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Rate constants for the reactions of isobutyl, neopentyl, cyclopentyl, and cyclohexyl radicals with molecular oxygen
Author(s) -
Wu Dihua,
Bayes Kyle D.
Publication year - 1986
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.550180505
Subject(s) - radical , chemistry , reaction rate constant , photodissociation , oxygen , photochemistry , mass spectrometry , analytical chemistry (journal) , organic chemistry , kinetics , physics , chromatography , quantum mechanics
Rate constants have been measured for the reactions of four hydrocarbon radicals with O 2 in the gas phase at room temperature. Laserflash photolysis was used to generate low concentrations of radicals. A photoinization mass spectrometer followed the radical loss as a function of time. The measured pseudo first‐order decay rate of the radical and the absolute oxygen concentration were combined to give the absolute rate constants (in units of 10 −12 cm 3 molec −1 s −1 ): isobutyl (2.9 ± 0.7); neopentyl (1.6 ± 0.3); cyclopentyl (17 ± 3); and cyclohexyl (14 ± 2). The cycloalkyl radicals have rate constants similar to those of other secondary radicals. However, the isobutyl and neopentyl radicals react more slowly than similar primary radicals. These new rate constants are compared in Figure 2 with the recently published correlation of reactive cross section with radical ionization potential.