Progress in mercury-free catalysts for acetylene hydrochlorination

Acetylene hydrochlorination to vinyl chloride monomer (VCM) plays a crucial role in the industrial manufacture of polyvinyl chloride (PVC). Nonetheless, traditional acetylene hydrochlorination relies heavily on mercury-based catalysts, which are severely harmful to both human health and the environment. Hence, developing mercury-free catalysts for efficient acetylene hydrochlorination to VCM has received extensive attention in the past years. In this review, we systematically summarize the recent achievements in mercury-free catalysts including noble/non-noble metal-based catalysts and metal-free catalysts in acetylene hydrochlorination with the focus on catalyst design, catalytic performance and the reaction mechanism. Moreover, the advantages and drawbacks of diverse mercury-free catalysts are comprehensively discussed. Eventually, we present the current challenges and opportunities for the exploration and application of mercury-free catalysts in industrial VCM production.