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Acrylates (
IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...
: prop-2-enoates) are the
salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
s,
ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...
s, and conjugate bases of acrylic acid. The acrylate ion is the anion . Often, acrylate refers to
ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...
s of acrylic acid, the most common member being methyl acrylate. These acrylates contain vinyl groups. These compounds are of interest because they are bifunctional: the vinyl group is susceptible to polymerization and the carboxylate group carries myriad functionalities.


Monomers

Acrylates are defined by the formula , where R can be many groups: * Acrylic acid * Methyl acrylate * Ethyl acrylate * 2-Chloroethyl vinyl ether * 2-Ethylhexyl acrylate * Butyl acrylate * Trimethylolpropane triacrylate (TMPTA) The versatility of the resulting polymers is owed to the range of R groups. File:Acrylate-anion.svg, The acrylate anion File:Trimethylolpropane triacrylate.svg, Trimethylolpropane triacrylate (TMPTA), a trifunctional acrylate ester File:Methylacrylat.svg, Methyl acrylate, an acrylic ester File:Hexandioldiacrylat.svg, Hexandiol diacrylate, a bifunctional acrylate File: Pentaerythritol tetraacrylate.png, Pentaerythritol tetraacrylate (PETA), a tetrafunctional acrylate File:Polyacrylate.svg, A generic polyacrylate


Acrylate derivatives

Methacrylates ( ) and cyanoacrylates ( ,) are closely related to acrylates. The feature a methyl and a nitrile in place of the H alpha to the carboxy functional group. They share several properties, being polymerized by radicals and being colorless. File:Methyl-methacrylate-skeletal.svg, Methyl methacrylate, precursor to "perspex" (plexiglass) File:Ethyl cyanoacrylate.svg, Ethyl cyanoacrylate, precursor to "super glue"


Polymers

Some acrylate polymers ( poly(methyl methacrylate) etc. not included): * Poly(methyl acrylate) (PMA) * Poly(ethyl acrylate) (PEA) * Poly(butyl acrylate) (PBA) Acrylate
monomer A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemis ...
s are used to form acrylate polymers. Most commonly, these polymers are in fact copolymers, being derived from two monomers.


Related polymers

In the same way that several variants of acrylic esters are known, so too are the corresponding polymers. Their properties strongly depends on the substituent. A large family of acrylate-like polymers are derived from methyl methacrylate and many related esters, especially polymethyl methacrylate. A second large family of acrylate-like polymers are derived from ethyl cyanoacrylate, which gives rise to cyanoacrylates. Yet another family of acrylate-related polymers are the polyacrylamides, especially the parent derived from acrylamide.


Other uses

In addition to forming polymers, acrylate esters participate in other reactions relevant to organic chemistry. They are Michael acceptors and dienophiles. They undergo transesterification.


Production

Acrylates are industrially prepared by treating acrylic acid with the corresponding alcohol in presence of a catalyst. The reaction with lower alcohols ( methanol,
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
) takes place at 100–120 °C with acidic heterogeneous catalysts ( cation exchanger). The reaction of higher alcohols ( ''n''-butanol, 2-ethylhexanol) is catalysed with
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...
in homogeneous phase. Acrylates of even higher alcohols are obtainable by transesterification of lower esters catalysed by titanium alcoholates or organic tin compounds (e.g. dibutyltin dilaurate).


See also

* Acrylate polymer * Sodium polyacrylate thickeners * Methacrylate


References

{{Authority control Carboxylate anions Monomers Acrylate esters