催化学报

催化学报 ›› 2006, Vol. 27 ›› Issue (12): 1063-1068.

• 研究论文 • 上一篇    下一篇

Ti-Si复氧化物载体对金催化剂上丙烯环氧化的影响

戴茂华,汤丁亮,袁友珠   

  1. 厦门大学化学化工学院化学系固体表面物理化学国家重点实验室, 福建厦门 361005
  • 收稿日期:2006-12-25 出版日期:2006-12-25 发布日期:2006-12-25

Effect of Ti-Si Mixed Oxide Support on Gold Catalysts for Gas-Phase Epoxidation of Propylene

DAI Maohua, TANG Dingliang, YUAN Youzhu*   

  1. State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
  • Received:2006-12-25 Online:2006-12-25 Published:2006-12-25

PDF

697

被引次数

16

摘要： 以TiCl4和SiCl4为原料,采用水解和非水水解溶胶-凝胶两种方法制备了一系列不同Ti含量的Ti-Si复氧化物载体,继而用沉积-沉淀法制得载金催化剂. 采用X射线衍射、紫外-可见漫反射光谱、 N2吸附和高分辨透射电镜对催化剂进行了表征,并考察了催化剂在氢气和氧气存在下的丙烯气相环氧化催化性能. 研究表明,钛含量在6%～14%范围内时,两种方法制得的Ti-Si复氧化物均为无定形结构,但采用非水水解溶胶-凝胶法制得的载体比表面积较高. 以非水水解溶胶-凝胶法制备的钛含量10%的Ti-Si复氧化物为载体得到的载金催化剂表现出较高的活性和选择性,反应60 min时,丙烯转化率为5.7%, 240 min后降为3.3%, 环氧丙烷的选择性稳定于95%左右. 还考察了非水水解溶胶-凝胶的陈化时间和金沉积-沉淀溶液的pH值等对反应结果的影响.

关键词: 非水水解, 溶胶-凝胶, 氧化钛, 氧化硅, 复氧化物, 金, 丙烯, 环氧化, 环氧丙烷

Abstract: Titania-silica mixed oxides prepared by hydrolytic and one-step non-hydrolytic sol-gel routes using TiCl4 and SiCl4 as precursors were employed as the gold catalyst supports for gas-phase epoxidation of propylene in O2 and H2. Characterization studies of the supports and catalysts were performed by means of X-ray diffraction, ultraviolet-visible absorption spectroscopy, N2 adsorption, and high-resolution transmission electron microscopy. The results indicated that the amorphous Ti-Si mixed oxides containing 6%[KG-45x]-[KG-20x]14% of Ti could be prepared by both sol-gel routes, but those by non-hydrolytic sol-gel afforded higher surface area and significant mesopores. A superior catalytic performance was obtained with the gold catalyst supported on the non-hydrolytic sol-gel Ti-Si mixed oxide containing 10% of Ti. The propylene conversion was 5.7% at the initial 60 min and 3.3% at 240 min of time on stream. The selectivity for propylene oxide was as high as 95%. The influences of aging time for the non-hydrolytic sol-gel and pH value for the Au deposition-precipitation on the performance of the Au catalyst were also discussed.

Key words: non-hydrolytic, sol-gel, titania, silica, mixed oxide, gold, propylene, epoxidation, propylene oxide