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Studies on toluidine blue reaction with sulfite in aqueous solution and role of Cu(II) as promoter
Author(s) -
Jonnalagadda S. B.,
Gollapalli N. R.
Publication year - 1999
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1999)31:8<539::aid-kin3>3.0.co;2-u
Subject(s) - chemistry , toluidine , sulfite , protonation , reaction rate constant , aqueous solution , ionic strength , stoichiometry , inorganic chemistry , reaction mechanism , ternary operation , reaction rate , sodium sulfite , limiting , catalysis , ion , kinetics , sodium , organic chemistry , physics , quantum mechanics , computer science , engineering , programming language , mechanical engineering
The kinetic and mechanistic details of the reaction between toluidine blue and sulfite were studied spectrophotometrically by monitoring the depletion of toluidine blue at 633 nm. The reaction had first‐order dependence on both the reactants, a stoichiometric ratio of 1:1 and a negative salt effect indicating the participation of TB + and SO 3 2− ions in the rate‐limiting step. The reaction products were leuco base of toluidine blue and sulfate. The reaction was pH dependent and hence studied at its optimum pH 7.2. Cu(II) acted as promoter by facilitating the formation of a ternary complex with the reactants. The protonation and stability constants of the reactants were determined and used in validating the mechanism. The activation parameters for the reactions in absence and presence of Cu(II) were determined and compared with other systems. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 539–549, 1999