Preparative Aspects of Supported Ni2P Catalysts for Reductive Upgrading of Technical Lignin to Aromatics

Supported Ni2P was evaluated as a hydrodeoxygenation (HDO) catalyst in the reductive upgrading of a soda lignin in supercritical ethanol by a hydrotalcite-derived mixed Cu-Mg-Al oxide (CuMgAlOx) catalyst. Various Ni2P catalysts were prepared by different approaches on silica, γ-alumina and a siliceous amorphous silica-alumina (ASA) supports. Calcined NiO/SiO2 precursors were impregnated with phosphate, phosphite and hypophosphite followed by reduction. With γ-alumina, the desired Ni2P could not be obtained, presumably due to the reaction of the P-source with alumina. NiO on ASA could be converted to Ni2P by addition of phosphite, preferably at a P/Ni ratio of 1. Low P/Ni ratio avoids blockage of the pores by P-oxide species remaining after reduction. By further comparison to a sol–gel prepared NiO/SiO2 and co-impregnated silica, it was established that the most active Ni2P catalyst was obtained by impregnation of NiO/SiO2 with phosphate at P/Ni = 1 and reduction at 620 °C. In combination with CuMgAlOx, more than half of soda lignin can be converted to aromatics monomers with a relatively high degree of deoxygenation and limited degree of ring hydrogenation. The co-catalyst system is more active than the separate catalysts

Hydro-pyrolysis of lignocellulosic biomass over alumina supported Platinum, Mo2C and WC catalysts

In-line hydro-treatment of bio-oil vapor from fast pyrolysis of lignocellulosic biomass (hydro-pyrolysis of biomass) is studied as a method of upgrading the liquefied bio-oil for a possible precursor to green fuels. The nobel metal (Pt) and non-noble metal catalysts (Mo2C and WC) were compared at 500 °C and atmospheric pressure which are same as the reaction conditions for fast pyrolysis of biomass. Results indicated that under the pyrolysis conditions, the major components, such as acids and carbonyls, of the fast pyrolysis bio-oil can be completely and partially hydrogenated to form hydrocarbons, an ideal fossil fuel blend, in the hydro-treated bio-oil. The carbide catalysts perform equally well as the Pt catalyst regarding to the aliphatic and aromatic hydrocarbon formation (ca. 60%), showing the feasibility of using the cheap non-noble catalysts for hydro-pyrolysis of biomass