Photolyse du propène et du méthyl-2-butène-2 vers 174 et à 163 nm

Abstract

We have studied the 163 nm photolysis of propene and of 2-methyl-2-butene and a few results on the 174 nm photolysis of propene are also included. At 163 nm (7.6 eV), the main decomposition processes of the photoexcited propene molecule are β(C—H) split (Ф = 0.565) and α(C—C) split (Ф = 0.335). Thus, the β(C—H)/α(C—C) ratio is close to 1.69. In the case of the photolysis of 2-methyl-2-butene, the same ratio is reversed: [Formula: see text] In another work, the ratio obtained in the photolysis of 2-butene was close to unity. Finally, in order to explain the allene and 1,3-butadiene formation in the photolysis of 2-methyl-2-butene, isomerisation of vinylic radical intermediates is proposed, in agreement with observations made by Callear and Lee.