Premium
Surfactant Effect on Kinetic of Reaction of Some Sulphonamides with p ‐Dimethylaminobenzaldehyde: Surfactant‐Modified Determination of Sulphonamides in Aqueous Solution
Author(s) -
Khalil Rabah A.,
AlKhiro Bashar Z.
Publication year - 2006
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200600084
Subject(s) - chemistry , aqueous solution , pulmonary surfactant , reaction rate constant , kinetics , reaction rate , sodium , inorganic chemistry , condensation reaction , chromatography , nuclear chemistry , organic chemistry , biochemistry , physics , quantum mechanics , catalysis
Kinetics of condensation reactions of six sulpha drugs (I‐VI) with p ‐dimethylaminobenzaldehyde (DAB) in a weakly acidic EthOH/H 2 O solution have been studied spectrophotometrically. The reaction was found to be first order with respect to DAB and zero order with respect to sulphonamide. The rate constants, activation energies, and other related thermodynamic functions have been determined. The effect of the presence of anionic surfactant sodium dodecyl sulphate (SDS) on the kinetics of this reaction in aqueous solution has been investigated. The observed rate constants increase with increasing the amount of SDS except for those of sodium sulphacetamide (VI). The surfactant molecules enhance the reaction rates (14–113 times) in concentrations less than critical micellar concentration (cmc). A developed spectrophotometric method for determining sulphonamides in aqueous solution by their reactions with an excess of DAB in the presence of SDS and HCl (pH = 2) at a wavelength of 447 nm has been introduced. Microgram amounts of sulphonamides can be estimated with accuracy better than ± 1.5% and reproducibility less than ± 0.064%. The results of application to sulphonamides in pure form indicate that the presented method is simple, sensitive, precise, accurate, and comparable to the colorimetric Bratton‐Marshall standard procedure. The effect of interferences and application of the presented method to two pharmaceutical preparations have been investigated.