Kinetics of gas-phase reactions of cyc-CF2CF2CF2CHFCH2 and trans-cyc-CF2CF2CF2CHFCHF with OH radicals between 253 and 328 K

Substitution Effects on the Reactivity and Thermostability of Five-Membered Ring Fluorides

Recently, five-membered ring fluorides (c-C5Fs) have been significantly desirable in green chlorofluorocarbon substitutes due to their practically flexible application in various fields and environmental friendliness. Detailed knowledge regarding different substitution effects on their environmental properties and thermal stability is very limited due to their high-cost experiments. Here, comprehensive density functional theory and ab initio molecular dynamics calculations were performed to explore the relative electrophilic and nucleophilic reactivity and thermostability of c-C5F chemicals. The electronic properties induced by substitution effects of c-C5Fs were first explored. The environmental friendliness of c-C5Fs including 1,1,2,2,3,3-hexafluorocyclopentane (F6A), 1,1,2,2,3,3,4-heptafluorocyclopentane (F7A), cis-1,1,2,2,3,3,4,5-octafluorocyclopentane (F8A), 3,3,4,4,5,5-hexafluorocyclopentene (F6E), 1,3,3,4,4,5,5-heptafluorocyclopentene (F7E), octafluorocyclopentene (F8E), 1-chloro-3,3,4,4,5,5-hexafluorocyclopent-1-ene (F6-1), and 1-chloro-2,3,3,4,4,5,5-heptafluorocyclopent-1-ene (F7-1) was validly confirmed. Besides, their thermal stabilities at 600 K temperature were concluded due to their flexible carbon skeletons, where both in-plane stability and slight aromaticity of F6E were in peculiar found to contribute substantially. We also would like to stress the future application of F6-1 due to its significant out-plane stability. This study may pave the way for the development of chlorofluorocarbon substitutes.

Atmospheric chemistry of a cyclic hydro-fluoro-carbon: kinetics and mechanisms of gas-phase reactions of 1-trifluoromethyl-1,2,2-trifluorocyclobutane with Cl atoms, OH radicals, and O3

Long path length FTIR-smog chamber techniques were used to study the title reactions in 700 Torr of N2 or air diluent at 296 ± 2 K. Values of k(Cl + 1-trifluoromethyl-1,2,2-trifluorocyclobutane (TFMTFCB)) = (1.16 ± 0.21) × 10-14 and k(OH + TFMTFCB) = (3.51 ± 0.88) × 10-14 cm3 molecule-1 s-1 were measured. No reactivity of TFMTFCB towards ozone was observed. The atmospheric lifetime of TFMTFCB is determined by the reaction with OH and is approximately 330 days. The chlorine initiated oxidation gives C(O)F2 and CF3C(O)F as the dominant products in yields of (92 ± 2)% and (89 ± 2)%, respectively. The OH radical initiated oxidation gives C(O)F2 and CF3C(O)F as the dominant products in yields of (91 ± 6)% and (84 ± 4)%, respectively. The GWP100 was calculated as 44. The atmospheric chemistry of the title compound, a cyclic halogenated alkane, is discussed in the context of other halogenated cyclo-alkanes.