HOT-ATOM CHEMISTRY OF 14C+ IN BENZENE . PARTIAL DEGRADATIONS AND SUGGESTED MECHANISMS

Seven 14C-products (toluene, cycloheptatriene, phenylacetylene, “U-2,” biphenyl, diphenylmethane, and phenylcycloheptatriene) from hot-atom reactions of 14C ions of 5-keV kinetic energy in solid (—196°) benzene have been partially degraded. The results indicate the formation of the intermediate 14C-carbenes, methylene, benzylidene, and cycloheptatrienylidene, and reactive 14-containing fragments, particularly a C2 species. Cyclo-heptatrienylidene and cycloheptatriene apparently undergo extensive isomerization during, or immediately following, their formation. This isomerization is compared with other known modes of isomerization of cycloheptatriene and found to be best represented as 1,2-hydrogen shifts, It appears that, in the system under investigation, a mechanism different from the thermal has to be assumed. © 1969, American Chemical Society. All rights reserved.