{{short description|Salt or ester of acrylic acid}} {{see also|Methacrylate}} thumb|The acrylate anion '''Acrylates''' (IUPAC: '''prop-2-enoates''') are the salts, esters, and conjugate bases of acrylic acid. The '''acrylate ion''' is the anion {{chem2|CH2\dCHCO2(-)}}. 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.<ref name=Ullmann>{{cite encyclopedia|author1=Takashi Ohara |author2=Takahisa Sato |author3=Noboru Shimizu |author4=Günter Prescher |author5=Helmut Schwind |author6=Otto Weiberg |author7=Klaus Marten |author8=Helmut Greim|title=Acrylic Acid and Derivatives|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2003|publisher=Wiley-VCH|location=Weinheim| doi=10.1002/14356007.a01_161.pub2|isbn=3527306730 }}</ref>
==Monomers== Acrylates are defined by the formula {{chem2|CH2\dCHCO2R}}, 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. <gallery caption="Structures of some acrylates" widths="120px" heights="100px" > 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 </gallery>
===Acrylate derivatives=== Methacrylates ( {{chem2|CH2\dC(CH3)CO2R}}) and cyanoacrylates ( {{chem2|CH2\dC(CN)CO2R}},) 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.<ref>{{cite encyclopedia|author1=Veerle Coessens |author2=Tomislav Pintauer |author3=Krzysztof Matyjaszewski |title=Functional polymers by atom transfer radical polymerization|year=2001|journal=Progress in Polymer Science|volume=26 |issue=3 |pages=337–377 | doi=10.1016/S0079-6700(01)00003-X}}</ref>
<gallery caption="Structures of some important modified acrylates" widths="120px" heights="100px"|left > File:Methyl-methacrylate-skeletal.svg|Methyl methacrylate, precursor to "perspex" (plexiglass) File:Ethyl cyanoacrylate.svg|Ethyl cyanoacrylate, precursor to "super glue" </gallery>
==Polymers== thumb|left|120px|Structure of a generic polyacrylate. Polyacrylates are ''derived'' from acrylates but do not contain acrylate groups. {{main|Acrylate polymer}} Some acrylate polymers (poly(methyl methacrylate) etc. not included): * Poly(methyl acrylate) (PMA) * Poly(ethyl acrylate) (PEA) * Poly(butyl acrylate) (PBA) Acrylate monomers are used to form acrylate polymers. Most commonly, these polymers are in fact copolymers, being derived from two monomers.<ref>{{cite encyclopedia|author1=Takashi Ohara |author2=Takahisa Sato |author3=Noboru Shimizu |author4=Günter Prescher |author5=Helmut Schwind |author6=Otto Weiberg |author7=Klaus Marten |author8=Helmut Greim |display-authors=3 |chapter=Acrylic Acid and Derivatives|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2002|publisher=Wiley-VCH |location=Weinheim|doi=10.1002/14356007.a01_161.pub2|isbn=978-3-527-30673-2}}{{subscription required}}</ref><ref>{{Cite web|url=http://pslc.ws/macrog/acrylate.htm|title = Polyacrylates}}</ref>
===Related polymers=== thumb|right|Structure of the backbone of a cyanoacrylate polymer. 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. <!--Polyacrylamide.svg-->
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).<ref>{{cite book |last1=Arpe |first1=Hans-Jürgen|title=Industrielle organische Chemie: bedeutende Vor- und Zwischenprodukte.|date=2007|publisher=Wiley-VCH|location=Weinheim |isbn=978-3-527-31540-6|edition=6}}</ref>
==See also== * Acrylate polymer * Sodium polyacrylate thickeners * Methacrylate
==References== {{reflist}}
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Category:Carboxylate anions Category:Monomers Category:Acrylate esters