光引发BrC_2F_4Br+C_2F_4调聚反应的光强影响

The Effect of Light Intensity on the Photoinduced BrC_2F_4Br＋C_2F_4 Telomerization Reaction

实验发现，在光引发BrC2F4Br＋C2F4调聚反应中，光强（或光功率密度）能影响产品分布。提出了反应机理：此反应由加成反应与复合反应组成，而链转移反应可忽略．由此进行了动力学计算，为与实验结果吻合，拟合得的加成反应BrC2F4＋C2F4的速率常数为（2±1）×107cm3·mol-1·s-1，Br（CZF4）n＞2＋C2F4的速率常数为（1．2±0．4）×107Cm3·mol-1·s-1．

BrC2F4Br+C2F4 reaction induced by different light source (KrF laser, Xelamp, low pressure Hg-lamp) has been investigated. Experiments show that the reaction product distribution depends not only on reaction composition, but on light intensity and light source as well. A reaction mechanism has been suggested and the rate constant of the addition reaction has been calculated by kinetic analysis, for BrC2F4+C2F4→BrC4F8 kadd=(2±1)×107cm3·mol-1·s-1 (room temp.); Br(C2F4)n>2+C2F4 addition reaction,kadd=(1.2±0.4)×107cm3·mol-1·s-1.