分子筛催化合成对氯甲苯的研究

为了有效提高甲苯氯化反应的对位选择性,研究了在分子筛催化作用下甲苯与氯气直接氯化制取对氯甲苯。实验获得的最佳工艺条件为:V(1,2-二氯乙烷)/V(甲苯)=2∶1,m(分子筛)/m(甲苯)=0.4∶1,m(助催化剂氯乙酸)/m(催化剂)=0.2∶1,氯气流量为0.7 mL/s,反应温度为50℃,反应时间为3 h。在最佳反应条件下,甲苯转化率可以达到79.6%,最终产物中对氯甲苯的质量分数为76%。使用分子筛催化直接氯化法生产对氯甲苯,可以大大简化工艺过程,减少副产物的产生,降低生产成本。

Synthesis of p-chlorotoluene with zeolite catalyst

To effectively enhance the contraposition selectivity of chlorinating reaction the p-chlorotoluene was prepared by direct chlorination of toluene and chlorine gas in the presence of zeolite catalyst.The optimum reaction conditions were obtained as follows∶ V(1,2-dichloroethane)∶ V(toluene)=2∶1,m(zeolite catalyst)∶m(toluene)=0.4∶1,m(chloroactic acid)∶m(zeolite catalyst)= 0.2∶1,the chlorine flux is 0.7 mL/s,the reaction temperature is 50 ℃,the reaction time is 3 h.At the above conditions the conversion of toluene is 79.6% and the mass fraction of final product p-chlorotoluene is 76%.The direct chlorinating reaction with zeolite catalyst can simplify technological process, decrease by-product,and reduce the production cost.