Synthesis of Methyl Lactate from Glucose over Alkali-Modified Sn-H-Y Catalysts

Abstract: Glucose transformation to methyl lactate was investigated over microporous Sn-H-Y- zeolite with SiO₂/Al₂O₃ ratio of 30 as well as alkali metal modified mesoporous dealuminated Sn-H-Y-zeolites in the temperature range of 150-180^oC. The catalysts were synthesized either by evaporation-impregnation or ion-exchange methods using a two-step procedure for Sn-and K-modification. The catalysts were characterized by several physico-chemical methods including SEM, TEM, pyridine adsorption-desorption FTIR, UV-VIS spectroscopy, solid state NMR-spectroscopy, nitrogen adsorption, TGA and CHNS for spent catalysts. The highest yield of methyl lactate of 72% was obtained at 150^oC over dealuminated K-Sn-H-Y-30 catalyst at complete glucose conversion. Especially low K/Sn ratio was preferential for maximizing methyl lactate yield. Catalyst regeneration and leaching were also investigated. Statement of Novelty: The impact of potassium on mesoporous Sn-modified H-Y-30 was elucidated resulting in a very high yield of methyl lactate (72%) in glucose transformation over dealuminated K-Sn-H-Y-30 catalyst.