THE INFLUENCE OF THE BLEACHING MEDIUM ON CAUSTIC EXTRACTION EFFICIENCY (II): OXIDIZED LIGNIN SOLUBILITY

摘要

Caustic extractions performed with>50/100 ethanol solutions severely hindered lignin removal from chlorine dioxide (Do) treated pulps. In this study, we show that the alkali solubility of an isolated Do lignin decreased as the concentration of ethanol in the medium was increased from 50 to 75/100. In addition, the amount of dissolved lignin in the alkaline extraction effluents approached its solubility limit when the medium contained more than 50/100 ethanol.