Investigating the Impact of Microporosity of Aminosilica Catalysts in Aldol Condensation Reactions for Biomass Upgrading of 5-Hydroxymethylfurfural and Furfuraldehyde to Fuels

Upgrading biomass to chemicals and fuels requires development of highly active and selective catalytic materials for important reactions such as the aldol condensation. The aldol condensation is a critical step to convert small molecules such as 5-hydroxymethylfurfural (HMF) and furfuraldehyde (FA) to larger complexes that can be used for fuels or chemicals. Whereas extensive work has examined aminosilica catalytic materials for aldol chemistry, these materials have received limited attention for HMF and FA conversion in spite of the capability of these materials to catalyze reactions in a cooperative manner. In this work, important structure-function relationships are investigated that demonstrate the impact of micropores in these materials. Materials are produced using a typical method (REG) and a method that produces limited to no micropores NMP). The materials are grafted with aminosilanes and characterized using standard techniques. It is found that materials with limited to no micropores are more active for the aldol reaction and condensation for both FA with acetone and HMF with acetone. Additionally, the materials are tested in recycle experiments that showed the NMP catalyst retained higher activity after four catalytic cycles than the REG catalyst. Overall, the results have important implications for the design of materials for upgrading biomass into chemicals and fuels.

Automated summary

Materials with limited or no micropores are more active for the conversion of HMF and FA. The NMP catalyst retains higher activity after recycle experiments.