NITROGEN TETROXIDE

Diamond	Hazard	Value	Description
0 3 0 ox	Health	3	Can cause serious or permanent injury.
	Flammability	0	Will not burn under typical fire conditions.
	Instability	0	Normally stable, even under fire conditions.
	Special	OX	Possesses oxidizing properties.

Red-brown liquid with a sharp, unpleasant chemical odor. Low-boiling (boiling point 21.15°C) and held as a liquid by compression. Density 1.448 g / cm3. Consists of an equilibrium mixture of brown NO2 (nitrogen dioxide) and colorless N2O4 (dinitrogen tetroxide). Evolves poisonous brown vapors. Cylinders and ton containers may not be equipped with a safety relief device. Prolonged exposure of the containers to fire or heat may result in their violent rupturing and rocketing.

• Strong Oxidizing Agent
• Water-Reactive
• Air-Reactive

Reacts with water to form nitric acid and nitric oxide.

Special Hazards of Combustion Products: Produces toxic gas when heated.

Behavior in Fire: Does not burn, but supports combustion of combustible materials such as wood. May cause fire or explode on contact with other materials. (USCG, 1999)

Very concentrated fumes produce coughing, choking, headache, nausea, pain in chest and abdomen; otherwise, few symtoms appear at time of exposure. After symptom-free period of 5-72 hours, pulmonary edema gradually develops, causing fatigue, restlessness, coughing, difficulty in breathing, frothy expectoration, mental confusion, lethargy, bluish skin, and weak, rapid pulse. Since NOX interferes with gas exchange in lungs, unconscious- ness and death by asphyxiation can result, usually within a few hours after onset of pulmonary edema. (USCG, 1999)

Liquid NITROGEN TETROXIDE is an oxidizing agent consisting of an equilibrium mixture of colorless dinitrogen tetraoxide (N2O4) and red-brown nitrogen dioxide (NO2). The exact composition of the mixture depends on the temperature with higher temperature favoring conversion to NO2. Vaporizes readily to give NO2, also an oxidizing agent. Noncombustible but can accelerate the burning of combustible materials. Reacts with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). Reacts with alkalis to form nitrates and nitrites [Merck 11th ed. 1989]. Corrodes steel if wet, but can be stored in steel cylinders if dry [Merck]. Reacts explosively with liquid ammonia even at very low temperatures (below its freezing point) [Mellor, 1940, Vol. 8, 54]. Reacts energetically with boron trichloride [Mellor, 1946, Vol. 5, 132]. Mixtures with metal carbonyls are hypergolic (enflame immediately). Mixtures with halocarbons, hydrazine derivatives, heterocyclic bases (pyridine), isopropyl nitrite/propyl nitrite, active metals (magnesium, calcium, etc.), nitroaromatics, nitrogen trichloride, phosphorus, triethylamine, unsaturated hydrocarbons may react explosively. Accidental mixing with hot cyclohexane caused an explosion [MCA Case History 128. 1962]. A mixture with acetonitrile and indium showed no evidence of change for a time and then detonated when shaken (ascribed to the catalyzed oxidation of acetonitrile) [Chem. & Ind., 1958, 1004]. Mixture with alcohols produced a violent explosion [Chem. Eng. News, 1955, 33, 2372]. Vapor reacts with barium oxide incandescently [Mellor, 1940, Vol. 8, 545]. A slow reaction between the vapor and formaldehyde became explosive near 180°C [Trans. Faraday Soc. 45:767-770. 1949]. Manganese and potassium both ignite in the vapor [Ann. Chem. et Phys.(2) 2:317]. The vapor and ozone react with the evolution of light and often explode when mixed [J. Chem. Phys. 18:366. 1920].

• Oxidizing Agents, Strong

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Expanded Polymeric Absorbents

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1067 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Fire Extinguishing Agents: Stop flow of gas (USCG, 1999)

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Do not touch or walk through spilled material. Keep combustibles (wood, paper, oil, etc.) away from spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. Ventilate the area. (ERG, 2020)

Rubber gloves; safety goggles and face shield; protective clothing; acid gas canister respirator or self-contained breathing apparatus. (USCG, 1999)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Nitrogen tetroxide	10544-72-6	Liquid							>480	>480	>480
Nitrogen tetroxide (21°C, liquid)	10544-72-6	Liquid								450
Nitrogen tetroxide (gaseous)	10544-72-6	Vapor							90	90	90

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

INHALATION: remove patient to fresh air and have him breathe as deeply as possible; call a doctor; enforce complete rest for 24-48 hours; keep warm; give oxygen if coughing starts; physician may administer morphine (10 mg.)

EYES AND

SKIN: flush with water for at least 15 min. (USCG, 1999)

• DINITROGEN TETRAOXIDE
• DINITROGEN TETROXIDE
• NITROGEN DIOXIDE/DINITROGEN TETROXIDE MIXTURE
• NITROGEN TETRAOXIDE
• NITROGEN TETROXIDE
• NITROGEN TETROXIDE, [LIQUID]
• OXIDES OF NITROGEN
• RED OXIDE OF NITROGEN