Effect of alcohols on the photooxidative behavior of diethyl sulfide

The reactions of singlet oxygen with diethyl sulfide (Et(2)S) in benzene alcohol mixtures have been examined. The salient discoveries include: (1) the rate constants of product formation, k(r), in benzene/methanol mixtures are a function of the concentration of methanol, (2) the ability of alcohols to supress physical quenching are a function of their pK(a)'s, and (3) trapping experiments with diphenyl sulfoxide are consistent with two distinct intermediates. A mechanism which involves formation of a persulfoxide followed by reaction with methanol to give a hydroperoxy-methoxy sulfurane is consistent with all of the results.