Synergistic Gold-Bismuth Catalysis for Non-Mercury Hydrochlorination of Acetylene to Vinyl Chloride Monomer
Gold has been proposed as an environmentally friendly catalyst for acetylene hydrochlorination for vinyl chloride monomer synthesis by replacing the commercially used mercury catalyst. However, long life with excellent activity is difficult to achieve because gold is readily reduced to metallic nanoparticles. The stability of gold limits its industrial application. In this paper, we promoted gold with bismuth for the hydrochlorination of acetylene. It was found that the Bi promotion leads to partial reduction to AuCl, rather than the complete reduction of Au to metallic nanoparticles in the absence of Bi. The optimized catalyst with a molar ratio of Bi/Au = 3:1 (0.3 wt % Au) showed comparable reactivity to 1.0 wt % Au catalyst and significantly improved stability. Furthermore, the gold-bismuth catalyst had higher activity and stability than the commercial mercury catalyst, is less toxic and more environmental-friendly, making it a potentially green, mercury-free industrial catalyst for acetylene hydrochlorination.
gold catalysis; hydrochlorination; mercury-free; synergistic catalysis; Au-Bi