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Kinetics of oxidation of some meta‐ and para‐substituted phenyl methyl sulfoxides by chloramine‐T in buffered ethanol–water
Author(s) -
Ganapathy K.,
Jayagandhi P.
Publication year - 1983
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.550150204
Subject(s) - chemistry , sulfoxide , disproportionation , chloramine t , kinetics , reaction rate constant , medicinal chemistry , ethanol , rate equation , reaction rate , dimethyl sulfoxide , order of reaction , rate determining step , first order , inorganic chemistry , photochemistry , organic chemistry , catalysis , physics , quantum mechanics , mathematics
The kinetics of oxidation of methyl phenyl sulfoxide by chloramine‐T (CAT) has been studied in buffered ethanol–water (1:1 v/v) of pH 7.0. The reaction was found to follow no simple‐order kinetics. A possible mechanism is suggested involving three rate‐controlling steps: (1) the reaction between RNHCl (R = CH 3 C 6 H 4 SO 2 ) and the sulfoxide, (2) the disproportionation of RNHCl, and (3) the reaction between RNCl 2 and the sulfoxide. A mixed‐order rate law is derived as rate/[C][SO] = k 1 + K d k 2 [C]/[SA]. The rate law is found to be obeyed for the meta‐ and para‐substituted phenyl methyl sulfoxides also. The ρ value is obtained using Hammett's σ constants. The ρ values obtained for the attack of both RNHCl and RNCl 2 with the sulfoxides are almost the same, showing that both are converting the sulfoxide to the same intermediate. A chlorinium ion transfer is suggested.