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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.
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]
More specifically, it is an aliphatic diisocyanate. It is a water white liquid at room temperature and is manufactured in relatively small quantities. It is also known as 4,4'-methylenedi(cyclohexyl isocyanate) or methylene bis(4-cyclohexylisocyanate) [2] and has the formula CH 2 [(C 6 H 10)NCO] 2.
MDA is also used extensively as a precursor to methylene diphenyl diisocyanate (MDI). Here, MDA is treated with phosgene to produce MDI. MDI, in turn, is a precursor to many polyurethane foams. [6] [7] Lower quantities are used as hardeners in epoxy resins and adhesives, as well as in the production of high-performance polymers. [3]
Formaldehyde is also a precursor to polyfunctional alcohols such as pentaerythritol, which is used to make paints and explosives. Other formaldehyde derivatives include methylene diphenyl diisocyanate, an important component in polyurethane paints and foams, and hexamine, which is used in phenol-formaldehyde resins as well as the explosive RDX.
methylene diphenyl diisocyanate (MDI) – used as a co-monomer with diols or polyols to form polyurethanes or with di- or polyamines to form polyureas; alkylbenzene – a general type of aromatic hydrocarbon, which can be used as a precursor for a sulfonate surfactant (detergent)
Methyl isocyanate (MIC) is an organic compound with the molecular formula CH 3 NCO. Synonyms are isocyanatomethane and methyl carbylamine.Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides and Haffmann Bromamide Degradation (such as carbaryl, carbofuran, methomyl, and aldicarb).
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