Esterification of glycerol with acetic acid over SO3H-functionalized phenolic resin

A series of SO3H-functionalized phenolic resin-based catalysts (PSPF-x) with different molar ratio of p-phenolsulfonic acid (PhOH-4-sa) and phenol (PhOH) were prepared via a facile polycondensation method, and employed in the esterification of glycerol with acetic acid under mild conditions. It was found that PSPF-3 (the molar ratio of PhOH-4-sa to PhOH in feed was 3: 1) exhibited excellent activity and stability. The detected conversion of glycerol was 81.6% with a 98.9% selectivity of MAG and DAG at 70 degrees C under stoichiometric molar ratio of acetic acid to glycerol (3:1) for 7 h. The highest turnover frequency of each acid site in PSPF-3 reached 341.1 h(-1) at the beginning of the reaction and it could be recycled for 5 times. Characterization results indicated that the performance of PSPF-3 could be attributed to its stable cross-linking structure, enhanced surface area and porosity. The reaction mechanism was proposed on the base of a series of experiments.