Synthesis of fuel bioadditive by esterification of glycerol with acetic acid over hydrophobic polymer-based solid acid

Abstract

The transformation of glycerol into high value-added derivatives has been of critical importance from the viewpoint of sustainable production of biodiesel. Among the reported processes, selective esterification of glycerol with acetic acid to a fuel bioadditive, including glycerol diacetate (DAG) and glycerol triacetate (TAG), is a research hot topic in both academic research and industrial application. In this work, a series of polydivinylbenzene-based solid acids (PDS) with different structural performances were prepared by a hydrothermal synthesis method and employed as catalysts for the acetylation of glycerol with acetic acid to DAG and TAG. The effects of PDS structure properties on the catalytic performance are discussed in detail with the help of various characterizations. PDS-THF prepared in tetrahydrofuran solvent was proven to be the most active catalyst among all the tested samples. In addition, glycerol could be almost completely converted into glyceryl acetates in the presence of PDS-THF, with a combined selectivity to DAG and TAG of 88.6% at its optimization condition. No obvious deactivation can be observed for PDS-THF after five runs, and the synergism of abundant acidic sites, suitable acidic site density and super hydrophobicity can account for its superior catalytic performance.