催化学报

催化学报 ›› 2006, Vol. 27 ›› Issue (5): 397-402.

• 研究论文 • 上一篇    下一篇

Pt/Al2O3/WO3/ZrO2催化剂对正己烷异构化反应的催化性能

杜宇乔,陈晓蓉,陈长林,徐南平   

  1. 南京工业大学化学化工学院, 江苏南京 210009
  • 收稿日期:2006-05-25 出版日期:2006-05-25 发布日期:2006-05-25

Catalytic Performance of Pt/Al2O3/WO3/ZrO2 Catalyst for Isomerization of n-Hexane

DU Yuqiao, CHEN Xiaorong, CHEN Changlin*, XU Nanping   

  1. College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu, China
  • Received:2006-05-25 Online:2006-05-25 Published:2006-05-25

PDF

1236

被引次数

53

摘要： 通过浸渍法制备了系列Pt/Al2O3/WO3/ZrO2催化剂样品,采用X射线衍射、傅里叶变换红外光谱和程序升温还原等方法表征了催化剂的结构、表面酸性和氧化还原性能,考察了不同反应条件下催化剂对正己烷异构化反应的催化性能. 结果表明, Pt的加入显著改变了WO3/ZrO2载体的氧化还原性,并使催化剂由单一的酸中心催化变成由酸中心与金属中心共同催化; Al2O3的加入增强了WO3与ZrO2之间的相互作用,增加了催化剂的Lewis酸位. 在n(H2)/n(n-C6H14)=1.5, WHSV=0.7 h-1, m(cat)=2.0 g, p=1.0 MPa, θ=220 ℃和t=3 h的反应条件下, Pt/Al2O3/WO3/ZrO2催化剂上正己烷的转化率和2,2-二甲基丁烷的选择性分别达到84.9%和22.9%,裂解反应产物的收率低于1.5%. 经 1000 h的寿命试验,催化剂没有出现失活.

关键词: 铂, 氧化铝, 氧化钨, 氧化锆, 负载型催化剂, 己烷, 异构化

Abstract: A series of Pt/Al2O3/WO3/ZrO2 catalyst samples were prepared by the impregnation method. The structure and redox properties of the catalyst samples were characterized by X-ray powder diffraction, temperatrue-programmed reduction of H2, and FT-IR spectroscopy. The catalytic performance of the samples for the n-hexane isomerization under different conditions was studied. The results showed that the addition of Pt has a great effect on the redox properties of tungstated zirconia. Owing to the presence of Pt, the n-hexane isomerization is catalyzed by metal and acid sites, and the selectivity for 2,2-dimethyl butane is significantly increased. The addition of Al2O3 can promote the interaction between tungsten oxide and zirconia and to increase the Lewis acidity. Under the conditions of n(H2)/n(n-C6H14)=1.5, WHSV=0.7 h-1, m(cat)=2.0 g, p=1.0 MPa, θ=220 ℃, and t=3 h, the conversion of n-hexane is 84.9%, the selectivity for 2,2-dimethyl butane reaches 22.9%, and the cracking yield of C4- is less than 1.5%. The stability of the Pt/Al2O3/WO3/ZrO2 catalyst for the n-hexane isomerization was further investigated. The catalyst exhibits excellent stability, and no deactivation after 1?000 h operation was detected.

Key words: platinum, alumina, tungsten oxide, zirconia, supported catalyst, hexane, isomerization