Spectroscopic Studies of Partial Oxidation Catalysts During Their Genesis & Use

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The effects of the preparation protocol on the physical and chemical properties of binary and ternary mixed-metal-oxide catalysts are investigated. Both bulk and supported catalyst systems are studied using laser Raman spectroscopy and Mossbauer spectroscopy (iron-57 and antimony-121) as well as other instrumental methods. Preparation variables include pH of precipitation, ratio of catalyst precursors, order of precipitation and lengths and temperatures of drying and calcination. Effects to be monitored include the phase composition of the catalysts, the oxidation states of the constituent metals, and the catalytic properties (activity and selectivity) of the solid catalysts. The latter will be represented by using the catalyst to affect the partial oxidation of propylene to acrolein in a flow reactor. Mixed metal oxides are used as catalysts in many chemical processes. They are attractive because of their high selectivities toward particular products, including many high- value-added products. However, the factors influencing selectivity are poorly understood, the extant processes having been developed empirically. This study is intended to elucidate these factors.