Liquid-phase hydrodechlorination of CCl₄ in a medium of ethanol with co-production of acetal and diethyl carbonate

During the liquid-phase hydrodechlorination (HDC) of CCl₄ over supported Pd or Pt catalysts in the presence of C₂H₅OH and molecular oxygen, the selective catalytic synthesis of CHCl₃ as well as the conversion of C₂H₅OH to diethyl carbonate (DEC) and 1,1-diethoxyethane (DEE) was observed. The protic solvent, C ₂H₅OH, could easily donate proton that reacts with the adsorbed chlorine on the catalyst surface to form HCl. This facile removal of chlorine from the catalyst surface could be the main reason for the enhancement of the catalytic stability and conversion of C₂H₅OH. The rate of DEC formation was accelerated with the increase in the partial pressure of molecular oxygen, and the selectivity to DEE was enhanced by the increased surface acidity of catalysts. Compared to the reactions of the hydrodechlorination of CCl₄ without C₂H₅OH, the conversion of CCl₄ and the selectivity to CHCl₃ was greatly enhanced in the presence of C₂H₅OH.