15-12: Chemical fractionation of Kraft black liquor by solvent extractions

Black liquor with high alkalinity is generated from Kraft chemical pulping. About half of the organic derivatives of wood are dissolved in the black liquor. However, in pulping process, potential valuable chemicals derived from lignin and hemicelluloses are devaluated and simply burnt at the mill site for energy recovery.

It has been suggested that black liquor could be a feedstock for producing valuable chemical products by chemical or biological conversion technology. Alcohol solvent can be used to extract phenolic compounds from black liquor selectivity and in high yield. Also, low molecular weight fractions of lignin are soluble in organic solvents with weak or moderate hydrogen bonding capacity. The objective of this study is to fractionate the valuable chemicals especially derived from lignin in black liquor by sequential solvent extraction.

Black liquor was obtained from Kraft pulping factory in South Korea. Black liquor was freeze dried without adjustment of pH and filtration. liquorIt was then extracted and fractionated by butanol, methanol, dichloromethane, chloroform, ethyl ether and dimethyl sulfoxide.

The characteristics of the fractions will be determined by GPC, alkaline nitrobenzene oxidation, HPLC, GC-MS and NMR spectroscopy.