A Kinetic-Study Of The Oxidation Of L-Ascorbic-Acid (Vitamin-C) In Solution Using An Isothermal Microcalorimeter

Wilson, R.J. and Beezer, A.E. and Mitchell, J.C. (1995) A Kinetic-Study Of The Oxidation Of L-Ascorbic-Acid (Vitamin-C) In Solution Using An Isothermal Microcalorimeter. Thermochimica Acta, 264 . pp. 27-40. ISSN 0040-6031. (The full text of this publication is not available from this repository)

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Official URL
http://dx.doi.org/10.1016/0040-6031(95)02373-A

Abstract

This paper reports the results of a microcalorimetric study of the oxidation of L-ascorbic acid in solution. The study of the oxidation reaction was carried out under varying conditions of pH, oxygen concentration, ascorbic acid concentration, temperature, addition of ethylene-diaminetetraacetic acid (EDTA) and addition of a radical scavenger. From these results it is proposed that ascorbic acid is oxidised in solution by molecular oxygen via an ascorbic acid radical, formed from the interaction of ascorbic acid and free metal in solution. The oxidation product, dehydroascorbic acid, then goes on to form other products by hydrolysis. The change in enthalpy associated with the oxidation reaction was determined as - 130.9 kJ mol(-1) and the reaction has a first order rate constant, with respect to the oxygen concentration, of 1.8 x 10(-4) s(-1). The rate of oxidation was found to increase with pH, oxygen concentration and concentration of metal in solution.

Item Type: Article
Uncontrolled keywords: ASCORBIC ACID; ISOTHERMAL MICROCALORIMETRY; KINETIC PARAMETERS; MECHANISM OF REACTION; THERMODYNAMIC PARAMETERS
Subjects: Q Science
Depositing User: I.T. Ekpo
Date Deposited: 29 Jun 2011 09:34
Last Modified: 29 Jun 2011 09:34
Resource URI: http://kar.kent.ac.uk/id/eprint/19133 (The current URI for this page, for reference purposes)
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