四氢呋喃开环聚合的研究——Ⅲ.本体聚合的总生长反应速度常数

用溴丙烯-高氯酸银或癸二酰氯-高氯酸银引发四氢呋喃在0℃进行本体聚合,测得总生长反应速度常数(k_p)分别为0.32×10~(-3)及0.38×10~(-3)升·克分子~(-1)·秒~(-1)。这样低的k_p值认为是由于ClO_4~-抗衡负离子具有强的亲核性所致。在溴丙烯-高氯酸银催化体系配此中加大银盐用量(到过量51％),引发诱导时间缩短,聚合速度加快,而k_p值的增大不明显。

STUDIES ON THE RING-OPENING POLYMERIZATION OF TETRAHYDROFURAN——Ⅲ. THE OVERALL RATE CONSTANTS OF PROPAGATION IN BULK POLYMERIZATION

The overall rate constants of propagation (kp) in the bulk polymerization of te-trahydrofuran using allyl bromide (AB) or sebacoyl chloride (SC) and silver perchlo-rate as binary catalyst systems were determined to be 0.32 × 10^-3 and 0.38 ×10^-3 l mol^-1. sec.^-1, resp. The evidently low kp values were interpreted by the high nucleophilicity of counterion ClO4-. With increasing the amount of AgClO4 in the composition of AB-AgClO4 catalyst system (up to 51% molar excess), the induction period of the initiation reaction decreases and the rate of polymerization increases,while the k_p value would in-crease rather insignificantly.