4,4'-Methylenedianiline

4,4'-Methylenedianiline (MDA) is an organic compound with the formula CH2(C6H4NH2)2. It is a colorless or white solid. It is produced on industrial scale as a precursor to polyurethanes.

4,4'-Methylenedianiline
Names
IUPAC name
Bis(4-aminophenyl)methane
Other names
4,4'-Diaminodiphenylmethane; 4,4'-Methylenebisbenzenamine; MDA; para, para'-Diaminodiphenyl-methane; Dianilinomethane; 4,4'-Diphenylmethanediamine
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.002.705
EC Number
  • 202-974-4
KEGG
RTECS number
  • BY5425000
UNII
UN number 2651
Properties
C13H14N2
Molar mass 198.269 g·mol−1
Appearance Pale brown, crystalline solid
Odor faint, amine-like[1]
Density 1.05 g/cm3 (100°C)
Melting point 89 °C (192 °F; 362 K)
Boiling point 398 to 399 °C (748 to 750 °F; 671 to 672 K)
0.125 g/100 ml (20 °C)
Vapor pressure 0.0000002 mmHg (20°C)[1]
Hazards
Main hazards potential carcinogen[1]
Flash point 190 °C; 374 °F; 463 K [1]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 0.010 ppm ST 0.100 ppm[1]
REL (Recommended)
 Ca[1]
IDLH (Immediate danger)
 Ca [N.D.][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Synthesis and applications

In the industrial production, MDA is produced by reaction of formaldehyde and aniline in the presence of hydrochloric acid.[2]

MDA is consumed mainly as a precursor to 4,4 ́-methylene diphenyl diisocyanate (MDI). MDA is treated with phosgene to give MDI. MDI is a precursor to many polyurethane foams.[3][4] Lower quantities are used as hardeners in epoxy resins and adhesives, as well as in the production of high-performance polymers.[2] MDA is hydrogenated to give 4,4-diaminodicyclohexylmethane, which is also used in polymer chemistry.[5]

Safety

MDA is considered a potential occupational carcinogen by the US National Institute for Occupational Safety and Health. The Occupational Safety and Health Administration has set a permissible exposure limit at 0.01 ppm over an eight-hour time-weighted average, and a short-term exposure limit at 0.10 ppm.[6]

It is suspected carcinogen.[3] It is included in the "substances of very high concern" list of the European Chemicals Agency (ECHA).[4] The compound was blamed in a mass poisoning in the vicinity of Epping, Essex, United Kingdom during 1965 during which 84 individuals were poisoned through accidental contamination of flour used to make bread.[7]

References
  1. NIOSH Pocket Guide to Chemical Hazards. "#0415". National Institute for Occupational Safety and Health (NIOSH).
  2. "Data on manufacture, import, export, uses and release of 4-4' diaminodiphenylmethane" (PDF). Archived from the original (PDF) on 2011-10-01.
  3. "ToxFAQs for 4,4'-Methylenedianiline". Agency for Toxic Substances and Disease Registry.
  4. "Background document for 4,4'-Diaminodiphenylmethane (MDA)" (PDF). European Chemicals Agency.
  5. Roose P, Eller K, Henkes E, Rossbacher R, Höke H (2005). "Amines, Aliphatic". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_001.
  6. "4,4'-Methylenedianiline". NIOSH Pocket Guide on Chemical Hazards.
  7. Kopelman H, Robertson MH, Sanders PG, Ash I (February 1966). "The Epping jaundice". British Medical Journal. 1 (5486): 514–6. doi:10.1136/bmj.1.5486.514. PMC 1843808. PMID 5902696.
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