Selective Liquefaction of Lignin from Bio-ethanol Production Residue Using Furfuryl Alcohol

Abstract

In order to obtain “clean” liquefied lignin, selective liquefaction of lignin from bio-ethanol production residue (BEPR) was conducted using an aromatic solvent, furfuryl alcohol. The effects of liquefaction time, temperature, and liquid ratio on the liquefaction yield were investigated. The results indicated that with the increasing of liquefaction temperature (120 to 170 °C) or liquid ratio (3 to 5:1), the liquefaction yield of lignin (LYL) increased, respectively. Liquefaction times of 15 to 120 min had no significant effect on the liquefaction yield. When liquefaction was conducted at 170 °C for 15 min with a ratio of 5/1 liquefying solvent to raw material, the LYL reached its highest level of 80.23%. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Gel permeation chromatography (GPC) analyses confirmed that the liquefaction process had great selectivity for lignin. Ash and carbohydrates in the raw material could be removed as liquefied residue.