Methacrylic acid, abbreviated MAA, is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
. 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
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...
s, especially
methyl methacrylate (MMA), and to
poly(methyl methacrylate) (PMMA). MAA occurs naturally in small amounts in the oil of
Roman chamomile
''Chamaemelum nobile'', commonly known as chamomile (also spelled camomile), is a low perennial plant found in dry fields and around gardens and cultivated grounds in Europe, North America, and South America. Its synonym is ''Anthemis nobili ...
.
Production
In the most common route, methacrylic acid is prepared from
acetone cyanohydrin, which is converted to methacrylamide sulfate using sulfuric acid. This derivative in turn is hydrolyzed to methacrylic acid, or esterified to methyl methacrylate in one step. Another route to methacrylic acid starts with
isobutylene
Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value.
Producti ...
, which obtainable by dehydration of
''tert''-butanol. Isobutylene is oxidized sequentially to
methacrolein
Methacrolein, or methacrylaldehyde, is an unsaturated aldehyde. It is a clear, colorless, flammable liquid.
Methacrolein is one of two major products resulting from the reaction of isoprene with OH in the atmosphere, the other product being m ...
and then methacrylic acid. Methacrolein for this purpose can also be obtained from
formaldehyde
Formaldehyde ( , ) ( systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...
and
ethylene. Yet a third route involves the
dehydrogenation
In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. A ...
of
Isobutyric acid.
Various green routes have been explored but they have not been commercialized. Specifically, the
decarboxylation of
itaconic acid,
citraconic acid, and
mesaconic acids affords methacrylic acid. Salts of methacrylic acid have been obtained by boiling citra- or meso-brompyrotartaric acids with
alkalis.
Pyrolysis of
ethyl methacrylate efficiently gives methacrylic acid.
Uses
Methacrylic acid is used in some nail primers to help
acrylic nails adhere to the nail plate.
Reactions
When fused with an alkali, it forms
propanoic acid.
Sodium amalgam reduces it to
isobutyric acid. A
polymer
A polymer (; Greek '' poly-'', "many" + '' -mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
ic form of methacrylic acid was described in 1880.
[.]
352px, left, Typical vinyl ester resin derived from bisphenol A diglycidyl ether and methacrylic acid.
[{{cite journal, last1=Pham, first1=Ha Q., last2=Marks, first2=Maurice J., title=Epoxy Resins, journal=Ullmann's Encyclopedia of Industrial Chemistry, year=2012, location=Weinheim, publisher=Wiley-VCH, doi=10.1002/14356007.a09_547.pub2, isbn=978-3527306732]
References
External links
Methacrylic Acid in Europe.
Monomers
Enoic acids
Foul-smelling chemicals
