Direct oxidation of propylene and other olefins on precious metal containing Ti-catalysts

The properties and performance of an O-2-H-2 system used for the direct oxi dation of olefins have been studied on the example of direct oxidation of p ropylene. Ti-catalysts modified by impregnation with palladium tetraminenit rate and platinum tetraminechloride and by followed reduction under various conditions were used as bifunctional catalysts. New investigations showed that the pre-impregnation of the catalyst with salt and the using of alcoho ls or ketones as solvent for the impregnation of the catalyst with precious metal improved the selectivity of propylene oxide (PO). Also the influence of other precious metals such as Ir or Au as promoters on titanium silical ite-1 (TS-1) has been studied. In addition to propylene, other olefins like styrene or terpenes were also tested in direct oxidation with an O-2-H-2 s ystem by using Pd/PtrTS-1 or Pd/Pt/Ti-MCM-41, respectively. The use of thes e olefins as substrate lead to low yields of the desired product and showed the limits of the O-2-H-2 oxidation system, so far. (C) 2001 Elsevier Scie nce B.V. All rights reserved.