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http://nopr.niscair.res.in/handle/123456789/16090| Title: | Mechanism of oxovanadium (IV)catalysed and uncatalysed bromate oxidation of lactic acid in acid medium: Evaluation of composite and individual kinetic and thermodynamic parameters |
| Authors: | Reddy, Ch Sanjeeva Kumar, T Vijaya |
| Issue Date: | Nov-1999 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Uncatalysed acid bromate oxidation of lactic acid (LA) exhibits fractional order (1.6) in [acid) and first order each in [Br(V)) and [LA]. Kinetic isotope effect (kH/kD=1) is absent, however an in verse solvent isotope effect (kH2O / kD2O = 1.78 at 313 K) is observed. The mechanism proposed consists of a rate determining formation of bromate ester due to the nucleophilic attack by the alcoholic / hydroxyl group at the bromine atom of HOBrO2/ H2O22Br+O, followed by a fast disproportionation of the ester through C-C bond cleavage to form products. Oxovanadium(lV)-catalysed LA-Br(V) reaction exhibits second order in [acid], fraction al order in [lactic acid) and first order each in [VOSO4] and [oxidant]. The envisaged mechanism assumes a ternary complex formation involving a binary complex of LA and V(IV) and protonated bromate, which subsequently decomposes to the intermediate/products. The rate constants involved for each step of thc react ions are evaluated along with their thermodynamic parameters. |
| Page(s): | 1188-1194 |
| URI: | http://hdl.handle.net/123456789/16090 |
| Appears in Collections: | IJC-A Vol.38A(11) [November 1999] |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| IJCA 38A(11) 1188-1194.pdf | 1.44 MB | Adobe PDF | View/Open |
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