Catalysts Based on Ni and Mg Oxides for the One-Pot Production of High Added-Value Products from Furfural

A family of NiO-MgO samples with Ni/Mg molar ratio between 0.10 and 0.30 are synthesized by co-precipitation and subsequent calcination. The characterization of the samples show the formation of a solid solution with a periclase structure in such a way that the Ni2+species are poorly reducible. After the reduction of the NiO-MgO samples at 500 degrees C, the catalysts are tested in the furfural (FUR) hydrogenation to obtain valuable products in a one-pot reaction. The catalysts are highly selective toward tetrahydrofurfuryl alcohol (THFA) with a yield above 50% in most cases as well as 1,2-pentanediol (1,2-PeD) and 1,5-pentanediol (1,5-PeD) with maximum yield of 22 and 23% after 22 h of reaction at 170 degrees C and 4 MPa of H2, respectively. The present work also suggests the presence of two routes in the furfuryl hydrogenation. The first one is associated with the reduction of furfural to furfuryl alcohol (FOL) and the hydrogenation of the ring yielding THFA. In the second route, once FOL is formed, the furanic ring is open to form 1,2-PeD and 1,5PeD. The Ni/MgO catalysts hydrogenate furfural to a wide range of compounds such as tetrahydrofurfuryl alcohol and pentanodiols. The presence of Ni2+ in the MgO structure facilitates the ring opening of the furanic ring to give PeDs, while Ni0 particles are responsible for the hydrogenation of both the aldehyde group and the double bonds of furfural to give THFA. image