Catalytic Mechanism Comparison Between 1,2-Dichloroethane-Acetylene Exchange Reaction and Acetylene Hydrochlorination Reaction for Vinyl Chloride Production: DFT Calculations and Experiments

The catalytic mechanism and activation energies of metal chlorides RuCl3, AuCl3, and BaCl2 for 1,2-dichloroethane (DCE)-acetylene exchange reaction were studied with a combination of density functional theory (DFT) calculations and experiments. Two reported reaction pathways were discussed and acetylene-DCE complex pathway was supported through adsorption energy analysis. The formation of the second vinyl chloride monomer (VCM) was proven to be the rate-determining step, according to energy profile analysis. Activity sequence of BaCl2 > RuCl3 > AuCl3 was predicted and experimentally verified. Furthermore, reversed activity sequences of this reaction and commercialized acetylene hydrochlorination reaction were explained: the adsorption abilities of reactants are important for the former reaction, but chlorine transfer is important for the latter.