Carbon‐Supported Au Catalyst in Acetylene Hydrochlorination: Enhancing Catalytic Performance by Complexation of Dicarbonyl Ligands

Abstract

Carbon-supported Au (Au/AC) has been proven to be one of the most promising catalysts in the field of acetylene hydrochlorination. However, the catalytic performance of conventional Au/AC catalyst is usually limited due to the unsatisfactory dispersion of active Au cation on the surface of the support, carbon deposition, and inevitable reduction to inactive Au nanoparticles. Herein, Au catalysts with highly dispersed Au cation were developed using the complexation of dicarbonyl ligand N-chlorosuccinimide (NCS) and N-methylsuccinimide (NMS). The obtained AuÀ NMS/AC and AuÀ NCS/AC catalysts with 0.1 wt.% Au loading possessed acetylene conversion of 98 % and 88 % at 180 °C and GHSV (C 2 H 2 ) of 160 h À 1 , which were clearly better than that of pristine Au/AC. The characterization results showed that coordination between Au cation and ligands enhanced the dispersion of Au species, suppressed the reduction of Au cation, and reduced the formation of carbon deposits. Density functional theory (DFT) calculations suggest that AuÀ NMS/AC and AuÀ NCS/AC catalysts follow a HClpreferred concerted addition reaction mechanism with lower reaction energy barrier. This favors the high activity and nuclearity stability of the Au center. This study provides great potential for the use of dicarbonyl ligands on Au-based catalysts in acetylene hydrochlorination.

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“…It has been widely reported that ligands could regulate the electronic properties of metal atom. , However, the elucidation of electron transfer and its effect mechanism is still insufficient. Hence, the dynamic atomic charge of the Cu atom was examined, as shown in Figure e.…”

Recent Progress in Haloalkene Synthesis by Hydrohalogenation (HX=HCl, HBr, HI) of Alkynes

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