Advances in Single-Atom-Catalyzed Acetylene Hydrochlorination

Abstract

The growing demand for polyvinyl chloride (PVC) calls for a cleaner technology for its production. Nonetheless, acetylene hydrochlorination, an industrially relevant technology for the manufacture of vinyl chloride monomer of PVC, is hampered by the use of toxic and volatile mercury chloride catalysts that pose severe threads to human health and the environments. This stimulated numerous research studies in the past decades on hunting alternative candidates to replace the mercury catalysts. Among the large numbers of catalyst families, distinct single-atom metal catalysts have been predicted or demonstrated as promising catalytic systems in the hydrochlorination chemistry, thus stimulating a wave in the broader explorations of this distinctive catalyst group in the last five years. In this Review, we summarize the recent advances of singleatom catalysts in acetylene hydrochlorination with the focus on their synthesis methods, catalytic performance, and reaction mechanism. The catalyst categories include single metal atoms of Au, Pt, Pd, Ru, Cu, and Fe and diatomic systems. Perspectives on the challenges and directions for future development regarding the innovation of synthetic strategies, recognition of performance descriptors, and developments of on-site characterization techniques are provided.

Asymmetric Ru-In atomic pairs promote highly active and stable acetylene hydrochlorination

“…Coke accumulation is an important indicator for measuring the stability of catalysts, thus, thermogravimetry (TG) was applied to determine coke deposition through the weight loss differences 56 , 57 . Fortunately, slight coke deposits (ca.…”

Progress in mercury-free catalysts for acetylene hydrochlorination

“…1 Particularly in China, PVC production surpasses 25% of the total output of the five major general plastics. 2,3 In industry, VCM serves as an essential chemical monomer for the production of PVC. 4 Today, ethylene-based and acetylene-based processes are primarily employed for VCM production (Fig.…”

Lattice-Strain Engineering in Ni–Ru Heterostructures for Efficient Acetylene Hydrochlorination toward Vinyl Chloride

“…Acetylene hydrochlorination is a crucial industrial process for the production of vinyl chloride monomer (VCM), the precursor of polyvinyl chloride (PVC). − However, commercial activated carbon-supported mercury chloride (HgCl 2 /AC) catalysts have faced strict restrictions due to the Minamata Convention on Mercury . − Considerable efforts have been dedicated to developing sustainable nonmercury catalysts, among which Ru-based catalysts have emerged as the most promising alternatives owing to their potent chlorine activation capability. − Nonetheless, effective C 2 H 2 activation to yield *CHCH species over Ru centers encounters challenges due to the elevated bond energy (835 kJ/mol) of the CC triple bond. − Furthermore, the formation of *CH 2 CH intermediates is also constrained by the targeted introduction of atomic *H to the *CHCH species, thereby compromising the overall hydrochlorination performance (Scheme S1). − Therefore, a highly efficient C 2 H 2 activation over the Ru structures has become the compelling objective for attractive VCM production.…”