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  • 1
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 17 (1977), S. 372-376 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: A new photoresist composed of cyclized cis-1, 4-polybutadiene has been developed. The resist has much higher sensitivity on exposure to ultraviolet light than the conventional resist from cyclized polyisoprene. This new resist has no resist-flow even at 250°C, and provides high resolution on baking at 200°C. Thermogravimetric analysis showed that the cyclized polybutadiene decomposes at temperature higher than cyclized polyisoprene.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 322-331 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: It was theorized that the heat stability of PVC may be improved by exchanging the “weak” (allylic and tertiary) chlorines by groups of higher bond strength, e.g., phenyl. Thus PVC was phenylated by φ3Al in carbon disulfide slurry for various times (1 to 5 hrs) and temperatures (from -30 to +45°C). The φ3Al concentration, temperature and time of φ3Al treatment greatly affect the ultimate heat stability of PVC. Significant improvement in the heat stability was obtained by treating PVC in carbon disulfide at 25°C for 1 hr. The mechanism of phenylation was studied by model experiments in which the possible structural irregularities in PVC were simulated by small molecule chlorine compounds, i.e., 3-chloro-1-butene, 1,3-dichloro-1-butene, 4-choro-2-pentene were models for terminal and inchain allylic chlorines, t-butyl chloride was the model for tertiary chlorine at branch site, and isopropyl chloride simulated regular secondary chlorines. The reactions between φ3Al and these chlorides were carried out at 35°C for various times and the NMR spectra were analyzed. The φ3Al + tBuCl reaction in carbon disulfide gives t-butylbenzene (Wurtz coupling) and isobutylene oligomers. Evidently φ3Al (or the φ2AlCl formed) dehydrochlorinates tBuCl to isobutylene which rapidly oligomerizes in the presence of Lewis acids. In aromatic diluents, i.e., benzene, chlorobenzene, and o-chlorotoluene, Friedel-Crafts t-butylation of the diluent occurs; in mesitylene t-butylation is absent presumably because of steric hindrance and small amounts of t-butylbenzene are formed by Wurtz coupling. All the allyl chlorides examined are rapidly phenylated by φ3Al in carbon disulfide at 35°C and yield the expected products: 3-chloro-1-butene → 1-phenyl-2-butene; 1,3-dichloro-1-butene → 1-chloro-3-phenyl-1-butene; 4-chloro-2-pentene → 4-phenyl-2-pentene. The kinetics of phenylation by φ3Al of model compounds have been studied and the following rate constants were obtained: kallyl = too fast to measure, ktBuCl = 1.0, and kiPrCl = 9 × 10-4 l/mole min. Evidently the rate of the φ3Al + RCl reaction is mainly determined by the stability of the R⊕ intermediate: substituted allylic⊕ ≫ tertiary⊕ ≫ secondary⊕.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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