Highly Selective Catalytic Dechlorination of Dichloromethane to Chloromethane over Al-Ti Mixed Oxide Catalysts

In this paper, a series of Al-Ti mixed oxides with different Al/Ti ratios are prepared by a simple sol-gel method and they are used as active catalysts for selective dechlorination of dichloromethane to chloromethane. The Al-Ti mixed oxide catalyst with the same molar ratio of Al and Ti shows the highest activity in dechlorination of dichloromethane. The strong and abundant Lewis acid sites in the Al-Ti mixed oxides formed along with Al-O-Ti bondings are responsible for the high catalytic activity toward the selective dechlorination reaction in this work. From a kinetic study, the activation energy of this reaction over the optimum Al-Ti mixed oxide catalyst appears to be 59.4 kJ mol(-1)based on Langmuir-Hinshelwood model. The improved catalytic performance suggests that the Al-Ti mixed oxide could be used as the effective catalyst for the highly selective dechlorination of dichloromethane to chloromethane.