Radiation chemistry of mixtures of ethane and hexafluoroethane in the gas phase

The gas phase radiolysis of mixtures of ethane and hexafluoroethane were studied at 50 torr pressure for systems containing 0 to 100 percent of the fluorocarbon, both pure and with 10 percent added oxygen. For the pure system, twenty-two products were identified, and the yields over the entire mixture range have been recorded. The major and minor radiolytic products were identified. It was observed that the addition of 10 percent oxygen substantially reduced the saturated hydrocarbon products, while the unsaturated hydrocarbon products were enhanced. The fact that pure fluorocarbon compounds were not formed in the mixtures, and that the hydrocarbon products were significantly enhanced over their ideal mixture lines indicated that decomposition of ethane is sensitized by the presence of hexafluoroethane and that a major process in the radiolysis of the mixtures is the ability of the hexafluoroethane to transfer charge and/or excitation energy to ethane, which subsequently decomposes, forming the hydrocarbon products. The results of this system were compared with the cyclohexane-perfluorocyclohexane system and the cyclobutane-perfluorocyclobutane system. This comparison revealed that in the radiolysis of fluorocarbon-hydrocarbon mixtures, the products resemble the pure hydrocarbon component rather than the pure fluorocarbon and that, as the chain length is lowered, energy (and/or charge) transfer to the hydrocarbon becomes much more important than protection of hydrocarbon by electron capture