Tompsett, Geoff

Profile Picture
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Research Assistant Professor, Department of Chemical Engineering
Last Name
First Name
Chemical Engineering

Search Results

Now showing 1 - 2 of 2
  • Publication
    Green Gasoline from Aqueous Phase Hydrodeoxygenation of Carbohydrate
    Li, Ning; Tempsett, Geoffrey A; Huber, George W
    Aqueous-phase hydrodeoxygenation (APHDO) is a promising technology to convert biomass-derived oxygenates into alkanes and oxygenates. Selectively breaking the C-O bond without C-C bond cleavage is the biggest challenge and key for this project. In the previous work of Dumesic’s group, it was shown that sorbitol can be converted to gasoline by APHDO over bifunctional catalysts (Pt/SiO2-Al2O3) that contain both metal and acid sites. However, the low octane number, high Reid vapor pressure and low yield of gasoline range compounds produced in such a process limited the real application of this technology. As the first part of this work, we investigated the reaction chemistry for the APHDO of sorbitol over Pt/SiO2-Al2O3 catalyst. From the analysis of gas phase and liquid phase products, more than 40 different compounds were identified. These compounds include dehydrated sorbitol (1,4-sorbitan, isosorbide), polyols, cyclic-ether alcohols, ketones, alkanes and CO2. From the APHDO of sorbitol and a series of model intermediates, it was found that the APHDO is mainly composed of three unit reaction: 1) C-C breaking reactions by decarbonyldration or retro-aldol reactions. 2) C-O bond cleavage (dehydration followed by hydrogenation). 3) Hydrogenation reactions. Then we investigated the effect of reaction conditions (temperature, pressure, and sorbitol concentration) and different acidic support. Base on the experience we got in above work, we achieved up to 70 % gasoline product by APHDO of sorbitol over Pt/Zirconium phosphate catalyst which was proved to be the best among the catalysts we investigated. The octane number and Reid vapor pressure were also improved by the new catalytic process.
  • Publication
    Optimizing the Shape Selectivity of Zeolite Catalysts for Biomass Conversion: The Kinetic Diameter
    Jae, Jungho; Tompsett, Geoffrey A; Foster, Andrew J; Auerbach, Scott M; Lobo, Raul F; Huber, George W
    We have studied the influence of catalyst pore size and morphology on the conversion of glucose to aromatics by catalytic fast pyrolysis using over 15 different zeolite catalysts having a variety of shapes and pore sizes. The estimated kinetic diameter for the catalytic pyrolysis products and reactants was used to determine the optimal pore size for zeolite catalysts for catalytic fast pyrolysis. Smaller oxygenate pyrolysis products including furans, hydroxyaldehydes, and organic acids are sufficiently small in diameter to diffuse easily into ZSM-5 (6.3 Å). Of the aromatic products only benzene, toluene, indane, indene, naphthalene, ethylbenzene and xylenes are of a sufficiently small size compared to the ZSM-5 pore. Zeolites type catalysts with a range of pore size 3.9-7.4Å were used for catalytic testing. From these an optimum pore size range of 5.7-6.6Å is identified to maximize aromatic yield. In addition to pore window size, zeolite pore structure and intersections are critical for the reaction mechanism. It is likely that this small pore size also limits the formation of larger aromatics including coke in the pores. Key words: Zeolite, Catalytic Fast Pyrolysis, Kinetic Diameter, Aromatics.