Quantum-Chemical Kinetic Study of the Unimolecular Decomposition Reactions of 1-Bromo-3-Chloropropane

Abstract

The pressure and temperature dependence of the thermal decomposition of 1-bromo-3-chloropropane has been theoretically investigated. The reaction takes place majorly through the elimination of HBr. Molecular properties of 1-bromo-3-chloropropane and transition states were derived from MN15/6-311++G(3df,3pd) and G4 quantum-chemical calculations. The resulting rate constants obtained from the unimolecular reaction rate theory for the high- A nd low-pressure limits of reaction BrCH2CH2CH2Cl → CH2CHCH2Cl + HBr at 400-1000 K were k∞= 6.1 × 1013exp(-57.2 kcal mol-1/RT) s-1and k0= [BrCH2CH2CH2Cl] 1.45 × 10-1(T/1000 K)-7.9exp(-55.9 kcal mol-1/RT) cm3molecule-1s-1. A value of-26.3 ± 1.0 kcal mol-1for the standard enthalpy of formation of 1-bromo-3-chloropropane at 298 K was derived.