Engineering of Lewis Acid Sites in Mesoporous Zeolite Achieves Record Fructose Yield of 71.5% for Glucose Isomerization in Ethanol

Abstract

ABSTRACT Lewis acid catalyzed glucose isomerization is a vital step in biorefinery, but it's restricted by the limited catalytic toolkit and reaction equilibrium. Herein, we report that engineering Lewis acid sites in a mesoporous zeolite can greatly boost productivity. Incorporating a few of Sn species into KIT‐6 zeolite with the assistance of phosphorylation delivered SnPO/KIT(x) materials with abundant Lewis acid sites and a few of Brønsted acid sites, while conserving the ordered mesoporous structure. Moreover, the Lewis acidic Sn sites have a coordination environment distinct from those in traditional zeolites and metal phosphates, as is crucial to facilitate isomerization and to control side‐reactions. Rigorous experiments showed that the use of SnPO/KIT(80) catalyst in two‐step isomerization process combined with adequate hydrolysis of ethyl fructoside attains a fructose yield of 71.5%, surpassing the state‐of‐the‐art catalytic systems, along with good reusability and tolerance to high‐concentration glucose. These findings highlight the great potential of precisely manipulating coordination environment of Lewis acid sites to boost catalytic performance.