Interfacial Hydrogen-Bond Network Regulation Tuned Water Dissociation Enables Selective Chlorination of Alkenes

Electrocatalytically selective chlorination of olefins in Cl--containing solutions is a sustainable method for synthesizing chlorohydrin/vicinal dichloride; however, controlling the selectivity is challenging. Here, aqueous/dimethyl carbonate (DMC) hybrid electrolytes with different H2O/DMC ratios are designed to modulate the ·OH formation to increase the corresponding selectivities. The combined results of in/ex situ spectroscopies and molecular dynamics simulations reveal the origin of high selectivity. TFSI- shields the transportation of free H2O to provide moderate ·OH formation for the synthesis of chlorohydrin. DMC reconstructs hydrogen bonds with free H2O to minimize the interaction between them and the anode, matching the requirements of vicinal dichloride production. Thus, these hybrid electrolytes not only achieve high selectivities of 80% and 76% for chlorohydrin and vicinal dichloride, respectively, but also enable the selective chlorination of other olefins with high isolated yields of up to 74%. This work provides a facile strategy to regulate the selectivity of anodic chlorination via a rational electrolyte design.