Copper(II) Hydroxide

Copper(II) Hydroxide is an inorganic chemical with the formula Cu(OH)2. It is weakly basic, and does not dissolve in water.

On reaction with ammonium hydroxide solution, it produces the water soluble complex Schweizer's Reagent. This is one of the few chemical compounds with the ability to dissolve cellulose, the most abundant polymer on the earth. This property is used in the production of a synthetic cellulose fiber known as rayon.

Preparation
Copper hydroxide is a bit complicated to make than would be expected and requires a multi step synthesis. Using the expected process of mixing stoichiometric sodium hydroxide and Copper(II) Sulfate yield copper hydroxide at first but for an unknown reason this product is unstable and will decompose to Copper(I) Oxide followed by oxidation to Copper(II) Oxide and will become a useless sludge.

A more effective method that produces a more stable product uses Tetraamminecopper(II) Sulfate as an intermediate. First a solution of copper sulfate is made and is added into a suitable large container. ammonia is then added causing copper hydroxide to precipitate out but this too is unstable so more ammonia is added until all the hydroxide redissolves into a clear dark purple solution. sodium hydroxide is then added which precipitates out the desired product in a stable form. the hydroxide can be added until the solution no longer has a purple hue of any kind and has become almost clear. the product is the filtered and dried. it should be stored in a somewhat airtight container to prevent carbon dioxide from turning it to Basic Copper(II) Carbonate.

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