Synthesis of fatty acid starch esters in supercritical carbon dioxide

Abstract

This manuscript describes an exploratory study on the synthesis of fatty acid/potato starch esters using supercritical carbon dioxide (scCO 2) as the solvent. The effects of process variables such as pressure (6–25 MPa), temperature (120–150 °C) and various basic catalysts and fatty acid derivatives (methyl- and vinyl esters and anhydrides) on the degree of substitution (DS) were explored in a batch reactor set-up. Products with a broad range of DS values (0.01–0.31) were obtained, the actual values depending on process conditions, type of catalyst and the fatty acid reagent. The combination of K 2CO 3 and vinyl laurate gave the highest DS values (DS = 0.31 at 150 °C, 8 MPa). The introduction of the fatty acid chains has a profound effect on product properties like hydrophobicity and thermal behavior.