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Kinetics and mechanism of oxidation of benzohydrazide by bromate catalyzed by vanadium(IV) in aqueous acidic medium
Author(s) -
Shewale S. A.,
Phadkule A. N.,
Gokavi G. S.
Publication year - 2008
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/kin.20296
Subject(s) - chemistry , vanadium , catalysis , bromate , protonation , hydrazide , potassium bromate , ionic strength , inorganic chemistry , reaction mechanism , hydrolysis , aqueous solution , reaction rate , medicinal chemistry , organic chemistry , bromide , ion
The reaction between benzohydrazide and potassium bromate catalyzed by vanadium(IV) was studied under pseudo‐first‐order condition keeping large excess of hydrazide concentration over that of the oxidant. The initiation of the reaction occurs through oxidation of the catalyst vanadium(IV), VO 2+ , to vanadium(V), VO + 2 , which then reacts with hydrazide to give N , N ′‐diacylhydrazine and benzoic acid as the products. The order in [H + ] is found to be two, and its effect is due to protonation and hydrolysis of oxidized form of the catalyst to form HVO 3 . The oxidized form of the catalyst, VO + 2 , forms a complex with the protonated hydrazide as evidenced by the occurrence of absorption maxima at 390 nm. The rate of the reaction remains unaffected by the increase in the ionic strength. The activation parameters were determined, and data support the mechanism. The detailed mechanism and the rate equation are proposed for the reaction. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 151–159, 2008