Introduction to TDI

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TDI: The English abbreviation for toluene diisocyanate. CAS number: 584-84-9. Beilstein number: 744602. Molecular formula: C9H6N2O2. Molecular weight: 174.16. Other names: Toluene diisocyanate, 2,4-diisocyanatotoluene, methylenephene, 2,4-diisocyanate, 4-methyl-1,3-phenylenediiisocyanate. Production method: Toluene is nitrated to produce nitrotoluene, which is then reduced to yield toluene diamine. TDI is obtained by reacting toluenediamine with phosgene (primarily the 2,4-isomer). Properties: Colorless liquid. It has a pungent smell. The gaze darkened. Sodium hydroxide or tert-butylamine can cause polymerization. It reacts with water to produce carbon dioxide. It is miscible with ethanol (decomposed), ether, propane, carbon tetrachloride, benzene, chlorobenzene, kerosene, olive oil, and diethylene glycol methyl ether. Toxic. There is a possibility of causing cancer. It is irritating. Relative density: (20/4°C): 1.2244. Freezing point: TDI-65, 3.5–5.5°C; TDI-80, 11.5–13.5°C; TDI-100, 19.5–21.5°C. Vapor pressure: (20°C), 0.01 mmHg. Flash point: (open cup), 132°C; Boiling point: 251°C. Heat of vaporization: (120–180°C), 337.04 KJ/kg (kcal/kg) (80.5). Refractive index: (20°C), 1.569. Toxic limit: 0.1 ppm. Storage: Store in a sealed container filled with argon or nitrogen, in a cool, dry place, away from light. Use: Preparation of polyurethane and macrocyclic crown ether compounds. Protein covalent crosslinking agents. Antibodies are fixed to plastic surfaces for radioimmunoassay. Hazardous nature(?): Category 6.1 toxic substances. Hazard code: 61111; UN number: 2078. Other relevant information: TDI (toluene diisocyanate) is a type of commonly used diisocyanate, and diisocyanates are important basic raw materials for polyurethane (PU) materials. The TDI commonly used in the polyurethane industry is a mixture of the two isomers, 2,4-TDI and 2,6-TDI, and includes three commonly used grades: TDI-80/20, TDI-100, and TDI-65/35. The number in front indicates the content of 2,4-TDI in the composition. For example, in T-80/20, the 80 indicates that its composition is 80% 2,4-TDI and 20% 2,6-TDI ； The 100 in TDI-100 indicates that it is essentially composed of 2,4-isomer TDI (about 98%), with very little of the 2,6-TDI isomer present. It is mainly used in the production of soft polyurethane foams, polyurethane elastomers, coatings, adhesives, etc. Main hazards of TDI: TDI is primarily found in paints used in renovation work. Excessive levels of free TDI can cause harm to the human body, mainly through allergic reactions and irritation, leading to symptoms such as eye pain, tearing, conjunctival redness, coughing, chest tightness, shortness of breath, asthma, red papules, maculopapules, and contact dermatitis. The international limit for free TDI is below 0.5%. Toluene diisocyanate is a colorless or pale yellow, transparent liquid with an irritating odor; it turns yellow under ultraviolet light ； Heating in alloy steel containers facilitates polymerization ； It can react with the hydroxyl groups in hydroxyl compounds, water, amines, and compounds containing active hydrogen to form carbamates, ureas, ureidoamines, and biurets, etc.