Solvent-Free Biocatalytic Synthesis of 2,5-bis-(Hydroxymethyl)Furan Fatty Acid Diesters from Renewable Resources

Abstract

Fatty acid diesters of 2,5-bis-(hydroxymethyl)furan (BHMF), promising candidates as sustainable bioadditives for increasing the cetane number of biodiesel fuels, were prepared through a solvent-free Novozym 435-mediated diesterification of BHMF with a fatty acid mixture (FAM) resulting from the hydrolysis of commercial sunflower oil. Under solvent-free conditions and a 15 mbar vacuum, high conversions into diesters were obtained in the heterogeneous reaction, after the gradual solubilization of BHMF. After optimization studies (temperature, reaction time, BHMF–FAM ratio, and biocatalyst loading), more than 97% conversion into diesters was achieved. The calculated sustainability metrics support the fact that the currently described solvent-free method represents an improved synthetic procedure for the preparation of BHMF fatty acid diesters.