Acrylate

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Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion CH2=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. [1]

Contents

Monomers

Acrylates are defined by the formula CH2=CHCO2R, where R can be many groups:

The versatility of the resulting polymers is owed to the range of R groups.

Acrylate derivatives

Methacrylates ( CH2=C(CH3)CO2R) and cyanoacrylates ( CH2=C(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. [2]

Polymers

Structure of a generic polyacrylate. Polyacrylates are derived from acrylates but do not contain acrylate groups. Polyacrylate.svg
Structure of a generic polyacrylate. Polyacrylates are derived from acrylates but do not contain acrylate groups.

Some acrylate polymers (poly(methyl methacrylate) etc. not included):

Acrylate monomers are used to form acrylate polymers. Most commonly, these polymers are in fact copolymers, being derived from two monomers. [3] [4]

Structure of the backbone of a cyanoacrylate polymer. CyanoacrylatePolymer.svg
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.

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). [5]

See also

Related Research Articles

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a compound derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

<span class="mw-page-title-main">Acrylic acid</span> Chemical compound

Acrylic acid (IUPAC: propenoic 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 a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually.

<span class="mw-page-title-main">Methyl methacrylate</span> Chemical compound

Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA).

<span class="mw-page-title-main">Acryloyl chloride</span> Chemical compound

Acryloyl chloride, also known as 2-propenoyl chloride or acrylic acid chloride, is the organic compound with the formula CH2=CHCO(Cl). It is a colorless liquid, although aged samples appear yellow. It belongs to the acid chlorides group of compounds.

<span class="mw-page-title-main">Ethyl cyanoacrylate</span> Chemical compound

Ethyl cyanoacrylate (ECA), a cyanoacrylate ester, is an ethyl ester of 2-cyano-acrylic acid. It is a colorless liquid with low viscosity and a faint sweet smell in pure form. It is the main component of cyanoacrylate glues and can be encountered under many trade names. It is soluble in acetone, methyl ethyl ketone, nitromethane, and methylene chloride. ECA polymerizes rapidly in presence of moisture.

<span class="mw-page-title-main">Acrylate polymer</span> Group of polymers prepared from acrylate monomers

An acrylate polymer is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.

<span class="mw-page-title-main">Methacrylic acid</span> Chemical compound

Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)COOH. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).

<span class="mw-page-title-main">Acrylic resin</span> Thermoplastic or thermosetting plastic

An acrylic resin is a thermoplastic or thermosetting plastic substance typically derived from acrylic acid, methacrylic acid and acrylate monomers such as butyl acrylate and methacrylate monomers such as methyl methacrylate. Thermoplastic acrylics designate a group of acrylic resins typically containing both a high molecular weight and a high glass transition temperature which exhibit lacquer dry capability. Acrylic resins designed for use in two component systems for crosslinking with isocyanate are referred to as polyols and are made with the monomers previously mentioned as well as hydroxy monomers such as hydroxy ethyl methacrylate. Acrylic resins are produced in different liquid carriers such as a hydrocarbon solvent or water in which case they are referred to as emulsions or dispersions and they are also provided in 100% solids bead form.

Synthetic resins are industrially produced resins, typically viscous substances that convert into rigid polymers by the process of curing. In order to undergo curing, resins typically contain reactive end groups, such as acrylates or epoxides. Some synthetic resins have properties similar to natural plant resins, but many do not.

<span class="mw-page-title-main">Ethyl acrylate</span> Chemical compound

Ethyl acrylate is an organic compound with the formula CH2CHCO2CH2CH3. It is the ethyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced for paints, textiles, and non-woven fibers. It is also a reagent in the synthesis of various pharmaceutical intermediates.

<span class="mw-page-title-main">Methyl acrylate</span> Chemical compound

Methyl acrylate is an organic compound, more accurately the methyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced to make acrylate fiber, which is used to weave synthetic carpets. It is also a reagent in the synthesis of various pharmaceutical intermediates. Owing to the tendency of methyl acrylate to polymerize, samples typically contain an inhibitor such as hydroquinone.

In polymer chemistry, a comonomer refers to a polymerizable precursor to a copolymer aside from the principal monomer. In some cases, only small amounts of a comonomer are employed, in other cases substantial amounts of comonomers are used. Furthermore, in some cases, the comonomers are statistically incorporated within the polymer chain, whereas in other cases, they aggregate. The distribution of comonomers is referred to as the "blockiness" of a copolymer.

<span class="mw-page-title-main">Methyl cyanoacrylate</span> Chemical compound

Methyl cyanoacrylate (MCA) is an organic compound that contains several functional groups: a methyl ester, a nitrile, and an alkene. It is a colorless liquid with low viscosity. Its chief use is as the main component of cyanoacrylate glues. It can be encountered under many trade names. Methyl cyanoacrylate is less commonly encountered than ethyl cyanoacrylate.

Butyl acrylate is an organic compound with the formula C4H9O2CCH=CH2. A colorless liquid, it is the butyl ester of acrylic acid. It is used commercially on a large scale as a precursor to poly(butyl acrylate). Especially as copolymers, such materials are used in paints, sealants, coatings, adhesives, fuel, textiles, plastics, and caulk.

Dimethylaminoethyl acrylate or DMAEA is an unsaturated carboxylic acid ester having a tertiary amino group. It is a colorless to yellowish, water-miscible liquid with a pungent, amine-like odor. DMAEA is an important acrylic monomer that gives basic properties to copolymers.

<span class="mw-page-title-main">Ethyl vinyl ether</span> Chemical compound

Ethyl vinyl ether is an organic compound with the chemical formula CH3CH2OCH=CH2. It is the simplest enol ether that is liquid at room temperature. It is used as a synthetic building block and a monomer.

<span class="mw-page-title-main">Ethyl methacrylate</span> Organic compound

Ethyl methacrylate is the organic compound with the formula C2H5O2CC(CH3)=CH2. A colorless liquid, it is a common monomer for the preparation of acrylate polymers. It is typically polymerized under free-radical conditions.

1,6-Hexanediol diacrylate is a difunctional acrylate ester monomer used in the manufacture of polymers. It is particularly useful for use in ultraviolet light cure applications. Furthermore, it is also used in adhesives, sealants, alkyd coatings, elastomers, photopolymers, and inks for improved adhesion, hardness, abrasion and heat resistance. Like other acrylate monomers it is usually supplied with a radical inhibitor such as hydroquinone added.

α,β-Unsaturated carbonyl compound Functional group of organic compounds

α,β-Unsaturated carbonyl compounds are organic compounds with the general structure (O=CR)−Cα=Cβ-R. Such compounds include enones and enals, but also carboxylic acids and the corresponding esters and amides. In these compounds the carbonyl group is conjugated with an alkene. Unlike the case for carbonyls without a flanking alkene group, α,β-unsaturated carbonyl compounds are susceptible to attack by nucleophiles at the β-carbon. This pattern of reactivity is called vinylogous. Examples of unsaturated carbonyls are acrolein (propenal), mesityl oxide, acrylic acid, and maleic acid. Unsaturated carbonyls can be prepared in the laboratory in an aldol reaction and in the Perkin reaction.

<span class="mw-page-title-main">Hydroxyethyl acrylate</span> Organic chemical-monomer

Hydroxyethyl acrylate is an organic chemical and a aliphatic compound. It has the formula C5H8O3 and the CAS Registry Number 818-61-1. It is REACH registered with an EU number of 212-454-9. It has dual functionality containing a polymerizable acrylic group and a terminal hydroxy group. It is used to make emulsion polymers along with other monomers and the resultant resins are used in coatings, sealants, adhesives and elastomers and other applications.

References

  1. ↑ Takashi Ohara; Takahisa Sato; Noboru Shimizu; Günter Prescher; Helmut Schwind; Otto Weiberg; Klaus Marten; Helmut Greim (2003). "Acrylic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_161.pub2. ISBN   3527306730.
  2. ↑ Veerle Coessens; Tomislav Pintauer; Krzysztof Matyjaszewski (2001). Functional polymers by atom transfer radical polymerization. pp. 337–377. doi:10.1016/S0079-6700(01)00003-X.{{cite encyclopedia}}: |journal= ignored (help)
  3. ↑ Takashi Ohara; Takahisa Sato; Noboru Shimizu; et al. (2002). "Acrylic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_161.pub2. ISBN   978-3-527-30673-2.(subscription required)
  4. ↑ "Polyacrylates".
  5. ↑ Arpe, Hans-Jürgen (2007). Industrielle organische Chemie: bedeutende Vor- und Zwischenprodukte (6 ed.). Weinheim: Wiley-VCH. ISBN   978-3-527-31540-6.
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