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

这项研究是正在进行的一项工作的扩展，该工作表明，在钾交换分子筛-L上负载的铂和锡在反应条件下具有高的异丁烷脱氢活性和高选择性以及GMOD的稳定性。这一发现被用反应动力学研究、吸附微量热研究和光谱研究来阐明碱修饰和载体性质的影响。将研究由以下四种组分组成的新催化剂，以确定所涉及的影响：(1)用作脱氢催化剂的过渡金属(镍和钯将尝试与铂一样)；(2)改性后过渡金属(锗、铅和锡)；(3)碱金属促进剂(Na、Rb、Cs以及钾)；以及(4)中性微孔载体。用微量热法研究了催化剂改性剂对探针分子与这些多组分催化剂相互作用的影响。红外、穆斯堡尔和核磁共振光谱的研究是为了阐明催化剂组分的化学状态，确定它们的分散性，并探索吸附的性质。低碳烷烃的选择性催化脱氢是生产《清洁空气法》规定的汽油重新配制所需的含氧物的关键工艺，对生产乙烯和丙烯等低碳烯烃也很重要。***

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. ***