SO_4^(2-)/ZrO_2-Al_2O_3催化剂表面酸性质对正丁烷异构化反应性能的影响研究

Study on the structure-reactivity correlation of SO_4^(2-)/ZrO_2-Al_2O_3 in n-butane isomerization reaction

采用"沉淀-浸渍"法制备一系列不同硫酸负载量的SO_4^(2-)/ZrO_2-Al_2O_3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℃、H_2∶C_4=2∶3和质量空速为3 h^(-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SO_4^(2-)/ZrO_2-Al_2O_3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Br?nsted酸性位,其中,强Br?nsted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。

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 3 h^-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 Br0nsted 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.