Influence of reaction conditions on solvolysis of organosolv lignin using water and green organic co-solvents as reaction medium

Abstract

This study investigated the non-catalyzed solvolysis of sulphur free organosolv lignin using mixtures of organic solvents (methanol, ethanol and 2-methyltetrahydrofuran) and water with emphasis on the novel biphasic 2-methyltetrahydrofuran (2-MTHF)/water reaction medium. The effect of co-solvents, co-solvent-to-water ratio and temperature were studied. 2-MTHF proved to be effective co-solvent with water that significantly suppressed char formation and also demonstrated promising protection effect on monoaromatic compounds. The yield of solvolyzed lignin (SL) and char were in the range of 40.0–88.6% and 10.4–0.1% respectively, based on initial amount of dried lignin. The yield of monoaromatics maximized to 67.2 mg g−1 of lignin at 310 °C and 60 min with syringol, syringaldehyde, 4-methylsyringol, 1,2,3-trimethoxy-5-methyl benzene and guaiacol as the main compounds.