Unprecedented Yield of Methyl-esterification with In-situ Generated Diazomethane in a Microchannel Reactor with Methanol as Solvent

Abstract Continuous synthesis of diazomethane followed by the in-situ methylesterfication has been seen as promising approach for broader use of chemical routes based on highly reactive component. In several studies proof-of-concept has been achieved. However, the yield of target product has been low. In this work, we report an underlying mechanism of the solvent effects on the low ester yields, mainly arising from the transesterification of the methyl ester products. When methanol was used as solvent, unprecedented high ester yield of above 99.5% was obtained. This overcomes the obstacle to practical application of methylesterfication with in-situ generated diazomethane.