Cas Number


Other Names

Tolylene diisocyanate

Methyl phenylene diisocyanate

The formula



Toluene diisocyanate (TDI) is an organic compound with the formula CH3C6H3(NCO)2. Two of the six possible isomers are commercially important: 2,4-TDI (CAS: 584-84-9) and 2,6-TDI (CAS: 91-08-7). 2,4-TDI is produced in the pure state, but TDI is often marketed as 80/20 and 65/35 mixtures of the 2,4 and 2,6 isomers respectively. It is produced on a large scale, accounting for 34.1% of the global isocyanate market in 2000, second only to MDI.[3] Approximately 1.4 billion kilograms were produced in 2000.

Physical and Chemical Properties
Physical state and Appearance : Liquid
Color : Colorless to light yellow
Boiling Point : 251°C (483.8°F)
Melting Point : 19.4°C (66.9°F)
Specific Gravity : 1.2244 (Water = 1)
Vapor Pressure : 0.01 mm of Hg (@ 20°C)
Vapor Density : 6 (Air = 1)
Odor Threshold : 0.449 ppm
Solubility : Soluble in cold water.
Purity, % : 99.5 min
Hydrolyzable Chloride, Wt ppm : 80 max
Acidity (as HCL), Wt ppm : 20 max
Total Chlorine, Wt ppm : 100 max
2.4 TDI Isomer, Wt % : 79 - 81

TDI is commonly used to manufacture.

Flexible foams – used for the fabrication of bedding, furniture, automotive seating, flexible packaging and carpet underlay; this is the largest market application for TDI.

“Foamed-in-place” polyurethane plastics – ranging from soft and sponge-like too hard and porous for use in furniture, packaging, insulation and boat building.

Polyurethane coatings – used on leather, wire, tank linings and masonry.

Elastomers – used to produce adhesives, films and linings, and abrasive wheels and other mechanical items that require abrasion and solvent resistance.

Rigid, “pour-in-place” foams – for use in appliances, and, in smaller amounts, packaging.

Urethane sealants – used in construction applications.

Cast elastomers – for production of articles such as roller blade wheels.