Methylisocyanat Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FLüCHTIGE FARBLOSE FLüSSIGKEIT MIT STECHENDEM GERUCH.
PHYSIKALISCHE GEFAHREN
D?mpfe sind schwerer als Luft. Sie k?nnen sich am Boden ausbreiten. Fernzündung m?glich. Die D?mpfe mischen sich leicht mit Luft. Bildung explosionsf?higer Gemische.
CHEMISCHE GEFAHREN
Polymerisiert in reinem Zustand. Kann polymerisieren beim Erhitzen und unter Einfluss von Metallen undKatalysatoren. Zersetzung bei Kontakt mit Wasser. Rasche Zersetzung bei Kontakt mit S?uren und Basen unter Bildung giftiger Gase (Cyanwasserstoff, Stickstoffoxiden, Kohlenmonoxid). Greift einige Kunststoff-, Gummi- und Beschichtungsarten an.
ARBEITSPLATZGRENZWERTE
TLV: 0.02 ppm, (als TWA); (Hautresorption); (ACGIH 2005).
MAK: 0.01 ppm, 0.024 mg/m? Spitzenbegrenzung: überschreitungsfaktor I(1); Sensibilisierung der Haut; Schwangerschaft: Gruppe D; (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den K?rper durch Inhalation, über die Haut und durch Verschlucken.
INHALATIONSGEFAHREN
Beim Verdampfen bei 20 °C kann sehr schnell eine gesundheitssch?dliche Kontamination der Luft eintreten.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz reizt stark die Augen, die Haut und die Atmungsorgane. ?tzend beim Verschlucken. Inhalation von D?mpfen kann zu Lungen?dem und zu Asthma führen (s. Anm.). Exposition kann zum Tode führen. Die Auswirkungen treten u.U. verz?gert ein. ?rztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Wiederholter oder andauernder Hautkontakt kann zu Sensibilisierung führen. M?glich sind Auswirkungen auf die Atmungsorgane. Fruchtbarkeitssch?digend oder entwicklungssch?digend.
LECKAGE
Gefahrenbereich verlassen! Fachmann zu Rate ziehen! Belüftung. Zündquellen entfernen. Ausgelaufene Flüssigkeit in abdichtbaren Beh?ltern sammeln. Ausgelaufene Flüssigkeit vorsichtig mit Natronlauge neutralisieren. Reste mit trockenem Sand oder inertem Absorptionsmittel aufnehmen und an einen sicheren Ort bringen. Chemikalienschutzanzug mit umgebungsluftunabh?ngigem Atemschutzger?t. NICHT in die Umwelt gelangen lassen.
R-S?tze Betriebsanweisung:
R12:Hochentzündlich.
R24/25:Giftig bei Berührung mit der Haut und beim Verschlucken.
R26:Sehr giftig beim Einatmen.
R37/38:Reizt die Atmungsorgane und die Haut.
R41:Gefahr ernster Augensch?den.
R42/43:Sensibilisierung durch Einatmen und Hautkontakt m?glich.
R63:Kann das Kind im Mutterleib m?glicherweise sch?digen.
S-S?tze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S27/28:Bei Berührung mit der Haut beschmutzte,getr?nkte Kleidung sofort ausziehen und 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 m?glich, dieses Etikett vorzeigen).
S63:Bei Unfall durch Einatmen: Verunfallten an die frische Luft bringen und ruhigstellen
S28:Bei Berührung mit der Haut sofort abwaschen mit viel . . . (vom Hersteller anzugeben).
S27:Beschmutzte, getr?nkte Kleidung sofort ausziehen.
Beschreibung
Methyl isocyanate (MIC) is an organic compound with the
molecular formula CH3NCO. MIC is an extremely toxic,
colorless, highly flammable liquid that evaporates quickly
when exposed to the air and has a sharp, strong odor. It is
hazardous to human health, and was involved in the Bhopal
disaster in December 1984, which resulted in the deaths of
more than 2250 individuals, with another 50 000 incapacitated,
and about 100 000 treated in area hospitals.
Chemische Eigenschaften
colourless liquid
Physikalische Eigenschaften
Clear, colorless, very flammable, posionous liquid with a sharp, unpleasant, penetrating odor.
Odor threshold concentration is 2.1 ppm (quoted, Amoore and Hautala, 1983).
Verwenden
In organic synthesis; in manufacture of carbamate pesticides.
Definition
ChEBI: The isocyanate that is methane modified by a single isocyanato substituent.
Vorbereitung Methode
Methyl isocyanate is
reacted with 1-naphthol to produce the carbamate insecticide
carbaryl and with α-methylthioisobutyrladoxime in the
industrial synthesis of aldicarb.
Air & Water Reaktionen
Highly flammable. Reacts exothermically with water to produce carbon dioxide, methylamine, dimethylurea and/or trimethylbiuret. Heat of reaction causes evolution of the vapors of the isocyanate. Reaction is relatively slow below 20°C but becomes violent at more elevated temperatures or in the presence of acids and bases.
Reaktivit?t anzeigen
Airborne vapors of METHYLISOCYANATE 1 X 500MG NEAT are explosive when exposed to heat, flame or sparks. Vapor may ignite on contact with strong oxidizing agents. Emits toxic fumes of nitriles and oxides of nitrogen when heated to decomposition [Lewis, 3rd ed., 1993, p. 860]. Caused the death of thousands in 1984 in Bhopal, India when released accidentally as a vapor following an exothermic reaction caused by contamination with water [Chem. Eng. News, 1985, 63(6), p. 27]. Reacts rapidly with acids and bases (including amines). May polymerize in contact with iron, tin, copper and certain other catalysts such as triphenylarsenic oxide, triethyl phosphine and tributyltin oxide. Polymerizes at elevated temperatures. Attacks some plastics, rubbers, and coatings [NTP].
Hazard
Flammable, dangerous fire risk. Toxic byskin absorption and a strong eye and upper respira-tory tract irritant.
Health Hazard
METHYLISOCYANATE 1 X 500MG NEAT is a skin irritant and can cause permanent eye damage. A concentration of 2 ppm has been reported toxic in humans. METHYLISOCYANATE 1 X 500MG NEAT attacks the respiratory system, eyes and skin. It can injure the lungs and bronchial airways, cause permanent eye damage, and death. Death has been attributed to various forms of respiratory distress.
Brandgefahr
Reacts violently with water. Extremely flammable; may be ignited by heat, sparks, or flames. Vapors may travel to a source of ignition and flash back. Container may explode violently in heat of fire. Vapor explosion and poison hazard indoors, outdoors, or in sewers. Runoff to sewer may create fire or explosion hazard. When heated to decomposition, METHYLISOCYANATE 1 X 500MG NEAT emits toxic fumes of nitrogen oxides. Avoid water, acids, alkali, amines, iron, tin, copper, and other catalysts. Avoid heat, flame, oxidizers, water. Hazardous polymerization may occur. METHYLISOCYANATE 1 X 500MG NEAT (MIC) will react with water, or in the presence of catalysts (such as sodium hydroxide, sodium methoxide, triphenylarsine, triethyl phosphine, metallic chlorides) to form either a cyclic trimer (trimethyl isocyanurate) or a gummy, resinous polymer. These reactions are exothermic, producing about 540 Btu per pound of MIC. Heat produced in these reactions may result in pressure build up and rupturing of tanks.
Sicherheitsprofil
Poison by inhalation,
ingestion, and skin contact. Human systemic
effects by inhalation: conjunctiva irritation,
olfactory and pulmonary changes. An
experimental teratogen. Other experimental
reproductive effects. Mutation data reported. A severe eye, skin, and mucous
membrane irritant and a sensitizer. It can be
absorbed through the skin. Exposure to
high concentrations of the vapor can cause
blindness; lung damage, including edema,
permanent fibrosis, emphysema, and
bronchitis; and gynecological effects. Most
deaths are a result of lung tissue damage.
This was the predominant cause of death in
the release of MIC in 1984 at Bhopal, India.
Effects of cyanide poisoning have been
noted but this may be due to impurities. A
flammable liquid and a very dangerous fire
hazard when exposed to heat, flame, or
oxiduers. To fight fire, use spray, foam,
CO2, dry chemical. Exothermic reaction
with water. When heated to decomposition
it emits toxic fumes of NOx and CN-.
m?gliche Exposition
Methyl isocyanate is used in carbamates and as chemical intermediate; in the manufacture
of a wide variety of pesticides; in the production of polyurethane foams and plastics. A release of this chemical was
involved in the world’s largest chemical accident, causing
the death of thousands of industrial workers in 1984
in Bhopal, India.
Carcinogenicity
Genetic and Related Cellular Effects Studies.
Mason et al. found that methyl isocyanate did not induce
mutagenic response in the Salmonella assay under test
conditions. It was also negative in the Drosophila test for
sex-linked recessive lethal mutations; however, it was positive
in the cultured CHO cells. Mason et al. found that
methyl isocyanate was positive in the mouse lymphoma
assay.
Environmental Fate
Chemical/Physical. Reacts with water forming 1,3-dimethylurea and carbon dioxide. In excess
water, the hydrolysis half-life is 9 min. (Castro et al., 1985)
Versand/Shipping
UN2480 Methyl isocyanate Hazard class: 6.1;
Labels: 6.1-Poison Inhalation Hazard, 3-Flammable liquid,
Inhalation Hazard Zone A
Inkompatibilit?ten
Highly flammable liquid. Vapors may
form explosive mixture with air. Rapid reaction in presence
of acid, alkalis, amine; iron, tin, copper, their salts; or their catalysts (such as triphenylarsenic oxide, triethylphosphine,
and tributyltin oxide). Exothermic reaction with water, producing carbon dioxide, highly flammable and air-reactive
methylamine, dimethylurea and/or trimethyl biuret. The
reaction with water is slow @ # 20C, but violent at
elevated temperatures and/or in the presence of acids
and bases. Elevated temperatures may cause explosive
polymerization. This chemical usually contains inhibitors to
prevent polymerization. Reacts with water, acids, alcohols,
glycols, amines, amides, ammonia, caprolactum, caustics,
strong oxidizers. Attacks some plastics, rubber or coatings.
Attacks some forms of plastic, rubber and coatings
Waste disposal
Consult with environmental
regulatory agencies for guidance on acceptable disposal
practices. Generators of waste containing this contaminant
(≥100 kg/mo) must conform to EPA regulations governing
storage, transportation, treatment, and waste disposal.
Incineration in the presence of a flammable solvent.
A flue gas scrubber is recommended as well.
Methylisocyanat Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Calciumoxid
Methylamin, gasf?rmig
Methylcarbamoylchlorid
Naphtha
Kaliumcyanat
Natriumcyanat
1,2-Dichlorbenzol
Dimethylsulfat
1,2,4-Dithiazolidine-3,5-dione, 4-methyl-
Carbamic acid, N-methyl-N-(trimethylsilyl)-, trimethylsilyl ester
Silanamine, 1,1,1-trimethyl-N-(methylcarbonimidoyl)-
Acetohydroxamsure
N-Methylbenzolsulfonamid
3-Methyl-1,1-diphenylharnstoff
Downstream Produkte
