Reaction of Esters with Thionyl Chloride Catalyzed by Zinc Halides

The ability of esters of primary and secondary alcohols butyl acetate and L‑menthyl acetate (2-isopropyl‑5-methylcyclohexyl acetate) to interact with thionyl chloride in the presence of zinc halides (chloride or bromide) was studied. 1-chlorobutane with a minor admixture of 2-chlorobutane (less than 3.6 %) was the main product of the reactions of butyl acetate. For L‑menthyl acetate, the main product was 2-chloro‑1-isopropyl‑4-methylcyclohexane with minor impurities mainly represented by 1-isopropyl‑4-methylcyclohexene and other six-membered unsaturated hydrocarbons. When ZnBr2 used as a catalyst, impurities of bromo- substituted hydrocarbons were found in the reaction products, which demonstrates the possibility of halogen atoms exchange between zinc halide and the resulting organic products of the reaction