100% triacetin selectivity was achieved in glycerol acetylation with acetic anhydride in 20-50 min in the presence of catalytic amounts of mesoporous sulfonated carbons and zeolite H-Y. Experimental results obtained over a range of solid acids with varying structure and acidic properties indicate that selectivity to triacetin was influenced mainly by the pore structure and catalyst surface acid site density. The shape selectivity effect over microporous zeolites was verified from the molecular dimensions of glycerol, monoacetin, diacetin and triacetin obtained from DFT calculations; on the contrary in mesoporous catalyst surface acid site density was responsible for determining triacetin selectivity. (C) 2015 Elsevier Inc. All rights reserved.