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101.
Ohne Zusammenfassung 相似文献
102.
Toshinobu Suzuki Naoya Kenbou Keiryo Mitsuhashi 《Journal of heterocyclic chemistry》1979,16(4):645-648
Three isomeric aminopyridines were reacted with an excess of benzoyl chloride in the presence of an excess of triethylamine, giving the corresponding dibenzoylaminopyridines in high yields. As an application of the dibenzoylation, the aminopyridines were also reacted with phthaloyl dichloride, resulting in appreciable yields of the respective N-pyridylphthalimides. The rate of the conversion under various conditions was studied with high pressure liquid chromatography in order to investigate the difference in reactivity among the three isomers. 相似文献
103.
Toshio Masuda Yoshinori Kuwane Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1982,20(4):1043-1050
Polymerization of 1-chloro-2-phenylacetylene was effected by the catalyst formed by UV irradiation of Mo(CO)6 in carbon tetrachloride to provide in high yield a polymer whose weight-average molecular weight reached 2 × 106. UV irradiation and an appropriate halogenated hydrocarbon were essential for the formation of active species. The formation of a metal carbene as active species was inferred. Poly(1-chloro-2-phenylacetylene) was a light-yellow solid having the structure $ \rlap{--} ({\rm CCl\dbondCPh\rlap{--} )}_n $. The polymer was soluble in aromatic and halogenated hydrocarbons, and a film could be formed from polymer solution. 相似文献
104.
105.
A. Mizote S. Kusudo T. Higashimura S. Okamura 《Journal of polymer science. Part A, Polymer chemistry》1967,5(7):1727-1739
The cationic polymerization of propenyl n-butyl ether (PBE) in methylene chloride with boron fluoride etherate at ?78°C. has been studied. The copolymerization of PBE with vinyl n-butyl ether (VBE) showed that both the isomers are more reactive than VBE, and their monomer reactivity ratios were found to be: 相似文献
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109.
Abstract To investigate the method of measurement of the initiation rate constant in cationic polymerization, styrene and α-methylstyrene are polymerized by triphenylmethyl stannic pentachloride (Ph3CSnCl5). Adding these monomers to a solution of Ph3CSnCl5, the strong absorption of triphenylmethyl cation at 400 to 450 mμ disappears. The rate of disappearance of the absorption at 430 mμ is proportional to the concentration of Ph3CSnCl5 and monomer. It is confirmed that this disappearance of the absorption is due to the conversion of triphenyl cation to styryl or α-methylstyryl cation. Therefore, the rate of consumption of triphenylmethyl cation corresponds to that of the addition of triphenylmethyl cation to the olefinic double bond in a monomer, that is, the rate of the initiation reaction. Considering the dissociation constant of Ph3CSnCl5, the initiation rate constants of styrene and α-methylstyrene in ethylene chloride solution at 30°C are 11.6 × 10?2 and 2.85 liters/mole-min, respectively. These values seem to be much smaller than the propagation rate constant of each monomer. However, the effect of polymerization conditions, for example, the kind of a monomer and the polarity of a solvent, on the initiation rate constant is the same as in the propagation reaction. This fact suggests the similarity of a reaction mechanism in both elementary reactions. 相似文献
110.
Hiroji Fukui Mitsuo Sawamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1993,31(6):1531-1542
A series of multifunctional malonate anions, [Na⊕?C(COOEt)2CH2]mC6H6?m(I; m = 2–4), were examined as polymer coupling agents for the living cationic polymerization of vinyl ethers initiated with the hydrogen iodide/zinc iodide (HI/ZnI2) initiating system. The bifunctional anion ( 2 ;I, m = 2), 1,4-[Na⊕?C(COOEt)2CH2]2C6H4, terminated living polymers of isobutyl vinyl ether (IBVE) (DP n = 10) almost quantitatively in toluene at ?15°C to give coupled living polymers with doubled molecular weights in 96% yield; the dianion 2 was dissolved in tetrahydrofuran containing 18-crown-6 for maintaining the solution homogeneous. The yield of the coupled polymers was increased with shorter living chains or in less polar solvents. Also by coupling via 2 , ABA block copolymers were obtained from living AB block polymers of IBVE and an ester-functionalized vinyl ether (CH2?CHOCH2CH2OCOCH3). Coupling of living poly(IBVE) with the trifunctional anion ( 3 ; I, m = 3) led to tri-armed polymers in 56% yield, whereas with the tetrafunctional version ( 4 ; I, m = 4), only three out of the four anions reacted to give another tri-armed polymer in 85% yield. © 1993 John Wiley & Sons, Inc. 相似文献