Applied Catalysis A: General, Vol.566, 15-24, 2018
Hydrochlorination of acetylene catalyzed by activated carbon supported highly dispersed gold nanoparticles
A series of Au catalysts were prepared with several representative solvents and evaluated for acetylene hydro chlorination. The results revealed that the activity of the catalyst is closely linked with the intrinsic properties of solvents. The catalytic performance of the catalysts increased with decreasing polarity of the solvents, and superior performance was achieved over the Au-isopropanol/AC catalyst, with a 84% stable conversion under reaction conditions of 180 degrees C and a gas hourly space velocity (GHSV) of 1200 h(-1); relative increases of 700.0% and 483.3%, respectively, in acetylene conversion were achieved compared with that achieved with traditional catalysts prepared with water and aqua regia. The substitution of the highly polar water and aqua regia with weakly polar and volatile alcohols altered the crystallization process of Au nanoparticles (NPs) during their formation. The various edges or defects in the formed multiple-twinned or polycrystalline particles provided new active sites for reactants. The altered solvents may enhance the interaction between the support and the Au species, highly dispersing and anchoring the active species and inhibiting their agglomeration and loss during the reaction. Moreover, the interaction also strengthens the adsorption capacity for reactants of the catalysts, enhancing their catalytic performance. This approach may provide an effective reference for exploring environmentally benign mercury-free catalysts for acetylene hydrochlorination.