Liquefaction of Fir Sawdust in Supercritical Ethanol with Dissolved Phosphotungstic Acid

Abstract

An environmentally benign approach is put forward with the focus on directly liquefying and depolymerizing Cunninghamia lanceolata (Lamb.) Hook. (Chinese fir) sawdust into ethyl levulinate (EL) under supercritical ethanol (scEtOH) conditions by using phosphotungstic acid (PTA) as a catalyst. The effects of parameters such as catalyst dosage, temperature, and reaction time on alcoholysis yield were investigated. The experimental results show that the biomass alcoholysis yield reached 95.35% with 0.5 g PTA as a catalyst at 260 °C for 30 min. Alcoholysis yield and quantitative content of EL depended on the catalyst. The light bio-oil was primarily composed of phenols, aldehydes, ketones, and esters. A high quantitative content of EL up to 20.82% (AR, Relative abundance) was achieved, compared to 0.73% AR when PTA was not added. Hence, scEtOH with dissolved PTA may offer novel media for both chemical reactions and biomass conversion technology as a replacement for environmentally undesirable organic solvents.

The Atmospheric Catalytic Liquefaction of Corn Stalk by Phosphoric Acid and Polyethylene Glycol For the Production of Biofuels

“…1601 cm-1 and 1512 cm-1 absorption peak was lignin benzene skeleton stretching vibration; C-O stretching vibration (methoxy benzene) was 1251cm-1 absorption peaks; beta glycosidic bond stretching vibration was 894 cm-1 absorption peaks, which was the characteristic absorption peak of cellulose. Liquefaction residue (curve A): 3398 cm-1, 2918 cm-1, 894cm-1 absorption peak was narrow and the intensity was weakened, which was caused by the liquefaction of cellulose in the raw material [51,52]. The disappearance of 1731 cm-1 absorption peak showed that the raw material in the hemicellulose has been basically lique ed.…”

Comparison of the Efficiency of Hetero- and Homogeneous Catalysts in Cellulose Liquefaction

“…The high acidity of heteropolyacids makes them good catalysts for liquefaction, the efficiency of which largely depends on the strength of the acid used. The use of heteropolyacids carries many advantages, including low toxicity, environmental friendliness, availability, and the ability to dissolve biomass in polar solvents [ 20 ].…”