Direct propylene epoxidation

J. Lu, X. Zhang, J. J. Bravo-Suarez, K. K. Bando, S. T. Oyama, Direct propylene epoxidation over barium promoted Au/Ti-TUD catalysts with Hz and Op Effect of Au particle size, J. Catal. doi 10.1016/j.jcat.2007.06.006. 

TABLE 10.1 Direct propylene epoxidation with O2 and H2 representative catalytic performance data... 

J. Chou, E. W. McFarland, Direct propylene epoxidation on chemically reduced Au nanoparticles supported on titania, Chem. Commun. (2004) 1648. 

Key Words Direct propylene epoxidation. Propylene oxide, Gold, Titanium, Propene, Au/Ti catalysts. Catalysis by gold. Titanium silicalite, TS-1, Gold/TS-1, Hydrogen peroxide, Kinetics, Design of experiments, Deposition-precipitation, Ammonium nitrate, Selective oxidation, Alkene epoxidation, Density functional theory, DFT calculations, QM/MM calculations. 2008 Elsevier B.v. 

As stated earlier, Taylor et al. [59] have reported commercially interesting PO formation rates for Au/TS-1 catalysts containing very low Au loading (0.01-0.05 wt.%). Careful examination of TEM micrographs was performed, but no nanometer-sized particles were observed. Again, this means that most of the catalytic activity is due to invisible Au clusters (<1 nm). Thus, invisible few-atom Au clusters, perhaps located inside the TS-1 pores, on Au/TS-1 catalysts with 0.01-0.05 wt.% Au as well as visible nanometer-sized Au particles prevalent on the external surface of Au/TS-1 catalysts containing >1 wt.% Au are catalytically active in direct propylene epoxidation. 

Recently, Dai et al. [86] investigated 4 wt.% Au catalysts supported on Ti02-Si02 mixed oxides prepared by nonhydrol)4 ic sol-gel synthesis route for direct propylene epoxidation. High-resolution TEM studies showed that the Au particle size was around 2-A nm. The Ti loading was varied systematically, and the best performance was observed over a catalyst containing 10 mol% Ti 61.3 gpo kg J j h... 

Lu, J., Zhang, X., Bravo-Suarez, J., et al. (2007). Direct Propylene Epoxidation over Barium-Promoted Au/Ti-TUD Catalysts with H2 and O2 Effect of Au Particle Size, J. Catal., 250, pp. 350-359. 

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