Esterification of lauric and oleic acids with methanol over oxidized and sulfonated activated carbon catalyst

A new activated carbon catalyst (AC) with relatively high density of -SO3H group was synthesized by HNO3 oxidation followed by sulfonation with H2SO4. After 10 wt% HNO3 oxidation for 8 h and subsequent sulfonation for 15 h, the total acid density and the density of the -SO3H group in AC were determined by titration to be 4.43 mmol/g and 0.93 mmol/g, respectively. The resulting AC exhibited relatively high catalytic performance for the esterification of lauric and oleic acid in methanol, which was due to an obvious increasing of -SO3H group density. In the meantime, the catalytic performance correlated with density of total acidity and esterification rates was also revealed.