PULSED-LASER INDUCED CHAIN ADDITION-REACTION OF BUTANAL TO DIETHYL MALEATE

By irradiation of a 5/1 mixture of butanal and diethyl maleate with a pulsed Nd-YAG laser (10 Hz, 13 ns), frequency tripled (lambda = 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 yie ld is a function of light intensity and can reach 280 in the range exp lored (I = 3020 to I = 0.303 KW.cm(-2)). The excited aldehyde produces the two radicals nPr-CHOH and nPr-CO. The nucleophilic acyl radical r eacts on the diethyl maleate to form an intermediary radical which giv es the adduct and a new acyl radical in the presence of an aldehyde mo lecule. The second radical nPr-CHOH captures a hydrogen from the aldeh yde producing another acyl radical and butanol.