Hydrochlorination of acetylene to vinyl chloride monomer over bimetallic Au–La/SAC catalysts

Abstract

Gold and gold-based bimetallic catalysts for acetylene hydrochlorination were prepared with HAuCl 4·4H 2O and LaCl 3·7H 2O as precursors and analyzed by the characterization methods of BET, XRD, SEM, TG and ICP-AES. The results indicate that pitch-based spherical activated carbon SAC is the optimal carrier; Au/C catalyst deactivates easily for coke deposition and the valence change of Au in the reaction, the addition of lanthanum to gold can weaken the occurrence of coke deposition and inhibit the valence change of gold to improve the stability of the catalyst; Under the reaction conditions of temperature 423 K, C 2H 2 hourly space velocity (GHSV) 360 h −1, feed volume ratio V (HCl)/V (C 2H 2) = 1.15 and Au loading of 1 wt%, the optimal atomic ratio of Au, La (a/a) was 1:3, the conversion of acetylene was up to 98% and the selectivity to VCM was more than 99.8%.