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Methyl acrylate is an
organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
, more accurately the
methyl 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 ar ...
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 ...
. It is a colourless liquid with a characteristic acrid odor. It is mainly produced to make
acrylate Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. 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 acry ...
fiber, which is used to weave synthetic carpets. It is also a
reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
in the synthesis of various pharmaceutical intermediates.


Production

The standard industrial reaction for producing methyl acrylate is
esterification 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 ar ...
with
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 a ...
under acid catalysis (
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 formu ...
,
p-toluenesulfonic acid ''p''-Toluenesulfonic acid (PTSA or ''p''TsOH) or tosylic acid (TsOH) is an organic compound with the formula CH3 C6H4 SO3H. It is a white extremely hygroscopic solid that is soluble in water, alcohols, and other polar organic solvents. The CH3C ...
or acidic ion exchangers.). The transesterification is facilitated because methanol and methyl acrylate form a low boiling
azeotrope An azeotrope () or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation.Moore, Walter J. ''Physical Chemistry'', 3rd e Prentice-Hall 1962, pp. 140–142 This ...
(
boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding envir ...
62–63 °C). The patent literature describes a one-pot route involving vapor-phase oxidation of propene or 2-propenal with oxygen in the presence of methanol.


Other methods

Methyl acrylate can be prepared by debromination of methyl 2,3-dibromopropanoate with
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
.F. Beilstein: ''Handbuch der organischen Chemie'', 3. Auflage, 1. Band. Verlag Leopold Voss, 1893, S. 501
Volltext
Methyl acrylate is formed in good yield on
pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...
of
methyl lactate Methyl lactate, also known as lactic acid methyl ester, is the organic compound with the formula CH3CH(OH)CO2CH3. It is the methyl ester of lactic acid. A colorless liquid, it is the simplest chiral ester. Being naturally derived, it is readily ...
in the presence of
ethenone In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula or . It is the simplest member of the ketene class. It is an important reagent for acetylations. Properties Ethenone is a highly reactive gas (a ...
(ketene). Methyl lactate is a renewable " green chemical". Another patent describes the dehydration of methyl lactate over
zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ・y where is either a metal ion or H+. These pos ...
s. The nickel tetracarbonyl-catalyzed
hydrocarboxylation Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbo ...
of acetylene with carbon monoxide in the presence of methanol also yields methyl acrylate. The reaction of methyl formate with acetylene in the presence of transition metal catalysts also leads to methyl acrylate. Both, the alcoholysis of propiolactone with methanol as well as the methanolysis of acrylonitrile via intermediately formed acrylamide sulfate are also proven but obsolete processes.


Use

Methyl acrylate is after
butyl acrylate 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 polybutylacrylate, which is used in paints, sealants, coa ...
and
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 ...
the third most important acrylic ester with a worldwide annual production of about 200,000 tons per year. Methyl acrylate reacts catalysed by Lewis bases in a
Michael addition In organic chemistry, the Michael reaction or Michael addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a carbon ...
with
amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...
s in high yields to β-alanine derivatives which provide amphoteric surfactants when long-chain amines are used and the ester function is hydrolysed subsequently. Methyl acrylate is used for the preparation of
2-dimethylaminoethyl acrylate Dimethylaminoethyl acrylate (2-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 import ...
by transesterification with
dimethylaminoethanol Dimethylethanolamine (DMAE or DMEA) is an organic compound with the formula (CH3)2NCH2CH2OH. It is bifunctional, containing both a tertiary amine and primary alcohol functional groups. It is a colorless viscous liquid. It is used in skin care produ ...
in significant quantities of over 50,000 tons / year. Methyl acrylate is used as a comonomer in the polymerization with a variety of acrylic and vinyl monomers. In doing so it has a similar range of uses as ethyl acrylate. When using methyl acrylate as comonomer resulting acrylic paints are harder and more
brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Bre ...
than those with the homologous acrylates. Copolymerizing methyl acrylate with acrylonitrile improves their melt processability to fibers, which could be used as precursors for carbon fibers. Acrylates are also used in the preparation of
poly(amidoamine) Poly(amidoamine), or PAMAM, is a class of dendrimer which is made of repetitively branched subunits of amide and amine functional group, functionality. PAMAM dendrimers, sometimes referred to by the trade name Starburst, have been extensively studie ...
(PAMAM)
dendrimer Dendrimers are highly ordered, branched polymeric molecules. Synonymous terms for dendrimer include arborols and cascade molecules. Typically, dendrimers are symmetric about the core, and often adopt a spherical three-dimensional morphology. The ...
s typically by Michael addition with a primary
amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...
. Methyl acrylate is the precursor to fibers that are woven to make carpets. Owing to its tendency to polymerize, samples typically contain an inhibitor such as hydroquinone.


Reactions

Methyl acrylate is a classic Michael acceptor, which means that it adds nucleophiles at its terminus. For example, in the presence of a base catalyst, it adds hydrogen sulfide to give the thioether: :2 CH2CHCO2CH3 + H2S → S(CH2CH2CO2CH3)2 It is also a good dienophile.


Safety

It is an acute toxin with an (rats, oral) of 300 mg/kg and a TLV of 10 ppm.


References

{{Authority control Acrylate esters Methyl esters Monomers