Global - Premier TDI: The Indispensable Building Block in Polyurethane Industry
Physical and Chemical Properties
Appearance and Odor: TDI typically presents as a colorless transparent or slightly yellowish, highly flammable liquid. It emits a pungent, strong, and distinctively irritating odor, which serves as an important sensory indicator of its presence.
Solubility and Reactivity: It can be readily mixed with a variety of organic solvents such as ethanol (with decomposition), diethylene glycol monoethyl ether, diethyl ether, acetone, carbon tetrachloride, benzene, chlorobenzene, kerosene, and olive oil. One of its most characteristic chemical properties is its reactivity with water, a reaction that generates carbon dioxide gas. Additionally, TDI can rapidly react with compounds containing active hydrogen atoms, a property that is harnessed in many industrial processes.
Key Physical Constants: TDI has a boiling point of around 247℃, which determines the temperature at which it transitions from a liquid to a gaseous state under normal atmospheric pressure. Its melting point ranges from 19.5 to 21.5℃, indicating the temperature below which it solidifies. The flash point of TDI is 127℃, meaning that at this temperature, it can produce flammable vapors in the presence of an ignition source. With a relative density of 1.217, it is denser than water, which has implications for its handling and separation in industrial and environmental contexts.
Application Areas
Polyurethane Foam Production: TDI is the cornerstone in the production of polyurethane foams, which are widely used in a plethora of industries. In the furniture sector, soft polyurethane foams made with TDI are the material of choice for creating comfortable and supportive cushions in sofas, armchairs, and mattresses. In the automotive industry, these foams are used in car seats, providing comfort and safety by absorbing shocks during driving. Additionally, TDI - based polyurethane foams are used in insulation applications, such as in refrigerators and building insulation materials, due to their excellent thermal insulation properties.
Coatings and Adhesives: TDI plays a crucial role in the formulation of high - performance coatings and adhesives. In the coatings industry, TDI - based polyurethanes are used to create durable, scratch - resistant, and chemically resistant coatings for a variety of substrates, including metals, plastics, and wood. These coatings are used in automotive finishes, floor coatings, and industrial equipment coatings. In the adhesives market, TDI - containing adhesives are valued for their strong bonding capabilities. They are used in the assembly of furniture, the bonding of automotive components, and in the construction industry for joining various building materials.
Elastomer Manufacturing: TDI is used to produce polyurethane elastomers, which combine the properties of rubber and plastic. These elastomers find applications in numerous areas, such as in the production of shoe soles, where they provide excellent flexibility, durability, and shock absorption. They are also used in the manufacturing of industrial seals and gaskets, where their resistance to chemicals, abrasion, and high temperatures makes them suitable for use in harsh environments.
Preparation Methods
Traditional Phosgenation Routes
2,4 - Amino Toluene Route: The process begins with melting 2,4 - amino toluene and dissolving it in chlorobenzene. This solution is then reacted with phosgene in a two - step process. First, a low - temperature reaction occurs within the temperature range of 35 - 45℃. Subsequently, a high - temperature reaction takes place at temperatures below 130℃. After the reactions are complete, nitrogen gas is introduced to expel any unreacted hydrogen chloride and excess phosgene. The chlorobenzene is then distilled off, and the final step involves vacuum distillation to obtain pure TDI.
Nitro Toluene Route: In this method, nitro toluene is first nitrated and then reduced to obtain 2,4 - diaminotoluene. This intermediate is then subjected to phosgenation, where it reacts with phosgene to form TDI. The reaction mixture is then processed to separate and purify the TDI product.
Emerging Alternative Methods
Non - Phosgene Routes: In recent years, there has been a growing focus on developing non - phosgene methods to produce TDI in an effort to reduce the environmental impact associated with phosgene use. For example, some research is exploring the use of alternative reagents and reaction conditions to create TDI without the need for phosgene. However, these methods are still in the developmental stage and have not yet achieved widespread commercial adoption.
Precautions
Health Hazards: TDI vapor poses significant risks to human health. It is highly irritating to the eyes, skin, and respiratory tract. Prolonged or repeated exposure can lead to severe health issues, including respiratory problems such as bronchitis, asthma - like symptoms, and in some cases, even more serious conditions like bronchiectasis and pulmonary heart disease. For instance, rats exposed to concentrations in the range of (0.5 - 1)×10⁻⁶ for 6 hours a day, over 5 - 10 days, have been shown to succumb to the toxic effects. In humans, inhaling concentrations as low as 0.0005mg/L can trigger severe coughing and shortness of breath.
Flammability and Explosion Risks: TDI is a flammable liquid, and its vapors can form explosive mixtures with air. When exposed to open flames, sparks, or high heat, there is a significant risk of combustion and explosion. Therefore, proper storage and handling procedures are essential to prevent such hazards.
Storage and Handling: TDI should be stored in a cool, well - ventilated warehouse that is away from direct sunlight, heat sources, and ignition sources. The storage containers must be tightly sealed to prevent vapor leakage. Given its reactivity with water and other substances, it should be stored separately from materials that could potentially react with it, such as oxidizing agents. During handling, appropriate personal protective equipment, including chemical - resistant gloves, safety goggles, and respiratory protection, should be worn to minimize exposure risks.
Specifications
| Product Name | Toluene Diisocyanate | |||||||||
| Chemical Formula | C9H6N2O2 | |||||||||
| Molecular Weight | 174.16 g/mol | |||||||||
| Appearance | Colourless to light yellow transparent liquid | |||||||||
| Melting Point | 19.5–21.5°C | |||||||||
| Boiling Point | 247°C | |||||||||
| Density | 1.22 g/cm³ | |||||||||
| CAS NO | 584-84-9 | |||||||||
| HS Code | 29291010 | |||||||||
| EINECS NO | 209-544-5 | |||||||||
| Application | Used for polyurethane foams, elastomers, coatings, adhesives. | |||||||||
Quality Control Sheet
| Product Name | Toluene Diisocyanate | ||||||
| PARAMETERS | STANDARD | Test Result | |||||
| The content of Toluene Diisocyanate%≧ | 99.5 | 99.96 | |||||
| Isomer Ratio(2,4/2,6) | 80.0/20.0±1 | 79.4/20.6 | |||||
| Hydrolysis chlorine% ≤ | 0.01 | 0.0032 | |||||
| Acidity(as HCL)% ≤ | 0.004 | 0.0005 | |||||
| Chroma(Hazen) ≤ | 25 | 10 | |||||