EFFICIENT CONVERSION OF BIOMASS INTO FURAN DERIVATIVES IN THE PRESENCE OF MAGNETIC CATALYSTS

The transformation of biomass into valuable chemicals is a sustainable alternative to fossil resources from economic and environmental viewpoints. The process can be improved using solid catalysts having magnetic properties, which are separated from the reaction medium by simple application of an external magnetic field. These new catalysts have been synthesized by two novel sustainable approaches, both assisted by microwave irradiation: the first is a one pot procedure, whereas the second consists in the preparation of the magnetic support and subsequently the reduction and the deposition of the selected metal. These new routes involve simple procedures, the use of a green solvent such as aqueous ethanol, short reaction times, good energy efficiency and the absence of any high-boiling stabilizing agent or organic surfactant. Novel heterogeneous acid catalysts based on maghemite or magnetite modified with perfluorosulfonic acid resins have been employed for the hydrolysis of biomass to 5hydroxymethylfurfural. Moreover, the activity of these novel magnetic catalysts based on Pt, Pd and Ru supported on magnetite has been studied for the selective oxidation of biomass-derived aqueous HMF to give valuable monomers such as 2,5-furandicarboxylic acid and 5-hydroxymethyl furoic acid. Pt/Fe3O4 and Pd/Fe3O4 resulted highly active in the oxidation of HMF to 2,5-furandicarboxylic acid and 5-hydroxymethyl furoic acid carried out under basic conditions at 40-60 °C. Using Pd/Fe3O4 catalyst at total conversion of HMF 80 % of HMFA yields were achieved, while with Pt/Fe3O4 at total conversion of HMF 50 % of FDCA yields were reached.