4,4′-Methylenedianiline (MDA) is an organic

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struct ...

with the formula CH₂(C₆H₄NH₂)₂. It is a colorless solid, although commercial samples can appear yellow or brown. It is produced on an industrial scale, mainly as a precursor to

polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan ...

Synthesis and applications

In the industrial production, MDA is produced by reaction of formaldehyde and aniline in the presence of hydrochloric acid. MDA is consumed mainly as a precursor to

Methylene diphenyl diisocyanate 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 i ...

(MDI). MDA is treated with

phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, espe ...

to produce MDI. MDI is a precursor to many

foams. Lower quantities are used as hardeners in epoxy resins and adhesives, as well as in the production of high-performance polymers. Additionally, hydrogenation of MDA can be performed to produce 4,4,diaminodicyclohexylmethane, which is also used in polymer chemistry.

Safety

MDA is considered a potential occupational carcinogen by the US National Institute for Occupational Safety and Health. The

Occupational Safety and Health Administration The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agenc ...

has set a

permissible exposure limit The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational S ...

at 0.01 ppm over an eight-hour time-weighted average, and a

short-term exposure limit A short-term exposure limit (STEL) is the acceptable average exposure over a short period of time, usually 15 minutes as long as the time-weighted average is not exceeded. STEL is a term used in occupational health, industrial hygiene and toxicolo ...

at 0.1 ppm. It is suspected

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substan ...

. It is included in the "

substances of very high concern A substance of very high concern (SVHC) is a chemical substance (or part of a group of chemical substances) concerning which it has been proposed that use within the European Union be subject to authorisation under the Registration, Evaluation, Au ...

" list of the European Chemicals Agency (

ECHA The European Chemicals Agency (ECHA; ) is an agency of the European Union which manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation, Authorisation and Restricti ...

). The compound was blamed in a mass poisoning in the vicinity of

Epping Epping may refer to: Places Australia * Epping, New South Wales, a suburb of Sydney ** Epping railway station, Sydney * Electoral district of Epping, the corresponding seat in the New South Wales Legislative Assembly * Epping Forest, Kearns, a he ...

Essex Essex () is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, and G ...

, United Kingdom during 1965 during which 84 individuals were poisoned through accidental contamination of flour used to make bread.

Related compounds

* 4,4'-Thiodianiline *

4,4'-Oxydianiline 4,4′-Oxydianiline (ODA) is an organic compound with the formula O( C6 H4 NH2)2. It is an ether derivative of aniline. This colourless solid is a useful monomer and cross-linking agent for polymers, especially the polyimides, such as Kapton. Us ...

Dapsone Dapsone, also known as 4,4'-sulfonyldianiline (SDA) or diaminodiphenyl sulfone (DDS), is an antibiotic commonly used in combination with rifampicin and clofazimine for the treatment of leprosy. It is a second-line medication for the treatment a ...

References

External links

* * * * {{DEFAULTSORT:Methylenedianiline, 4,4'- Anilines IARC Group 2B carcinogens Mass poisoning