The Very low‐pressure pyrolysis of 2‐phenylethylamine. The enthalpy of formation of the aminomethyl radical

The thermal unimolecular decomposition of 2‐phenylethylamine (PhCH 2 CH 2 NH 2 ) into benzyl and aminomethyl radicals has been studied under very‐low‐pressure conditions, and the enthalpy of formation of the aminomethyl radicals, Δ H ° f , 298K (H 2 NCH 2 ·) = 37.0 ± 2.0 kcal/mol, has been derived from the kinetic data. This result leads to a value for the C—H bond dissociation energy in methylamine, BDE(H 2 NCH 2 —H) = 94.6 ± 2.0 kcal/mol, which is about 3.4 kcal/mol lower than in C 2 H 6 (98 kcal/mol), indicating a sizable stabilization in α‐aminoalkyl radicals.