Stickstoffdioxid Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
RöTLICH- BRAUNES GASODER BRAUNEODER GELBE FLüSSIGKEIT MIT STECHENDEM GERUCH.
PHYSIKALISCHE GEFAHREN
Das Gas ist schwerer als Luft.
CHEMISCHE GEFAHREN
Starkes Oxidationsmittel. Reagiert sehr heftig mit brennbaren und reduzierenden Stoffen. Reagiert mit Wasser unter Bildung vonSalpetersäure und Stickstoff(II)-oxid. Greift viele Metalle in Gegenwart von Wasser an.
ARBEITSPLATZGRENZWERTE
TLV: 3 ppm (als TWA); 5 ppm (als STEL); Krebskategorie A4 (nicht klassifizierbar als krebserzeugend für den Menschen); (ACGIH 2005).
MAK: Krebserzeugend Kategorie 3B; (DFG 2008).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation.
INHALATIONSGEFAHREN
Eine gesundheitsschädliche Konzentration des Gases in der Luft wird beim Entweichen aus dem Behälter sehr schnell erreicht.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz verätzt die Haut und die Atemwege. Inhalation des Gases oder Dampfs kann zu Lungenödem führen (s.Anm.). Exposition weit oberhalb der Arbeitsplatzgrenzwerte kann zum Tod führen. Die Auswirkungen treten u.U. verzögert ein. ärztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Möglich sind Auswirkungen auf Immunsystemund Lunge mit nachfolgender Senkung der Abwehrbereitschaft. Tierversuche zeigen, dass die Substanz möglicherweise fruchtbarkeitsschädigend oder entwicklungsschädigend wirken kann.
LECKAGE
Gefahrenbereich verlassen! Fachmann zu Rate ziehen! Belüftung. NICHT mit Sägemehl oder anderen brennbaren Absorptionsmitteln binden. Dampf mit feinem Wassersprühstrahl niederschlagen. Benutztes Wasser mit Kreide oder Soda neutralisieren. Gasdichter Chemikalienschutzanzug mit umgebungsluftunabhängigem Atemschutzgerät.
R-Sätze Betriebsanweisung:
R26:Sehr giftig beim Einatmen.
R34:Verursacht Verätzungen.
S-Sätze Betriebsanweisung:
S9:Behälter an einem gut gelüfteten Ort aufbewahren.
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S28:Bei Berührung mit der Haut sofort abwaschen mit viel . . . (vom Hersteller anzugeben).
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
Beschreibung
nitrogen dioxide is a reddish-brown
gas (or yellow liquid) with a strong, acrid odor. Nitrogen dioxide readily dimerizes to produce
N2O4.nitrogen dioxide are nonfl ammable, toxic gases.The federal government has established air quality standards for nitrogen dioxide
at 0.053 partsper million (ppm), which equals 100μg (micrograms) per cubic meter.Nitrogen dioxide is highly soluble in water and forms nitric acid (HNO3), and nitric oxide
is slightly soluble and forms nitrous acid (HNO2).
Nitrogen dioxide is
a strong oxidizing agent and causes corrosion.Nitrogen dioxide is used as an oxidizing agent, a catalyst in oxidation reactions, an inhibitor,
as a nitrating agent for organic reactions, as a flour bleaching agent, and in increasing the
wet strength of paper.
Chemische Eigenschaften
Nitrogen dioxide (and nitrogen tetroxide, the
solid dimer) is a dark brown gas (above 21 C) or a yellow,
fuming liquid or colorless solid with a pungent, acrid odor.
The solid form is colorless below about 11 C; it is found
structurally as N2O4.
Physikalische Eigenschaften
Reddish-brown gas; pungent irritating odor; liquefies to a yellow liquid at 21.2°C; liquefies under pressure to a brown fuming liquid, commercially known as nitrogen tetroxide which actually is an equilibrium mixture of nitrogen dioxide and dinitrogen tetroxide, N
2O
4; converts to a colorless crystalline solid at -11.2°C; refractive index 1.40 at 20°C; density of gas in air 1.58 (air=1); density of liquid 1.449 g/mL at 20°C; critical temperature 158.2°C; critical pressure 99.96 atm; decomposes in water forming nitric acid; reacts with alkalies; soluble in concentrated nitric and sulfuric acids; soluble in chloroform and carbon disulfide.
Occurrence
Nitrogen dioxide is an intermediate in producing nitric acid. It also is used in the lead chamber process for making sulfuric acid. It is used as a nitrating and oxidizing agent, in rocket fuels, in the manufacture of hemostatic cotton and other oxidized cellulose compounds, and in bleaching flour. Nitrogen dioxide occurs in trace concentrations in the atmosphere due to oxidation of nitric oxide in air. It also is found in exhaust gases of internal combustion engines, in industrial waste gases from plants using nitric acid, and in cigarette smoke. Brown color of smog in many industrial urban areas is attributed to nitrogen dioxide.
History
nitrogen dioxide was prepared in 1772 by Joseph Priestley
(1733–1804) and described in his volumes Experiments and Observations of Different Kinds
of Air published between 1774 and 1786. Priestley called nitric oxide nitrous air, nitrogen
dioxide nitrous acid vapor, and nitrous oxide phlogisticated nitrous air, but also referred to the
dioxide. Priestley prepared nitric oxide by reacting nitric acid with a metal such as copper:
3Cu(s) + 8HNO3(aq) → 2NO(g) + 3Cu(NO3)2(aq) + 4H2O(l).
Verwenden
Nitrogen dioxide is an intermediate in producing nitric acid. It also is used in the lead chamber process for making sulfuric acid. It is used as a nitrating and oxidizing agent, in rocket fuels, in the manufacture of hemostatic cotton and other oxidized cellulose compounds, and in bleaching flour. Nitrogen dioxide occurs in trace concentrations in the atmosphere due to oxidation of nitric oxide in air. It also is found in exhaust gases of internal combustion engines, in industrial waste gases from plants using nitric acid, and in cigarette smoke. Brown color of smog in many industrial urban areas is attributed to nitrogen dioxide.
Definition
A brown gas produced by the dissociation
of dinitrogen tetroxide (with which it is in
equilibrium), the dissociation being complete
at 140°C. Further heating causes dissociation
to colorless nitrogen monoxide
and oxygen:
2NO
2(g) = 2NO(g) + O
2(g)
Nitrogen dioxide can also be made by
the action of heat on metal nitrates (not the
nitrates of the alkali metals or some of the
alkaline-earth metals).
Allgemeine Beschreibung
A reddish brown gas or yellowish-brown liquid when cooled or compressed. Shipped as a liquefied gas under own vapor pressure. Vapors are heavier than air. Toxic by inhalation (vapor) and skin absorption. Noncombustible, but accelerates the burning of combustible materials. Cylinders and ton containers may not be equipped with a safety relief device.
Air & Water Reaktionen
Combines with oxygen to form NITROGEN DIOXIDE, a brown gas that is deadly poisonous [Merck 11th ed. (1989]. Decomposes in water to form nitric acid and nitric oxide, reacts with alkalis to form nitrate and nitrites [Merck 11th ed. 1989]. The liquid nitrogen oxide is very sensitive to detonation, in the presence of water.
Reaktivität anzeigen
NITROGEN DIOXIDE (nitrogen peroxide) is a strong oxidizing agent. Powdered aluminum burns in the vapor of carbon disulfide, sulfur dioxide, sulfur dichloride, nitrous oxide, nitric oxide, or nitrogen peroxide [Mellor 5:209-212. 1946-47]. Boron trichloride reacts energetically with nitrogen peroxide, phosphine, or fat and grease [Mellor 5:132. 1946-47]. Nitrogen peroxide and acetic anhydride reacted to form tetranitromethane, but resulted in an explosion [Van Dolah 1967]. Nitrogen peroxide forms explosive mixtures with incompletely halogenated hydrocarbons [Chem. Eng. News 42(47):53. 1964]. During an experiment to produce lactic acid by oxidizing propylene with nitrogen peroxide, a violent explosion occurred. These mixtures (olefins and nitrogen peroxide) form extremely unstable nitrosates or nitrosites [Comp. Rend. 116:756. 1893]. Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container [Handling Chemicals Safely 1980]. Corrosive to steel when wet, but may be stored in steel cylinders when moisture content is 0.1% or less.
Hazard
Inhalation may be fatal. Can react strongly
with reducing materials. Lower respiratory tract
irritant. Questionable carcinogen.
Health Hazard
The acute toxicity of nitrogen dioxide by inhalation is high. Inhalation may cause shortness of
breath and pulmonary edema progressing to respiratory illness, reduction in the blood's oxygen
carrying capacity, chronic lung disorders and death; symptoms may be delayed for hours and
may recur after several weeks. Toxic effects may occur after exposure to concentrations of 10
ppm for 10 min and include coughing, chest pain, frothy sputum, and difficulty in breathing.
Brief exposure to 200 ppm can cause severe lung damage and delayed pulmonary edema, which
may be fatal. Nitrogen dioxide at concentrations of 10 to 20 ppm is mildly irritating to the eyes;
higher concentrations of the gas and liquid NO2-N2O4 are highly corrosive to the skin, eyes, and
mucous membranes. Nitrogen dioxide can be detected below the permissible exposure limit by
its odor and irritant effects and is regarded as a substance with adequate warning properties.
Animal testing indicates that nitrogen dioxide does not have carcinogenic or reproductive effects.
It does produce genetic damage in bacterial and mammalian cell cultures; however, most studies
in animals indicate that it does not produce heritable genetic damage.
Flammability and Explosibility
Nitrogen dioxide is not combustible (NFPA rating = 0) but is a strong oxidizing
agent and will support combustion. Cylinders of NO2 gas exposed to fire or intense
heat may vent rapidly or explode.
Materials Uses
When dry (0.1 percent moisture or less), nitrogen dioxide is not corrosive to mild steel at ordinary temperatures and pressures. Numerous
metals and alloys such as carbon steel, stainless
steel, aluminum, nickel, and Inconel are satisfactory for handling and storage. Under wet
conditions, stainless steels resistant to about 60
percent nitric acid serve best.
Equipment parts, such as valve stems, which
are partly in contact with the atmosphere,
should be stainless steel with sufficient chromium content to resist corrosion caused by
leaks through stuffing boxes. Good quality ceramic bodies and Pyrex are satisfactory for handling wet or dry nitrogen dioxide.
Among the plastics, Teflon and Kel-F films
are most satisfactory. Koroseal and Saran are
useful but have a limited service life. In general,
the vinyl plastics do not hold up well with nitrogen dioxide. Asbestos and asbestos-graphite are
satisfactory for valve stuffing boxes. Koroseal
has given reasonably good service in this use.
For use on pipe threads, graphite-disodium silicate (waterglass) is recommended, and hydrocarbon lubricants should be avoided.
Sicherheitsprofil
Experimental poison by
inhalation. Moderately toxic to humans by
inhalation. An experimental teratogen.
Other experimental reproductive effects.
Human systemic effects by inhalation:
pulmonary vascular resistance changes,
cough, dpspnea, and other pulmonary
changes. Mutation data reported. Violent
reaction with cyclohexane, F2,
formaldehyde, alcohols, nitrobenzene,
petroleum, toluene. When heated to
decomposition it emits toxic fumes of NOx.
See also NITRIC OXIDE.
mögliche Exposition
Nitrogen dioxide is found in automotive
and diesel emissions. Nitrogen dioxide is an industrial
chemical used as an intermediate in nitric and sulfuric acid
manufacture; it is used in the nitration of organic compounds;
it is used as an oxidizer in liquid propellant rocket
fuel combinations. It is also used in firefighting, welding
and brazing.
Lager
Cylinders of nitrogen dioxide should be stored and used
in a continuously ventilated gas cabinet or fume hood.
Versand/Shipping
UN1067/124 Dinitrogen tetroxide, Hazard Class:
2.3; Labels: 2.3-Poisonous gas, 5.1-Oxidizer, 8-Corrosive
material, Inhalation Hazard Zone A. UN1975 Nitric oxide
and dinitrogen tetroxide mixtures or Nitric oxide and
nitrogen dioxide mixtures, Hazard Class: 2.3; Labels:
2.3-Poisonous gas, 5.1-Oxidizer, 8-Corrosive material,
Inhalation Hazard Zone A. 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.
Inkompatibilitäten
A strong oxidizer. Reacts violently with
combustible matter, chlorinated hydrocarbons; ammonia,
carbon disulfide; reducing materials. Reacts with water,
forming nitric acid and nitric oxide. Attacks steel in the
presence of moisture.
Waste disposal
Destroy by incineration with
the addition of hydrocarbon fuel, controlled in such a way
that combustion products are elemental nitrogen, CO2, and
water. Consult with environmental regulatory agencies for
guidance on acceptable disposal practices. Generators of
waste containing this contaminant (≥100 kg/mo) must conform
with EPA regulations governing storage, transportation,
treatment, and waste disposal.
Stickstoffdioxid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
