Copper(II) acetate

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Copper(II) acetate
Copper acetate2.jpg
Copper(II) acetate monohydrate
Names
IUPAC names
Copper(II) acetate
Tetra-μ2-acetatodiaquadicopper(II) (hydrated)
Other names
Copper acetate
Copper(II) ethanoate
Copper diacetate
Cupric acetate
Verdigris
Identifiers
Jmol-3D images Image
Properties
CuC4H6O4
Cu(CH3COO)2
Molar mass 181.63 g/mol (anhydrous)
199.65 g/mol (hydrate)
Appearance Dark green crystalline solid (anhydrous)
Blue-green crystalline solid (monohydrated)
Odor Odorless
Density 1.882 g/cm3 (hydrate) (at 20 °C)
Melting point Decomposes above 145 °C[1]
Boiling point 240 °C (464 °F; 513 K)
7.2 g/100 mL (hydrated)
Solubility Soluble in ethanol
Slightly soluble in diethyl ether and glycerol
Hazards
Safety data sheet FischerScientific
Lethal dose or concentration (LD, LC):
710 mg/kg oral (rat)
Related compounds
Related compounds
Copper(I) acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Copper(II) acetate or cupric acetate is a salt of copper with the formula Cu(CH3COO)2, sometimes shortened to Cu(OAc)2. Copper(II) acetate is generally encountered as monohydrate. Anhydrous Cu(OAc)2 is a dark green crystalline solid, while the monohydrate is more bluish-green.

Properties

Chemical

Copper(II) acetate can be used to couple terminal alkynes to give a 1,3-diyne, process known as Eglinton reaction:

Cu2(OAc)4 + 2 RC≡CH → 2 CuOAc + RC≡C−C≡CR + 2 HOAc

Heating a mixture of anhydrous copper(II) acetate and copper metal yields copper(I) acetate:

2 Cu + Cu2(OAc)4 → 4CuOAc

Physical

Copper(II) acetate is a dark green (anhydrous) or blue-green (monohydrate) solid, soluble in water.[2] Copper(II) acetate has a color that is slightly difficult to properly capture on camera.
Copper(II) acetate in small crystals

Availability

Copper(II) acetate can be purchased online.

Preparation

Copper(II) acetate monohydrate can be made by reacting a copper base with acetic acid.

2 CH3COOH + CuO → Cu(CH3COO)2 + H2O
2 CH3COOH + Cu(OH)2 → Cu(CH3COO)2 + H2O + 2H2O

Common vinegar can be used for this reaction, though impurities will precipitate when the solution is concentrated.

If you want to use copper metal, you will also need to add diluted hydrogen peroxide to the solution.

Anhydrous copper(II) acetate can be made by heating the monohydrate at 100 °C in a vacuum.

Copper(II) acetate can also be prepared from copper(II) hydroxide or basic copper carbonate by the addition of acetic acid followed by evaporation of the solution.[3]

Projects

  • Make glacial acetic acid
  • Grow large crystals
  • Pigment
  • Preparation of cis- and trans-Bis(glycinato)copper(II) Monohydrate[4]

Handling

Safety

Copper(II) acetates is irritant and toxic.

Storage

Copper(II) acetate should be stored in closed bottles. The anhydrous form should be kept in air-tight containers.

Disposal

Can be reduced with a metal such as zinc or iron to metallic copper which can be recycled.

References

  1. http://pubs.acs.org/doi/pdf/10.1021/ed053p397
  2. http://woelen.homescience.net/science/chem/exps/copper_acetates/index.html
  3. https://en.crystalls.info/Copper(II)_acetate
  4. https://webs.wofford.edu/hilljb/Chem%20323/CopperGlycine.pdf

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