Not just sugar! Lewis‐acidic Sn‐MWW zeolites are obtained through postsynthesis functionalization of deboronated B‐MWW with Sn. These materials are highly active, selective, and recyclable catalysts for the conversion of triose sugars to methyl lactate (in methanol) and lactic acid (in water). They also demonstrate good performance in the conversion of hexose sugars and sucrose to methyl lactate.

Sn‐Beta zeolite was prepared by acid dealumination of Beta zeolite, followed by dehydration and impregnation with anhydrous SnCl4. The formation of extraframework Sn (EFSn) species was prevented by the removal of unreacted SnCl4 in a methanol washing step prior to calcination. The resulting Sn‐Beta zeolites were characterized by X‐ray diffraction, Ar physisorption, NMR, UV/Vis, and FTIR spectroscopy. These well‐defined Lewis acid zeolites exhibit good catalytic activity and selectivity in the conversion of 1,3‐dihydroxyacetone to methyl lactate. Their performance is similar to a reference Sn‐Beta zeolite prepared by hydrothermal synthesis. Sn‐BEA zeolites that contain EFSn species exhibit lower catalytic activity; the EFSn species also catalyze formation of byproducts. DFT calculations show that partially hydrolyzed framework Sn‐OH species (open sites), rather than the tetrahedral framework Sn sites (closed sites), are the most likely candidate active sites for methyl lactate formation.

In recent years, various protocols on preparing Lewis acidic Sn‐β zeolite hydrothermally and postsynthetically have been reported. However, very little is known about the effects of different synthesis protocols on the Sn(IV) speciation in the final material. Even the effects of individual synthesis parameters within a certain preparation method have not been studied systematically. Here, we demonstrate that hydrothermally synthesized Sn‐β zeolites prepared via very similar recipes show significantly different 119Sn‐NMR spectra, suggesting different Sn site speciation. Among postsynthetically prepared Sn‐β zeolites, less variation in the resulting 119Sn‐NMR spectra have been observed, indicating a more reproducible synthesis procedure compared to hydrothermal synthesis in fluoride media. This work highlights the importance of 119Sn‐NMR measurements to elucidate the precise local geometry of the Sn heteroatoms in Sn‐β, and the need to quantify the number of reactive Sn sites on each sample that participate in a given catalytic reaction, in order to accurately compare materials prepared by different routes.

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Both enantiomers of the novel benzimidazole‐derived bidentate P,N‐ligand (I) are synthesized (not shown) and applied to Ir‐catalyzed hydrogenation reactions.