Theoretical enthalpies of formation and C–H bond dissociation enthalpies of n-bromopropane and its free radicals

The enthalpies of formation of n-bromopropane (CH3CH2CH2Br) and its free radicals (CH2CH2CH2Br, CH3CHCH2Br and CH3CH2CHBr) were estimated by molecular orbital integrated methods using several working chemical reactions with four variants of theoretical approaches (levels) and four extended basis sets. The recommended standard enthalpies of formation are: CH3CH2CH2Br, −19.5 ± 0.6 kcal mol−1, in excellent agreement with the only experimental datum available; CH2CH2CH2Br, 28.7 ± 0.3; CH3CHCH2Br, 23.1 ± 1.4; and CH3CH2CHBr, 25.7 ± 0.6 kcal mol−1. These enthalpies of formation correspond to bond dissociation enthalpies of DH0298(H– CH2CH2CH2Br)=101.6 ± 1.0; DH0298(CH3CH–HCH2Br)=96.0 ± 2.1; and DH0298(CH3CH2CHBr–H)=98.6 ± 1.2 kcal mol−1.