Biomass is a renewable and clean resource, and great interest is devoted to its conversion into fuels and fine chemicals. In particular, furfural emerges as a key platform molecule. In this view, it is an urgent need to develop eco-efficient and intensified processes affording the conversion of furfural into added-value chemicals in a minimum number of steps. In this PhD thesis, we engineered single-reactor tandem reactions, where furfural is transformed into target chemicals in a one-pot fashion without separation of reaction intermediates. To this aim, multifunctional catalysts, showing high activity, selectivity and reusability, are required. As a first example, we conceived a single-reactor tandem process for the aldol condensation/crotonization reaction between furfural and methyl isobutyl ketone (MIBK), followed by hydrogenation with molecular H2. Two robust bifunctional catalysts were developed and optimized based on Pd/HPSAPO-5 with hierarchical porosity and Brønsted acidity, and Pd/Al2O3, with Lewis acidity. The catalysts exhibited high yield to THF-derivatives and were reusable in multiple steps without decrease of catalytic activity. As a second example, we conceived a single-reactor tandem process for the benzoin condensation of furfural to furoin, followed by reductive amination of the as-generated furoin with NH3 and molecular H2. A high yield of 2-amino-1,2-di(furan-2-yl)ethan-1-ol could obtained over combined silica-supported benzimidazole and Ru/Al2O3.
Keywords: Biomass, Furfural, Aldol condensation, Hydrogenation, Amination