Cost-effective production of organosolv lignin from woody biomass using ethanol-water mixed solvent at mild conditions

Abstract

A cost-effective process has been developed for fractionating pine sawdust into lignin and cellulose fractions in an ethanol-water mixed solvent. The effects of temperature, different types of catalysts (i.e., strong acid, weak acid and alkali), and residence time, with respect to yields and purity of the crude lignin (degraded products) and crude cellulose (solid residue) were investigated. It is found that the purity of crude lignin was higher but with a lower product yield under a weak acid or alkali catalysis in comparison to strong acid treatments. According to the analysis results, the optimal conditions for fractionation process were as follows: a mixed solvent of ethanol-water (1:1, v/v), 15 % formic acid (based on dry biomass), 180 °C, and 60 min. The yield of the resulted crude lignin was 29.2 % with a purity of 54.6 %, and yield of crude cellulose was 64.6 % with a high purity of 84.3 %.