Mesoporous carbon with controllable pore sizes as a support of the AuCl3 catalyst for acetylene hydrochlorination

Abstract

Mesoporous carbon materials with controllable pore sizes within the range of 5.6–40.5 nm were successfully synthesized using colloidal silica as hard templates and boric acid as the pore expanding agent. The catalytic properties of the 0.5% AuCl₃ loaded mesoporous carbon catalysts towards acetylene hydrochlorination were tested in a fixed-bed reactor. Under reaction conditions of 180 °C, C₂H₂ hourly space velocity = 720 h⁻¹ and HCl/C₂H₂ feed volume ratio = 1.15, it was found that larger mesoporous carbon supports could accelerate the reaction rate, resulting in higher acetylene conversion. The AuCl₃ catalyst supported on mesoporous carbon with a pore size of about 40.5 nm displayed excellent catalytic activity (acetylene conversion was above 83%). The dependence of regular catalytic performance on pore size is important for acetylene hydrochlorination because large pore sizes enable fast molecular diffusion, thus suppressing coke formation.