CATALYTIC PRODUCTION OF GAMMA-VALEROLACTONE FROM BIOMASS-BASED LEVULINIC ACID

Gamma-valerolactone (GVL), which has been recently shown to be able to be converted into butane, represents a future source for both fuel alternatives and renewable materials. GVL can be formed from the hydrogenation of levulinic acid (LA), however, when lower cost unprocessed biomass is utilized to form levulinic and formic acid, other organic compounds are created, primarily from the hemicelluloses portion, which interfere with the GVL creation. Therefore a two step process was studied as a means to create a higher purity process that maximized LA and FA yield. Mild sulfuric acid extraction experiments on hybrid poplar (Populus maximowiczii x nigra) samples were performed and optimized. 91% of pentosan can be extracted from the poplar chips under optimal conditions, with more than 93% of hexosan retained for LA production. The resulting hexosan enriched biomass was then subjected to a series of experiments employing high sulfuric acid and temperature to form LA and FA with yield of over 60% achieved. Finally, the LA and FA were catalytically converted to GVL, which could be purified through solvent extraction with nearly 100% conversion achieved.