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Oxidation of mandelic acid by alkaline potassium permanganate. A kinetic study
Author(s) -
Panari Rafeek G.,
Chougale Ravindra B.,
Nandibewoor Sharanappa T.
Publication year - 1998
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199807)11:7<448::aid-poc23>3.0.co;2-a
Subject(s) - chemistry , mandelic acid , permanganate , potassium permanganate , ionic strength , inorganic chemistry , manganate , reaction rate constant , alkali metal , reaction mechanism , reaction rate , aqueous solution , activation energy , kinetics , organic chemistry , catalysis , thermodynamics , power (physics) , physics , battery (electricity) , quantum mechanics
The kinetics of the oxidation of mandelic acid (MA) by permanganate in aqueous alkaline medium at a constant ionic strength of 1.0 mol dm −3 were studied spectrophotometrically. The reaction shows first‐order kinetics in [permanganate ion] and fractional order dependences in [MA] and [alkali]. Addition of products, manganate and aldehyde have no significant effect on the reaction rate. An increase in ionic strength and a decrease in dielectric constant of the medium increase the rate. The oxidation process in alkaline medium under the conditions employed in the present investigation proceeds first by formation of an alkali permanganate complex, which combines with mandelic acid to form another complex. The latter decomposes slowly followed by a fast reaction between the free radical of mandelic acid and another molecule of permanganate to give products. The reaction constants involved in the mechanism were derived. There is good agreement between the observed and calculated rate constants under different experimental conditions. The reaction was studied at different temperatures and activation parameters were computed with respect to the slow step of the proposed mechanism. © 1998 John Wiley & Sons, Ltd.