Study on Catalyst Deactivation Mechanism During Cracking of 1, 1, 2-Trichloroethane to Vinylidene Chloride

In order to explain the deactivation mechanism of the catalyst during the catalytic cracking of 1, 1, 2-trichloroethane to vinylidene chloride, the gas-phase catalytic cracking reaction was designed to obtain the deactivated catalyst. Solid-phase microextraction GC-MS characterization was performed to confirm deactivated species on the surface of the deactivated catalyst. Combining the characterization results and first-principles DFT calculations, a possible inactivation reaction pathway is proposed. Under the condition that cesium chloride supported coconut shell activated carbon is used as a catalyst, 1, 1, 2-trichloroethane is cracked to remove one molecule of hydrogen chloride to generate dichloroethylene. In the actual reaction process, tandem side reactions will occur to generate chloroacetylene, which is an unstable species. Chloroacetylene will self-polymerize to form dichlorobutadiene, and further self-polymerize to form aromatic compounds, which become the precursors of carbon deposition, thus covering the active components on the catalyst surface to cause catalyst deactivation. These conclusions perfectly explain the deactivation of the catalyst during the catalytic cracking of 1, 1, 2-trichloroethane to vinylidene chloride, thus providing an excellent theoretical basis for further research on methods to inhibit deactivation. Breaking through the key problem of catalyst deactivation will make it possible to replace the saponification reaction with catalytic cracking in industry.