| Autor: |
P. Siddeswaran, H.V.K. Udupa, V.K. Venkatesan, R. Chandrasekharan, C. J. Indira |
| Rok vydání: |
1975 |
| Předmět: |
|
| Zdroj: |
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry. 64:233-246 |
| ISSN: |
0022-0728 |
| DOI: |
10.1016/s0022-0728(75)80019-2 |
| Popis: |
The electroreduction of dialdehyde starch (DAS) on a DME in lithium hydroxide and sodium hydroxide solutions has been studied in detail at temperatures in the range 35–55°C. The polarographic wave has been found to be mainly diffusion controlled. The adsorption of DAS on mercury in lithium hydroxide has been studied with an a.c. bridge. The DAS has been found to be adsorbed in the potential range −0.30 to −1.50 V (vs. SCE). It has also been found that the dissolution of mercury in the potential region −0.3 to −0.1 is reduced in the presence of DAS. The electro-reduction of DAS on a rotating amalgamated gold disc electrode in 1 M NaOH has also been studied by the linear sweep voltammetric technique. The linear sweep voltammograms (l.s.v.) show that the limiting current of the step observed at −1.51 V increases with increasing sweep rate and decreasing rotation speed. The DAS is known to undergo alkaline degradation. The results of the present study indicate that the polarographic wave and the well-defined step in the l.s.v. are due to the reduction of DAS and not due to the reduction of any of the degradation products of DAS such as glycolaldehyde, glyoxylic acid or glyoxal. The increase of the limiting current of the step in the l.s.v. with increasing sweep rate as well as decreasing rotation speed has been explained. The l.s.v.'s obtained after an initial oxidation of Hg at ±0.0 V (vs. SCE) show two well-defined peaks in the potential region where a wide peak due to the reduction of mercuric oxide (in the absence of DAS) is observed. The appearance of these peaks as well as a small peak and a well-defined step at −1.30 V (vs. SCE) in addition to the reduction step due to DAS in the l.s.v. have been explained. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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