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Influence of Pt–Pd/TS-1 Catalyst Preparation on Epoxidation of Olefins with Hydrogen Peroxide

The catalytic performance of the platinum–palladium/titanium silicalite, which was a common catalyst for the direct epoxidation of olefins with hydrogen and oxygen, was tested by epoxidation of allyl chloride with hydrogen peroxide. The epoxidation capacity of the TS-1catalyst was reduced after loading palladium and platinum on it. Ti leaching and crystallinity decrease were observed by XRD and FT-IR. The decomposition of hydrogen peroxide was accelerated by the supported Pd and Pt. These contributed to the loss of epoxidation capacity of TS-1. Ti leaching and crystallinity decrease were probably main causes. We propose that the Ti leaching had the most important influence on the loss of epoxidation capacity

The recovery of palladium with the use of ion exchange resins

Separation of precious metals is possible with the use of ion exchange resins. Selective ion exchange resins are being developed by the industry for the chloride complexes of the precious metals. The loading isotherms and the kinetics of loading palladium onto an anion resin, Amberlite IRA 900, has been determined. Amberlite IRA 900 is a macro reticular polystyrene type I strongbase anion exchange rsein containing quaternary ammonium groups. Pure K 2PdCl 4 was used for the preparation of the single metal solution. The resin as well as the various test solutions were rolled in plastic bottles for 2 days to ensure equilibrium was attained. The best equilibrium fit was obtained with the Freundlich model. The Freundlich model also fit the kinetic data very well.