title: Pretreatment and fractionation of wheat straw using various ionic liquids.
abstract: Pretreatment of lignocellulosic biomass with ionic liquids (ILs) is a promising and challenging process for an alternative method of biomass processing. The present work emphasizes the examination of wheat straw pretreatment using ILs, namely, 1-butyl-3-methylimidazolium hydrogensulfate ([bmim][HSO4]), 1-butyl-3-methylimidazolium thiocyanate ([bmim][SCN]), and 1-butyl-3-methylimidazolium dicyanamide ([bmim][N(CN)2]). Only [bmim][HSO4] was found to achieve a macroscopic complete dissolution of wheat straw during pretreatment. The fractionation process demonstrated to be dependent on the IL used. Using [bmim][SCN], a high-purity lignin-rich material was obtained. In contrast, [bmim][N(CN)2] was a good solvent to produce high-purity carbohydrate-rich fractions. When [bmim][HSO4] was used, a different behavior was observed, exhibiting similarities to an acid hydrolysis pretreatment, and no hemicellulose-rich material was recovered during fractionation. A capillary electrophoresis (CE) technique allowed for a better understanding of this phenomenon. Hydrolysis of carbohydrates was confirmed, although an extended degradation of monosaccharides to furfural and hydroxymethylfurfural (HMF) was observed.
authors.affiliation: Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia, Lisboa, Portugal.
authors.forename: André M da Costa
authors.initials: AM
authors.lastname: Lopes
authors.forename: Karen G
authors.initials: KG
authors.lastname: João
authors.forename: Ewa
authors.initials: E
authors.lastname: Bogel-Łukasik
authors.forename: Luísa B
authors.initials: LB
authors.lastname: Roseiro
authors.forename: Rafał
authors.initials: R
authors.lastname: Bogel-Łukasik
mesh_terms: D002482:Cellulose / Q000737:chemistry; D005591:Chemical Fractionation; D006868:Hydrolysis; D052578:Ionic Liquids / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D002482:Cellulose