Analysis of organic acids in the waste-liquor of aspen auto-catalyzed ethanol-water pulping

In accordance with the complex components and high value by-products characteristics of waste-liquor from aspen auto-catalyzed ethanol-water pulping, analysis of organic acids in the waste-liquor was carried out in this paper. Waste-liquor was prepared and then extracted by ether after lignin separation. Then the ether extract was qualitatively analyzed by Gas Chromatography-Mass Spectrometer. Results showed that there were almost 25 species complex components in the waste-liquor such as acids, esters and lignin of low molecular weight. Moreover, the contents of acetic acid and formic acid were higher comparatively. Vacuum distillation was also used to separate lignin from the waste-liquor. All the fractions were analyzed by volumetric analysis and Gas Chromatography as well. It was revealed that the total acid content was 0.043mol/L, and the contents of acetic acid and formic acid were 1.8635g/L(0.031mol/L) and 0.665g/L(0.0144mol/L), respectively, by the analysis of Gas Chromatography.