Copper chromite

Copper chromite is a complex inorganic composition Cu₂Cr₂O₅, but often containing barium oxide that is used to catalyse certain reactions in organic synthesis.^[1] It was first described in 1908.^[2] A variety of composition are recognized including Cr₂CuO₄·CuO·BaCrO₄ [[chemical abstracts registry number is 99328-50-4) and Cr2Cu2O5 (CAS# 12053-18-8). The latter is sometimes intentionally poisoned with quinoline, when the catalyst is used for decarboxylation reactions. The catalyst was developed in North America by Adkins and Lazier partly based on interrogation of German chemists after World War II in relation to the Fischer-Tropsch process.^[3] The catalyst Cr₂CuO₄·CuO·BaCrO₄ is prepared by addition of a solution containing both barium nitrate and copper(II) nitrate to a solution of ammonium chromate. This resulting precipitate is calcined at 350-400 C.^[4]

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Illustrative reactions

• hydrogenation of ester compounds to the corresponding alcohols. For example, sebacion, derived from the acyloin condensation of dimethyl sebacate, is hydrogenated to 1,2-cyclodecanediol by this catalyst.^[5] Phenanthrene is also reduced, at the 9,10 position.
• hydrogenolysis of 2-fufuryl alcohol to 1,5-pentanediol at 250-300 °C under 3300-6000 psi of H₂.^[6]
• decarboxylation of α-phenylcinnamic acid to cis-stilbene.^[7]

Reactions involving hydrogen are conducted at relatively high gas pressure (135 atm) and high temperatures (150-300 °C) in a so-called hydrogenation bomb. More active catalysts requiring less vigrous conditions are known but are typically derived from more expensive metals, such as platinum.

References

1. ^ Cladingboel, D. E. “Copper Chromite” in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley & Sons. DOI: 10.1002/047084289X.rc221
2. ^ Gröger, M. “Über Ammoniumdoppelchromate” Zeitschrift fur anorganische Chemie volume 58, page 412-426 (1908).doi:10.1002/zaac.19080580138; “Chromite aus basischen Chromaten” ibid. volume 76, page 30-38 (1912). doi:10.1002/zaac.19120760103 10.1002/zaac.19120760103
3. ^ Fischer-Tropsch Archive
4. ^ Lazier, W. A.; H. R. Arnold, H. “Copper Chromite Catalyst” Organic Syntheses, Collected Volume 2, p. 142 (1943). http://www.orgsyn.org/orgsyn/pdfs/CV2P0142.pdf.
5. ^ Blomquist, A. T.; Goldstein, A. "1,2-Cyclodecanediol" Organic Syntheses Collected Volume 4, p.216. http://www.orgsyn.org/orgsyn/pdfs/cv4p0216.pdf
6. ^ Kaufman, D.; Reeve, W. “1,5-Pentanediol” Organic Syntheses, Collected Volume 3, p.693 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0693.pdf
7. ^ Buckles, R. E.; Wheeler, N. C. “cis-Stilbene” Organic Syntheses, Collected Volume 4, p.857 (1963). http://www.orgsyn.org/orgsyn/pdfs/CV4P0857.pdf

References

1. ^  The Copper-Chromium Oxide Catalyst for Hydrogenation Homer Adkins, Edward E. Burgoyne, Henry J. Schneider J. Am. Chem. Soc.; 1950; 72(6); 2626-2629. First Page
2. ^  CAS registry [7440-47-3] & [1317-38-0]