Aliphatic C-H Bond Scission Processes in Diphenylmethane and 2-Benzyl- and 4-Benzylpyridine. The Heat of Formation of the Diphenylmethyl and α-Phenylethyl Radical in the Gas Phase

Article abstract of DOI:10.1021/j150665a048

Very low-pressure pyrolysis (VLPP) of the title compounds indicates both C-C and C-H bond rupture.Rate constants for all six processes are compatible with A factors of 1E15.3 s^-1 and activation energies of 81.4 kcal mol^-1 for C-H rupture in diphenylmethane and 82.3 kcal mol^-1 for all the other C-H and C-C bond-breaking processes.The derived heat of formation of diphenylmethyl radical is 69.0 kcal mol^-1.This is in excellent agreement with other studies and indicates that C-H bond rupture in phenylmethanes behaves analogously to C-C rupture.The "extra stabilization" in diphenylmethyl radical when compared with α-phenylethyl radical is ca. 4 kcal mol^-1.