Free radical addition to olefins. Part 14. - Addition to trifluoromethyl radicals to fluoroethylenes

John N. Cape, Alan C. Greig, John M. Tedder, John C. Walton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)

Abstract

A competitive method has been used to determine the relative Arrhenius parameters for the addition of trifluoromethyl radicals to specific sites in fluoroethylenes taking the addition to one end of ethylene as standard. olefin (site→) † k2/k2 ethylene (E2-E 2 ethylene)/kcal mol-1 † A2/A 2 ethylene →CH2=CHF 0.48 0.49±0.13 0.85±0.07 →CH2=CF2 0.15 1.20±0.34 0.60±0.06 →CHF=CH2 0.056 1.92±0.46 0.51±0.10 →CHF=CF2 0.031 1.91±0.05 0.28±0.06 →CF2=CH2 0.0055 3.24±0.96 0.23±0.08 →CF2=CHF 0.016 2.65±0.72 0.35±0.07 →CF2=CF2 0.12 1.74±0.22 0.87±0.09 † expressed per active site. The relative activation energies correlate well with those for the addition of other halogenoalkyl radicals to the same olefins. The A-factors have been calculated from absolute rate theory using two models of the transition state, one resembling the products and the other resembling the reactants. Comparison of the calculated and experimental A-factors suggests that formation of the bond between the trifluoro-methyl radical and the alkene has proceeded sufficiently far, in the transition state, to cause significant breaking of the alkene double bond.

Original languageEnglish
Pages (from-to)592-601
Number of pages10
JournalJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
Volume71
DOIs
Publication statusPublished - 1 Jan 1975

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