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Toluene diisocyanate (TDI) is an organic compound with the formula CH 3 C 6 H 3 (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.
The global market for diisocyanates in the year 2000 was 4.4 million tonnes, of which 61.3% was methylene diphenyl diisocyanate (MDI), 34.1% was toluene diisocyanate (TDI), 3.4% was the total for hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), and 1.2% was the total for various others. [18]
It is mainly used to manufacture toluene diisocyanate, which is a key raw material in polyurethane chemistry. [4] It is still the starting material used when non-phosgene methods of production of toluene diisocyanate are used. [5] [6] It is also a degradation product of polyurethane materials produced using toluene diisocyanate.
Most DNT is used in the production of toluene diisocyanate, which is used to produce flexible polyurethane foams. DNT is hydrogenated to produce 2,4-toluenediamine, which in turn is phosgenated to give toluene diisocyanate. In this way, about 1.4 billion kilograms are produced annually, as of the years 1999–2000. [6]
A blocked isocyanate can be added to materials that would normally react with the isocyanate such as polyols.They do not react at normal ambient room temperature. A formulation containing a blocked isocyanate is a single component material (and thus usually considered more convenient) but reacts like a two-component product but will not react until heated to the temperature required for ...
Methylene diphenyl diisocyanate (MDI) is an aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. The 4,4′ isomer is most widely used, and is also known as 4,4′-diphenylmethane diisocyanate. [3] This isomer is also known as Pure MDI.
Nitration of toluene gives mono-, di-, and trinitrotoluene, all of which are widely used. Dinitrotoluene is the precursor to toluene diisocyanate, a precursor to polyurethane foam. Trinitrotoluene (TNT) is an explosive. Complete hydrogenation of toluene gives methylcyclohexane. The reaction requires a high pressure of hydrogen and a catalyst.
Toluene diisocyanate This page was last edited on 8 September 2024, at 19:29 (UTC). Text is available under the Creative Commons Attribution-ShareAlike 4.0 ...