[Chemical Knowledge]：The nature, use, upstream and downstream raw materials, storage methods of toluene diisocyanate, toluene diisocyanate is toxic

Properties of Toluene Diisocyanate

Toluene diisocyanate (TDI, full name Toluene Diisocyanate) is an important organic compound, the molecular formula is C9H6N2O2. It is a colorless to light yellow liquid at room temperature, with a strong pungent odor. TDI has high reactivity, in particular its isocyanato (-NCO) group can react with active hydrogen-containing compounds (e. g., amines, alcohols) to form urea or urethane linkages. This feature makes TDI widely used in industry. TDI is also toxic, and may cause allergic reactions to the skin and respiratory tract when exposed or inhaled, so strict safety precautions are required when handling.

Use of Toluene Diisocyanate

TDI is mainly used in the production of polyurethane (PU) materials. Polyurethane has excellent wear resistance, elasticity and chemical resistance, widely used in various types of foam materials (such as soft and hard foam), elastomers, coatings, adhesives, sealants and other fields. In the flexible polyurethane foam, TDI is the main isocyanate raw material, these foams are widely used in furniture, mattresses, car seats and other fields. In rigid polyurethane foam, TDI is also used in building insulation, refrigeration equipment and packaging materials. TDI also has important applications in the production of polyurethane elastomers, such as shoe soles, industrial tires and rollers.

Toluene diisocyanate upstream raw material

The main upstream feedstocks for the production of TDI include toluene and phosgene. Toluene is an important organic solvent. Dinitrotoluene (DNT) is generated by nitration reaction, and then diamine toluene (TDA) is generated by hydrogenation reaction. TDA reacts with phosgene (COCl_2) to generate TDI. phosgene is a highly toxic compound produced by the reaction of carbon monoxide with chlorine. Therefore, the production process of TDI involves multiple chemical reaction steps and the handling of highly toxic substances, which requires strict process control and safety measures.

Toluene diisocyanate downstream products

The downstream products of TDI are mainly various types of polyurethane products. According to different applications, polyurethane can be divided into flexible foam, rigid foam, elastomer, coating, adhesive and sealant. Soft foam is mainly used in furniture and mattress manufacturing to provide a comfortable sitting and lying experience. Rigid foam is used in building insulation and refrigeration equipment, with excellent thermal insulation properties. Polyurethane elastomers are widely used in shoe soles, industrial tires and rollers due to their excellent mechanical properties. Polyurethane coatings are used in the surface coating of automobiles, buildings and furniture to provide excellent protection and decorative effects. Adhesives and sealants are widely used in construction and industrial fields, and have good bonding and sealing properties.

Production Process of Toluene Diisocyanate

The production process of TDI mainly includes the following steps: toluene generates dinitrotoluene (DNT) through nitration reaction; then, DNT generates diamine toluene (TDA) through hydrogenation reaction; then, TDA reacts with phosgene to generate toluene diisocyanate (TDI). Among them, the nitration reaction is usually carried out in the mixed acid of sulfuric acid and nitric acid, the hydrogenation reaction is carried out under high temperature and high pressure, and the phosgenation reaction needs to strictly control the temperature and reaction conditions to ensure the purity of the product and the safety of the reaction. The entire production process requires a high level of technical and equipment support, as well as strict safety and environmental protection measures.

Toluene diisocyanate storage method

Due to the high chemical reactivity and toxicity of TDI, its storage requires special attention. TDI should be stored in a cool, dry, well-ventilated warehouse, away from fire, heat and strong oxidants. Storage containers shall be well sealed to prevent leakage and moisture absorption. During operation, workers should wear suitable protective equipment, such as protective gloves, protective glasses and gas masks, to avoid direct contact with TDI or inhalation of its vapors. The warehouse shall be equipped with emergency spraying equipment and leakage emergency treatment equipment to deal with possible accidental leakage and contact accidents.

TOLUENE DIISOCYANATE MARKET PROSPECT

With the continuous development of the global industry and construction industry, the demand for polyurethane materials is increasing, thus driving the growth of the TDI market. Especially in the fields of furniture manufacturing, automobile industry and building insulation, the demand for TDI is particularly strong. Environmental issues and safety risks in the TDI production process also place higher demands on the industry. In the future, green chemical industry and safety production will become an important development direction of the TDI industry. Enterprises need to continuously improve their technical level and management capabilities to meet the dual challenges of market and supervision.

Toluene diisocyanate as an important chemical raw material, has a wide range of uses and good market prospects, but its production and use in the process of safety and environmental protection issues also need to be highly valued. Through continuous improvement of production processes and safety management, the TDI industry is expected to achieve sustainable development in the future.