Preparation of sulfonated carbon derived from orange peel and its application in esterification

Abstract Sulfonated carbon derived from orange peel (SAC-OP-x) was prepared by hydrothermal partially carbonization. Their catalytic performances for the esterification of oleic acid with methanol and citric acid with n-butanol were investigated. The prepared catalysts were characterized by XRD, FT-IR, N2 physisorption, elemental analysis, Raman and FT-IR of adsorbed pyridine. The FT-IR of adsorbed pyridine showed the existence of Bronsted acid sites and Lewis acid sites in the SAC-OP-x samples. Moreover, the SAC-OP-x sample with sulfonation time of 2 hours exhibited the maximum conversion of oleic acid and citric acid with 92.8% and 81.3% under the optimum conditions, respectively.