# Acrylate

Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion CH$_2$=CHCO−2. Often, acrylate refers to esters 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 CH$_2$=CHCO$_2$R, 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.
* Structures of some acrylates
* The acrylate anion
* Trimethylolpropane triacrylate (TMPTA), a trifunctional acrylate ester
* Methyl acrylate, an acrylic ester
* Hexandiol diacrylate, a bifunctional acrylate
* Pentaerythritol tetraacrylate (PETA), a tetrafunctional acrylate
* A generic polyacrylate

### Acrylate derivatives

Methacrylates ( CH$_2$=C(CH$_3$)CO$_2$R) and cyanoacrylates ( CH$_2$=C(CN)CO$_2$R,) 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.
* Structures of some important modified acrylates
* Methyl methacrylate, precursor to "perspex" (plexiglass)
* Ethyl cyanoacrylate, precursor to "super glue"

## Polymers

Some acrylate polymers (poly(methyl methacrylate) etc. not included):
* Poly(methyl acrylate) (PMA)
* Poly(ethyl acrylate) (PME)
* Poly(butyl acrylate)
Acrylate monomers 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) 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 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).