Synergy in Lignin Upgrading by a Combination of Cu-Based Mixed Oxide and Ni-Phosphide Catalysts in Supercritical Ethanol.

ABSTRACT: The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu-Mg-Al oxide (CuMgAlO _x ) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e. Ni/SiO₂, Ni₂P/SiO₂, and Ni/ASA (ASA = amorphous silica alumina), with the aim of combining lignin depolymerization and HDO in a single reaction step. While the silica-supported catalysts were themselves hardly active in lignin upgrading, Ni/ASA displayed comparable lignin monomer yield as CuMgAlO _x . A drawback of using an acidic support is extensive dehydration of the ethanol solvent. Instead, combining CuMgAlO _x with Ni/SiO₂ and especially Ni₂P/SiO₂ proved to be effective in increasing the lignin monomer yield, while at the same time reducing the oxygen content of the products. With Ni₂P/SiO₂, the lignin monomer yield was 53 wt %, leading to nearly complete deoxygenation of the aromatic products.

SUBMITTER: Koranyi TI 

PROVIDER: S-EPMC5384481 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature