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The kinetics of the reactions of peroxydisulphate with alcohols (methanol, ethanol, propan-1 -01, propan-2-01, and butanol) and with acetaldehyde have been studied. Their radical-chain behaviour has been established. Using a radical-scavenger method it has been shown that the chain-initiating step is the monomolecular homolysis of the peroxydisulphate anion. The 'limiting' concentration of the reducing agents, the mean kinetic chain length, and the overall energy of activation have been determined. The mechanism of the autoinhibition of the reaction of primary alcohol with peroxydisulphate has been discussed.Analysis of literature data shows that there are two main and contradictory opinions on the mechanism of alcohol oxidation with peroxydisulphate ion, radical-chain and non-radical mechanisms. Bartlett and Cotman' have reported that in the presence of methanol the rate of peroxydisulphate decomposition increases 25-fold and the overall rate law is (1). Theseauthors suppose that the reaction is radical-chain, and there are two parallel reactions for the chain initiation, monomolecular and bimolecular [reactions (2) and ( 3)]. Kolthoff et d 2 have Levitt and Malinowski l 1 have investigated the propan-2-01 oxidation at temperatures 2 50 "C. They established the rate law (7) where 0 ,< n ,< 1. n depends on the alcohol R = k[P][PriOH]" (7) concentration. The overall energy of' activation was 25 kcal mol-'. anions decreased the reaction rate. They put forward the heterolytic monomolecular cleavage (8) of S 2 0 8 2 -S2OS2-SO4'-+ so4 (8) S20a2 + CH30H -HS04-+ SO4-' + e H 2 0 H (3)

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