(532b) An Ionic Liquid Pretreatment Process That Includes IL Recycling and a Characterization of Pretreatment Fractions From Corn Stover

Dibble, D., Sandia National Laboratory
Li, C., Lawrence Berkeley National Laboratory
Sun, L., Joint BioEnergy Institute
Benke, P., Joint BioEnergy Institute
George, A., Sandia National Laboratory
Singh, S., Joint BioEnergy Institute

Ionic liquid pretreatment has been shown to be an effective means of delignification and decrystallization of biomass and result in enhanced enzymatic saccharification rates. An additional advantage of this technology is the ability to fractionate biomass components into separate product streams. In this talk we describe a new method of recovering and fractionating solutes, including lignin and soluble carbohydrate oligomers, from the ionic liquid [C2mim][OAc] after the pretreatment of corn stover. This new method avoids the formation of gel-phase intermediates during biomass precipitation, can result in very low residual IL content in processed biomass, and simplifies the recovery of IL and residual IL solutes without requiring the addition of difficult to recover materials such as salts or acids. We also present our extensive characterization of biomass fractions from corn stover by 2-D NMR, wet chemical analysis, enzymatic saccharification rate, and provide details, including mass flow and closure, of a closed-loop ionic liquid recovery and recycling process.