VLPR study of the reaction Br + CH3CHO

The reaction {article}{empty}{document}Br + CH₃ CHO1→ HBr + CH₃ CO{document} has been studied by VLPR at 300 K. We find k1 = 2.1 × 1012 cm3/mol s in excellent agreement with independent measurements from photolysis studies. Combining this value with known thermodynamic data gives k‐1 = 1 × 1010 cm3/mol s. Observations of mass 42 expected from ketene suggest a rapid secondary reaction: in which step 2 is shown to be rate limiting under VLPR conditions and k2 is estimated at 1012.6 cm3/mol s from recent theoretical models for radical recombination. It is also shown that 0 ⩽ E1 ⩽ 1.4 kcal/mol using theoretical models for calculation of A1 and is probably closer to the lower limit. Reaction −1 is negligible under conditions used.