Zhang Wen-min1, Liu Yi-wu2, Li Hao1, Zhang Xiao-min1*
(1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China; 2. College of Chemistry and Chemical Engineering, Neijiang Normal University, Neijiang 641000, China)
Abstract: Titanium-containing hexagonal mesoporous silicas(Ti-HMS) with different Ti contents have been prepared using dodecylamine as template. Nitrogen-incorporated Ti-HMS molecular sieves were preparation by NH3 at high temperature. Ti-HMS and Nitrogen-incorporated Ti-HMS supported Au catalysts were obtained by a deposition-precioitation method. The catalytic performance was evaluated by the direct gas phase epoxidation of propylene using hydrogen and oxygen. The samples were characterized by nitrogen isothermal adsorption-desorption, XRD, FT-IR, DR UV-Vis, ICP-AES and HRTEM. The results showed that Ti-HMS molecular sieves are hexagonal mesoporous in structure. Titanium species exist in tetra-coordinated state. Superior performance was obtained with the Au catalyst supported on Ti-HMS was modified by NH3 at 850℃. 6.28% of propylene conversion, and 83.10% of PO selectivity can be obtained at 373 K in the initial 30 min of time-on-stream. The propylene conversion and PO selectivity were 4.74 and 82.49％ after running 270min. The performance of the Au catalyst for propylene epoxidation was improved by N-modified of the Ti-HMS supports.
Key words: Ti-HMS; Nitridation; Nano-gold catalysts; Propylene epoxidation
E-mail: xmzhang@cioc.ac.cn
Journal of Molecular Catalysis, Vol. 25, Issue 3, 2011, 213~219
