Selective coupling of methyl chloride to vinyl chloride over dispersed NaVO3

Vinyl chloride (C₂H₃Cl) is an important monomer in polymer chemistry. Its polymer product, polyvinyl chloride (PVC), ranks among the five major general-purpose plastics. Currently, the industrial production of vinyl chloride monomer (VCM) primarily includes direct hydrohalogenation of coal-derived acetylene using toxic HgCl₂ catalysts, ethylene generated from petroleum undergoes direct chlorination and oxychlorination via the ethylene balance process (EBP), and the thermal cracking of ethylene dichloride (EDC). Since the middle of the 1950s, these processes have been extensively utilized by vinyl chloride manufacturers and constitute practically the entirety of global production capacity. However, existing vinyl chloride production processes face several challenges, including high raw material costs, significant energy consumption, and substantial pollution, prompting the search for new approaches with industrial application prospects. Recent studies indicate that using ethane derived from natural gas as a raw material can produce vinyl chloride at a lower cost and with reduced CO₂ emissions, however, it still relies on C₂ hydrocarbons for production. Consequently, synthesizing vinyl chloride from cost-effective and sustainable C₁ raw materials, while minimizing environmental repercussions, continues to pose a considerable challenge. The production of C₂H₃Cl from CH₃Cl (MCTV) represents a promising non-petroleum route for synthesizing C₂ alkenes from C₁ molecules. Exploration of new MCTV catalysts is crucial for advancing its sustainable chemical industry.

Recently, a research team led by Prof. Jie Fan from Zhejiang University, China demonstrated highly dispersed NaVO₃ nanoparticles on the surface of CeO₂ can effectively capture ^•CH₂Cl radicals from the oxidative pyrolysis of CH₃Cl and selectively convert them into C₂H₃Cl, achieving a C₂H₃Cl selectivity of 56.7% and a CH₃Cl conversion of 56.6% at 750 °C. They validated the controllable coupling of ^•CH₂Cl radicals over highly dispersed NaVO₃ using in-situ synchrotron-based vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS).

The findings suggests that enhanced dispersion of NaVO₃ can improve the reaction efficiency of ^•CH₂Cl radicals, thereby promoting their controllable transformation into C₂H₃Cl. Overall, our results provide direct experimental evidence that the highly dispersed NaVO₃ acts as new active sites for the surface-confined coupling of ^•CH₂Cl radicals, highlighting that increasing the dispersion of metal oxyacid active sites in coupling catalysts can enhance the reaction efficiency of radicals and improved MCTV performances. These findings represent a significant advancement in the controlled transformation of C1 radicals and provide a guidance for the design of advanced coupling catalysts for MCTV. The results were published in Chinese Journal of Catalysis (DOI: 10.1016/s1872-2067(25)64732-2).    2022YFA1505500 92045301  91845203

About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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