Copper aspirinate

Copper(II) aspirinate is an aspirin chelate of copper(II) cations (Cu²⁺). It is used to treat rheumatoid arthritis.

Preparation

Copper aspirinate can be prepared by several methods. In one route of preparation, an excess of acetylsalicylic acid is dissolved in aqueous sodium carbonate. Sodium hydroxide is not suitable for this purpose, because it will hydrolyse acetylsalicylic acid (ASA) into salicylic acid and sodium acetate.

2 HC₉H₇O₄ + Na₂CO₃ → 2 NaC₉H₇O₄ + CO₂↑ + H₂O

The resulting solution is then filtered to remove any undissolved acetylsalicylic acid and is mixed with a solution containing Cu²⁺ cations (copper(II) sulfate is suitable), precipitating bright blue crystals of copper aspirinate immediately. The crystals can then be filtered from solution, washed, and recrystallized. An excess of acetylsalicylic acid is used in the first step, because it eliminates the possibility of unreacted carbonate anions precipitating the copper in this step.

4 NaC₉H₇O₄ + 2 CuSO₄ → C₃₆H₂₈Cu₂O₁₆↓ + 2 Na₂SO₄

Medicinal Use

Copper aspirinate has been proven effective as a treatment for rheumatoid arthritis.^[1]

Other Uses

The use of copper aspirinate as a pigment in PVC and Polystyrene has also been investigated. ^[2]

External Links

IR Spectrum from Eckerd College's Chem Department

Footnotes

↑ "Rheumatoid Arthritis (RA)". Copper Development Association. June 2000.
↑ Allan, J R (1991). "A Study of the Performance of Bis(acetylsalicylate) Copper(II) and the Cobalt(II), Nickel(II) and Copper(II) Complexes of Pyridine-3,4-dicarboxylic Acid as Colouring Materials for Poly(vinyl chloride) and Polystyrene". Eur. Polym. J. 27 (7): 669–672. Unknown parameter |coauthors= ignored (help); line feed character in |title= at position 71 (help)

[1] "Rheumatoid Arthritis (RA)". Copper Development Association. June 2000.

[2] Allan, J R (1991). "A Study of the Performance of Bis(acetylsalicylate) Copper(II) and the Cobalt(II), Nickel(II) and Copper(II) Complexes of Pyridine-3,4-dicarboxylic Acid as Colouring Materials for Poly(vinyl chloride) and Polystyrene". Eur. Polym. J. 27 (7): 669–672. Unknown parameter |coauthors= ignored (help); line feed character in |title= at position 71 (help)

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