This thesis consists of a study of the reactions of certain organic peroxoacids with certain model stain molecules. The peroxoacids in question were peroxobenzoic and monoperoxophthalic acid. The model compounds were; methyl orange, methyl red, flavone, alizarin, salicylaldoxime and salicylaldehyde. A brief study was also made of the reactions of peroxobenzoic acid with; para-vinylbenzoic acid, sorbic acid, cinnamic acid, ethanol and acetaldehyde. Rate versus pH plots were developed and, where possible, reaction products were identified and mechanisms suggested. In some cases activation parameters were measured. The possibility of transition metal ion catalysis was investigated in most cases.