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Acrylates (
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
File:Methyl-methacrylate-skeletal.svg, Methyl methacrylate, precursor to "perspex" (plexiglass)
File:Ethyl cyanoacrylate.svg, Ethyl cyanoacrylate, precursor to "super glue"
Some acrylate 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
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 base
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the reve ...
s of acrylic acid
Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has ...
. 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
Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has ...
* 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.
Acrylate derivatives
Methacrylates ( ) andcyanoacrylate
Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. They are derived from ethyl cyanoacrylate and related esters. The cyanoacrylate group in the monomer rapidly polymerizes in the presence ...
s ( ,) 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.
Polymers
Some acrylate polymers (poly(methyl methacrylate)
Poly(methyl methacrylate) (PMMA) is a synthetic polymer derived from methyl methacrylate. It is a transparent thermoplastic, used as an engineering plastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and bran ...
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 cyanoacrylate
Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. They are derived from ethyl cyanoacrylate and related esters. The cyanoacrylate group in the monomer rapidly polymerizes in the presence ...
s.
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
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...
, 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
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
). 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
An acrylate polymer (also known as acrylic or polyacrylate) is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.
Acrylate polymer is commonly used ...
* Sodium polyacrylate thickeners
* Methacrylate
References
{{Authority control Carboxylate anions Monomers Acrylate esters