Process performance and kinetics of the esterification of diketene to methyl acetoacetate in helical continuous-flow microreactors

The esterification of 4-methyleneoxetan-2-one (diketene) and methanol to obtain methyl acetoacetate (MAA) was conducted in a helical continuous-flow microreactor with triethylamine and 4-methylbenzenesulfonic acid (TsOH) as the catalyst in the absence of a solvent. The effects of the initial molar ratios of methanol to diketene and catalyst to diketene, reaction temperature, and residence time on the esterification reaction were also investigated and optimized. Under optimal conditions, the yield and selectivity of the reaction system for MAA exceeded 97% with only 120 s. In addition, a kinetic model of the esterification reaction inside helical continuous-flow microreactor was established with acceptable model performance. This work demonstrates that the combination of helical continuous flow and esterification, which is designed to provide researchers with a unique process, is also key to assessing the relevant esterification mechanism.