THE KINETICS OF MECHANISMS OF METHYL 2-BROMOPROPIONATE AND 2-BROMOPROPIONIC ACID PYROLYSES UNDER MAXIMUM INHIBITION

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-degrees-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 k1(s-1) = (13.10 +/- 0.34) - (211.4 +/- 4.4)kJ mol-1(2.303RT)-1; for 2-bromopropionic acid, log k1(s-1) = 12.41 +/- 0.29) - (180.3 +/- 3.4)kJ mol-1(2.303RT)-1. The bromoacid yields acetaldehyde, CO and HBr. Because of this result, the mechanisms is believed to proceed via a polar five-membered cyclic transition state.