Chemical Properties
Cyanogen is a colorless, flammable, com-
pressed liquefied gas at room temperature. At deadly levels
only, it has a pungent, almond-like odor.
Definition
ChEBI: A dinitrile that is ethane substituted by two cyano groups.
General Description
A colorless gas with an odor of almonds. Freezes at -28°C and boils at -20.7°C. Shipped as a liquid confined under its vapor pressure. The gas is heavier than air and a flame can travel back to the source of leak very easily. Prolonged exposure to fire or intense heat may cause the containers to violently rupture and rocket. Used to make other chemicals, as a fumigant, and as a rocket propellant.
Air & Water Reactions
Highly flammable. Soluble in water and slowly decomposed by water to oxalic acid and ammonia.
Reactivity Profile
Colorless, flammable, highly toxic gas. CYANOGEN can react explosively with strong oxidants (dichlorine oxide, fluorene, oxygen, ozone). When heated to decomposition or on contact with acids, acid fumes, water or steam CYANOGEN will react to produce deadly hydrogen cyanide gas and oxides of nitrogen [Sax, 9th ed., 1996, p. 945].
Health Hazard
Vapor irritates eyes and causes giddiness, headache, fatigue, and nausea if inhaled.
Potential Exposure
Cyanogen is currently used as an
intermediate in organic syntheses; at one time, it was used
in poison gas warfare.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, includ-
ing resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medi-
cal attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is advised for 24 to 48 hours. If frost-
bite has occurred, seek medical attention immediately; do
NOT rub the affected areas or flush them with water. In
order to prevent further tissue damage, do NOT attempt to
remove frozen clothing from frostbitten areas. If frostbite
has NOT occurred, immediately and thoroughly wash con-
taminated skin with soap and water.
Shipping
UN1026 Cyanogen, Hazard Class: 2.3; Labels:
2.3-Poisonous gas, 2.1-Flammable gas, Inhalation Hazard
Zone B. Cylinders must be transported in a secure upright
position, in a well-ventilated truck. Protect cylinder and
labels from physical damage. The owner of the compressed
gas cylinder is the only entity allowed by federal law
(49CFR) to transport and refill them. It is a violation of
transportation regulations to refill compressed gas cylinders
without the express written permission of the owner.
Incompatibilities
Chemically unstable in rising tempera-
tures. May form explosive mixture with air. Explosive reac-
tion with strong oxidizers (e.g., dichlorine oxide, fluorine).
Forms toxic gases on contact with acids, including hydro-
gen cyanide. Slowly hydrolyzed in water to form hydrogen
cyanide, oxalic acid, and ammonia.
Description
Cyanogen is a colorless, flammable, compressed liquefied gas at room temperature. At deadly levelsonly, it has a pungent, almond-like odor. Molecular weight=52.04; Boiling point=221℃; Relative density(gas)=1.82; Freezing/Melting point=2 28℃; Vaporpressure=5.1 atm at 25℃; Relative vapor density(air=1)=1.82. Explosive limits: LEL=6.6%;UEL=32.0%. Hazard Identification (based on NFPA-704M Rating System): Health 4, Flammability 4, Reactivity 2.Soluble in water; solubility=1%.
Note: The irritant properties of cyanogen have been testedusing both human male and female subjects, 21-65 yearsof age. The distinctive bitter almond smell of cyanogencould not be detected at concentrations of 50, 100, and250 ppm. When exposed to 8 ppm for 6 min or 16 ppm for6-8 min, immediate eye and nose irritation occurred.
Waste Disposal
Return refillable compressed
gas cylinders to supplier. Incineration; oxides, or nitrogen
are removed from the effluent gas by scrubbers and/or ther-
mal devices.
Production Methods
Cyanogen can be prepared by slowly dropping potassium
cyanide solution into copper sulfate solution or by heating
mercury cyanide.
Production Methods
Cyanogen is prepared (1) by reaction of sodium cyanide and copper sulfate solutions, whereby one half the cyanogen is evolved as cyanogen gas and one half remains as cuprous cyanide. From the filtered cuprous cyanide, by treatment with ferric chloride solution, cyanogen is evolved with accompanying formation of ferrous chloride, (2) by heating ammonium oxalate COONH4·COONH4 with phosphorus pentoxide, water being abstracted. Small amounts of cyanogen are present in blast furnace gas and raw coal gas.
Reactions
Cyanogen (CN)2 is a colorless gas of marked characteristic odor, very poisonous, density 1.8 (air equal to 1.0), soluble. When passed into water at 0 °C, cyanogen forms hydrocyanic acid plus cyanic acid, but at ordinary temperatures the reaction is complex. With sodium hydroxide solution, there is formed with cyanogen sodium cyanide plus sodium cyanate, with dilute sulfuric acid oxamic acid COOH·CONH2, oxalic acid COOH·COOH. By reaction with tin and hydrochloric acid, cyanogen is reduced to ethylene diamine CH2·NH2·CH2·NH2. Cyanogen reacts with hydrogen to form hydrocyanic acid, and with metals, e.g., zinc, copper, lead, mercury, silver, to form cyanides.
Cyanogen, (1) when burned in air produces a violet flame forming carbon dioxide and nitrogen in the outer part and carbon monoxide and nitrogen in the inner part, (2) when exploded with oxygen produces carbon dioxide or carbon monoxide and nitrogen depending upon the ratio of oxygen to cyanogen (2 volumes oxygen plus 1 volume cyanogen yields 2 volumes carbon dioxide plus 1 volume nitrogen; 1 volume oxygen plus 1 volume cyanogen yields 2 volumes carbon monoxide plus 1 volume nitrogen). The flame spectrum contains characteristic bands in the blue and violet. By means of the electric spark, the electric arc or a red hot tube, cyanogen is decomposed into carbon plus nitrogen. When heated at ordinary pressure at about 300 °C, or under 300 atmospheres pressure at about 225°, cyanogen is converted into paracyanogen, a brown powder, also formed when mercuric cyanide is heated.
Fire Hazard
Highly flammable, burns with a purpletinged flame; vapor density 1.8 (air = 1); the vapor may travel a considerable distance to an ignition source and flash back; fireextinguishing procedure: use a water spray to fight fire and keep fire-exposed containers cool; shut off the flow of gas.
Cyanogen forms an explosive mixture with air within the range of 6.6–32%. Liquid cyanogen can explode when mixed with liquid oxygen. When mixed with an acid or water or when heated to decomposition, it produces toxic fumes.
storage
Cyanogen is stored outside or in a detached area: cool, dry, and well ventilated, and isolated from acid, acid fumes, and water. It is shipped in high-pressure metal cylinders of.
