Frontiers in Catalysis Science and Engineering
2011
Daniel E. Resasco
Douglas and Hilda Bourne Chair
George Lynn Cross Professor
School of Chemical, Biological and Materials Engineering
University of Oklahoma
"MODEL COMPOUND STUDIES TOWARDS THE CATALYTIC UPGRADE OF PYROLYSIS OIL IN VAPOR AND LIQUID PHASES"
Tuesday, August 16, 2011
EMSL Auditorium - 9:00AM
An effective approach to stabilize pyrolysis oil is conducting the refining before condensation of the vapors occurs. Degradation by further reaction (oligomerization) occurs in the liquid phase and accelerates when the liquid is subsequently heated for fractionation or other processing. The proposed "catalytic cascade" incorporates a series of reactions that include: (a) formation of C-C bonds to extend the carbon backbone of short oxygenates to the desired gasoline/diesel range; (b) incorporation of short carbon fragments (C1-C3) into the aromatic ring of phenolic compounds; (c) deoxygenation of the resulting products to monofunctional compounds or hydrocarbons. The different catalysts used in this cascade include: basic catalysts (MgO, ZrO2, CsX zeolites), acidic catalysts (H-ZSM5, H-beta zeolites), mixed oxides (CeZrO2), supported metal catalysts (Cu, Ni, Ru, Pd supported on carbon nanotubes and monolith). These catalysts are used in the vapor phase or in liquid (biphasic) systems. The latter employs nanoparticle catalysts to stabilize water/oil emulsions and to conduct reactions at the liquid/liquid interface to benefit from the differences in solubility exhibited by the reactants (bio-oil) and products (bio-fuels) and achieve continuous reaction/separation.
Prof. Jingyue (Jimmy) Liu
Director, Center for Nanoscience
Professor, Department of Physics & Astronomy
Professor, Department of Chemistry & Biochemistry
"Nanostructures for Catalysis and Energy Production"
Friday, May 13, 2011
EMSL Auditorium - 1:30PM
» Research Highlight: Large Problem, Tiny Answer
Energy is not only the driver for improving the quality of human life but also critical to our survival. To power the planet for a better future, it is imperative to develop new processes for effective use of energy and to develop sustainable and clean energy resources. Catalysis, the essential technology for accelerating desired chemical transformations, plays an important role to realizing environmentally friendly and economically feasible processes for producing energy carriers and for converting them into directly usable energy. Design and synthesis of controlled nanostructures can help us address some key issues encountered in understanding the fundamental processes and dynamics of catalyzed reactions. We have recently synthesized both nanostructured metal oxides and shape-controlled metal nanocrystals, and applied them to the systematic investigation of catalytic processes for steam reforming of alcohols and the oxidation of carbon monoxide on nanoscale facets. Aberration-corrected scanning transmission electron microscopy techniques have been used to elucidate the atomic structures of the active phases. The ability of sub-Ångström resolution imaging with in situ capabilities available in a modern aberration-corrected TEM/STEM provides us excellent opportunities to study the dynamic behavior of nanostructures and to understand their synthesis-structure-performance relationships. Recent progresses in synthesizing novel metal oxide nanostructures for energy harvest and storage will also be discussed.
Prof. Manos Mavrikakis
University of Wisconsin - Madison
Department of Chemical & Biological Engineering
"On the role of hydrogen in heterogeneously catalyzed reactions"
Monday, March 14, 2011
EMSL Auditorium - 1:00PM
Hydrogen is a frequent participant in several heterogeneously catalyzed reactions, including Fischer-Tropsch Synthesis (FTS) of fuels, ammonia synthesis, oxygen reduction reaction (ORR), NO reduction, preferential oxidation of CO in the presence of H2 (PROX), etc. Having analyzed the detailed aspects of the reaction mechanism for a number of these reactions on various transition metal and alloy surfaces using first-principles methods, some common principles governing the role of hydrogen in a wide range of catalytic transformations begin to emerge. In this presentation, we will discuss these common mechanistic principles by examples, including FTS, NO-reduction, ORR, PROX, through an analysis of the energetics of alternative elementary reaction steps and the resulting potential energy diagrams. Connections to observations from experimental studies provide an invaluable perspective for the evaluation of our theoretical assessments.
Prof. Thomas B. Rauchfuss
University of Illinois
Department of Chemistry
William H. & Janet B. Lycan Professor of Chemistry
"Synthetic Analogues for the Active Sites of the Hydrogenase Enzymes"
Monday, February 28, 2011
EMSL Auditorium - 10:00AM
The lecture will summarize recent progress in modeling the behavior of the hydrogenase enzymes. Emphasis will be on reactivity of reduced diiron and nickel-iron thiolates toward protons, oxidizing equivalents, and other electrophiles. Work on the FeFe models, which is more advanced, will show the importance of both the redox and internal base modules of this active site. Work on NiFe systems will highlight progress—the preparation of Ni-Fe-hydrides—and gaps.
Prof. Michael T. Klein
University of Delaware, Energy Institute
Department of Chemical Engineering
"Molecule-based Modeling of Heavy Hydrocarbon Structure and Reaction"
Wednesday, February 23, 2011
EMSL Auditorium - 10:00AM
The considerable interest in molecule-based models of heavy hydrocarbon structure and reaction is motivated by the need to predict both upstream and downstream properties of these materials. This is because the molecular composition is an optimal starting point for the prediction of mixture properties. The potential advantages of molecule-based modeling are thus clear. Less readily apparent, however, is that the development and operation of molecular models comes with a large requirement for model construction and solution time as well as analytical and reactivity information.
Prof. Christopher W. Jones
Georgia Institute of Technology
School of Chemical & Biomolecular Engineering
School of Chemistry and Biochemistry
J. Carl & Sheila Pirkle Faculty Fellow
"Heterogenized M-Salen Catalysts for Enantioselective Reactions: Catalyst Design, Structure-Reactivity Trends, and Deactivation Pathways"
Monday, January 31, 2011
EMSL Auditorium - 1:00PM
» Research Highlight: A Personality Change for a Catalyst
Metal salen complexes are widely applied as catalysts for numerous important enantioselective reactions. The reactions catalyzed by metal salen complexes generally follow either (i) monometallic mechanisms (e.g. Mn-salen for epoxidation or Ru-salen for cyclopropanation), whereby a single metal complex promotes the catalytic reaction or (ii) bimetallic mechanisms, where cooperation between two metal complexes is required for efficient catalysis (e.g. Co-salen for epoxide ring-opening or Al-salen conjugate additions of cyanide). The design of effective heterogenized catalysts should therefore take into account the reaction mechanism, as reactions in category (i) are hypothesized to be optimized by accessible yet isolated supported metal salen complexes, whereas reactions of type (ii) are hypothesized to require efficient complex mobility, facilitating metal salen—metal salen cooperative interactions.
Here, several new designs for (a) soluble polymer or oligomer supported metal salen complex catalysts, (b) insoluble polymer resin supported complexes, and (c) insoluble porous silica supported are described. Their utility in the cooperative Co-salen catalyzed hydrolytic kinetic resolution of epoxides and the monometallic Ru-salen catalyzed enantioselective cyclopropnantion of olefins is reported. The kinetics of the reactions using both fresh and recycled catalysts are compared. Most catalysts are shown to deactivate during use, and the mechanisms of deactivation are explored. Strategies to reduce or mitigate catalyst deactivation are described.
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