Acid catalysed acetylene-allene isomerisations

Abstract

The isomerisation of l-hexyne, 2-hexyne, 3-hexyne, 1,2-hexadiene and 2,3-hexadiene have been studied in solutions of sulphuric acid in sulpholane. The probable mechanism of the isomerisations involving carbonium ions has been outlined. There appears to be no rearrangement of the intermediate carbonium ions involving hydride ion shifts. Free energy changes in the isomerisation were not determined, since equilibration studies could not be carried out due to side reactions during the isomerisations.