MASS SPECTRA OF ISOMERS .3. CYCLO-OCTADIENE AND DERIVATIVES OF CYCLOBUTANE AND CYCLOHEXENE OF MOLECULAR FORMULA C8H12

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.