C-Based Route for Vinyl Chloride Synthesis with Environmental and Economic Benefits.

Selective coupling of C platform molecules to C olefins is a cornerstone for establishing a sustainable chemical industry based on nonpetroleum sources. Vinyl chloride (CHCl), one of the top commodity petrochemicals, is commercially produced from coal- or oil-derived C hydrocarbon (acetylene and ethylene) feedstocks with a high carbon footprint. Here, we report a C-based route for vinyl chloride synthesis via the selective oxidative coupling of methyl chloride. This is enabled by a solid catalyst, featuring tungstate nanoclusters embedded in a zirconia matrix, which effectively captures ·CHCl radicals homogeneously generated in CHCl oxy-pyrolysis and selectively couples them into CHCl. In situ synchrotron-based vacuum ultraviolet photoionization mass spectrometry provides direct experimental evidence of the homogeneous-heterogeneous reaction mechanism. The process achieves methyl chloride conversion of 10-65% with a high vinyl chloride selectivity (60-75%) at a reaction temperature of 650-750 °C, which is much lower than the traditional pyrolysis (>850 °C). The catalyst delivers stable performance (at a vinyl chloride yield of ca. 30%) with no deactivation observed during a 50 h test. Furthermore, combining with reaction of methanol and HCl to produce methyl chloride, we establish a methanol-to-vinyl chloride (MTV) route with the potential for significant reductions in climate change impact (24%) and cost (38%) compared to the state-of-the-art ethylene-based balanced process. A more remarkable 237% reduction in climate change impacts can be anticipated in the future-oriented green scenario for the MTV process primarily attributed to the utilization of renewable C feedstocks that results in negative net contributions to the overall impacts.