279855 Hydrodeoxygenation of Palmitic Acid Using Mo2 C

Wednesday, October 31, 2012: 8:30 AM
315 (Convention Center )
Allison Franck1, Phillip Savage1 and Levi T. Thompson1,2,3, (1)Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, (2)Hydrogen Energy Technology Laboratory, Ann Arbor, MI, (3)Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI

The hydrolysis of triglycerides yields fatty acids that can be upgraded to remove the oxygen thereby creating hydrocarbons that used as a drop-in replacement for petroleum derived liquid fuels.  In this paper we report results for the hydrodeoxygenation (HDO) of palmitic acid in high temperature water using nanostructured Mo2C. Previous studies have shown that Pt/C and Pd/C catalysts are highly active in aqueous environments; however, early transition metal carbides are an attractive alternative due to their significantly lower cost. For some reactions, these materials possess catalytic properties similar to those of platinum group metals. Compared to noble metals, the Mo2C catalyst promoted HDO of fatty acids in aqueous conditions, versus decarboxylation of the carboxylic acids. HDO retains an extra carbon on the hydrocarbon chain, removing the oxygen as H2O versus CO2 in decarboxylation. Effects of temperature (370– 400 °C), time (0.5 – 6h), and water density at supercritical conditions (0.17 – 0.52mL/cm3) were studied. Liquid products were analyzed using GC/MS and GC/FID. Characterization of Mo2C was done using N2 physisorption (BET surface area analysis) and x-ray diffraction (XRD). Higher temperatures and longer times resulting in higher conversions of palmitic acid and a higher yield of hexadecane. Increased water density (higher reactor pressure) caused decreases in both conversion of the fatty acid and yield of hexadecane. Other products from the reaction included C7- C15 hydrocarbons and C16 alcohols, aldehydes and ketones. The XRD patterns of the spent catalyst showed formation of an oxide phase, indicating that the catalyst oxidized and potential instabilities at reaction conditions in water in the absence of H2. HDO of palmitic acid was also studied in organic solvents and in the presence of H2 at variable partial pressures to determine the stability of the Mo2C at reaction conditions

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