Lignin Liquefaction in Supercritical Water

摘要: Two lignins obtained from aqueous methanol organosolv pulping of aspen wood have been liquefied when suspended in water and heated to slightly above the critical temperature water. Liquefaction was carried out a stirred autoclave presence palladium on carbon catalyst low partial pressure hydrogen (730 psi). Injection lignin suspensions into pre-heated permitted study reaction time effects minimizing effect heat-up time. The were converted good yield brown viscous oils, that soluble ethyl acetate. Other products included an acetate insoluble fraction (~10%) carbon-containing gases (~10%), e.g. monoxide, dioxide, methane, ethane, etc. highest yields (~70%) oil after 5–20 minutes. Yields decreased 45 minutes with increasing formation gases. apparent molecular-weight distributions 2–3 fold smaller than starting lignins, indicating substantial depolymerization had taken place. volatile oils contained syringols, guaiacols, catechols phenol. Increasing syringols guaiacols catechols.