Abstract

By irradiation of a 5/1 mixture of butanal and diethyl maleate with a pulsed Nd-YAG laser (10 Hz, 13 ns), frequency tripled (λ = 355 nm), diethyl butanoyl succinate is formed by addition. The quantum yield is greater than 1 which means that a chain mechanism occurs which was not the case in previous studies with a mercury lamp. The quantum yield is a function of light intensity and can reach 280 in the range explored (I = 3020 to I = 0.303 KW.cm^-2). The excited aldehyde produces the two radicals nPr-ĊHOH and nPr—ĊO. The nucleophilic acyl radical reacts on the diethyl maleate to form an intermediary radical which givs the adduct and a new acyl radical in the presence of an aldehyde molecule. The second radical nPr—ĊHOH captures a hydrogen from the aldehyde producing another acyl radical and butanol.