Nuclear recoil 18F atoms undergo hot F-for-F and F-for-H atomic substitution and hot F-for-CH3 and F-for-CF3 alkyl replacement reactions in CH3CF3. The primary absolute yields corresponding to these processes are 3.56±0.07, 8.22±0.09, 5.79±0.31, and 8.5±2.5% (estimated value), respectively. The total primary hot yield for organic products is 26.1±2.5%, and that for all hot reactions including F-to-HF and F-to-F2 abstraction is 83±3%. There is no evidence in favor of hot F-for-2F or F-for-2H double substitution reactions in CH3CF3. Recoil 18F exhibits approximately a sixfold systematics preference for alkyl replacement reactions at the carbon-carbon bond in CH3CF3 relative to the average of substitution reactivities at carbon-fluorine and carbon-hydrogen bonds. The per-bond preference for primary substitution reactions at carbon-hydrogen relative to carbon-fluorine bonds is 2.30±0.06. The sums of primary hot yields for organic products are comparable for recoil 18F in CH3CF3 vs recoil 3H in alkanes, so that these two recoil systems differ principally in that 18F exhibits a preference for alkyl replacement reactions, whereas recoil 3H exhibits a preference for T-for-H substitution. All the organic products from primary 18F hot reactions exhibit extensive unimolecular decomposition.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry