PROCESSES FOR PURIFYING A CELLULOSIC MATERIAL

摘要

A process for treating a cellulosic material comprising extracting hemicellulose from the cellulosic material with an extractant comprising a cellulose solvent and a co-solvent to selectively extract hemicellulose therefrom and separating the extracted hemicellulose to form a cellulosic product comprising less hemicellulose than the cellulosic material. The extractant comprises a cellulose solvent and a co-solvent. The cellulose solvent is selected from the group consisting of an ionic liquid, an amine oxide and combinations thereof, and the co-solvent may preferably have a normal boiling point less than 120C, or less than 100C. The cellulosic product advantageously retains its cellulosic fiber morphology. The processes involve separating and recovering the hemicellulose and separating and recycling various process streams employed in the process.