Fabrication of sulfonated carbon catalyst from biomass waste and its use for glycerol esterification

Abstract

Sulfonated carbon catalysts were prepared by sulfonation of carbonized catkins from willow under different sulfonated conditions. Such materials were characterized by SEM, EDS, FTIR and TGA. The results indicated that sulfonated conditions might influence the acid density of the sulfonated carbon catalysts, but did not influence the microtubular structure. These sulfonated carbon catalysts exhibited high acid capacity, good thermal stability and better catalytic activity for the glycerol esterification. With a molar ratio of acetic acid to glycerol of 5:1, a catalyst amount of 5wt.% and a reaction temperature of 393K for 2h, glycerol was almost completely transformed into a mixture of glycerol esters including monoacetate, diacetate and triacetate. Controlling of acid density of the catalysts and reaction conditions could obtain highly desired products. Meanwhile, the hydrophobic property of these sulfonated carbon catalysts led to some tolerance to water. Moreover, excellent reusability of the catalyst was also confirmed by repeated experiments.