Ethyl acrylate is an organic compound with the formula CH2CHCO2CH2CH3. It is the ethylester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced for paints, textiles, and non-woven fibers.[5] It is also a reagent in the synthesis of various pharmaceutical intermediates.
The large number of possible comonomer units and their combination in copolymers and terpolymers with ethyl acrylate allows the realization of different properties of the acrylate copolymers in a variety of applications in paints and adhesives, paper, textile and leather auxiliaries together with cosmetic and pharmaceutical products.
As Michael acceptor and HX acceptor
Ethyl acrylate reacts with amines catalyzed by Lewis acids in a Michael addition to β-alanine derivatives in high yields:[13]
The nucleophilic addition at ethyl acrylate as an α,β-unsaturated carbonyl compound is a frequent strategy in the synthesis of pharmaceutical intermediates. Examples are the hypnoticglutethimide or the vasodilatorvincamin (obsolete by now)[14] or more recent therapeutics such as the COPD agent cilomilast or the nootropicleteprinim.[15]
Ethyl acrylate is also used as a flavoring agent. It has been found as a volatile component in pineapples and Beaufort cheese[18] and is a secondary component in vanilla flavor obtained from heat extraction of vanilla in amounts of up to 1 ppm. In such high concentrations it negatively affects the extracted aroma.[19]
The International Agency for Research on Cancer stated, "Overall evaluation, ethyl acrylate is possibly carcinogenic to humans (Group 2B)."[21] The United States Environmental Protection Agency (EPA) states, "Human studies on occupational exposure to ethyl acrylate... have suggested a relationship between exposure to the chemical(s) and colorectal cancer, but the evidence is conflicting and inconclusive. In a study by the National Toxicology Program (NTP), increased incidence of squamous cell papillomas and carcinomas of the forestomach were observed in rats and mice exposed via gavage (experimentally placing the chemical in the stomach). However, the NTP recently determined that these data were not relevant to human carcinogenicity since humans do not have a forestomach, and removed ethyl acrylate from its list of carcinogens."[22] However, ethyl acrylate also increased the incidence of thyroid follicular cell adenoma in male mice, and thyroid follicular cell adenoma or carcinoma (combined) in male rats exposed through inhalation.[23]
It is possibly carcinogenic and it is toxic in large doses, with an LD50 (rats, oral) of 1020 mg/kg. As of October 2018, the FDA withdrew authorization for its use as a synthetic flavoring substance in food.[24]
One favorable safety aspect is that ethyl acrylate has good warning properties; the odor threshold is much lower than the concentration required to create an atmosphere immediately dangerous to life and health. Reports of the exact levels vary somewhat, but, for example, the EPA reports an odor threshold of 0.0012 parts per million (ppm),[22] but the EPA's lowest level of health concern, the Acute Exposure Guideline Level-1 (AEGL-1) is 8.3 ppm,[25] which is almost 7000 times the odor threshold.
However, as a possible carconigen, NIOSH maintains "that there is no safe level of exposure to a carcinogen. Reduction of worker exposure to chemical carcinogens as much as possible through elimination or substitution and engineering controls is the primary way to prevent occupational cancer."[26]
^WO 1999031042, J.-M. Paul, J.-P. Gamet, "Method for conditioning long chain alkyl acrylates", published 1995-06-24, assigned to Elf Atochem S.A.
^EP 1284954, Gerhard Nestler, Jürgen Schröder, "Verfahren zur herstellung von estern ungesättigter carbonsäuren", published 2003-02-26, assigned to BASF Aktiengesellschaft
^US 5409629, Jan E. Shulman, Charles E. Jones, "Use of acrylic acid/ethyl acrylate copolymers for enhanced clay soil removal in liquid laundry detergents", published 1995-04-25, assigned to Rohm and Haas Company
^Jose Cabral, Pierre Laszlo, Loïc Mahé, Marie-Thérèse Montaufier, S. Lalatiana Randriamahefa (1989), "Catalysis of the specific Michael addition: The example of acrylate acceptors", Tetrahedron Letters (in German), vol. 30, no. 30, pp. 3969–3972, doi:10.1016/S0040-4039(00)99297-9{{citation}}: CS1 maint: multiple names: authors list (link)
^Pharmazeutische Wirkstoffe: Synthesen, Patente, Anwendungen; von A. Kleemann u. J. Engel; 2., neubearb. u. erw. Aufl.; Stuttgart, New York; Thieme; 1982, ISBN3-13-558402-X
^D. Lednicer, The Organic Chemistry of Drug Synthesis, Volume 7, J. Wiley & Sons, 2008, ISBN978-0-470-10750-8
^Mozingo, Ralph; Patterson, L. A. (1940). "Methyl β-Bromopropionate". Organic Syntheses. 20: 64. doi:10.15227/orgsyn.020.0064.
