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VLPR study of the reaction Br + CH 3 CHO
Author(s) -
Islam Tajmeri S. A.,
Marshall Roger M.,
Benson Sidney W.
Publication year - 1984
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550160911
Subject(s) - chemistry , limiting , ketene , photodissociation , analytical chemistry (journal) , medicinal chemistry , photochemistry , organic chemistry , mechanical engineering , engineering
The reaction \documentclass{article}\pagestyle{empty}\begin{document}${\rm Br} + {\rm CH}_3 {\rm CHO}\buildrel1\over\rightarrow{\rm HBr} + {\rm CH}_3 {\rm CO}$\end{document} has been studied by VLPR at 300 K. We find k 1 = 2.1 × 10 12 cm 3 /mol s in excellent agreement with independent measurements from photolysis studies. Combining this value with known thermodynamic data gives k ‐1 = 1 × 10 10 cm 3 /mol s. Observations of mass 42 expected from ketene suggest a rapid secondary reaction:\documentclass{article}\pagestyle{empty}\begin{document}$${\rm Br} + {\rm CH}_3 {\rm CO}\buildrel2\over\rightarrow[{\rm CH}_3 {\rm COBr}]^* \buildrel3\over\rightarrow{\rm HBr} + {\rm CH}_2 {\rm CO}$$\end{document}in which step 2 is shown to be rate limiting under VLPR conditions and k 2 is estimated at 10 12.6 cm 3 /mol s from recent theoretical models for radical recombination. It is also shown that 0 ⩽ E 1 ⩽ 1.4 kcal/mol using theoretical models for calculation of A 1 and is probably closer to the lower limit. Reaction −1 is negligible under conditions used.