The additionrateconstants of five differently substituted benzoyl radicals to butyl acrylate were determined by continuous-wave time-resolved EPR (TR-EPR at X-band (9 GHz) and at W-band (95 GHz)) spectroscopy. Remarkably, the reactivity of the benzoyl radicals, is divided into two domains: One is established at low (<1.25 M) concentrations of butyl acrylate with rateconstants in the range of 106
EPR studies on the photofragmentation of 2,2-dialkyl-2-alkylaminoacetophenones
作者:Detlev Leopold、Hanns Fischer
DOI:10.1039/p29920000513
日期:——
Free radical reactions induced by photolysis of 2,2-dialkyl-2-alkylaminoacetophenone photocuring agents have been studied by continuous wave (CW) and time-resolved EPR spectroscopy. In all solvents alpha-cleavage from the triplet state is the major process. In hydrogen donor solvents it is accompanied by photoreduction followed by a rapid amine elimination from the ketyl radical intermediate. The benzoyl and alpha-aminoalkyl radicals resulting from alpha-cleavage readily add to acrylonitrile whereas radicals formed by photoreduction do not.