Identification of phenylmethylene in alcohol-water solutions in the presence of pyridine and hydrogen peroxide

Abstract

Alcoholic solutions (ButOH: chlorobenzene, 9: 1 v/v) of the styrene epoxide-p-toluenesulfonic acid system (Ar, 343 K) containing H2O2 were studied. Hydrogen peroxide was used for the first time as a competing with pyridine reagent-interceptor of phenylmethylene intermediates in order to study the possibility of their spectrophotometric identification under conditions of an inert atmosphere. In the presence of fixed amounts of water and different types of carbene traps (pyridine, oxygen, hydrogen peroxide), difference spectra of solutions of the epoxy-acid system were obtained, which confirmed the formation of phenylmethylene intermediates under these conditions. The results of measuring the rate of oxygen absorption by solutions of the system containing traps made it possible to estimate the ratio of the rate constants for the reaction of phenylmethylene with oxygen and hydrogen peroxide.