The oxidative degradation and C–C coupling reaction of dibenzoazepine derivatives by peroxydisulfate ion and sulfate radical in aqueous mediaReport as inadecuate




The oxidative degradation and C–C coupling reaction of dibenzoazepine derivatives by peroxydisulfate ion and sulfate radical in aqueous media - Download this document for free, or read online. Document in PDF available to download.

Reaction Kinetics, Mechanisms and Catalysis

, Volume 107, Issue 1, pp 1–17

First Online: 22 June 2012Received: 13 April 2012Accepted: 26 May 2012

Abstract

The kinetics of the oxidation of imipramine and opipramol using peroxydisulfate salts in the presence of a large excess of dibenzoazepine derivative TCA in acidic sulfate media was studied using UV–vis spectroscopy. The reaction between imipramine and S2O8 proceeds via the formation of two intermediates: a free organic radical and a dimeric dication. Further reaction of the intermediate dimeric dication leads to a positively charged radical dimer as one final product. Simultaneously, two other substituent cleavage degradation processes occur, leading to two dimeric derivatives. The first product, the positively charged radical dimer, and the next main product, a radical dimer without one alkyl substituent, were identified by EPR measurements. The measured kinetic trace is not first order and revealed a sigmoid shape with a characteristic induction time. The rate constants were determined by numerical analysis based on ordinary differential equations ODEs. The reaction between opipramol and S2O8 proceeds by a two consecutive reaction scheme. The kinetics of the first degradation step were studied independently of the slower degradation reactions. Linear dependences, with zero intercept, of the pseudo-first-order rate constants kobs on TCA were determined for the first degradation process of opipramol.

KeywordsDibenzoazepines  Imipramine Opipramole Kinetics  Oxidative degradation Electronic supplementary materialThe online version of this article doi:10.1007-s11144-012-0463-z contains supplementary material, which is available to authorized users.

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Author: Joanna Wiśniewska - Grzegorz Wrzeszcz - Stanisław Koter - Tomasz Ligor

Source: https://link.springer.com/







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