Facile and regioselective mono- or diesterification of glycerol derivatives over recyclable phosphazene organocatalyst

Abstract

P1 phosphazene is a strong non-ionic base able to catalyze the esterification of various glycerol derivatives with fatty methyl esters at room temperature – properties responsible for the selectivity observed in this study. Indeed, when the reaction was conducted at room temperature in an organic solvent, and especially in acetonitrile, we showed that the different fatty glycerides produced could be trapped during the catalytic process as a pure product by simple precipitation. Using these experimental conditions, it was therefore possible to perfectly and selectively control the successive esterification steps of various glycerol derivatives and the regioselectivity of this reaction, affording a very competitive alternative to the enzymatic pathway. Moreover, the precipitation of the reaction products during the catalytic process affords a very facile purification work up, and allows the recycling of both the organic solvent and the organocatalyst, therefore limiting the environmental impact of the presented process.