Hydrogen cyanide

Legality: CWC Schedule 3

CONVENTION ON THE PROHIBITION OF THE DEVELOPMENT, PRODUCTION, STOCKPILING AND USE OF CHEMICAL WEAPONS AND ON THEIR DESTRUCTION

ANNEX ON CHEMICALS

A. GUIDELINES FOR SCHEDULES OF CHEMICALS

Guidelines for Schedule 3

The following criteria shall be taken into account in considering whether a toxic chemical or precursor, not listed in other Schedules, should be included in Schedule 3:

(a) It has been produced, stockpiled or used as a chemical weapon;

(b) It poses otherwise a risk to the object and purpose of this Convention because it possesses such lethal or incapacitating toxicity as well as other properties that might enable it to be used as a chemical weapon;

(c) It poses a risk to the object and purpose of this Convention by virtue of its importance in the production of one or more chemicals listed in Schedule 1 or Schedule 2, part B;

(d) It may be produced in large commercial quantities for purposes not prohibited under this Convention.

Production of this substance may be illegal in some jurisdictions under certain circumstances. Bottom line: Do not produce this chemical without checking to make sure that you may do so legally.

 

 

Hydrogen cyanide
CWC LIST I/II/III SUBSTANCE

Chemical formula	HCN
OTP appearance	pale blue liquid
Index of refraction	1.2675
Molar Mass(g/mol)	27.0253
Density(g/cc)	0.687
Melting Point(°C)	-14 to -12°C
Boiling Point(°C)	25.6-26.6
Solubility in water(g/L)	misc
Solubility in ethanol(g/L)	misc
Immediate Danger to Life and Health	50ppm (inh)
NFPA 704	0 4 2

Uses

Justification Questioned

Other

• Key reagent for producing nitriles and cyanides
• Used to produce lactic acid
• Used to produce WHO LEM components sodium nitroprusside and prussian blue

Natural occurrence

• Does occur naturally in trace quantities in some vegetables (cyanohydrin breakdown products)

Hazards

• Inhalation, ingestion, skin contact: lethal
• See Cyanide poisoning treatment

Production

Extraction

See benzaldehyde for production of hydrogen cyanide from enzymatic decomposition of amigdalin.

Synthesis

Prussian Blue

Thermally decompose prussian blue in an inert environment

Fe₄(Fe(CN)₆)₃

{

→

400-700°C}

4 Fe + Fe₃C + 7 C + 5 (CN)₂ + 4 N₂

Alkali cyanides

Combine sodium cyanide or potassium cyanide with hydrochloric acid or sulfuric acid

NaCN + HCl → NaCl + HCN

KCN + H₂SO₄ → KHSO₄ + HCN

Disposal

React with sodium hydroxide solution, producing sodium cyanide, or the similar potassium salts. Alternatively, it can be combusted above 538°C.

See Also

• Mineral acid interconversion