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Kinetics and mechanism of autocatalyzed reaction between Phenyl Hydrazine and Toluidine blue in aqueous solution
Author(s) -
Jonnalagadda S. B.,
Nattar K.
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)31:2<83::aid-kin1>3.0.co;2-6
Subject(s) - chemistry , toluidine , hydrazine (antidepressant) , aqueous solution , kinetics , mechanism (biology) , reaction mechanism , photochemistry , organic chemistry , catalysis , chromatography , physics , quantum mechanics , philosophy , epistemology
The kinetics and mechanism of reduction of aqueous toluidine blue (TB + ) by phenyl hydrazine (Pz), which exhibits nonlinear behavior, is studied spectrophotometrically at 630 nm. Typical kinetic curves exhibited autocatalytic characteristics. The role of H + as an autocatalyst is established. Rate constants for the uncatalyzed and acid catalyzed reactions are determined. The forward rate constants for the uncatalyzed and acid catalyzed reactions were 1.4 × 10 −2 M −1 s −1 and 60 M −1 s −1 . Reaction products are toluidine white, phenol, and an azo dye. From the stoichiometric ratios, the major reaction is Pz + 2 TB + + H 2 O = PhOH + 2 TBH + 2 H + + N 2 . The rate expression and a detailed 12‐step reaction mechanism supported by simulations are proposed. ©1999 John Wiley & Sons, Inc. Int J Chem Kinet: 31: 83–88, 1999