Rare-gas sensitized radiolysis of gaseous isobutene: ionic processes

Irradiation of isobutene at low pressure in the presence of suitable scavengers or mixed with the rare gases Ar, Kr, and Xe shows that 2-methyl-but-2-ene is partially formed in ionic processes. These processes involve polymeric ions of isobutene formed in "head-to-head" reactive encounters with neutral isobutene. The resulting ionic species, which have internal structural tension, can isomerize with a subsequent elimination of ethylene, or decompose to give 2-methyl-but-2-ene. The rare-gas sensitized radiolysis confirms the already established reaction channels for formation of the main products.