Catalytic Conversion of Carbohydrates to Methyl Lactate Using Isolated Tin Sites in SBA‐15

Abstract

A series of Sn‐SBA‐15 catalysts were synthesized using a post‐synthetic metal implantation method for converting carbohydrates to methyl lactate. The tin species were highly dispersed and isolatedly grafted in the framework of SBA‐15 under the tin salt concentration between 2 and 25 wt%. They solely provided a large number of Lewis acid sites, which showed robust activity for carbohydrates conversion in contrast to the performance of tin dioxide domains or particles. Over a Sn‐SBA‐15 catalyst (Si/Sn molar=150), the Lewis acid density was 45.9 μmol/g, and methyl lactate yield reached a high value of 57.0 % from inulin conversion in methanol at 433 K for 20 h, without the formation of methyl levulinate by‐product. The Sn‐SBA‐15 catalysts were rather stable under reaction conditions, and cycled at least for 4 times without deactivation.

Synergistic Production of Methyl Lactate from Carbohydrates Using an Ionic Liquid Functionalized Sn‐Containing Catalyst

“…Combining the results of the present study and numerous previous reports, a plausible reaction pathway was proposed for production of MLA from fructose catalyzed by Sn(salen)/IL. It is generally accepted that the reaction pathway for converting fructose to MLA involves multistep reactions, including retro‐aldol condensation, isomerization, dehydration, and esterification ,,,,,,. The experimental results provided a deeper insight into the reaction pathway and mechanism of action of the Sn(salen)/IL catalyst.…”

“…Furthermore, it exhibits superior catalytic performance in catalyzing the isomerization, retro‐aldol condensation, and dehydration of glucose or its isomers as well as intramolecular 1,2‐hydride shift to MLA, which is considered as state‐of‐the‐art active site that favors the formation of MLA from carbohydrates in methanol. It is most likely related to the coordination ability of the unoccupied orbital of Sn 4+ , which results in the activation of an oxygen in fructose ,. To investigate the influence of various types of ligands and compositions on the catalytic activity of Sn 4+ ‐based catalysts, a series of experiments relating to the conversion of fructose to MLA were conducted to evaluate the catalytic performance.…”

Advances in porous and nanoscale catalysts for viable biomass conversion

“…The significance of Lewis acidity of Sn-SBA-15 catalysts was also noticed for the conversion of carbohydrates to methyl lactate. 184 About 57% yield of methyl lactate was obtained from inulin over Sn-SBA-15 catalyst (Si/Sn molar = 150), which contained 45.9 mmol/g Lewis acid density. A mesoporous SiO 2 -Al 2 O 3 catalyst with Si/Al ratio of 18 provided improved HMF yields (63%) from glucose (entry 5, Table 1).…”

Catalytic Upgrading of Biomass‐Derived Sugars with Acidic Nanoporous Materials: Structural Role in Carbon‐Chain Length Variation

“…Much attention has been devoted to the one‐pot conversion of di‐ or polysaccharides into LA/AL, as driven by the more abundant nature of polysaccharides in raw biomass, compared with monosaccharides . In general, the combination of Lewis and Brønsted acid sites is a prerequisite for the transformation of di‐ or polysaccharides into LA/AL through a sequential reaction process, including hydrolysis, isomerization, retro‐aldol condensation, and the conversion of triose into LA/AL.…”