Assessing the Impact of Various Cosolvents and Sulfolane During Biomass Reactions At Subcritical and Supercritical Conditions

Conversion of biomass into chemicals and sugars under subcritical and supercritical conditions was studied using pure cellulose and corn stover samples. Reactions were performed at temperatures ranging from 200 to 350 ^oC  in the presence of a variety of cosolvents including acetone, methanol, CO₂, and water. Initially, a 1 liter high pressure batch reactor was used. The product composition of a cellulose-methanol reaction at 300^oC analyzed by GCMS, HPLC and NMR consisted of a mixture of organic acids, sugars, and several undetermined components. Some of the organic acids identified in the reaction product included acetic, hexanoic, heptanoic and malonic acids. Additionally, some of the sugars identified were levoglucosan, D-Allose, and D-Galactose. The product composition of a corn stover-methanol reaction at 300^oC suggested the presence of ketones, aromatic hydrocarbons, and methyl ester derivatives. As evidenced by the results, reactions at high pressures are possible, although they are often accompanied by complex product compositions and an unreacted residue of cellulose and lignin. In addition to studying  the effects of these cosolvents, ongoing work will focus on the effects of incorporating sulfolane into the reactions and analyzing how it impacts the biomass reaction routes.