevated temperature, ethyl benzoate by ball-milling, p-cresol, AlEt3, and TiCl4produced a catalyst that contained a single EPR observable Ti+3 species A, which was strongly attached to the catalyst surface, had a D3h symmetry, and no other Ti+3 ion in an immediately adjacent site. Species A constitutes only 20% of all the trivalent titaniums; the remainder is EPR-silent and may be attributed to those Ti+3 ions that have adjacent sites occupied by one or more Ti+3 ions. Activation with preformed AlEt3/methyl-p-toluate complexes produced a single Ti+3 species (C) with rhombic symmetry and displaying 27Al superhyperfin splitting which has attributes for a stereospecific active site. This species is unstable under polymerization conditions and is transformed to another species with axial symmetry and solubilization. Both processes could lead to catalyst deactivation and loss of stereospecificity. Catalysts activated by AlEt3 and methyl-p-toluate separately in various sequential orders produced a multitude of EPR-observable Ti+3 species with varying degrees of motional freedom deemed detrimental to stereospecific polymerization of α-olefins.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200909
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  • 4
    Electronic Resource
    Electronic Resource
    Magnesium-chloride-supported high-mileage catalysts for olefin polymerization. II. Reactions between aluminum alkyl and promoters (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2445-2460 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions between AlEt3 and the modifiers, promoters, and coactivators of a typical magnesium-chloride-supported, high-activity propylene polymerization catalyst were studied. Infrared, MS analysis of the gas evolved, and GC-MS of the hydrolysis products for the reaction between AlEt3 and p-cresol showed rapid and quantitative reactions with p-cresol either in the support or solution. The reaction products from AlEt3 and esters were hydrolyzed, acidified, and dehydrated. The resulting carbonyl and olefinic compounds were identified by GC-MS. Proton and carbon nuclear magnetic resonance (NMR) techniques were also used to study these reactions. The expected intermediates were found in the PMR and CMR spectra. The mechanisms of reactions were proposed. The results of this study showed that when AlEt3 and esters are used as coactivators reaction products that can significantly influence the performance of the catalyst are formed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200908
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  • 5
    Electronic Resource
    Electronic Resource
    Magnesium chloride supported high-mileage catalysts for olefin polymerization. I. Chemical composition and oxidation states of titanium (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2019-2032 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical composition of a MgCl2-supported, high-mileage catalyst has been determined at every stage of its preparation. Ball milling of MgCl2 with ethyl benzoate (EB) resulted in the incorporation of 95% of the EB present to give MgCl2·EB0.15. A mild reaction with a half-mole equivalent of p-cresol (PC) at 50°C for 1 h resulted in near quantitative retention of p-cresol by the support. The composition is now approximately MgCl2·EB0.15P̌0.5. Addition of an amount of AlEt3 corresponding to half-mole equivalent of p-cresol liberated one mole of ethane per mole of p-cresol, thus signaling quantitative reaction between the two components. The support contains on the average one ethyl group per Al. Further reaction with TiCl4 resulted in the incorporation of titanium of approximately 8, 38, and 54% in the oxidation states of +2, +3, and +4, respectively. The ratio of Al to Ti in the catalyst lies in the range of 0.5-1.0. Only 19% of all the Ti+3 species in the catalyst can be observed by electron paramagnetic resonance (EPR); these are attributable to isolated Ti+3 complexes. The remaining EPR silent Ti+3 species are believed to be bridged to another Ti+3 by Cl ligands. The total Cl content is equal to the sum of 2 × Mg + 3 × Al + 3.5 × Ti. Most of the p-cresol moiety apparently disappeared from the support, leaving much of ethyl benzoate in the catalyst. Activation with AlEt3/methyl-p-toluate complex reduces 90% of the Ti+4 in the catalyst to lower oxidation states. The ester apparently moderates the alkylating power of AlEt3 to avoid excessive formation of divalent titanium sites. There appears to be a constant fraction of 1/4-1/5 of the titanium which is isolated and the remainder is in bridged clusters independent of the oxidation states of titanium.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200805
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