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.
Production
The standard industrial reaction for producing methyl acrylate is
esterification of acrylic acid with
methanol under acid catalysis (
sulfuric acid, p-toluenesulfonic acid or acidic ion exchangers.
). The transesterification is facilitated because methanol and methyl acrylate form a low boiling
azeotrope (
boiling point 62–63 °C).
The patent literature
Other methods
Methyl acrylate can be prepared by
debromination of methyl 2,3-dibromopropanoate with
zinc.
[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 of
methyl lactate in the presence of
ethenone (ketene).
Methyl lactate is a renewable "
Green chemistry". Another patent
describes the dehydration of methyl lactate over
.
The nickel tetracarbonyl-catalyzed hydrocarboxylation of acetylene with carbon monoxide in the presence of methanol also yields methyl acrylate.[W. Reppe, J. Liebigs Ann. Chem., 582 (1), 116-132 (1953)] The reaction of methyl formate with acetylene in the presence of transition metal catalysts also leads to methyl acrylate.[H.-J. Arpe, Industrielle Organische Chemie, 6. Aufl., Wiley-VCH Verlag, Weinheim, 2007, .] are also proven but obsolete processes.
Use
Methyl acrylate is after
butyl acrylate and
ethyl acrylate the third most important acrylic ester with a worldwide annual production of about 200,000 tons in 2007.
[ CEH Marketing Research Report Acrylic Acid and Esters, SRI Consulting, July 2007.] Poly(methyl acrylate) is a tacky material near room temperature, and as such it is not particularly useful as a structural material. Commonly, methyl acrylate (and other acrylate esters) are
with other alkenes to give useful engineering plastics.
A variety of
are used, including
styrene and other acrylates.
[DOW Methyl acrylate, Product Safety Assessment] The resulting copolymers give acrylic paints that are harder and more
Brittleness 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.
Methyl acrylate is the precursor to fibers that are woven to make carpets.
Amino derivatives
Methyl acrylate reacts catalysed by
in a
Michael addition with
in high yields to β-alanine derivatives which provide amphoteric surfactants when long-chain amines are used and the ester function is hydrolysed subsequently.
Acrylates are also used in the preparation of poly(amidoamine) (PAMAM) typically by Michael addition with a primary amine.
Methyl acrylate is used for the preparation of 2-dimethylaminoethyl acrylate by transesterification with dimethylaminoethanol in significant quantities of over 50,000 tons / year.
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.
