284357 Tungsten Incorporated Ordered Mesoporous Silicates As Catalysts for Epoxidation of Olefins

Thursday, November 1, 2012: 5:15 PM
321 (Convention Center )
Madhav Ghanta, Chemical and Petroleum Engineering, Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, KS, Wenjuan Yan, Department of Chemical and Petroleum Engineering, Center for Environmentally Beneficial Catalysis, Lawrence, KS, Anand Ramanathan, Center for Environmentally Beneficial Catalysis, The University of Kansas, Lawrence, KS and Bala Subramaniam, Department of Chemical and Petroleum Engineering, Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, KS

Tungsten was incorporated into three dimensional ordered mesoporous silicates (KIT-6 and KIT-5) synthesized by hydrothermal methods. The resulting materials, W-KIT-61 and W-KIT-5, were found to have a narrow pore size distribution ranging from 6-9 nm. The surface area decreased from 927 to 625 m2/g and from 798 to 431 m2/g for KIT-6 and KIT-5, respectively with an increase in tungsten content. The synthesized materials show ethylene epoxidation activity to ethylene oxide (EO) at mild temperatures (<40 °C) and pressure (~50 bars) using H2O2 as oxidant and methanol as solvent. The EO productivity was highest for low loading of tungsten (Si/W = 100); at this loading, the tungsten is incorporated into the framework of the support and is present in the highly active WO4 form. Epoxidation activity of tungsten based catalysts is found to be similar to Ag-based catalyst used in conventional process (0.7-4.4 g EO/h/g Ag). At higher metal loadings (or low Si/W ratios), catalytically inactive WO3 species were observed (XRD and Raman studies). Recycle studies established catalyst durability.

1. Ramanathan, A.; Subramaniam, B.; Badloe, D.; etal. Direct incorporation of tungsten into ultra-large-pore three-dimensional mesoporous silicate framework: W-KIT-6. J Porous Mater, 2011.


Extended Abstract: File Not Uploaded