作者:Bong Kim、Piotr Kirszensztejn、Durgadas Bolikal、Steven L. Regen
DOI:10.1021/ja00344a024
日期:1983.3
homogeneous reactions. The absolute rates measured for the homogeneous and the initial intraresin displacement in dioxane were similar; with n-hexane and toluene as solvents, polymeric rates were considerably slower than those of their homogeneous counterparts. Intraresin displacement was rapid even when a poor swelling solvent (n-hexane) was used. As the rate of intrapolymeric reaction decreased (through
研究了氯甲基化聚苯乙烯上乙酸铵侧基置换树脂内的动力学特征,作为温度、溶胀溶剂和交联密度的函数。在所有情况下,树脂内置换都以快速的初始速率进行,然后是非常缓慢的阶段;后者代表成为“动力学隔离”的那部分反应物。在使用的各种溶胀条件下,第一阶段的活化自由能在 24.4-26.8 kcal mol/sup -1/ 的范围内,这与类似的均相反应中发现的相似。在二恶烷中测量的均相和初始树脂内置换的绝对速率相似;以正己烷和甲苯为溶剂,聚合速率比它们的均质对应物慢得多。即使使用溶胀性差的溶剂(正己烷),树脂内置换也很快。随着聚合内反应速率的降低(通过降低温度、增加交联密度或改变溶剂),“动力学隔离”位点的百分比增加。