Copper phosphotungstate-catalyzed microwave-assisted synthesis of 5-hydroxymethylfurfural in a biphasic system

In this paper, we have described a novel route to produce 5-hydroxymethylfurfural (HMF), valuable platform molecule obtained from biomass. Metal-exchanged Keggin heteropolyacid salts were used as catalysts, in microwave-assisted reactions carried out water-ethyl acetate biphasic system. To avoid the use of homogenous Brønsted acid which are corrosive and difficult be reused, exchanged protons heteropolyacids with transition metal cations. These evaluated fructose dehydration, being Cu3/2PW12O40 most active selective catalyst, achieving 81% HMF yield, after 15 min reaction at 413 K under microwave irradiation. The effects cation, anion or heteropolyanion present catalyst evaluated. greatest efficiency was attributed its high Lewis acidic strength allows coordinates water molecules, consequently generating H3O+ ions medium. addition, assessing dehydration presence other Copper [i.e., CuCl2 Cu(NO3)2], conclude plays too key role. higher softness phosphotungstic should stabilize protonate intermediates better than chloride nitrate anions, favouring way reaction. Finally, although has been soluble, it easily reused by removing aqueous phase adding new load substrate dissolved ethyl acetate. runs successfully repeated without loss activity catalyst.