Free-Mercury Catalytic Acetylene Hydrochlorination Over Bimetallic Au-Bi/gamma-Al2O3:A Low Gold Content Catalyst

摘要

Gold and gold-based bimetallic catalysts for acetylene hydrochlorination were prepared with HAuCl(4)aEuro cent 4H(2)O and BiCl3 as precursors and gamma-Al2O3 as the support. Their catalytic performances for acetylene hydrochlorination were tested in a fixed-bed reactor under the fixed reaction conditions of temperature 150 A degrees C, C2H2 hourly space velocity 120 h(-1), feed volume ratio V (HCl)/V (C2H2) = 1.05. Then they were analyzed by the characterization methods of BET, XRD, SEM, TG, TPR and XPS. The results showed that the Au/gamma-Al2O3 catalyst exhibited a high activity with only 0.1 wt% Au loading but it deactivated easily for both coke deposition and valance change. With the addition of Bi, it inhibited the reduction of Au3+ to Au-0 in both the preparation and the reaction process. Besides, the coke deposition was apparently weakened. The best catalytic performance was obtained over 0.1Au5Bi/gamma-Al2O3 catalyst with an acetylene conversion of 96 % and a selectivity to VCM of more than 99 % (Au loading, only 0.1 wt%) for running more than 10 h.