MClx (M = Hg, Au, Ru; x=2, 3) catalyzed hydrochlorination of acetylene - A density functional theory study

Density functional theory (DFT) calculations were used to study the mechanism for the hydrochlorination of acetylene catalyzed by MClx (M = Hg, Au, Ru; x = 2, 3). For the three catalysts, the reaction occurs via a one-shift chlorine atom transfer, which avoids the formation of highly stable complex species. The adsorbed HCl acts as a chlorine donor, while the C2H2 favors the chlorine abstraction. The calculated real activation barrier decreases in the order: HgCl2 > AuCl3 > RuCl3, which suggests that the RuCl3 would be a good candidate catalyst for the hydrochlorination of acetylene.