Reaction of tert-butyl hypochlorite with carbonium ion from styrene epoxide in an acidic alcoholic solution

Abstract

The kinetic regularities of the change in the concentration of tert-butyl hypochlorite in the presence of the binary system (BS) styrene epoxide—p-toluenesulfonic acid in a tert-butanol solution were studied using iodometry and HPLC and compared with the data obtained earlier for hydroperoxide decomposition. The expressions for the rates of transformation of Bu^tOCl, epoxide, and ROOH in the BS through the reactant concentrations are of the same type (the first order for the acid and the zero order for epoxide, Bu^tOCl, and ROOH) and indicate that the reactions are related to epoxide heterolysis. Dioxygen ceases ROOH decomposition in the BS but exerts no effect on the decrease in the concentration of Bu^tOCl, which efficiently inhibits the O₂ uptake in the BS and almost an order of magnitude retards the accumulation of benzaldehyde (the product of styrene epoxide oxidation) with a low (up to 15%) decrease in the heterolysis rate. The inhibition effect is due to the heterolytic interaction of Bu^tOCl with the carbocation formed by the cleavage of the three-membered ring of protonated styrene epoxide. The introduction of Bu^tOCl in the BS decreases the stationary concentration of the carbocation and, as a consequence, the stationary concentration of phenylcarbene responsible for O₂ uptake.