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Micellar‐accelerated hydrolysis of organophosphate and thiophosphates by pyridine oximate
Author(s) -
Kandpal Neha,
Dewangan Hitesh K.,
Nagwanshi Rekha,
Ghosh Kallol K.,
Satnami Manmohan L.
Publication year - 2018
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.21217
Subject(s) - chemistry , bromide , cationic polymerization , hydrolysis , micelle , thiophosphate , pyridinium , inorganic chemistry , reaction rate constant , pyridine , ammonium bromide , acid dissociation constant , medicinal chemistry , organic chemistry , pulmonary surfactant , kinetics , aqueous solution , biochemistry , physics , quantum mechanics
Rate constants for the hydrolysis reaction of phosphate (paraoxon) and thiophosphate (parathion, fenitrothion) esters by oximate (pyridinealdoxime 2‐PyOx − and 4‐PyOx − ) and its functionalized pyridinium surfactants 4‐(hydroxyimino) methyl)‐1‐alkylpyridinium bromide ions (alkyl = C n H 2 n +1 , n = 10, 12, 14, 16) have been measured kinetically at pH 9.5 and 27°C in micellar media of cationic surfactants cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB). Acid dissociation constant, p K a , of oximes has also been determined by spectrophotometric, kinetic, and potentiometric methods. The rate acceleration effects of cationic micelles have been explored. Cationic micelles of the pyridinium head group (CPB) showed a large catalytic effect than the ammonium head group (CTAB). The effects of pH, oximate concentration, and surfactants have been discussed.