(636f) Conversion of Loblolly Pine Wood In Ionic Liquids

Conversion of cellulose and wood in the ionic liquid 1-butyl-3-methyl-imidadzolium chloride has received considerable attention in the last years. The chloride anions of the ionic liquid disrupt hydrogen bonds between different polysaccharide chains resulting in the unique capability of this medium to dissolve cellulose. This property makes 1-butyl-3-methyl-imidadzolium chloride an interesting reaction medium for the conversion of cellulose and hemicellulose to monomer, e.g. monosaccharides, furfural, 5-hydroxymethylfurfural (HMF). In aqueous phase these conversions are limited by the accessibility of the carbohydrates within the complex biomass matrix.

In this work, it is demonstrated that acid catalyzed conversion of loblolly pine wood in 1-butyl-3-methyl-imidadzolium chloride occurs at much lower temperatures than in aqueous phase. At 120 °C the entire carbohydrate fraction of wood is converted into water soluble products within 2 h, while the lignin fraction remains as an insoluble residue. The water soluble products include polysaccharides, monosaccharides, furfural and HMF. The influence of the reaction temperature, water concentration and acid concentration are investigated. Under more severe conditions (higher temperature, higher acid concentration), solid degradation products, so-called humins, are formed by re-polymerization of the dissolved monomers.

Further insight in the reaction network involved in these transformations was obtained by studying the acid catalyzed conversion of model compounds in 1-butyl-3-methyl-imidadzolium chloride was studied.