CATALYTIC HYDRODECHLORINATION OF 1,2-DICHLOROETHANE AND TRICHLOROETHYLENE OVER RH/SIO2 CATALYSTS

Reactions of hydrogen with 1,2-dichloroethane and trichloroethylene have been investigated over Rh/SiO2catalysts at 365–553 K and 0.1 MPa. The major products of the reactions are HCl and C2H6. The selectivity for CjH6 increases with increasing temperature. C2H2Cl is a minor product for the dichloroethane reaction; partially dechlotinated products, i.e. C2H5Cl, C2H2Cl2, C2H3Cl, and C2H2Cl2, constitute the minor products for the trichloroethylene reaction. The selectivity for the partially dechlorinated C2 hydrocarbons decreases with increasing temperature. Cl dissociated from chlorinated hydrocarbons poisons the catalyst. Regeneration of catalyst by hydrogen treatment restores the catalyst to more than 70% of the initial activity for the trichloroethylene reaction. Probing the hydrogenation activity of the used Rh/Si02and RhCl3/Si02with ethylene hydrogenation shows that the presence of Cl on Rh/Si02decreases hydrogenation but increases ethylene hydrogenolysis activities. © 1992, Taylor & Francis Group, LLC. All rights reserved.