PHOTOINITIATORS AND PHOTOINITIATION .10. THE PHOTODECOMPOSITION OF SOME CARBOXYLIC ESTERS OF ALPHA-HYDROXYMETHYLBENZOIN

Authors
GROENENBOOM CJ HAGEMAN HJ OOSTERHOFF P OVEREEM T VERBEEK J
Citation
Cj. Groenenboom et al., PHOTOINITIATORS AND PHOTOINITIATION .10. THE PHOTODECOMPOSITION OF SOME CARBOXYLIC ESTERS OF ALPHA-HYDROXYMETHYLBENZOIN, Journal of photochemistry and photobiology. A, Chemistry, 107(1-3), 1997, pp. 253-259
Citations number
44
Categorie Soggetti
Chemistry Physical
Journal title
Journal of photochemistry and photobiology. A, Chemistry → ACNP
ISSN journal
10106030
Volume
107
Issue
1-3
Year of publication
1997
Pages
253 - 259
Database
ISI
SICI code
1010-6030(1997)107:1-3<253:PAP.TP>2.0.ZU;2-I
Abstract
The photodecomposition of some carboxylic esters of alpha-hydroxymethy lbenzoin was studied using electron spin resonance (ESR) and proton nu clear magnetic resonance-chemically induced dynamic nuclear polarizati on (H-1 NMR-CIDNP) techniques. Exclusive alpha-cleavage into benzoyl a nd alpha-hydroxy-alpha-acyloxymethylbenzyl radicals through the triple t excited state was observed. The alpha-hydroxy-alpha-acyloxymethylben zyl radicals mainly undergo disproportionation with the other radicals present to give benzoylmethyl carboxylates. Elimination of carboxylic acids from the alpha,alpha-disubstituted benzyl radicals occurs to so me extent, but at a much lower rate than the elimination of sulphonic acids from the corresponding alpha-hydroxy-alpha-sulphonyloxymethylben zyl radicals generated from the sulphonic esters of alpha-hydroxymethy lbenzoin. (C) 1997 Elsevier Science S.A.