Kinetics and mechanism of oxidation of DL-α-alanine by permanganate ion in acid perchlorate media

Abstract

REFAT M. HASSAN. Can. J. Chem. 69, 2018 (1991. The kinetics of permanganate oxidation of DL-a-danine in aqueous perchloric acid solution at a constant ionic strength of 2.0 mol dm-' has been investigated spectrophotomemcally. The reaction was found to show second-order kinetics overall with respect to each of the reactants in the slow initial stage; the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. The added salts lead to the prediction that Mn(II1) and (or) Mn(IV) play a very important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed.Key words: kinetics, oxidation, reduction, amino acids, permanganate.REFAT M. HASSAN. Can. J. Chem. 69, 2018 (1991). Faisant appel i une mtthode spectrophotomttrique et opCrant en solution aqueuse d'acide perchlorique i une force ionique constante de 2.0 mol dm-3, on a CtudiC la cinttique de l'oxydation de la DL-a-alanine par le permanganate. On a trouv6 que, dans sa phase initiale lente, la reaction est globalement du deuxikme ordre impliquant chacun des rtactifs; toutefois, cette cinttique n'est pas maintenue dans la phase finale, relativement rapide, de la rCaction. L'effet des sels ajoutCs laisse croire que les ions Mn(II1) et (ou) Mn(IV) jouent des r6les trbs importants dans la cinktique de la rtaction. On discute d'un mCcanisme qui serait en accord avec la cinCtique observte.

Autocatalytic Oxidation of Thiamine Hydrochloride (Vitamin B1 ) by Permanganate in Aqueous Sulfuric Acid Medium: A Kinetic and Mechanistic Study

“…From the values of slope and k 1 , K 1 was calculated, K 1 = 0.67 ± 0.05 mol dm −3 at 25°C. The obtained value of K 1 agrees reasonably well with the literature [10]. Using these values, the rates under different experimental conditions were calculated and compared with experimental data.…”

“…In general, reduction of the permanganate, in acid media goes to either Mn(IV) or Mn(II) having the reduction potential [9] of the couple Mn(VII)/Mn(IV): 1.695 V and Mn(VII)/Mn(II): 1.51V. In acid medium, it exists in different forms, viz., HMnO 4 , H 2 MnO 4 + , HMnO 3 , Mn 2 O 7 , and depending on the nature of the reductant the oxidant has been assigned both the inner sphere and outer sphere mechanism pathways in their redox reactions [10,11].…”

Kinetics and mechanism of the reduction of gold(III) by glycine in acetate buffer

“…There are reports on the oxidation of glycine by diperiodatoargentate(III) [18] and pyridinium bromochromate [34], where the products were HCHO along with NH 4 + and CO 2 . Oxidation of DL-alanine [35], b-phenyl alanine [35,36] and DL-leucine [37] gave rise to the formation of similar reaction products like NH 4 + , CO 2 and the corresponding aldehydes. On the basis of the proposed mechanism, the rate of disappearance of Au(III) may be written as…”

Novel synthesis of diketocarboxymethyl‐celluose as bipolymer precursors

“…Although permanganate ion is a powerful oxidizing agent for most organic substrates, [1][2][3][4][5][6] the oxidation of macromolecules by this oxidant has received little attention.…”