Tuning the electronic environment of the atoms coordinating CuClx species to regulate vinyl chloride production

Abstract

Ligand engineering has proved to be effective in fine-tuning copper (Cu) catalyst performance for acetylene hydrochlorination. This study combines density-functional theory (DFT) and experimental characterization to analyze a series of phenylphosphine-based ligands. We demonstrate that electron transfer from the ligand's coordinating atom to the Cu active site governs catalytic activity, with a linear correlation established between acetylene conversion and the Mulliken charge of the coordination atom. Optimal catalytic performance and reactant adsorption occurred at a Cu-to-ligand molar ratio between 4 : 1 and 8 : 1. Furthermore, in situ DRIFTS analysis revealed that the ligand moderated acetylene adsorption, thereby suppressing carbon deposition and enhancing catalyst stability. This work offers a theoretical framework for designing efficient ligand-modified Cu catalysts for acetylene hydrochlorination.