Kinetics of Cyclopropyl Radical Reactions. 1. Absolute Rate Constants for Some Addition and Abstraction Reactions

Article abstract of DOI:10.1021/ja00329a041

The reactions of cyclopropyl radicals produced in the photodecomposition of bis(cyclopropylformyl)peroxide have been examined with the use of laser flash photolysis techniques.For example, the reactions with styrene, β-methylstyrene, 1,4-cyclohexadiene, and carbon tetrachloride have rate constants in benzene at 298 K of (1.5+/-0.3)x10⁷, (2.0+/-0.5)x10⁶, (7.9+/-0.3)x10⁶, and (1.5+/-0.2)x10⁶ M^-1 s^-1, respectively. in the case of carbon tetrachloride, a study of the temperature dependence of the kinetics (1:4 benzene:CF2ClCFCl2) in the 0 to 68 deg C range yields log (k₁₄/M^-1 s^-1)=(8.7+/-0.4)-(3.5+/-0.6)/θ, where θ=2.3RT kcal/mol.For addition reactions, the kinetics at 298 K follow the order Ph.>c-C3H5.>RCH2CH2..For H-atom abstractions the reactivities of Ph. and c-C3H5. do not follow a simple relationship, though both are more reactive than RCH2CH2. radicals.