Bi/AC modified with phosphoric acid as catalyst in the hydrochlorination of acetylene

Abstract

A series of H₃PO₄-modified Bi/AC catalysts with different P/Bi ratios were prepared by an incipient wetness impregnation method for the acetylene hydrochlorination reaction. The C₂H₂ conversion reduced in the following sequence: BiP_0.5/AC > BiP₁/AC > Bi/AC > BiP_0.1/AC > BiP₂/AC > BiP₃/AC. BiP_0.5/AC exhibited highest catalytic activity, with 82% conversion of C₂H₂ and 92% selectivity for vinyl chloride, among the catalysts that were investigated. Characterization was carried out using N₂ adsorption/desorption analysis, powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, temperature-programmed reduction, atomic emission spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that BiOCl was the main active species in the acetylene hydrochlorination reaction. The addition of H₃PO₄ promoted the dispersion of the Bi active component, strengthened the interaction between the metal and the support, and reduced the loss of the active component during the hydrochlorination of acetylene.