Ionic liquids as media for biomass processing: opportunities and restrictions.

The present study provides insight into the dissolution behavior of renewable materials in ionic liquids. Beech, spruce and rye straw were dissolved in 1-ethyl-3-methylimidazolium acetate as the ionic liquid of choice, which is currently one of the most frequently used cation-anion combinations among ionic liquids for biomaterial processing. The dissolution was followed by selective precipitation of cellulose, hemicelluloses, and lignin. The obtained lignin was analyzed with Curie-point pyrolysis gas chromatography/mass spectrometry (Cu-Py-GC/MS) and the separated cellulose/hemicellulose fractions with gel permeation chromatography (GPC). Time dependence of the dissolution process was studied on rye straw, eucalyptus kraft pulp and beech sulfite pulp. The results show a changing dissolution profile over time, which is due to progressing degradation of the cellulose in the ionic liquid. [ABSTRACT FROM AUTHOR]