Ruthenium Chloride Catalyzed Oxidation of Fast Green FCF Dye with 1-Chlorobenzotriazole in HCl Medium: A Spectrophotometric Kinetic and Mechanistic Study

Abstract

Fast Green FCF is a synthetic food dye. The kinetics study of Fast Green FCF with 1-chlorobenzotiale in HCl medium in presence of RuCl3 catalyst has been spectrophotometrically investigated at AE›max 625 nm and at the temperature of 301 K. The reaction exhibited a pseudo -first order rate on [FGF] and first order on each of [CBT], [H+] and [Ru(III)]. Negligible effect was observed by the addition of reduced product [BTA] to the reaction mixture. The addition acrylonitrile under the experimental conditions fails to induce the polymerization. Thermodynamic parameters are calculated. The absence of hydride transfer during oxidation reaction was indicated by the observed solvent isotope effect. Effects of ionic strength dielectric constant of the medium on the reaction rate have been also studied. LC-MS spectral data identifies the oxidation products. An appropriate rate law is deduced by the proposed reaction scheme, which is account for the observed kinetic data.