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采用改进的酚钠法及端羟基测定法对环氧乙烷促进的低浓度磷钨杂多酸引发的四氢呋喃聚合反应过程中生长链浓度的测定表明 ,杂多酸分子中的三个质子均参与了引发反应 ,各引发一个聚合链 .采用醋酸酐为促进剂时杂多酸引发四氢呋喃聚合反应生长链浓度测定的结果也证明了这一点 .由此测得在 0℃和 2 0℃时四氢呋喃聚合反应链增长表观速率常数分别为 3 78× 10 -3 和 1 98× 10 -2 L·mol-1·s-1,这与四氢呋喃按离子型生长链增长时的反应速率常数相近 .说明PW12 引发的THF聚合反应是通过氧离子活性中心增长的
The determination of the growth chain concentration during the polymerization of tetrahydrofuran by low concentration of tungstophosphoric acid induced by ethylene oxide with modified sodium phenolate method and hydroxyl end group determination method showed that all three protons in the heteropoly acid molecule were involved The reaction was initiated with each initiating a polymerization chain as evidenced by the results of the determination of the chain length of the polymerization of tetrahydrofuran by the polymerization of tetrahydrofuran with acetic anhydride as the promoter, from which the polymerization of tetrahydrofuran at 0 ° C and 20 ° C The apparent rate constants of the reaction chain growth were 3 78 × 10 -3 and 1 98 × 10 -2 L · mol -1 · s -1, respectively, which is similar to the reaction rate constant of tetrahydrofuran growing by ionic growth chain. Initiated polymerization of THF is through the oxygen ion active center of growth