Innovative Dual–Reactor Reaction-Separation System for High-Stereoselective Synthesis of <i>Trans</i> -1,2-dichloroethylene

A liquid-phase photochemical-reaction-separation coupling process based on a tandem dual-reactor system for high-stereoselective synthesis of trans -1,2-dichloroethylene ( trans -DCE) under metal catalyst-free conditions was designed. This process induces chlorine gas cleavage via ultraviolet light to generate chlorine radicals and transfers acetylene into the liquid phase using acetonitrile solvent, thereby enhancing the process selectivity, safety, and efficiency. Experimental results demonstrate that, under optimized operating conditions, the initial selectivity toward trans -DCE reaches 84.7% and remains above 70% after continuous operation for 5 h. Mechanistic and semiempirical kinetic modeling revealed the formation pathway of the tetrachloroethane byproduct. The established kinetic models align with quantum chemical calculation results, revealing the superiority of the trans pathway. This study provides a scalable high stereoselective synthesis method and offers theoretical foundations and engineering paradigms for the industrial application of highly reactive gases.