Copper(II) hydroxide



Copper(II) hydroxide
IUPAC name Copper(II) hydroxide
Other names Cupric hydroxide
Identifiers
CAS number 20427-59-2
Properties
Molecular formula (OH)2
Molar mass 97.561 g/mol
Appearance Blue or blue-green solid
Density 3.37 g/cm3, solid
Melting point

n/a, decomposes into CuO

Solubility in water insoluble
ethanol insoluble
Hazards
Main hazards Skin, Eye, & Respiratory Irritant
NFPA 704
0
2
0
 
R-phrases R36 R37 R38
S-phrases S26
Flash point Non-flammable
Related Compounds
Other anions Cu(NO3)2, CuCO3
Other cations Al(OH)3
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Copper(II) hydroxide (copper. The typical color of copper hydroxide is blue. Some forms of copper(II) hydroxide are sold as "stabilized" copper hydroxide, quite likely a mixture of copper(II) carbonate and hydroxide. These are often greener in color.

History

Copper(II) hydroxide has been known to man since alchemists were probably the first to manufacture it.[1] This was easily done by mixing solutions of lye and blue vitriol, both chemicals which were known in antiquity.

It was produced on an industrial scale during the 17th and 18th centuries for use in pigments such as blue verditer and Bremen green.[2] These pigments were used in ceramics and painting.[3]

Chemical Properties

Synthesis

Copper(II) hydroxide can be produced by adding a small amount of anode is used, often made from scrap copper.

"Copper in moist air slowly acquires a dull green coating. The green material is a 1:1 mole mixture of Cu(OH)2 and CuCO3."[4]

2Cu(s) + H2O(g) + CO2(g) + O2(g) ---> Cu(OH)2(s) + CuCO3(s)

This is the alloy statues such as the Statue of Liberty.

Reactions

Moist samples of copper(II) hydroxide slowly turn black due to the formation of copper(II) oxide.[5] When it is dry, however, copper(II) hydroxide does not decompose unless it is heated to 185°C.[6]

Copper(II) hydroxide reacts with a solution of cellulosic fiber.

Since copper(II) hydroxide is mildly alkali, forming [Cu(OH)4]2-.[7]

Use as an organic reagent

Copper(II) hydroxide has a rather specialized role in organic synthesis. Often, when it is utilized for this purpose, it is prepared in situ by mixing a soluble copper(II) salt and potassium hydroxide.

It is sometimes used in the synthesis of aryl ethylenediamine with 1-bromoanthraquinone or 1-amino-4-bromoanthraquinone to form 1-((2-aminoethyl)amino)anthraquinone or 1-amino-4-((2-aminoethyl)amino)anthraquinone, respectively.


Copper(II) hydroxide also converts acid octanoic acid.


Natural occurrence

Copper(II) hydroxide is found in several different Azurite (2CuCO3 • Cu(OH)2 ) and carbon dioxide from the atmosphere to form a basic copper(II) carbonate.

Uses

Copper(II) hydroxide has been used as an alternative to the Bordeaux mixture, a fungicide and nematacide.[8] Nowadays, it is disfavored because of environmental contamination problems. Copper(II) hydroxide is also occasionally used as ceramic colorant.

Precautions

Copper(II) hydroxide is a skin, eye and respiratory irritant. Always wear safety glasses when handling copper hydroxide. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

References

  1. Roscoe, H. E., & Schorlemmer, C. (1879). A Treatise on Chemistry 2nd Ed, Vol 2, Part 2. MacMillan & Co. (p 498).
  2. Paquette, Leo A. (1995). Encyclopedia of Reagents for Organic Synthesis, 8 Volume Set. Wiley. ISBN 0-4719-3623-5.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Copper(II)_hydroxide". A list of authors is available in Wikipedia.