Copper Acetates
Basic copper acetate (verdigris) was at one time made in France by interleaving copper metal sheets with fermented grape skins and dregs left after wine manufacture. After some time when the copper sheets had become coated with verdigris they were removed, exposed to the air for a few days and then replaced. This process was repeated until the whole sheet had become corroded. The resulting product was known as blue verdigris and was used as a fungicide at 1 kg basic copper acetate in 500 litres water.
Present manufacture is based on the action of acetic acid on copper metal, copper oxide or copper carbonate. They can also be prepared by treating a copper sulphate solution with lead acetate. Copper acetates are used as an intermediate in the manufacture of Paris green (cupric aceto-arsenite); as a catalyst in a number of organic reactions including rubber aging; as a chemical in textile dyeing; and as a pigment for ceramics. Copper acetates have also been used for impregnating kraft paper to produce an anti-tarnish wrapping paper for high grade silver ware.
Cuprous Oxide
Can be produced either electrolytically from copper or by the action of alkaline reducing agents on copper sulphate solutions. Formulated proprietary brands of cuprous oxide are extensively employed as fungicides and seed dressings. Another important application is in anti-fouling paints. Other uses include the colouring of porcelain and glass.
Cupric Oxide (black copper oxide)
Can be produced either by adding caustic soda to hot copper sulphate solutions or by treating copper scale with nitric acid and heating to redness. Cupric oxide is used in the ceramic industry for imparting blue, green or red tints in glasses, glazes and enamels. It is occasionally employed for incorporation in mineral supplements for insuring against an insufficiency of copper in the diet of animals. Among its other uses is the preparation of cuprammonium hydroxide solutions for the rayon industry.
Cupric Chloride
Obtained either by dissolving cupric oxide in hydrochloric acid or by the action of chlorine on copper. Its principal use is in the petroleum industry for sweetening (catalytic oxidation of the mercaptans) and as an ingredient of catalysts for other chemical processes. It is also used as a mordant in calico printing and dyeing.
Copper Oxychloride
Is a basic copper chloride and is usually manufactured either by the action of hydrochloric acid on copper metal or by the air oxidation of cuprous chloride suspensions. It has a number of applications, by far the most important being as an agricultural fungicide for which purpose it is extensively employed in formulated form as dusts, wettable powders and pastes.
Cuprous Chloride
Prepared either by heating a solution of cupric chloride with copper turnings or by the action of a reducing agent, such as sulphur dioxide, on a mixture of common salt and copper sulphate solution. The petroleum industry uses cuprous chloride in their "oil sweetening" process. Ammoniacal solutions of cuprous chloride are employed for the absorption of any carbon monoxide which may be present in a gas as an impurity.
Cupric Nitrate
Produced either by dissolving copper carbonate in nitric acid or direct from copper and nitric acid. It has a number of small uses, such as in ceramics, in dyeing as a mordant, in fireworks and in photography.
Copper Cyanide
Manufactured from sodium cyanide and copper sulphate. It is mainly used for copper electroplating.
Copper Soaps
Usually made by the interactlon of the corresponding soap with copper sulphate solution. Small quantities of these, such as copper stearate, copper oleate and copper abietate (from resins), are employed mainly for rot-proofing textiles, ropes, etc. They are also used in paints as they are soluble in oils, white spirits, etc.
Copper Naphthenate
Usually manufactured either from copper sulphate and naphthenic acid in combination with an alkali or by heating naphthenic acid and copper oxide. It is widely used as an oil-based wood preservative and as a rot-proofing agent.
Anhydrous and Monohydrated Copper Sulphate
Obtained by heating copper sulphate pentahydrate when four molecules water of crystallization are removed the product becomes copper sulphate monohydrate which is green in colour. At a higher temperature all the water of crystallization is removed and anhydrous copper sulphate is the white powder which results. They can also be obtained by crystallization from copper sulphate pentahydrate in boiling sulphuric acid. The main applications are in the production of proprietary wood preservatives and agricultural fungicides as well as for the production of a number of copper compounds. Sometimes they are utilised to detect the presence of moisture.