- 作者: --
- 作者服務機構: Department of Chemistry, College of Science, University of Mosul, Mosul, Iraq
- 中文摘要:
Kinetics of condensation reactions of six sulpha drugs (I-VI) with p-dimethylaminobenzaldehyde (DAB) in a weakly acidic EthOH/H2O 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. - 英文摘要: --
- 中文關鍵字: Sulpha drugs; Sulphonamide; p-Dimethylaminobenzaldehyde; Sodium dodecyl sulphate; Surfactant.
- 英文關鍵字: --