The effect of a membrane reactor upon catalyst deactivation during hydrodechlorination of dichloroethane

The hydrodechlorination of 1,2-dichloroethane was studied over a Rh/SiO₂ catalyst. The catalyst deactivated with use; only part of the deactivation was reversible. The reversible deactivation could be quantitatively accounted for by assuming quasi-equilibrium between surface chlorine and gas phase HCl. An empirical power-law rate expression was found that adequately described the kinetics when used in combination with this assumption of quasi-equilibrium. Experimental results as well as simulation showed that a membrane reactor can reduce the degree of catalyst deactivation by selective removal of HCl. The membrane reactor can also lessen deactivation through dilution of the reaction zone. In this study, using a porous membrane, the predominant effect is one of dilution, not selective HCl removal.