Authors: Jimenez-Gomez, CP; Cecilia, JA; Garcia-Sancho, C; Moreno-Tost, R; Maireles-Torres, P

Article.
ACS Sustain. Chem. Eng.. vol: 7. page: 2168-0485.
Date: APR 15. 2019.
Doi: 10.1021/acssuschemeng.8b06155.

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 degrees 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 degrees 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 degrees C, by feeding a furfural solution in cyclopentylmethyl ether (5 vol % furfural) under a H-2 stream (H-2: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 h, attaining a FUR conversion of 65%, with a furan yield following a similar trend (55%), while furfuryl alcohol was almost negligible (only 6%). The regeneration after calcination led to the sintering of Ni nanoparticles, thus decreasing the furan yield..