Catalytic upgrading of biopolyols derived from liquefaction of wheat straw over a high-performance and stable supported amorphous alloy catalyst

Post-refining of crude biomass liquefaction-derived polyols (biopolyols) to remove undesired carbonyl compounds is essential to improve the quality of biopolymers. One of the dominated carbonyl compounds in the crude biopolyols, butyl levulinate (BL), was hydrogenated to gamma-valerolactone (GVL) over Cu-modified NiCoB amorphous alloy catalyst to explore a high-efficient hydrogenation upgrading catalyst. Cu0.5Ni1Co1B catalyst with metallic Cu particle size of 10.2 nm and the highest BL conversion of 74.6% was supported on the acid activated attapulgite (H+-ATP) material. The synergistic effect between acidic and hydrogenated active centers in Cu0.5Ni1Co1B/H+-ATP catalyst was proved by NH3-temperature programmed desorption (NH3-TPD) to promote the conversion of carbonyl compounds compared to unsupported Cu0.5Ni1Co1B catalyst. Reaction temperature also showed a positive effect on the removal of carbonyl compounds especially for the acids and their esters. Under the optimum reaction conditions (140 degrees C, 1.0 MPa), the relative content of carbonyl compounds in crude biopolyols showed an obvious decrease of 10.3%, while the hydroxyl number of biopolyols increased by 140 mg KOH/g. Gas chromatography-mass spectrometry (GC-MS) analysis results indicated that the conversion of ethylene glycol condensation products and their monoesters or diesters of acetic acid and propionic acid was the major reaction during the process of hydrogenation upgrading of crude biopolyols. Cu0.5Ni1Co1B/H+-ATP catalyst also exhibited well stability for the aqueous-phase hydrogenation of crude biopolyols without deactivation in five times run.