Hexachloroplatinic acid alumina

Figure 9.13. Preparation of a bifunctional Pt/Al203 catalyst. The alumina support is impregnated with an aqueous solution of hexachloroplatinic acid (H2PtCl6) and HCl.The competitive adsorption between C and...

Platmum(0)-l,3-divinyl-l,l,3,3-tetramethyldisiloxane (Karstedt catalyst) in xylene and hexachloroplatinic acid (40wt% Pt) as a 1% solution in THF was purchased from Aldrich chemical. 1,1,3,3-Tetramethyldisiloxane (Aldrich) was used without further purification. Divinylbenzene 960 (DVB), which is a mixture of 96% divinylbenzene (meta and para isomers) was purified from the phenolic inhibitor by stirring with 5% by weight basic alumina rmtil the TLC showed the complete removal of inhibitor. The alumina was filtered using Whatman GF/F (0.7 pm). THF was distilled using benzophenone ketyl rmder a nitrogen atmosphere. 

As example, the spent FCC catalysts were tested and compared for different combustion tests. The catalysts were promoted with 300 and 800 ppm Pt and Ce on alumina (220 m /g) and mixed oxides (1-5). Platinum was impregnated with hexachloroplatinic acid (H2PtCl6) and calcined at 500 °C. Then, it was treated... 

Spieker and Regalbuto [16] mention as one of the three adsorption mechanisms the complexation of the hexachloroplatinate ions with the dissolved oxide. The reaction will proceed where the acid solution contacts the alumina and, thus, immobilizes the platinum. The other two adsorption mechanisms involve chemical interactions between the metal complexes of the precursor and the surface of the solid support, and pure electrostatic interaction of charged complexes of the precursor with oppositely charged sites on the surface of the support. Results obtained by Roth and Reichard [17] demonstrate the immobilization by local neutralization of the hexachloroplatinum acid by reaction with the support. When an aqueous ammoniacal solution of platinum diamino dinitrite solution is impregnated, reaction with the surface of the support does not proceed, and a more uniform platinum profile results. 

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