15-09: Integration of chemical catalysis with extractive fermentation to produce blend stocks for jet and diesel fuels

Monday, April 29, 2013
Exhibit Hall
Zachary C. Baer1, Sanil Sreekumar2, Sasisanker Padmanabhan3, F. Dean Toste1, Harvey W. Blanch1 and Douglas S. Clark1, (1)Chemical and Biomolecular Engineering, UC Berkeley, Berkeley, CA, (2)Chemistry, UC Berkeley, Berkeley, (3)Chemical and Biomolecular Engineering, UC Berkeley, CA
Acetone, a product of solventogenic Clostridia’s acetone-butanol-ethanol (ABE) fermentation, harbors nucleophilic α-carbons, which are amenable to C-C bond formation with the electrophilic α-carbon of the alcohols (ethanol and n-butanol).  These inherent functionalities enable coupling chemistry to form higher molecular weight hydrocarbons, similar to those found in current jet and diesel fuels, by a transition-metal-catalyzed alkylation reaction.  Here we describe the integration of biological and chemocatalytic routes to efficiently convert ABE fermentation products into ketones, ranging from 2-pentanone to 6-undecanone, by a palladium-catalyzed alkylation.  Tuning of the reaction conditions permits production of either predominately gasoline or predominately jet and diesel blend stocks.  The integration of the two technologies, ABE fermentation and the alkylation reaction, is made possible by in situ liquid-liquid extraction (LLE) of the ABE with a non-toxic extractant.  This process provides a means to selectively produce gasoline, jet, and diesel blend stocks from lignocellulosic and cane sugars at yields near their theoretical maxima.  Additionally, we demonstrate optimization of both the catalyst and fermentation to predictably favor the production of hydrocarbons larger than C11.