Research progress on mercury-free catalysts for acetylene hydrochlorination

As an important thermoplastic, polyvinyl chloride (PVC) is widely used in many fields such as building materials and households. Vinyl chloride monomer (VCM) is the main raw material for the synthesis of PVC. There are two main methods for the synthesis of VCM: acetylene method (also called “calcium carbide method”) and ethylene method. In China, acetylene method based on coal is the mainstream process in the PVC industry, and almost all of the catalysts used are activated-carbon-loaded HgCl2 catalysts. However, the leaching of Hg is causing serious environmental problems. Therefore, research and development of new mercury-free catalysts is an urgent need to achieve a green production of PVC. In this paper, we focus on the research progress of mercury-free catalysts in acetylene hydrochlorination, including three aspects: 1) non-mercury metal-based catalysts such as Au, Ru, Pd; 2) heteroatom-doped carbon-based metal-free catalysts; 3) other types of catalysts, such as nitrides, ionic liquids and molecular sieve.