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The nature of detectable short-lived intermediates is of extreme importance in studies on the mechanisms of permanganate oxidations of both inorganic and organic compounds.2 In the oxidation of unsaturated carboxylic acids mangane~e(II1)~ and mangane~e(1V)~ have been detected. Manganese(V) ester^^-^ are

The reaction of permanganate ion with pyruvic acid and lactic acid has been studied in aqueous solutions containing 0.10-2.0 mol dm-3 alkali. In this range of HOconcentration the reaction 2Mn04 -+ Substrate -2Mn04 *-+ product is followed slowly by the reduction of manganate, thus, the above process can be studied separately. In the case of lactic acid (LA), the reactive species is alkoxy anion, and the deprotonation constant could be calculated from the kinetic data. A mechanism based on electron abstraction from the alkoxy anion has been proposed. In the case of pyruvic acid (PA) oxidation may proceed with participation of enolate anion, or hydrate anion, or an adduct. These three possibilities have been investigated.

A study was made on the kinetics and mechanism of the reaction 2Mn042-+ Product 2Mn04-+ S in aqueous solutions of 0.10 to 2.0 mol dm-3 alkaline concentrations. The substrates (S) applied were ethane-l,a-diol (ethylene glycol), glycol aldehyde, glycollic acid, and glyoxylic acid. Glycol aldehyde and glyoxylic acid were present in the form of dihydrate. In each case alkoxy anion is the reactive form and the Kg constant of deprotonation can be calculated from the kinetic data.A mechanism based on electron abstraction is suggested. Manganate reacts with these substrates much slower than permanganate.