메틸 이소시아네이트

메틸 이소시아네이트 속성

메틸 이소시아네이트 C화학적 특성, 용도, 생산

개요

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.

화학적 성질

colourless liquid

물리적 성질

Clear, colorless, very flammable, posionous liquid with a sharp, unpleasant, penetrating odor. Odor threshold concentration is 2.1 ppm (quoted, Amoore and Hautala, 1983).

용도

In organic synthesis; in manufacture of carbamate pesticides.

생산 방법

Methyl isocyanate is reacted with 1-naphthol to produce the carbamate insecticide carbaryl and with α-methylthioisobutyrladoxime in the industrial synthesis of aldicarb.

정의

ChEBI: The isocyanate that is methane modified by a single isocyanato substituent.

공기와 물의 반응

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.

반응 프로필

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].

위험도

Flammable, dangerous fire risk. Toxic byskin absorption and a strong eye and upper respira-tory tract irritant.

건강위험

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.

화재위험

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.

Safety Profile

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-.

잠재적 노출

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.

환경귀착

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)

운송 방법

UN2480 Methyl isocyanate Hazard class: 6.1; Labels: 6.1-Poison Inhalation Hazard, 3-Flammable liquid, Inhalation Hazard Zone A

비 호환성

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

폐기물 처리

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.

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