Non-mercury catalytic acetylene hydrochlorination over bimetallic Au–Co(iii)/SAC catalysts for vinyl chloride monomer production

Abstract

Several gold-based catalysts including Au, Au–La(III), Au–Co(II), and Au–Co(III) were prepared and assessed for acetylene hydrochlorination, combining with characterizations of low-temperature N₂ adsorption/desorption, thermogravimetric analysis, X-ray diffraction, temperature-programmed reduction, inductively coupled plasma-atomic emission spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The best catalytic performance was obtained over Au1Co(III)3/SAC catalysts with an acetylene conversion of 92% and a selectivity to VCM of 99.9%. It is indicated that the additives of Co(III), Co(II) and La(III) are preferential to stabilize the catalytic active Au⁺ species and inhibit the reduction of Au³⁺ to Au⁰ in the preparation process of Au-based/SAC catalysts. The addition of these additives can greatly inhibit the occurrence of coke deposition on the catalyst surface, and also inhibit the catalyst sintering, thereby improving the activity and long-term stability of the Au-based catalysts.