Innovative Au-Sn-SiO2 bifunctional material for the upgrading of glycerol to methyl lactate
(2022) Chemical Research in Flanders - Chemistry Conference for Young Scientists (CRF-ChemCYS) — Location: Blankenberge, Belgium (12.October.2022)
Files
AbstractMargotChemCYS2022.pdf
Restricted Access - Adobe PDF
- 168.43 KB
Details
- Authors
- Abstract
- The interest of the scientific community has recently moved toward the development of efficient catalytic process for biomass valorization as it represents a promising alternative to the existing petro-based technologies. Glycerol, the main by-product of biodiesel production, can be upgraded to methyl lactate (ML), a key platform molecule for different industrial applications (green solvent for nitrocellulose synthesis, raw materials for cosmetics and healthcare formulations). The reaction is known to proceed via the oxidation of glycerol to dihydroxyacetone (DHA), followed by the rearrangement with methanol to yield the targeted lactate.[1] Gold nanoparticles with diameters below 5 nm show high catalytic activity in glycerol oxidation and tin-based catalysts show the appropriate Lewis activity to convert DHA to ML (Fig 1 a). [2-3] It is appealing to combine both catalytic species to perform the cascade reaction directly from glycerol to ML, using a single bifunctional solid catalyst. In this work, we propose a novel one-pot strategy for the preparation of a new type of bifunctional heterogeneous catalysts. This new material is synthesized leveraging on the aerosol-assisted sol-gel process and consists of Au nanoparticles embedded in a mesoporous Sn-doped silica. The obtained bifunctional catalyst, AuSnSiO2, displayed excellent textural properties (SSA = 440 m².g-1, Vp = 0.11 cm³.g-1, Dp = 5 nm) and the two metals were successfully and homogeneously incorporated in the material (Fig. 1 b). The formation of gold nanoparticles via the one-pot strategy was first investigated and optimized without the presence of Sn (AuSiO2) to obtain gold nanoparticles with a diameter of 3.1 nm active in the oxidation of glycerol to DHA (XGly = 59%, YDHA = 18%). The poor yield observed was caused by the overoxidation of DHA on highly active gold nanoparticles. When mechanically mixing his catalyst with a SnSiO2 catalyst to perform the cascade reaction to ML, no significant improvements of the catalytic performance were observed (XGly = 71%, YML = 19%). Working with the bifunctional catalyst, on the other hand, enhanced the methyl lactate yield. While the gold nanoparticles size in AuSnSiO2 remained small (3.4 nm), the further rapid ransformation of DHA to ML on the nearby Sn sites resulted in a significant boost in selectivity to ML (overall yield up to 31% with a glycerol conversion of 61%). These results highlight the interest of bringing together in one unique material two catalytic species to run efficiently a cascade reaction. The proximity between the two active sites is the key to enhance the selectivity toward methyl lactate during the cascade reaction. [4]
- Affiliations
Citations
Van der Verren, M., Aprile, C., & Debecker, D. (2022). Innovative Au-Sn-SiO2 bifunctional material for the upgrading of glycerol to methyl lactate. Chemical Research in Flanders - Chemistry Conference for Young Scientists (CRF-ChemCYS), Blankenberge, Belgium. https://hdl.handle.net/2078.5/105001