水热改性SO_4^(2-)/Al_2O_3/ZrO_2的制备及其对正丁烷异构化反应的催化性能  

Preparation of SO_4^(2-)/Al_2O_3/ZrO_2 through Digestion Modification and Its Catalytic Activity in n-Butane Isomerization

作　　者：曹崇江[1] 陈长林[1] 徐南平[1] 

机构地区：[1]南京工业大学化学化工学院

出　　处：《应用化学》2007年第11期1240-1244,共5页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金资助项目(20476047)

摘　　要：通过控制Zr(OH)4在母液中的回流时间,制备水热改性的Zr(OH)4。用X射线衍射、热重、氮气吸附等测试技术对Zr(OH)4和催化剂的理化性质进行分析,并通过正丁烷异构化反应考察了不同水热处理对催化剂活性的影响。结果表明,水热处理能够提高Zr(OH)4热稳定性及其在焙烧过程中的结晶温度和晶相转变温度。但长时间100℃下的水热处理,消耗了前躯体Zr(OH)4中部分羟基,影响了硫酸根与载体表面的稳定性结合继而影响到催化剂的催化性能。实验结果表明,随着水热时间的增加,样品的热稳定性,比表面积不断增大,但硫含量并不是单调递增。经96h水热处理制得的催化剂含硫质量分数低于1.1%,异构化反应中的转化率小于20%。而经水热回流处理24h制备的催化剂样品硫质量分数为1.45%,在正丁烷异构化反应中显示出优异的催化性能,250℃下的稳态转化率大于46%,接近该条件的平衡转化率。Zirconium hydroxide was produced by digestion of hydrous oxide at 100 ℃ with the control of reflux time. The structural information, surface area and thermal stability were characterized by means of XRD, TG-DTG, chemical analysis and N2 adsorption-desorption techniques. The zirconium hydroxide obtained by digestion can be used to prepare SO4^2-/Al2O3/ZrO2 solid acid and the catalytic activities of these materials were examined in n-butane isomerization. The data show the crystallization and the transformation from the metastable tetragonal phase to the monoelinie phase were retarded with digestion during calcination. However, the hydroxyl of hydrous zirconia decreased with long time digestion which showed a passive effect on retaining surface sulfated and catalytic activity. With digestion time increasing, the thermal stability and surface area increased while the sulfated content was not monotonically increasing. The results show the sulfated content of catalyst was less than 1.1% after 96 h digestion and its n-butane conversion was no more than 20%. In contrast, the sulfated content of the catalyst was 1.45% after 24 h digestion refluxing. The n-butane conversion on the resulting catalyst was more than 46% , which is close to the equilibrium conversion of n-butane.

关 键 词：氢氧化锆 同体酸 水热法 正丁烷 异构化 

分 类 号：O643.3[理学—物理化学]