The role of aluminum in Sn-Al-beta zeolite catalyzing the conversion of glucose to methyl lactate

•The range of the Si/Al ratio of the zeolite was increased after dealumination and desiliconization of the H-beta molecular sieve.•In the presence of methanol, the Sn-beta zeolite efficiently accelerated the transformation of glucose into methyl lactate.•The structural integrity of the molecular sieve was affected differently by dealumination and desiliconization.•The process of desiliconization regulated the form of Al in Sn-Al-beta zeolite, and further affected the condition of inserted Sn.•Tin and aluminum in different forms interact to make Lewis acids of different potencies. The preparation of H-Beta zeolites with different Si/Al ratios (Si/Al=14, Si/Al=288) was obtained by desiliconization and dealumination. Subsequently, Sn-Al-Beta catalysts were prepared by tin grafting and used for the conversion of glucose to methyl lactate. The results indicate that the yield of methyl lactate from the catalyst obtained using the parent H-beta synthesis with a high Si/Al ratio is higher than that of methyl lactate from the parent catalyst with a low initial Si/Al ratio. And the maximum methyl lactate yield of 46.66% was achieved on Sn-Al-Beta (DSi-277). In contrast, the yield of methyl lactate on Sn-Al-Beta (DAl-493) was 24.54%. Results from spectroscopic analysis and probe molecular FTIR indicated that the post-synthesis process altered the structure of the zeolite, which changed its aluminum concentration and existence form (1.8ppm chemical shift), Additionally, when the aluminum interacted with the Sn that had been added to the zeolite, it encouraged the Sn transformation to the high energy state and created the weaker Lewis acid site, as well as more effective action to improve reaction yield. [Display omitted]