Kinetic Approach to the Mechanism of Reduction of (7-Amino-8-Methyl-Phenothiazin-3-Ylidene)-Dimethyl-Ammonium Chloride by Thiocyanate Ion in Acidic Medium
The kinetics of reduction of (7-Amino-8-methyl-phenothiazin-3-ylidene)-Dimethyl-Ammonium Chloride (hereafter referred to as TB) by thiocyanate ion have been studied in acidic medium under the pseudo-first order condition of excess [SCN-] at 30 ± 1°C, [H+] = 1 x 10-3 mol dm-3 and ionic strength, I = 0.50 mol dm-3 (NaCl). The stoichiometry of the reaction was observed to be 1:1 mole ratio of TB to SCN ions. The redox reaction follows second order kinetics at constant hydrogen ion concentration and the rate also increases with increase in hydrogen ion concentration. The overall reaction conforms to the rate law.
