Patent ID: 8435355

Claim:
A process for fractionating a lignocellulosic material comprising cellulose, hemicellulose and lignin into a cellulose-enriched fraction, the process comprising: contacting the lignocellulosic material with a solvent wherein the solvent consists essentially of an ionic liquid; dissolving cellulose and hemicellulose of the lignocellulosic material into the ionic liquid; dissolving lignin of the lignocellulosic material into the ionic liquid while leaving a portion of the lignin of the lignocellulosic material undissolved, the resulting dissolved cellulose, dissolved hemicellulose, dissolved lignin, undissolved lignin and ionic liquid forming a mixture; and separating a cellulose-enriched fraction from the mixture, the cellulose-enriched fraction characterized by a weight percent of glucose solids that is at least about 10 percentage points greater than the weight percent glucose attributable to cellulose and hemicellulose in the lignocellulosic material.