Abstract

An online Raman analysis technique was used for the first time to study the mechanism underlying the synthesis of 5-bromomethylpyridine-2,3-dicarboxylic acid methyl ester (CMPE) via a bromination reaction with 5-methylpyridine-2,3-dicarboxylic acid dimethyl ester (MPE) as the raw material, N-bromosuccinimide (NBS) as the brominating reagent, and azobisisobutyronitrile (AIBN) as an initiator. The apparent thermodynamics and the reaction kinetics of bromination reaction of MPE were explored, a reaction kinetics model was established, and the bromination reaction of MPE was a typical reaction initiated by free radicals. The activation energy of bromination of MPE was 37.02 kJ mol^–1, and the apparent reaction heat was 2.23 kJ mol^–1 (calculated in the moles of NBS). The adiabatic temperature rise was 6.30°C under thermal runaway. The kinetic equation of the synthesis reaction: r = 3.26 × 10⁶exp(–37.02/RT)\(C_{{{\text{NBS}}}}^{{1.52}}\).