A study was made of the oxidation of p, p'-dichlorobenzyl sulfide to sulfoxide by peroxybenzoic and p-methoxyperoxybenzoic acids in toluene, and by peroxybenzoic, p- methoxy-, p-methyl-, p-chloro-and p-nitroperoxybenzoic acids in isopropyl alcohol. The differences in oxidation rates between peroxyacids were found to be influenced approximately 60% by differences in activation energy and 40% by differences in ...