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Toluene diisocyanate exists in two isomeric forms (2,4-toluene diisocyanate and 2,6-toluene diisocyanate), which have similar properties and effects. Toluene diisocyanate is produced commercially as an 80:20 (2,4-toluene diisocyanate:2,6-toluene diisocyanate) mixture of the two isomers. At room temperature, the mixture is a clear, pale yellow liquid with a sharp, pungent odor. It should be stored under refrigeration, away from light and moisture in a tightly closed container in an inert atmosphere. Toluene diisocyanate is insoluble in water and miscible with most common organic solvents. Toluene diisocyanate is made by reacting toluene diamine with carbonyl chloride (phosgene). Toluene diisocyanate is commonly used as a chemical intermediate in the production of polyurethane foams, elastomers, and coatings, paints, varnishes, wire enamels, sealants, adhesives, and binders. It is also used as a cross-linking agent in the manufacture of nylon polymers. 2,4-Toluene diisocyanate is used as a chemical intermediate in the production of polyurethane products, such as foams, coatings, and elastomers.

TOLUENE-2,4-DIISOCYANATE is explosive in the form of vapor when exposed to heat, flame or sparks. Undergoes potentially violent polymerization reaction with strong bases or acyl chlorides. Reacts with water to liberate carbon dioxide. Potential explosion if stored in polyethylene containers due to absorption of water through the plastic. Emits very toxic fumes of oxides of nitrogen when heated to decomposition [Lewis, 3rd ed., 1993, p. 1251].

Reacts with water with the evolution of carbon dioxide and formation of insoluble polyureas that are relatively nontoxic and inert [Merck 11th ed. 1989)].

Can cause death. Contact with skin may cause allergic eczema. Substance is very corrosive to eyes. Chronic exposure may cause chronic lung disease. As a vapor TDI is a powerful irritant to the respiratory tract. Chronic loss of respiratory function may occur. Acute asthmatic bronchitis or frank asthma may occur. A splash in the eyes of workmen has caused keratitis and conjunctivitis. This compound causes inflammation of the skin, also chemical pneumonitis and pulmonary edema.

Exposures to toluene diisocyanate cause severely irritating effects especially to the mucous membranes and tissues. Inhalation of toluene diisocyanate produces euphoria, ataxia, mental aberrations, vomiting, abdominal pain, respiratory sensitization, bronchitis, emphysema, and asthma. The mechanism by which toluene diisocyanate produces toxic symptoms is not known, but the compound is highly reactive and may inactivate tissue biomolecules by covalent binding. Acute and chronic exposures to toluene diisocyanate produce health disorders of the skin, the respiratory system, the CNS, and the gastrointestinal tract. A number of occupational studies have reported that chronic exposures to toluene diisocyanate reduce lung function among workers associated with the production Exposures to toluene diisocyanate cause severely irritating effects especially to the mucous membranes and tissues. Inhalation of toluene diisocyanate produces euphoria, ataxia, mental aberrations, vomiting, abdominal pain, respiratory sensitization, bronchitis, emphysema, and asthma. The mechanism by which toluene diisocyanate produces toxic symptoms is not known, but the compound is highly reactive and may inactivate tissue biomolecules by covalent binding. Acute and chronic exposures to toluene diisocyanate produce health disorders of the skin, the respiratory system, the CNS, and the gastrointestinal tract. A number of occupational studies have reported that chronic exposures to toluene diisocyanate reduce lung function among workers associated with the production of polyurethane foam Exposure to toluene diisocyanate produces severe respiratory problems and individuals with pre-existing breathing diffi culties may be more susceptible to its effects. It causes irritation of the respiratory tract. Concentration-dependent effects occur, often after a delay of 4–8 h and may persist for 3–7 days. Exposures to high-concentration inhalation of toluene diisocyanate cause symptoms of toxicity, such as chest tightness, cough, breathlessness, infl ammation of the bronchi with sputum production and wheezing with possible accumulation of fl uid in the lungs. Previously exposed occupational workers and users have been reported to develop symptoms of infl ammation of the lungs on re-exposure to even extremely low levels of toluene diisocyanate. Flu-like symptoms, such as fever, malaise, shortness of breath, and cough, can develop 4–6 h after exposure and persist for 12 h or longer. In sensitized workers/individuals, asthmatic attacks occur after exposure to extremely low toluene diisocyanate air concentrations (0.0001 ppm). The asthmatic reactions occur immediately and/or delayed (4–8 h). Exposure to toluene diisocyanate leads to reactive airway dysfunction syndrome (RADS), a chemically or irritant-induced type of asthma. Children may be more vulnerable because of relatively increased minute ventilation per kilogram and failure to evacuate an area promptly when exposed.

When heated to decomposition TOLUENE-2,4-DIISOCYANATE emits very toxic fumes of cyanide and nitrogen oxides. Reacts violently with amines, alcohol, bases and warm water causing fire and explosion hazards. Avoid strong oxidizers, water, acids, bases, amines, etc., cause foam and splatter. Avoid heating. Hazardous polymerization may occur. Concentrated alkaline compound such as sodium hydroxide or tertiary amines may cause run-away polymerization. Slow, not hazardous polymerization may occur above 235F.

Toluene diisocyanate (TDI), (OCN)2C6H3CH3, is a water-white to pale-yellow liquid with a sharp, pungent odor. It reacts with water to release carbon dioxide. The specific gravity is 1.22, which is heavier than water. TDI is toxic by inhalation and ingestion, and is a strong irritant to skin and other tissue, particularly the eyes. The TLV is 0.005 ppm in air, and the IDLH is 10 ppm. The target organs are the respiratory system and the skin. The four-digit UN identification number is 2078. The NFPA 704 designation is health 3, flammability 1, and reactivity 3. The white section at the bottom of the diamond has a W with a slash through it, indicating water reactivity. The primary uses of TDI are in the manufacture of polyurethane foams, elastomers, and coatings.

Clear, colorless to light yellow liquid with a pungent, fruity odor. Odor threshold concentration in air is 2.14 ppm_v (Leonardos et al., 1969).

In the manufacture of polyurethane foams and other elastomers.

Occupational asthma is the principal cause of work-related respiratory disease in the industrial world. Toluene-2,4-diisocyanate (TDI) is one of the most common respiratory sensitizers leading to occupational asthma.

TDI (toluene diisocyanate) is an important basic raw materials of polyurethane. TDI is a mixture of 2,4-TDI and 2,6-TDI two kinds of isomers, including 3 kinds of commonly used grades: TDI-80/20, TDI-100 and TDI-65/35. Mainly used in the production of flexible polyurethane foam and polyurethane elastomer coatings, adhesives, etc..

Toluene-2,4-diisocyanate is one of the mostextensively used isocyanates. It is usedin the production of rigid and flexibleurethane foams, elastomers, and coatings. Inaddition to its use as a pure compound, itis commercially available as a mixture of2,4- and 2,6-isomers (80 : 20% and 65 : 35%ratios, respectively).

ChEBI: A toluene meta-diisocyanate in which the isocyanato groups are at positions 2 and 4 relative to the methyl group on the benzene ring.

Toxic by ingestion and inhalation; strong irritant to skin and tissue, especially to eyes. Respiratory sensitization.

TDI is a combustible liquid (NFPA rating = 1). Explosive limits in air are 0.9 to 9.5% by volume. Carbon dioxide or dry chemical extinguishers should be used for TDI fires.

Reactivity with Water: A non violent reaction occurs forming carbon dioxide gas and an organic base; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Slow polymerization occurs at temperatures above 113°F. The reaction is not hazardous; Inhibitor of Polymerization: Not pertinent.

Acute toxicity. Industrial experience has demonstrated that acute exposure to TDI vapors can produce severe irritant effects on mucous membranes, the respiratory tract, and the eyes. An acute attack of an asthma-like syndrome may occur. Exposure to high concentrations may lead to chemical bronchitis with severe bronchospasm, chemical pneumonitis, pulmonary edema, headache, and insomnia.With sufficient exposure, all persons would appear to experience these effects even on their first exposure.
Chronic and subchronic toxicity. Repeated exposures at lower concentrations of TDI may produce a chronic-like syndrome in many people. Symptoms may include coughing, wheezing, tightness or congestion in the chest, and shortness of breath and appear to be related to hypersensitization. Interstitial pulmonary fibrosis does not occur from moderately elevated exposures to TDI (mean 0.07, peak 0.2 ppm).
Exposure to TDI may lead to immunological sensitization. Some individuals become sensitized on first exposure; others may develop symptoms after exposure over days, months, or years. Other workers have experienced only minimal or no respiratory symptoms for several months of low level exposure, then suddenly develop acute asthmatic reactions to the same level. The nature of the sensitization process is unknown, and many authors have referred to it as an “allergy;” the respiratory response in sensitized people is referred to as true asthma, comparable to asthma excited by pollens and other exoallergens. Some TDI-sensitized people, however, have no history of prior allergic disease.

Chemical/Physical. Slowly reacts with water forming carbon dioxide and polyureas (NIOSH, 1997; Windholz et al., 1983).

work with TDI should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles and impermeable gloves should be worn at all times to prevent eye and skin contact.

It is purified by fractionation in a vacuum and should be stored in a dry atmosphere. It is soluble in organic solvents but reacts with H2O, alcohols (slowly) and amines, all of which could cause explosive polymerisation. It darkens on exposure to light. It has a sharp pungent odour, is TOXIC and is IRRITATING TO THE EYES. [Siefken Justus Liebigs Ann Chem 562 75, 96, 127 1949, Bayer Angew Chem 59 257 1947.] It is a reagent for covalent crosslinking of proteins [Wold Methods Enzymol 25 623 1972.] [Beilstein 13 IV 243.]

Contact with strong oxidizers may cause fires and explosions. Contact with water, acids, bases, and amines can lead to reactions that liberate heat and CO2 and cause violent foaming and spattering. TDI will attack some forms of plastic, rubber, and coatings.

Excess TDI and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.