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The kinetics and mechanisms of methyl 2‐bromopropionate and 2‐bromopropionic acid pyrolyses under maximum inhibition
Author(s) -
Chuchani Gabriel,
Dominguez Rosa M.,
Rotinov Alexandra
Publication year - 1991
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.550230904
Subject(s) - chemistry , kinetics , torr , toluene , acetaldehyde , polar , medicinal chemistry , organic chemistry , thermodynamics , physics , quantum mechanics , astronomy , ethanol
The kinetics of the gas phase pyrolyses of methyl 2‐bromopropionate and 2‐bromopropionic acid were studied in a seasoned, static reaction vessel and under maximum inhibition of the free radical suppressor toluene. The working temperature and pressure range was 310–430°C and 26.5–201.5 torr, respectively. The reactions proved to be homogeneous, unimolecular, and obeys a first‐order rate law. The rate coefficients are expressible by the following equations: for methyl 2‐bromopropionate, log k 1 (s −1 ) = (13.10 ± 0.34) − (211.4 ± 4.4)kJ mol −1 (2.303 RT ) −1 ; for 2‐bromopropionic acid, log k 1 (s −1 ) = (12.41 ± 0.29) − (180.3 ± 3.4)kJ mol −1 (2.303 RT ) −1 . The bromoacid yields acetaldehyde, CO and HBr. Because of this result, the mechanism is believed to proceed via a polar five‐membered cyclic transition state.