Phenylmethylene, an intermediate of perchloric acid catalyzed oxygen absorption by styrene oxide in a polar solvent

Under conventional conditions of styrene oxide conversion catalyzed by perchloric acid in an alcohol solution (ButOH-chlorobenzene (9 : 1 by vol.), 343 K), an iminium ylide absorption band (λmax ≈ 460–470 nm) was recorded in the presence of pyridine trap, which corresponds to the adduct of pyridine and phenylmethylene. In the presence of oxygen, another intermediate product was detected, the absorption band of which (λmax ≈ 400 nm) coincides with the corresponding carbonyl oxide absorption. A similar observation was made earlier for the acid-catalyzed conversion of styrene oxide in the presence of p-toluenesulfonic acid in alcohol and acetonitrile solutions. Thus, the obtained results confirm formation of active intermediate species of carbene nature in two epoxide-acid systems.