Sodium cyanide

  • Sodium Cyanide
  • Sodium cyanide
  • Blue soda
  • Blue Acid Sodium

Colorless, crystalline powder with a faint odor bittermandelartigem

Fixed

1.60 g · cm -3

561.7 ° C

1500 ° C

1 hPa ( 800 ° C)

Readily soluble in water: 580 g · l-1 in water (20 ° C)

Risk

3.8 mg · m-3

  • 2.8 mg · kg -1 ( LDLO, man, oral)
  • 4.7 mg · kg -1 ( LD50, rat, oral)

-87.5 KJ / mol

Template: Infobox chemical / molecular formula search available

Sodium cyanide is the sodium salt of hydrocyanic acid (HCN). At room temperature it is a colorless, hygroscopic crystalline powder that smells slightly bitter almond-like.

Representation

Sodium cyanide is obtained by neutralization of hydrocyanic acid with sodium hydroxide according to the Andrussow process. Starting materials for the synthesis of methane, ammonia and oxygen.

The subsequent neutralization results in sodium cyanide.

Previously, sodium cyanide was obtained by the Castner -Keller- method by the reaction of molten sodium with ammonia to form sodium amide and by calcination of sodium amide with coal:

Properties

Sodium cyanide is highly toxic. When it arrives in large quantities into the environment, it is a heavy burden on the ecosystem. Sodium cyanide decomposes in contrast to potassium cyanide easily in warm aqueous solution and causes sodium and ammonia.

Use

Sodium cyanide is used together with potassium cyanide to obtain gold, silver and other metals ( cyanide ).

In electroplating, it is used for various Cyanide baths, such as cyanide copper, brass, bronze, zinc, cadmium and gold baths.

In the metal processing molten sodium cyanide comes to cure certain types of steel ( hardened steels ) are used.

The Organic Chemistry uses sodium cyanide for synthesis of nitriles.

Safety

It is important to ensure that Natriumcyanidstaub and vapors are not inhaled. Containers must be tightly closed and stored in a cool, dry place.

Decomposition

Since sodium cyanide is highly toxic to living organisms ( see cyanide poisoning ), it may not re-enter via the waste water into the environment, but must be completely oxidized in a wastewater treatment plant. This is done in the following manner:

1 by treatment with sodium hypochlorite ( NaClO ) to the following equation:

The treatment with sodium hypochlorite has the disadvantage that the AOX value of the waste water rises sharply.

2 by the addition of hydrogen peroxide ( H2O2).

3 Treatment with ozone (O3 )

By oxidation to 4 carbon or platinum anode with the aid of direct current.

Goal of detoxification is a complete decomposition of the sodium cyanide to carbon dioxide and nitrogen.

Proof

Detection of cyanide ions:

At an alkaline cyanide solution (II ) sulfate solution is added in a substoichiometric iron. If cyanide is present, formed after acidification and addition of iron (III ) chloride solution ( caution: HCN formation! ) Prussian Blue.

CAS registry number PubChem Vapor pressure Dangerous Substances Directive (67/548/EEC) Iron(III) chloride CRC Handbook of Chemistry and Physics Angewandte Chemie Digital Object Identifier Integrated Authority File
210590
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