7393-45-5Relevant articles and documents
Kinetics of Cyclopropyl Radical Reactions. 1. Absolute Rate Constants for Some Addition and Abstraction Reactions
Johnston, Linda J.,Scaiano, J. C.,Ingold, K. U.
, p. 4877 - 4881 (1984)
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.
Kinetics of elementary reactions in the chain chlorination of cyclopropane
Hurley, Michael D.,Schneider, William F.,Wallington, Timothy J.,Mann, David J.,DeSain, John D.,Taatjes, Craig A.
, p. 2003 - 2010 (2007/10/03)
The kinetics of elementary reactions involved in the chain chlorination of cyclopropane were studied using a combination of absolute and relative rate constant measurements and first principles electronic structure calculations. Absolute rate coefficients for the reaction of Cl with cyclopropane were measured between 293 and 623 K by a laser-photolysis/CW infrared absorption method. To support the experimental investigations, first principles electronic structure calculations were performed. Vibrational spectra of c-C3H5Cl, c-C3H4Cl2, and c-C3H3Cl3 were calculated. Gem-C3H4Cl2 is calculated to be the kinetically and thermodynamically most favored dichlorocyclopropane. The computational results were consistent with a model in which gem-C3H4Cl2 is the predominant product of chlorination of C3H5Cl, and gem-C3H3Cl3 is the only product of chlorination of gem-C3H4Cl2. Chlorocyclopropane was ～ a factor of 10 times more reactive than cyclopropane toward chlorine atoms at 296 K and is converted into dichlorocyclopropane.
Solvent pressure effects in free radical reactions. 2. Reconciliation of the gas and condensed phase chlorination of cyclopropane
Tanko, James M.,Suleman, N. Kamrudin
, p. 5162 - 5166 (2007/10/02)
The results reported herein demonstrate that the chemoselectivity (SH2 ring opening vs abstraction of a cyclopropyl hydrogen) associated with the free radical chlorination of cyclopropane is solvent dependent. Internal pressure is implicated as the solvent parameter responsible for the observed solvent effect. (Solvents of high internal pressure favor the SH2 process; hydrogen abstraction becomes more important in solvents of low internal pressure or in the gas phase.) Extrapolation of the solution phase results to zero internal pressure accurately predicts the gas-phase result, suggesting that the difference in chemoselectivity between the vapor- and condensed-phase reactions is attributable to internal pressure in the condensed phase medium. No evidence for the chlorine atom cage effect is found in the chlorination of cyclopropane.
