Mass spectra of isomers. Part III. Cyclo-octadiene and derivatives of cyclobutane and cyclohexene of molecular formula C8H12

Abstract
The mass spectra of trans-1,2-divinylcyclobutane, 4-vinylcyclohexene and 1,5-cyclo-octadiene have been examined. The similarity between the spectra of these compounds is probably a consequence of a major fragmentation pathway in each compound proceeding through a common intermediate, while the differences in the relative abundances of some of the ions is postulated as being a result of alternative routes for fragmentation of the isomers. The values of 100//Σ/ for the major ions at electron beam energies of 70 and 20 eV are reported and interpreted in terms of the proposed fragmentation routes.
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