Dissociation of acetyl bromide: an experimental and theoretical study Original Research Article

We examine the ground state dissociation pathways of acetyl bromide, CH3C(O)Br, using infrared multiphoton dissociation and ab initio molecular orbital theory. Experiments reveal stable products C2H6, CH3Br, and CO which are consistent with the CBr bond fission pathway. However, production of C2H4 is consistent with ketene (CH2CO) formation, which has been a suggested intermediate in the dissociation of CH3C(O)Br. Calculations indicate that the activation energy for the molecular dissociation of CH3C(O)Br into ketene and HBr exceeds the CBr bond energy of 64 kcal mol−1 by about 30 kcal mol−1, implying that ketene may be formed by secondary chemistry rather than by molecular dissociation of acetyl bromide.