Bond dissociation energies from equilibrium studies. Part 4.—The equilibrium Br2+ CH4⇌ HBr + CH3Br. Determination of D(CH3—Br) and ΔH °f(CH3Br, g)

Abstract

The equilibrium Br₂+ CH₄⇌ HBr + CH₃Br (2) has been studied in the range 347–477°C, with equilibrium being approached from both sides. Products additional to those required by eqn (2) were formed but it is believed that reliable values of the equilibrium constant K₂ have been measured. Third-law calculations lead to ΔH^°₂=–26.4 ± 0.7 kJ mol^–1 at 298 K from which ΔH^°_f(CH₃Br, g)=–34.3 ± 0.8 kJ mol^–1.