Free Radical Yields in the Radiolysis of Gaseous Hexafluoroethane

Abstract

The radiolysis of gaseous hexafluoroethane yields CF4(G= 2.5), C3F8(G= 0.31) and C4F10(G= 0.10) as major products. In the presence of Br2, Cl2 or HCl these products are scavenged and replaced by yields of CF3 and C2F5 scavenged products. The yields of these scavenged products are independent of pressure above 5 mol % scavenger and are ∼G= 2.6 for both CF3 and C2F5 radicals. In the presence of chlorine and HCl, not all the CF4 is scavengeable even though the CF3 and C2F5 radical yields are independent of scavenger concentration. Statistical combination–cross combination ratios may be used to reconcile the observed radical yields with the yields of stable fluorocarbon products. Competition kinetics in the Br2+ Cl2+ BrCl system indicate that some of the CF3 scavenged products are due to either hot radicals or ions.