Kinetics and mechanism of reaction of toluidine blue with acidic bromate

✍ Scribed by S. B. Jonnalagadda; N. Musengiwa

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 209 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:2<111::aid-kin2>3.0.co;2-v

✦ Synopsis

The detailed kinetics of the reaction of toluidine blue {phenothiazine-5-ium, 3amino-7(dimethylamino)-2-methyl chloride, tolonium chloride, with potassium bro-ϩ Ϫ TB Cl } mate and with aqueous bromine reaction were studied. In most of the experiments, the kinetics were monitored by following the rate of consumption of at with excess acid ϩ TB 590 nm and bromate. The reaction exhibited complex kinetic behavior. Initial reaction was slow and after an induction time, the concentration decreased fast. It had first-order dependence ϩ TB on both and bromate, and second-order dependence on Under excess bromate con-ϩ ϩ TB H . ditions, the stoichiometric ratio of to bromate was Demethylated sulfoxides were ϩ TB 1 : 1. found at the reaction products. Sharp increase in the overall potential synchronized with the increase in bromine levels and the fast depletion of The role of bromide ion and bromine ϩ [TB ]. in the reaction was established. A multi-step reaction mechanism is proposed consistent with the experimental results.