A study of the recoil labeling of fluothane with 82Br during neutron irradiation

1,1,1-Trifluoro-2-chloro-2-bromoethane labeled with 82Br(fluothane-82Br) was purely separated from neutron-irradiated fluothane by means of a gaschromatographic technique. The maximum radiochemical yield of fluothane-82Br was 38.3% when the target material was irradiated with neutrons to nvt of 3.4 x 1016 n.cm-2. Of the many organic species produced by the recoil events following the radiative neutron capture and subsequent (I.T.) processes, CF382Br and CF3CHBr82Br were also identified. In order to elucidate the mechanism of recoil labeling, the scavenger effects were examined in the CF3CHClBr-Br2 system, Br2 being used as a radical scavenger. The ''high-energy'' yields of CF3CHCl82Br thus estimated were approximately 3.6 to 4.8%. It was suggested that most of the 82Br-labeled species were formed through the ''thermal'' processes including the reaction of 82Br with the organic radicals produced by the radiolysis of the parent fluothane. (auth.)