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Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.46A [2007] >
IJC-A Vol.46A(09) [September 2007] >
| Title: | Oxidation of aspartic acid by water soluble colloidal MnO₂ in absence and presence of ionic and nonionic surfactants |
| Authors: | Akram, Mohd.
Altaf, Mohammad
Din, Kabir-ud |
| Issue Date: | Sep-2007 |
| Publisher: | CSIR |
| IPC Code: | Int. Cl. ⁸ C07B33/00 |
| Abstract: | The kinetics of the oxidation of aspartic acid by water-soluble form of colloidal manganese dioxide has been studied in acidic perchlorate media. Monitoring the disappearance of the colloidal MnO₂ spectrophotometrically at 390 nm has been used to follow the kinetics. The reaction is first-order in both [MnO₂] and [aspartic acid] but fractional-order in [HClO₄]. The results suggest formation of an adsorption complex between aspartic acid and MnO₂. The complex decomposes in a rate-determining step, leading to the formation of a free radical, which again reacts with the colloidal MnO₂ in a subsequent fast step to yield the product. The anionic micelles of sodium dodecyl sulfate have no effect on the oxidation rate whereas the rate constant increased with increase in [TX-100] which has been explained in terms of mathematical model proposed by Tuncay et al. A mechanism in agreement with the observed kinetic results is proposed and discussed. Freundlich isotherm is used to explain the adsorption of aspartic acid on colloidal MnO₂. Different activation parameters (Ea, ΔH#, ΔS#) have been evaluated and discussed. |
| Page(s): | 1427-1431 |
| ISSN: | 0376-4710 |
| Source: | IJC-A Vol.46A(09) [September 2007]
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