Metal cluster hydrodesulfurization catalysts based on ternary molybdenum sulfides

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1999
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Thompson, Robert
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Glenn L. Schrader
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Chemical and Biological Engineering

The function of the Department of Chemical and Biological Engineering has been to prepare students for the study and application of chemistry in industry. This focus has included preparation for employment in various industries as well as the development, design, and operation of equipment and processes within industry.Through the CBE Department, Iowa State University is nationally recognized for its initiatives in bioinformatics, biomaterials, bioproducts, metabolic/tissue engineering, multiphase computational fluid dynamics, advanced polymeric materials and nanostructured materials.

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The Department of Chemical Engineering was founded in 1913 under the Department of Physics and Illuminating Engineering. From 1915 to 1931 it was jointly administered by the Divisions of Industrial Science and Engineering, and from 1931 onward it has been under the Division/College of Engineering. In 1928 it merged with Mining Engineering, and from 1973–1979 it merged with Nuclear Engineering. It became Chemical and Biological Engineering in 2005.

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1913 - present

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  • Department of Chemical Engineering (1913–1928)
  • Department of Chemical and Mining Engineering (1928–1957)
  • Department of Chemical Engineering (1957–1973, 1979–2005)
    • Department of Chemical and Biological Engineering (2005–present)

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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 HDS reactions with thiophene, while also exhibiting initial surface areas near 200m2/gm. The stability and activity of these materials is dependent upon the pretreatment procedure. Surface area and porosity data have revealed a decrease in surface area and an increase in average pore size as the pretreatment temperature is increased. Temperature-programmed analysis studies were performed in conjunction with XPS to examine how the oxidation states change as a function of pretreatment temperature. The mechanism through which these new reduced ternary molybdenum sulfides convert to the crystalline Chevrel phase was also determined;The low temperature synthesis route of these new reduced molybdenum sulfides has allowed the synthesis of new cluster compounds, such as Pt(Mo6S8 )S. X-ray photoelectron spectroscopy, laser Raman spectroscopy, infrared spectroscopy and microprobe analysis indicate that this new material is structurally similar to other cluster compounds we have synthesized. Pretreatment of PtMoS in hydrogen at 950°C results in its conversion to the previously unknown crystalline Chevrel phase.

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Fri Jan 01 00:00:00 UTC 1999