| Autor: |
Mukai, Masahiro, Yamauchi, Seigo, Hirota, Noboru, Koyanagi, Motohiko, Futami, Hiroshi |
| Zdroj: |
Bulletin of the Chemical Society of Japan; June 1992, Vol. 65 Issue: 6 p1679-1684, 6p |
| Abstrakt: |
The photochemical α-cleavage reactions of benzoin, benzoin methyl ether (BME) and deoxybenzoin (DOB) in methylcyclohexane and benzene have been studied by means of the time-resolved EPR technique. Strong emissive CIDEP spectra of the radicals produced by the α-cleavage reactions are observed in benzoin and BME. From the analysis of the hyperfine splittings they are assigned as benzoyl and α-hydroxybenzyl radicals in the case of benzoin and benzoyl and α-methoxybenzyl radicals in BME. It is clearly shown that the cleavage reaction takes place in the T1(nπ*) states of these carbonyls and the triplet mechanism (TM) is mainly responsible for the CIDEP spectra. From the time profile of the CIDEP signals it is also shown that the produced radicals react almost exclusively with each other. In the case of DOB, the α-cleavage is found to be much less efficient and a hydrogen abstraction reaction is more dominant at room temperature. It is concluded that the cleavage rate constant (kc) is in the order, kc(BME) > kc(benzoin) >> kc(DOB). |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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