Microcalorimetric, Kinetic, and Spectroscopic Studies of Multi-component Catalysts for Dehydrogenation of Light Paraffins

点击翻译按钮获取中文摘要

James Dumesic Abstract This study is an extension of an ongoing effort that has shown that platinum and tin supported in potassium-exchanged zeolite-L exhibits high activity and high selectivity for dehydrogenation of isobutane as well as gmod stability under reaction conditions. This finding is examined to elucidate the effects of alkali modification and support properties using reaction kinetics studies, adsorptive microcalorimetric studies, and spectroscopic studies. New catalysts formulated from the following four components will be studied to define the effects involved: (1) a transition metal active as a dehydrogenation catalyst (nickel and palladium will be tried as well as platinum); (2) a modifying post-transition metal (germanium and lead as well as tin); (3) an alkali-metal promotor (sodium, rubidium, and cesium as well as potassium), and (4) a neutral microporous support. Microcalorimetric studies are used to investigate the effects of catalyst modifiers on the interaction of probe molecules with these multicomponent catalysts. Infrared, Mossbauer, and nuclear magnetic resonance spectroscopic studies are conducted to illuminate the chemical states of the catalyst components, to determine their dispersions, and to probe the nature of adsorbates. Selective catalytic dehydrogenation of light paraffins is the key enabling process for the production of the oxygenates needed for the reformulation of gasoline as mandated by the Clean Air Act, and is also important for the production of light olefins such as ethylene and propylene. ***