THE APPLICATION OF INSITU ELECTROCHEMICAL ELECTRON-SPIN-RESONANCE TO EC AND ECE PROCESSES - THE REDUCTION OF 2-NITROPROPANE
Radical intermediates may be generated at a channel electrode located within an ESR cavity. Theory describing the ESR signal-flow rate-current behaviour for EC and ECE processes is given where the chemical step is assumed to be first-order. An analytical expression for the current-flow rate variatio...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1984
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| Summary: | Radical intermediates may be generated at a channel electrode located within an ESR cavity. Theory describing the ESR signal-flow rate-current behaviour for EC and ECE processes is given where the chemical step is assumed to be first-order. An analytical expression for the current-flow rate variation for an ECE process at a channel electrode is also given. Experiments carried out on the reduction of 2-nitropropane at mercury electrodes in the pH range 8.6-10.5 are described. ESR signals due to the 2-nitropropane radical anion were seen and the reduction shown to be an ECE process. Experimental data was found to be in good agreement with theory. Measurements of the rate constant for the decay of the 2-nitropropane radical anion from four independent methods namely from the steady-state ESR signal, transient ESR signals, the current-flow rate behaviour and also the current-rotation speed variation at a rotating disc electrode all gave values close to 0.30 s-1. The mechanism of the reduction is discussed and an estimate made of the shortest lived radical that might be studied by in situ electrochemical ESR. © 1984. |
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