Synthesis and Catalytic Properties of Vanadium-Phosphorus- Silicon Oxides

研究了催化剂制备和处理对正丁烷部分氧化制顺丁烯二酸酐VPO(VPO)催化剂结构和活性的影响。核心策略是将硅引入VPO体系，影响催化剂的形态、氧化还原电位和酸性；硅应该稳定钒基焦磷酸盐相，被认为有利于预期的催化效果。制备的催化剂材料通过X射线衍射、傅里叶变换光声光谱、X射线光电子能谱、化学吸附和动力学测量进行了表征，以确定其结构、形态和活性。还考察了水蒸气对催化剂的酸性、活性和选择性的影响。顺丁烯二酸酐是一种重要的工业产品，是生产多种重要单体、药物和农药的化学中间体。现在它是由丁烷催化氧化制成的；原料的低成本使这一点是可行的，尽管产量有限。这项工作的目标是找出产量限制的原因；如果它能被绕过，经济影响将是重大的。

This is a study of the effects of catalyst preparation and treatment on the structure and reactivity of VPO (vanadium phosphorus oxide or "vanadium phosphate") catalysts for the partial oxidation of n-butane to maleic anhydride. The core strategy is the incorporation of silicon into the VPO system, influencing the morphology, redox potential, and acidity of the catalyst; silicon should stabilize the vanadyl pyrophosphate phases, considered beneficial for the desired catalytic effect. Catalyst materials prepared are characterized by X-ray diffraction, Fourier-transform photoacoustic spectroscopy, X-ray photoelectron spectroscopy, chemisorption, and kinetic measurements to establish structure, morphology, and activity. Also examined is the effect of water vapor on the acidity, activity, and selectivity of the catalysts. Maleic anhydride is an important industrial product as a chemical intermediate in the production of a number of important monomers, drugs, and pesticides. It is now made by catalytic oxidation of butane; the low cost of the feedstock makes this feasible despite the limited yield. The objective of this work is to identify the cause of the yield limitation; if it can be circumvented, the economic impact would be major.