Acrylates (

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 Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s, and

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...

s of

acrylic acid 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 ...

. The acrylate ion is the anion C H₂=CHC OO⁻. Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acrylates contain

vinyl group In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound contai ...

s. These compounds are of interest because they are bifunctional: the vinyl group is susceptible to polymerization and the carboxylate group carries myriad functionalities. Modified acrylates are also numerous, some examples being methacrylates (CH₂=C(CH₃)CO₂R) and cyanoacrylates (CH₂=C(CN)CO₂R). Acrylate can also refer to polyacrylates prepared through the polymerization of the vinyl groups of acrylate monomers. 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:Methyl-methacrylate-skeletal.png,

Methyl methacrylate 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) ...

File:Ethyl cyanoacrylate.svg,

Ethyl cyanoacrylate Ethyl cyanoacrylate (ECA), a cyanoacrylate ester, is an ethyl ester of 2-cyano-2-propenoic 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 encount ...

, precursor to "super glue" File: Pentaerythritol tetraacrylate.png, Pentaerythritol tetraacrylate (PETA), a tetrafunctional acrylate File:Polyacrylate.svg, A generic polyacrylate (notice how the vinyl group has been functionalized)

Use

Acrylates and methacrylates (the salts and esters of methacrylic acid) are common

monomer In chemistry, a monomer ( ; '' mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification ...

s in

polymer A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...

s, forming the

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 use ...

s. Acrylates easily form polymers. A variety of acrylate-functionalized monomers are known.

Monomers

Acrylate

s, used to form acrylate polymers, are based on the structure of

, which consists of a

and a

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxyli ...

ester end or a nitrile. Other typical acrylate monomers are derivatives of acrylic acid, such as

methyl methacrylate 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) ...

in which one vinyl hydrogen and the carboxylic acid hydrogen are both replaced by

methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ...

groups, and

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecula ...

in which the carboxylic acid group is replaced by the related

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including me ...

group. Other examples of acrylate monomers are: *

Methacrylate Methacrylates are derivatives of methacrylic acid. * Methyl methacrylate * Ethyl methacrylate * Butyl methacrylate * Hydroxyethyl methacrylate Hydroxyethylmethacrylate (also known as glycol methyacrylate) is the organic compound with the chemic ...

s * Methyl acrylate *

Ethyl acrylate 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 ...

* 2-Chloroethyl vinyl ether * 2-Ethylhexyl acrylate *

Hydroxyethyl methacrylate Hydroxyethylmethacrylate (also known as glycol methyacrylate) is the organic compound with the chemical formula . It is a colorless viscous liquid that readily polymerizes. Hydroxyethylmethacrylate is a monomer that is used to make various polymer ...

* Butyl acrylate * Butyl methacrylate * TMPTA

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 and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is ...

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

) takes place at 100–120 °C with acidic

heterogeneous catalysts In chemistry, heterogeneous catalysis is catalysis where the phase of catalysts differs from that of the reactants or products. The process contrasts with homogeneous catalysis where the reactants, products and catalyst exist in the same phas ...

( cation exchanger). 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 ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular fo ...

in homogeneous phase. Acrylates of even higher alcohols are obtainable by

transesterification In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. The reaction ca ...

of lower esters catalysed by titanium alcoholates or organic tin compounds (e.g. dibutyltin dilaurate).

References

{{reflist Carboxylate anions Monomers Acrylate esters

Use

Monomers

Production

See also

References