4,4'-Methylenedianiline
4,4'-Methylenedianiline (MDA) is an organic chemical with the formula CH2(C6H4NH2)2. It is a colorless solid, though commercial samples can look yellow or brown. It is produced on a large scale by reacting formaldehyde with aniline in the presence of hydrochloric acid.
Uses and importance:
- MDA is a key building block for making polyurethanes. It is used to produce methylene diphenyl diisocyanate (MDI), which is widely used to make polyurethane foams.
- It is also used as a monomer for other polymers, including polyamides, polyimides, and polyimines.
- Smaller amounts serve as hardeners in epoxy resins and adhesives and are used in some high-performance polymers.
- Hydrogenation of MDA gives another polymer-building block, 4,4'-diaminodicyclohexylmethane.
- In chemistry, MDA can act as a bidentate ligand in metal coordination compounds.
Safety and hazards:
- MDA is considered a potential carcinogen. OSHA sets exposure limits of 0.01 ppm over an 8-hour period and 0.1 ppm for short-term exposure.
- It is listed as a substance of very high concern by the European Chemicals Agency.
- A notable poisoning incident occurred in 1965 near Epping, England, when flour contaminated with MDA caused many illnesses.
Quick facts:
- Molecular formula: C13H14N2; molar mass about 198 g/mol
- Appearance: colorless solid (may appear yellow or brown)
- Odor: faint, amine-like
- Density: about 1.05 g/cm3
- Melting point: ~89°C; boiling point: ~398–399°C
- Water solubility: about 0.125 g per 100 ml at 20°C
This page was last edited on 3 February 2026, at 20:50 (CET).