Kinetics and mechanism of reaction of [[4-nitrophenyl] sulphonyiy] acetic acid with alkali in diaoane-water media

ABSTRACT

The reaction of [[4-nitrophenyl]methyl]sulphonyl]acetic acid with sodium hydroxide in aqueous-dioxane media leads to the reduction of the vitro group with the formation of 4,4-diformylazoxybenzene and 4,4-dicarboxyazoxybenzene as the main reaction products. The reaction mechanism was verified by trapping of the intermediates namely [alpha-hydroxy-4-nitrosobenzyl]sulphonyl acetic acid, and 4-nitrosobenzaldehyde as well as the H/D exchange of the active methylene group in the parent compound. The kinetics of the reaction with excess alkali in different dioxane-water mixtures were studied spectrophotometrically. The rate constants of the two consecutive steps of the reaction and their activation thermodynamic parameters were calculated and discussed on the bases of the solvent composition of the media. A comparison of the reactivity with that of the corresponding sulphide was also discussed