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Rate constants for reactions of perfluorobutylperoxyl radical with alkenes
Author(s) -
Nahor G. S.,
Neta P.
Publication year - 1991
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550231008
Subject(s) - chemistry , radiolysis , reaction rate constant , allylic rearrangement , radical , photochemistry , hydrogen atom abstraction , substituent , double bond , kinetics , medicinal chemistry , organic chemistry , catalysis , physics , quantum mechanics
Perfluorobutylperoxyl radicals were produced by radiolytic reduction of perfluorobutyl iodide in aerated methanol solutions. Rate constants for the reactions of this peroxyl radical with various organic compounds were determined by kinetic spectrophotometric pulse radiolysis. The rate constants for alkanes and alkenes were determined by competition kinetics using chlorpromazine as a reference. The results indicate that hydrogen abstraction from aliphatic compounds takes place with a rate constant that is too slow to measure in our system (<10 5 M −1 s −1 ), and that abstraction of allylic and doubly allylic hydrogens is slow compared with addition. Addition to alkenes takes place with rate constants of the order of k = 10 6 − 10 8 M −1 s −1 . Good correlation was obtained between log k and the Taft substituent constants σ* for the various substituents on the double bond. Perfluorobutylperoxyl radical is found to be more reactive than trichloromethylperoxyl and other peroxyl radicals.