用于氯苯硝化的固体超强酸催化剂的制备及性能研究

摘要

将环境友好的WO3/ZrO2固体超强酸催化剂用于氯苯液相单硝化反应,提出绿色硝化工艺路线.用共沉淀法制备WO3/ZrO2固体超强酸催化剂,通过XRD,TG-DSC,BET和NH3-TPD方法研究了催化剂制备过程中条件改变对WO3/ZrO2结构的影响,并考察了该催化剂对氯苯液相单硝化反应的催化性能.结果表明,WO3/ZrO2固体超强酸的催化活性与氧化钨含量、焙烧温度及晶相结构密切相关.在氧化钨含量为20％(wt)时,经973 K高温焙烧,WO3/ZrO2固体超强酸显示较高的催化活性,单硝基氯苯产率为75.6％,对/邻比为3 73.%In order to develop the nitration technology without environmental pollution nuisance, the environmentally friendly solid superacid catalyst WO3/ZrO2 prepared by the coprecipitation method was used for the liquid phase mononitration of chlorobenzene. The influences of different preparation conditions on the structure of WCyZrO2 were studied by the helps of XRD, TG-DSC, BET and NH3-TPD, respectively, and those on the catalytic activity for the liquid phase mononitration of chlorobenzene were investigated. The results show that the activity of WO3/ZrO2 solid superacid is closely related with the WO3 content, calcination temperature and crystal structure. The catalyst with 20%(wt) WO3 and calcined at 973 K shows higher catalytic activity with the yield of chlorobenzene mononitration of 75.6% and the para-ortho isomer ratio of 3.73.