Competitive adsorption of alcohols over heteroatom zeolites hinders the catalytic conversion of sugar

In the catalysis of glucose from bulk methanol to Lewis acid centers via zeolite pores, MES-ATR-IR and PSD detected competitive adsorption driven by hydrogen bonding ascribed to the hydroxyl of the solvent, substrate, and interface. The phase-resolved spectra show a change from methanol- to glucose-silicon hydroxyl bonds, which slows the rate of Lewis acid center carbonyl activation. Moreover, increased silicon hydroxyl binding to glucose results in lower acidity of metal centers in the process. It almost eliminates the variations in reactivity caused by metal identity. In contrast, the absence of hydroxyl at the solvent, substrate, or interface prevents competitive adsorption and brings out the acidity of different metal centers, with Sn > In > Hf > Ti > Zr being the order of binding ability to the carbonyl. This study contributes to the development of zeotype metal center local environments for substrate and solvent matching in various reaction networks.