Zr-doped phosphorus-containing activating carbons catalysts for the valorization of furfural into valuables products in one-pot reaction

Olive stones have been used to synthesize activated carbon using H₃PO₄ as activating agent under pyrolytic treatment. Then, Zr species have been incorporated by impregnation and subsequent calcination, obtaining acid catalysts with Lewis and Brønsted sites, which are involved in the one-pot reaction of furfural in value-added products. All catalysts display a high micro- and mesoporosity. The catalysts showed different behavior as a function of the temperature, obtaining full conversion after 24 hours at 110 ºC, being mainly selective towards furfuryl alcohol and i-propyl furfuryl ether. The study at higher temperature (170 ºC) reached the full conversion after only 45 minutes, being preferentially selective towards i-propyl levulinate and γ-valerolactone. The catalysts are prone to suffer deactivation processes due to the formation of humins on the surface of the catalysts, which cause a decrease of the available active sites.