(16a) Effects of Solvent Selection on Efficient Furfural Production

Conversion of 5-carbon (C₅) sugars in biomass to furfural is an early step in the value chain to producing renewable value-added chemicals such as furfural alcohol, methyl tetrahydrofuran, tetrahydrofuran, 1,4 butanediol, and other four and five-carbon chemical intermediates. Molar yields of furfural from C₅ sugars are limited by competitive reactions to form humins. The commercially practiced technology for furfural production involves the simultaneous conversion of C₅ sugars in solid biomass and steam stripping of the resulting furfural. The process has a molar yield between 45-55 mol%.

Recently, researchers have examined more efficient methods of converting aqueous C₅ sugars, generally available as byproduct streams from pulp and paper manufacturing, into furfural in a two-liquid phase process. In this process, a water-immiscible organic solvent and acid catalyst are added to the aqueous C₅ stream. The organic solvent is used to selectively partition furfural away from the acid catalyst in the aqueous phase, thereby reducing the formation of humins and increasing furfural selectivity.

In this talk we will discuss the overall process considerations used to select an optimized solvent and the effect of the solvent on the energy load on distillation column used to separate furfural from the organic solvent. We will discuss the how varying the 4-tert-butyl phenol content in solvent and the organic to aqueous phase ratio affected the xylose conversion rate. We observed a 3x increase in reaction rate over the parameter space explored. The likely reasons and the implications of this finding will be discussed.