The important role of weak Brønsted acid site of Sn-β in conversion of sucrose to methyl lactate

Sucrose is an abundant, cheap and sustainable substrate for producing high value-added chemicals. In this work, the role of weak Brønsted (B) acid site of Sn-β zeolite was revealed in sucrose conversion to methyl lactate (MLA). Sn-β zeolites were prepared by post-synthesis and hydrothermal synthesis in F ‒ media and modified by Mg 2+ to tune the B acidity. The acidity of the zeolites was characterized by FT-IR spectroscopy of pyridine/CD 3 CN adsorption and hydroxyl region. Their catalytic performance for sucrose conversion to MLA in methanol indicates that weak B acid sites of silanols are indispensible for breaking the glycosidic bond of sucrose, so the highest MLA yield was obtained over the postsynthesized Mg-Sn-β-P with moderate amount of weak B acid sites of silanols, strong L acid sites and no strong B acid sites, which juggled the alcoholysis/hydrolysis of sucrose and the retro-aldol of C 6 monosaccharide to MLA, and at the same time inhibited the dehydration side-reaction.