Shape selectivity and acidity effects in glycerol acetylation with acetic anhydride: Selective synthesis of triacetin over Y-zeolite and sulfonated mesoporous carbons

• Selective synthesis of triacetin from glycerol and acetic anhydride.
• Product selectivity determined by catalyst pore size and surface acid site density.
• Y-zeolite and mesoporous sulfonated carbon are most active and selective in triacetin synthesis.

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.

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