Preparation and properties of solid superacid catalysts for chlorobenzene nitration

In order to develop the nitration technology without environmental pollution nuisance, the environmentally friendly solid superacid catalyst WO ₃/ZrO ₂ prepared by the coprecipitation method was used for the liquid phase mononitration of chlorobenzene. The influences of different preparation conditions on the structure of WO ₃/ZrO ₂ were studied by the helps of XRD, TG-DSC, BET and NH ₃-TPD, respectively, and those on the catalytic activity for the liquid phase mononitration of chlorobenzene were investigated. The results show that the activity of WO ₃/ZrO ₂ solid superacid is closely related with the WO ₃ content, calcination temperature and crystal structure. The catalyst with 20%(wt) WO ₃ 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.