Rhodium-platinum oxide

Rhodium-platinum oxide (Rh–Pt oxide), or Nishimura's catalyst, is an inorganic compound used as a hydrogenation catalyst.^[2]

Rhodium-platinum oxide

Names
IUPAC name Rhodium(III) oxide / Platinum(IV) oxide
Other names Rh–Pt oxide, Nishimura's catalyst
Identifiers
Properties
Chemical formula	Rh2O3 / PtO2
Molar mass	253.81 / 227.09 (anhydrous)
Appearance	Black powder[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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).^[3][4] 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.^[5][6][7]

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).^[2][4] 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

References

1. Heuser, Heidi. "Nishimura's catalyst". Product Number: 3000034604. Umicore: Precious Metal Chemistry. Retrieved 29 January 2016.
2. Nishimura, Shigeo (2001). Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis (1st ed.). New York: Wiley-Interscience. pp. 42–43, 182, 389–390, 408, & 414–571. ISBN 9780471396987.
3. Nishimura, Shigeo (1961). "Hydrogenation and Hydrogenolysis. V. Rhodium-Platinum Oxide as a Catalyst for the Hydrogenation of Organic Compounds". Bulletin of the Chemical Society of Japan. 34 (1): 32–36. doi:10.1246/bcsj.34.32.
4. Nishimura, Shigeo (1961). "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. 34 (10): 1544–1545. doi:10.1246/bcsj.34.1544.
5. Nishimura, Shigeo (1960). "Hydrogenation and Hydrogenolysis. III. Rhodium-Platinum Oxide as a Catalyst for the Hydrogenation of the Aromatic Nucleus". Bulletin of the Chemical Society of Japan. 33 (4): 566–567. doi:10.1246/bcsj.33.566.
6. Stocker, J. H. (1962). "Communications to the Editor". The Journal of Organic Chemistry. 27 (5): 2288–2292. doi:10.1021/jo01053a077.
7. Nishimura, Shigeo; Taguchi, Hisaaki (1963). "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. 36 (3): 353–355. doi:10.1246/bcsj.36.353.