(116e) Facile Synthesis of Sn-BEA for Isomerization of Cellulosic Sugars

Isomerizations of triose sugars (dihydroxyacetone to glyceraldehyde), pentose sugars (xylose to xylulose), and hexose sugars (glucose to fructose) are key intermediate steps for converting biomass into fuels and platform chemicals. Sn-BEA, a stannosilicate microporous material with zeolite BEA topology, exhibites unique Lewis acidity and recently reseives considerable attention due to its high catalytic activity and selectivity in the isomerization of sugars¹. However, the conventional synthesis of Sn-BEA requires a long crystallization time (11 to 40 days) and utilization of toxic and environmentally unfriendly hydrofluoric acid. In the present work, we developed a series of methods for the facile synthesis of Sn-BEA catalyst.

   In this study, we highlight that the Sn-BEA catalysts with a tunable particle size can be synthesized in 3 hours using a seeded growth method². Furthermore, Sn-BEA was successfully synthesized in a fluorine-free medium for the first time. The crystals obtained from both methods were characterized by XRD, SEM, nitrogen sorption experiments, and probe molecules adsorbed FT-IR. It is shown that the catalytic activity of the synthesized Sn-BEA is closely related to coordination environment of Sn and the hydrophobic nature of the samples. The study provides a set of Sn-BEA samples with different structural properties allowing for fundamentally understanding the catalytic activity of Sn sites within the molecular sieves and developing seletive Lewis acid catalyst for biomass conversion.

References:

1.         Moliner, M.; Roman-Leshkov, Y.; Davis, M. E., "Tin-containing zeolites are highly active catalysts for the isomerization of glucose in water". Proc. Natl. Acad. Sci. U. S. A. 2010, 107 (14), 6164-6168.

2.         Chang, C. C.; Wang, Z. P.; Dornath, P.; Cho, H. J.; Fan, W., "Rapid synthesis of Sn-Beta for the isomerization of cellulosic sugars". RSC Adv. 2012, 2 (28), 10475-10477.