Monday, May 2, 2011
Grand Ballroom C-D, 2nd fl (Sheraton Seattle)
The application of ionic liquids (ILs) to pretreat lignocellulosic biomass has been shown to enhance the efficiency of biofuel production. Previous studies on the mechanism of the mitigated biomass recalcitrance upon IL pretreatment suggest that the complex structures of cellulose, hemicellulose and lignins in plant cell walls are disrupted, which in general resulted in improved accessibility of cellulose to enzymes. While the ILs can effectively dissolve biomass at elevated temperatures and destroy the native crystal structure of cellulose, the impact of IL on the structure of lignin is still not clear. In this work, we applied several analytical techniques to characterize the changes in physio-chemical structures of a technical lignin (Low sulfate lignin from Sigma-Aldrich) in dilute solutions. The shape and aggregations of lignin molecules in water and DMSO are studied by Small Angle Neutron Scattering (SANS), and its molecular weight is measured by Light Scattering (LS). Both NMR and FT-IR are used for the characterization of its chemical structures.