Aliovalent-substituted chromium-based catalysts for the hydrofluorination of tetrachloroethylene

摘要

New aliovalent-doped chromium oxide and fluoride catalysts have been prepared by coprecipitation techniques to obtain solid solutions The catalysts have been characterized by,e.g.,X-ray BET and pyridine adsorption analysis and tested for their catalytic activity in the gasphase reaction of C_2Cl_4 with HF.The latter reaction involves several consecutive steps and produces the expected C_2HCl_xF_y (x+y=5) compounds but also soem perhalogenated compounds the formatin of which needs further explanation Reactin data obtained with a (Cr,Mg)(F,OH)_x catalyst were used to calculate reaction rates and activation energies of all the consecutive steps which could be successfully used to predict the reaction outcomes under varying experimental conditions.