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Chemical engineering

Inorganic Chemistry

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Full-Text Articles in Engineering

Synthesis And Characterization Of Nanostructured Aluminas , Weihua Deng Jan 2005

Synthesis And Characterization Of Nanostructured Aluminas , Weihua Deng

Retrospective Theses and Dissertations

In the work, mesoporous aluminas were produced by nonionic supramolecular templating and characterized to determine the stability of their physical structure during extended calcination at elevated temperatures. The effect of synthesis temperature on the physical structure of these materials and the resulting thermal evolution from synthesized aluminum hydroxide to transitional alumina was studied using thermogravimetric analysis. A high resolution multiple quantum magic angle spinning NMR spectroscopy method was used to determine quantitatively the evolution of the aluminum coordination during the thermal processing. The mesoporous alumina exhibited high stability upon prolonged heating, which is essential for their future applications in catalytic ...


Metal Cluster Hydrodesulfurization Catalysts Based On Ternary Molybdenum Sulfides , Robert Kirk Thompson Jan 1999

Metal Cluster Hydrodesulfurization Catalysts Based On Ternary Molybdenum Sulfides , Robert Kirk Thompson

Retrospective Theses and Dissertations

Catalysts based on metal sulfide cluster compounds such as Chevrel phases (MxMo6S8) have been shown to possess high activity and selectivity for hydroprocessing reactions. Previous methods of preparing crystalline Chevrel phases have involved high temperature, solid-state synthetic routes which produce low surface area materials (0.1--1.0m2/gm). In our recent research, lower temperature syntheses via solution precursors have been explored as routes to these materials. The discovery of a new class of compounds, M2x/n n+(Mo6S8)Sx (n = 1--3) has resulted. These new reduced ternary molybdenum sulfides have been shown to have both high activity and selectivity in ...


A Kinetic Study On The Adsorption And Reaction Of Hydrogen Over Silica-Supported Ruthenium And Silver-Ruthenium Catalysts During The Hydrogenation Of Carbon Monoxide , David Paul Vanderwiel Jan 1998

A Kinetic Study On The Adsorption And Reaction Of Hydrogen Over Silica-Supported Ruthenium And Silver-Ruthenium Catalysts During The Hydrogenation Of Carbon Monoxide , David Paul Vanderwiel

Retrospective Theses and Dissertations

An interesting phenomenon in bimetallic catalysis is the synergistic effect between two metals during CO hydrogenation. For example, addition of Ag to Ru catalysts results in a dramatic decrease in the specific activity of the catalyst, even though Ag alone does not appreciably adsorb H2 or CO. A series of Ag-Ru/SiO2 catalysts containing 0, 3, 10, 20 and 30 atomic percent silver was used to examine the kinetics of the adsorption and reaction of H2 on Ru during CO hydrogenation. CO was saturatively adsorbed at room temperature on each catalyst, followed by subsequent reaction with ambient H2 at 460 ...


Reduced Molybdenum Oxidation States In Hydrodesulfurization Catalysis By Chevrel Phases , Mark Eugene Ekman Jan 1991

Reduced Molybdenum Oxidation States In Hydrodesulfurization Catalysis By Chevrel Phases , Mark Eugene Ekman

Retrospective Theses and Dissertations

The catalytic activities of reduced (relative to Mo[superscript]4+) molybdenum sulfides, known as Chevrel phases, have been evaluated for thiophene and benzothiophene hydrodesulfurization (HDS) and 1-butene hydrogenation (HYD). These materials have been found to have HDS activities comparable to, or greater than, model unpromoted and cobalt-promoted MoS[subscript]2 catalysts; in contrast, Chevrel phases exhibit low activities for 1-butene HYD;X-ray powder diffraction and laser Raman spectroscopy analysis of the used (10 hours of thiophene reaction) catalysts indicated that the bulk structures were stable under reaction conditions. XPS analysis demonstrated that reduced molybdenum oxidation states were present at the ...