Rhodium-platinum oxide explained

Rhodium-platinum oxide (Rh–Pt oxide), or Nishimura's catalyst, is an inorganic compound used as a hydrogenation catalyst.^[1]

Uses

Rh–Pt oxide is used to reduce various aromatic compounds to their respective cycloalkanes or saturated heterocycles under mild conditions (i.e. often at room temperature and atmospheric pressure).^{[2] [3]} In this application, Rh–Pt oxide is superior to other group 10 catalysts such as platinum dioxide. Furthermore, the catalyst can be used to carry out the reaction with minimal losses of oxygen containing functional groups via hydrogenolysis.^{[4] [5] [6]}

Preparation

An aqueous solution of rhodium chloride, chloroplatinic acid, and sodium nitrate is evaporated and then fused in a porcelain dish between 460-480°C until the oxides of nitrogen cease (≈10 minutes). The resulting solidified mass is then washed with distilled water and dilute sodium nitrate followed by drying with calcium chloride to yield the catalyst. Typically the ratio of metals used for the catalyst is 3:1 Rh/Pt or 7:3 Rh/Pt.

See also

• Rhodium-catalyzed hydrogenation
• Rhodium(III) oxide
• Wilkinson's catalyst
• Platinum black
• Platinum on carbon
• Palladium on carbon
• Birch reduction

Notes and References

1. Book: Nishimura. Shigeo. Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis. 2001. Wiley-Interscience. New York. 9780471396987. 42–43, 182, 389–390, 408, & 414–571. 1st.
2. Nishimura. Shigeo. Hydrogenation and Hydrogenolysis. V. Rhodium-Platinum Oxide as a Catalyst for the Hydrogenation of Organic Compounds. Bulletin of the Chemical Society of Japan. 1961. 34. 1. 32–36. 10.1246/bcsj.34.32. free.
3. Nishimura. Shigeo. Rhodium-Platinum Oxide as α Catalyst for the Hydrogenation of Organic Compounds. II. Catalyst Preparation and Effects of Platinum in Rhodium-Platinum Oxide . Bulletin of the Chemical Society of Japan. 1961. 34. 10. 1544–1545 . 10.1246/bcsj.34.1544.
4. Nishimura. Shigeo. Hydrogenation and Hydrogenolysis. III. Rhodium-Platinum Oxide as a Catalyst for the Hydrogenation of the Aromatic Nucleus. Bulletin of the Chemical Society of Japan. 1960. 33. 4. 566–567. 10.1246/bcsj.33.566. free.
5. Stocker. J. H.. Communications to the Editor. The Journal of Organic Chemistry. 1962. 27. 5. 2288–2292. 10.1021/jo01053a077.
6. Nishimura. Shigeo. Taguchi. Hisaaki. Hydrogenation and Hydrogenolysis. VII. Selective Hydrogenation of Aromatic Compounds Containing C–O Linkages Liable to Hydrogenolysis with a Rhodium-Platinum Oxide under high Pressures. Bulletin of the Chemical Society of Japan. 1963. 36. 3. 353–355. 10.1246/bcsj.36.353. free.