Acid catalysts for glucose isomerization and 5-hydroxymethylfurfural etherification

One of modern society’s fundamental problems concerns the extensive use of fossil resources that are dangerous both to environment and people. Several solutions are being studied in order to reduce the environment threatening and, among those, the use of biomass is a viable option because of the low environmental impact and the low cost. Starting from biomasses it is possible to obtain glucose that is considered one of the most important building blocks from renewable resources. The isomerization of glucose to fructose is extremely important since it is an equilibrium reaction and it is thermodynamically prohibited to obtain fructose yields higher than the imposed one. Because of this, fructose is an expensive compound but is still largely used in the chemical industry considered that from it it is possible to obtain 5-hydroxymethylfurfural (HMF), an important platform molecule, with an easy and fast dehydration process. HMF is, as said before, an important platform molecule used as starting material in different chemical processes due to the different functional groups that it possesses. HMF etherification is one of these because it gives the opportunity to obtain precursors of biofuel. The type of precursor obtained highly depends on the type of sites present on the catalyst. In this work both the reaction conditions of glucose isomerization to fructose and HMF etherification were studied. For the isomerization reaction a commercial zeolite was used to catalyze the reaction while for the HMF etherification two different types of materials were synthesized: mixed metal oxides and zeolites. The optimization of these two materials was also studied, especially for what concerns the zeolites that were modified first with a dealumination and then with the intercalation of Zr in the empty Al sites.