Stability of the catalyst for gas phase synthesis of 1,1-dichloroethene

Dehydrochlorination of 1,1,2-trichloroethane to prepare 1,1-dichloroethene using solid catalysts in gas phase is an environmental friendly process, and almost 100% effective atom utilization can be achieved. Catalytic performance of activated carbon, silica and alumina for 1,1,2-trichloroethane dehydrochlorination to prepare 1,1-dichloroethene was investigated. The high stability of activated carbon and deactivation mechanism were analyzed by BET, EDS, TG-MS, XRD, and comparison experiments between fresh and deactivated catalysts with high temperature treatment were studied. The results show that the stability of activated carbon is far better than silica and alumina when studied under 300℃, 1 atmosphere, 30 mL·min^-1 N₂ and 0.4 mL of catalyst. Silica has the maximum carbon deposition quantity per unit time per unit area of 146.3×10^-7g, while alumina and activated carbon have a medium value of 91.4×10^-7 g and 1.1×10^-7 g, respectively. The deactivated catalysts can regain activity after high temperature treatment in air but not in N₂. The results suggest that catalyst deactivation is mainly caused by carbon deposition.