title: In situ determination of lignin phenolics and wood solubility in imidazolium chlorides using (31)P NMR.
abstract: Corn stover, Norway spruce, and Eucalyptus grandis were pulverized to different degrees. These samples were subjected to quantitative analyses, upon the basis of predissolution into the imidazolium chloride-based ionic liquids [amim]Cl and [bnmim]Cl followed by labeling of hydroxyl groups as phosphite esters and quantitative (31)P NMR analysis. Analysis of different pulverization degrees provided semiempirical data to chart the solubility of Norway spruce in these ionic liquids. Further method refinment afforded an optimized method of analysis of the lignin phenolic functionalities, without prior isolation of the lignin from the fiber. The lignin in these samples was further enriched using cellulase and acidolysis treatments, allowing for comparison with the fibrous samples. Analysis of all samples charts the polymerized-monomer availability for each stage of the treatment. Conditions required for adequate signal-to-noise ratios in the (31)P NMR analysis were established with a notable improvement observed upon the lignin enrichment steps.
authors.affiliation: Laboratory of Organic Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki, Finland. alistair.king@helsinki.fi
authors.forename: Alistair W T
authors.initials: AW
authors.lastname: King
authors.forename: Luca
authors.initials: L
authors.lastname: Zoia
authors.forename: Ilari
authors.initials: I
authors.lastname: Filpponen
authors.forename: Anna
authors.initials: A
authors.lastname: Olszewska
authors.forename: Haibo
authors.initials: H
authors.lastname: Xie
authors.forename: Ilkka
authors.initials: I
authors.lastname: Kilpeläinen
authors.forename: Dimitris S
authors.initials: DS
authors.lastname: Argyropoulos
mesh_terms: D002712:Chlorides; D005052:Eucalyptus; D007093:Imidazoles; D008031:Lignin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010636:Phenols / Q000032:analysis*; D028222:Picea; D012995:Solubility; D012996:Solutions; D014934:Wood / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D002712:Chlorides; D007093:Imidazoles; D010636:Phenols; D012996:Solutions; D008031:Lignin