SO2-4/ZrO2-Al2O3催化剂表面酸性质对正丁烷异构化反应性能的影响研究

摘要

A series of alumina-promoted sulfated zirconia catalysts were prepared by precipitation-impregnation method.The catalysts were characterized by N2 sorption, pyridine adsorption Fourier transform infrared spectroscopy (Py-FTIR), X-ray diffraction (XRD).Their catalytic performance in n-butane isomerization was evaluated in a continuous flow type fixed-bed micro-reactor at atmospheric pressure, 200℃, and H2∶C4=2∶3, with a weight hourly space velocity of n-butane (WHSV) of 3h-1.The structure-reactivity relationship between surface acidity and catalytic behavior was revealed.Py-FTIR indicates that the sulfated treatment enhances the strength and density of catalytic Brnsted acid sites, which are essential for n-butane isomerization.Therefore, sulfated treatment can significantly improve the activity of n-butane isomerization, and Lewis acidity has no direct effect on it.%采用"沉淀-浸渍"法制备一系列不同硫酸负载量的SO2-4/ZrO2-Al2O3催化剂,利用N2吸附-脱附、Py-FTIR、XRD等手段对催化剂进行表征.在常压、200℃、H2∶C4=2∶3和质量空速为3h-1的反应条件下,在固定床微型反应评价装置上考察了硫酸负载量对SO2-4/ZrO2-Al2O3催化正丁烷异构化反应性能的影响.Py-FTIR结果表明,硫酸化处理为催化剂表面提供了丰富的Brnsted酸性位,其中,强Brnsted酸性位在正丁烷异构化反应中起重要作用,因此,硫酸化处理可显著提高正丁烷异构化活性,而Lewis酸性位与之没有直接关系.