三相催化下氯化苄与亲核试剂反应动力学的研究

Kinetics of Nucleophlic Displacement Reactions on Benzyl Chloride Through Triphase Catalysis.

本文是用季铵盐类相转移催化剂连接到二乙烯基苯交联聚苯乙烯上,形成不溶性的固体高分子相转移催化剂,在此催化剂下研究了以氯化苄的甲苯溶液为有机相和以亲核试剂的水溶液为水相的取代反应动力学。用气相色谱法定量的研究了搅拌速度、温度、不同的亲核试剂对反应的影响。实验表明:反应速率常数随搅拌速度增加而增加,当搅拌速度达到某个定值后,反应速度常数不再变化;反应速率常数随温度升高而增加,并得到了氯化苄与硫氰酸钾反应的表观活化能;还指出了在三相催化下,氯化苄与不同亲核试剂反应时的负离子活性次序为SCN^->I^->Br^-。

The kinetics of the reactions benzyl chloride ( organic phase) with nucleophilic reagen ts (aqueous phase) catalyzed by polymeric phase-transfer catalyst, cross-linked polystyrene resins (solid phase)bearing quternary ammonium group, has been in-vestigated. The rate of reaction exhibied a pseudo-first-order dependency on benzyl chloride in our experiments. The rate constant of reaction has been studied as a function of stirring speed, temperaure and a variety of nucleophilic reagents by gas chromatography. Rate, constants increased with the increase of stirring speed up to 1200rpm, and then remained constant beyond this value. The order of the reactivites for the anions are SCN->I->Br-. The rate constants increased as temperature increased. In the reaction of benzyl chloride in toluene with aqueous nucleophilic reagents, apparent activation energies was determined.