A study was made of the autooxidation of benzoin in organic-aqueous sodium hydroxide emulsions in the presence of several quaternary ammonium salts. The rate of the reaction was found to be accelerated by these salts, probably by ion pair extraction. In pyridine and acetonitrile systems the reaction was almost exclusively the formation of benzoate. Neither benzil nor benzaldehyde were intermediates in the oxidation process. The rate law for the reaction was found to be which led to the conclusion that the rate-determining step in the catalyzed pathway was the reaction of oxygen with the ion pair:
which led to the conclusion that the rate-determining step in the catalyzed pathway was the reaction of oxygen with the ion pair: 