Selective Production of Furan from Gas-Phase Furfural Decarbonylation on Ni-MgO Catalysts

Abstract

A series of Ni-MgO catalysts (Ni/Mg molar ratio: 0.1–0.3), prepared by a coprecipitation-calcination-reduction methodology, was characterized and evaluated in the gas-phase hydrogenation of furfural. In all cases, after reduction at 500 °C, nickel species were present as very tiny metal Ni(0) nanoparticles and forming part as Ni(II) of a NiO-MgO solid solution, as inferred from XRD and XPS techniques. The decarbonylation process of furfural was favored at reaction temperatures as low as 190 °C. The most active catalyst was that with a Ni/Mg molar ratio of 0.25, maintaining a furfural conversion of 96% after 5 h of time-on-stream at 190 °C, by feeding a furfural solution in cyclopentylmethyl ether (5 vol % furfural) under a H2 stream (H2:furfural molar ratio = 11.5 and WHSV = 1.5 h–1). Furan was the main product, with a yield of 88%, whereas furfuryl alcohol was formed at lower reaction temperature and shorter contact time. However, the catalyst suffers a gradual deactivation during a catalytic test of 24 ...