Acrylate

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

Main article: 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.

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).

References

References

1. (2003). "Acrylic Acid and Derivatives". Wiley-VCH.
2. (2001). "Functional polymers by atom transfer radical polymerization". Progress in Polymer Science.
3. {{cite encyclopedia. (2002). Wiley-VCH
4. "Polyacrylates".
5. (2007). "Industrielle organische Chemie: bedeutende Vor- und Zwischenprodukte.". Wiley-VCH.