Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)CO2H. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its , especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).
Various green routes have been explored but they have not been commercialized. Specifically, the decarboxylation of itaconic acid, citraconic acid, and affords methacrylic acid. Salts of methacrylic acid have been obtained by boiling citra- or meso-brompyrotartaric acids with .
Pyrolysis of ethyl methacrylate efficiently gives methacrylic acid. This article also describes pyrolysis of ethyl methacrylate.
It is used in some nail primers to help Artificial nails adhere to the nail plate.
copolymer consisting partially of methacrylic acid are used in certain types of tablet coatings in order to slow the tablet's dissolution in the digestive tract, and thus extend or delay the release of the active ingredient.
MAA occurs naturally in small amounts in the oil of Roman chamomile.
MMA is used in the synthesis of some vinyl ester resins.
Methacrylic acid undergoes several reactions characteristic of α,β-unsaturated acids (see acrylic acid). These reactions include the Diels–Alder reaction and . Esterifications are brought about by acid-catalyzed condensations with alcohols, alkylations with certain alkenes, and transesterifications. Epoxide ring-opening gives hydroxyalkyl esters.
Sodium amalgam reduces it to isobutyric acid. A form of methacrylic acid was described in 1880..
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