97/00998 Unique fractionation of biomass to polyols provides inexpensive feedstock for liquid fuels process

Abstract

Previous work in this laboratory established a unique process that converts C{sub 5} and C{sub 6} polyols (straight-chain hydrocarbons with a hydroxyl group on each carbon) to hydrocarbons using hydroiodic acid and phosphoric acids. Polyols, such as sorbitol and xylitol, are commercially available from highly purified glucose and xylose but are expensive. To use less costly and renewable biomass resources as feedstock for this process, the biomass must first be fractionated (e.g. by steam explosion 2) for cellulose and/or hemicellulose recovery; these polysaccharides can then be hydrolyzed and reduced to polyols. We are investigating a one-step Russian method 3 to directly convert raw {open_quotes}biomass-to-polyols{close_quotes} (BTP) to determine more definitive optimum reaction conditions and the economics of this method for comparison to using steam-exploded cellulose. In the Russian method, biomass is subjected to simultaneous dilute acid hydrolysis and catalytic hydrogenation at {approximately}170{degrees}C and {approximately}50 atm H{sub 2} (cold), thus trapping the incipient aldoses as their corresponding, but less reactive, polyols (alditols). The possibility of converting lignite via the BTP method was studied.