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Ethyl acrylate
Ethyl acrylate
Ethyl acrylate
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Ethyl acrylate[1][2]
Skeletal structure of ethyl acrylate
Ball-and-stick model of the ethyl acrylate molecule
Names
Preferred IUPAC name
Ethyl prop-2-enoate
Other names
Ethyl propenoate
Ethyl acrylate
Acrylic acid ethyl ester
Ethyl ester of acrylic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.945 Edit this at Wikidata
EC Number
  • 205-438-8
KEGG
RTECS number
  • AT0700000
UNII
UN number 1917
  • InChI=1S/C5H8O2/c1-3-5(6)7-4-2/h3H,1,4H2,2H3 checkY
    Key: JIGUQPWFLRLWPJ-UHFFFAOYSA-N checkY
  • InChI=1/C5H8O2/c1-3-5(6)7-4-2/h3H,1,4H2,2H3
    Key: JIGUQPWFLRLWPJ-UHFFFAOYAN
  • CCOC(=O)C=C
Properties
C5H8O2
Molar mass 100.117 g·mol−1
Appearance Colorless liquid
Odor Acrid[3]
Density 0.9405 g/mL
Melting point −71 °C (−96 °F; 202 K)
Boiling point 99.4 °C (210.9 °F; 372.5 K)
1.5 g/100 mL
Solubility organic solvents
Vapor pressure 29 mmHg (20°C)[3]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Carcinogenic
GHS labelling:
GHS02: FlammableGHS07: Exclamation mark
Danger
H225, H302, H312, H315, H317, H319, H332, H335
P210, P233, P240, P241, P242, P243, P261, P264, P270, P271, P272, P280, P301+P312, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P333+P313, P337+P313, P362, P363, P370+P378, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
2
3
2
Flash point 15 °C (59 °F; 288 K)
Explosive limits 1.4%-14%[3]
Lethal dose or concentration (LD, LC):
2180 ppm (rat, 4 hr)
3894 ppm (mouse)[4]
1204 ppm (rabbit, 7 hr)
1204 ppm (guinea pig, 7 hr)[4]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 25 ppm (100 mg/m3) [skin][3]
REL (Recommended)
 Carcinogen[3]
IDLH (Immediate danger)
 Ca [300 ppm][3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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.[5] It is also a reagent in the synthesis of various pharmaceutical intermediates.

Production

[edit]

Ethyl acrylate is produced by acid-catalysed esterification of acrylic acid, which in turn is produced by oxidation of propylene. It may also be prepared from acetylene, carbon monoxide and ethanol by a Reppe reaction. Commercial preparations contain a polymerization inhibitor such as hydroquinone, phenothiazine, or hydroquinone ethyl ether.[5]

Dow Inc., BASF and Arkema are the two largest producers of Ethyl Acrylate in the United States.

Reactions and uses

[edit]

Precursor to polymers and other monomers

[edit]

Ethyl acrylate is used in the production of polymers including resins, plastics, rubber, and denture material.[6]

Ethyl acrylate is a reactant for homologous alkyl acrylates (acrylic esters) by transesterification with higher alcohols through acidic or basic catalysis. In that way speciality acrylates are made accessible, e.g. 2-ethylhexyl acrylate (from 2-ethylhexanol) used for pressure-sensitive adhesives, cyclohexyl acrylate (from cyclohexanol) used for automotive clear lacquers, 2-hydroxyethyl acrylate (from ethylene glycol) which is crosslinkable with diisocyanates to form gels used with long-chain acrylates (from C18+ alcohols)[7] as comonomer for comb polymers for reduction of the solidification point of paraffin oils and 2-dimethylaminoethyl acrylate (from dimethylaminoethanol[8]) for the preparation of flocculants for sewage clarification and paper production.

As a reactive monomer, ethyl acrylate is used in homopolymers and copolymers with e.g. ethene, acrylic acid and its salts, amides and esters, methacrylates, acrylonitrile, maleic esters, vinyl acetate, vinyl chloride, vinylidene chloride, styrene, butadiene and unsaturated polyesters.[9] Copolymers of acrylic acid ethyl ester with ethene (EPA/ethylene-ethyl acrylate copolymers) are suitable as adhesives and polymer additives, just like ethene vinyl acetate copolymers.[10] Copolymers with acrylic acid increase the cleaning effect of liquid detergents,[11] copolymers with methacrylic acid are used as gastric juices tablet covers (Eudragit).[12]

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

[edit]

Ethyl acrylate reacts with amines catalyzed by Lewis acids in a Michael addition to β-alanine derivatives in high yields:[13]

Michael addition of an amine to ethyl acrylate

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 hypnotic glutethimide or the vasodilator vincamin (obsolete by now)[14] or more recent therapeutics such as the COPD agent cilomilast or the nootropic leteprinim.[15]

Ethyl 3-bromopropionate is prepared by hydrobromination of ethyl acrylate.[16]

Dienophile

[edit]

With dienes, ethyl acrylate reacts as a good dienophile in Diels–Alder reactions e.g. with buta-1,3-diene in a [4+2] cycloaddition reaction to give a cyclohexene carboxylic acid ester in a high yield.[17]

Natural occurrence

[edit]

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]

Safety

[edit]
A railway tank car carrying ethyl acrylate, displaying hazardous materials information including a diamond-shaped U.S. DOT placard showing a UN number[20]

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]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Ethyl acrylate

View on Grokipedia
from Grokipedia
Ethyl acrylate is an with the C₅H₈O₂ (CH₂=CHCOOCH₂CH₃), a colorless to pale yellow liquid at with a pungent, acrid , serving primarily as a reactive in the synthesis of acrylic polymers and copolymers. It exhibits key physical properties including a molecular weight of 100.12 g/mol, a of 99.4 °C, a of -71 °C, a of 0.92 g/cm³ at 20 °C, and moderate in (1.5 g/100 mL at 20 °C). As a highly flammable substance with a of 9–15 °C and explosive limits of 1.4–14% in air, it requires careful handling to prevent exothermic , which can occur if not stabilized with inhibitors like . Ethyl acrylate is predominantly produced through the esterification of with under acidic conditions, often catalyzed by or other strong acids, followed by to purify the product; alternative processes include the reaction of with in the presence of . In industry, it is a key building block for manufacturing water-based adhesives (especially pressure-sensitive types), paints and coatings, finishes, and non-woven fibers, where it imparts flexibility, , and durability to polymers when copolymerized with monomers like or styrene. It also finds applications in sealants, plasticizers, and pharmaceutical intermediates, contributing to products in , automotive, and consumer goods sectors. From a and perspective, ethyl acrylate is classified as a and eye irritant, a potential sensitizer, and a possible , with exposure risks including respiratory and systemic toxicity to organs like the lungs and liver upon or . Occupational exposure limits are set at 25 ppm (100 mg/m³) TWA by OSHA, reflecting its and need for inhibitors to maintain stability during storage and transport below 35 °C. Environmentally, it has low persistence, being readily biodegradable under aerobic conditions in water, with low potential.

Properties

Physical properties

Ethyl acrylate is a colorless at , characterized by its acrid and pungent , which has an odor threshold as low as 0.0012 ppm. Its molecular is C₅H₈O₂, with a of CH₂=CHCOOCH₂CH₃, and a molecular weight of 100.12 g/mol. The compound exhibits typical physical characteristics of an unsaturated , including moderate volatility and flammability, which influence its handling in industrial settings. Due to its tendency to polymerize under certain conditions, ethyl acrylate is often stabilized with inhibitors during storage and transport. Key physical properties are summarized in the following table:
PropertyValueConditions/Source
AppearanceColorless liquid
99–100 °C1013 mbar
Melting point−71 °C
0.922 g/cm³20 °C
29 mmHg20 °C
9 °C (closed cup)
1.40620 °C
Solubility in 1.5 g/100 mL20 °C
Miscible with organic solvents
Explosive limitsLower: 1.4%; Upper: 14% (vol% in air)
Vapor density3.45 (air = 1)
383 °C

Chemical properties

Ethyl acrylate is classified as an α,β-unsaturated , characterized by the presence of both an and an . This compound exhibits notable instability, being prone to exothermic free when uninhibited, which necessitates the addition of stabilizers such as 10–20 ppm monomethyl ether of to prevent unintended reactions during storage and handling. It also undergoes slow in neutral aqueous conditions, with a reported of approximately 3.5 years at 7 and 25 °C. In terms of reactivity, ethyl acrylate participates in free radical polymerization due to its activated double bond, undergoes electrophilic addition across the alkene, and is susceptible to nucleophilic attack at the β-carbon via Michael addition mechanisms. Regarding oxidation, it reacts with photochemically generated hydroxyl radicals in the atmosphere, with an estimated half-life of about 16 hours, and with ozone. The α-proton (the vinyl hydrogen adjacent to the carbonyl) possesses a pKa of approximately 25, reflecting moderate acidity typical of ester α-hydrogens stabilized by the adjacent carbonyl. The molecule is weakly basic, attributable to the lone pairs on the ester oxygen, though specific pKa values for the conjugate acid are not well-documented for this compound. Spectroscopic characterization confirms its structure: infrared (IR) spectroscopy reveals characteristic absorptions at 1720 cm⁻¹ for the C=O stretch and 1630 cm⁻¹ for the C=C stretch. In ¹H (NMR) spectroscopy (in CDCl₃), key signals appear at δ 1.3 (triplet, 3H, CH₃), δ 4.1 (quartet, 2H, OCH₂), and δ 5.8–6.4 (multiplet, 3H, vinyl protons).

Production

Industrial methods

The primary industrial method for producing ethyl acrylate involves the acid-catalyzed esterification of with , where is first obtained through the vapor-phase oxidation of in a two-stage process: is oxidized to using a catalyst at approximately 370°C, followed by further oxidation to with a molybdenum-based catalyst at around 300–350°C. The esterification reaction typically employs or a strong acid cation-exchange as the catalyst, conducted in a fixed-bed reactor with an excess of to drive the equilibrium toward product formation and minimize side reactions. The reaction proceeds at temperatures of 60–80°C under , with the crude ester mixture subsequently purified by distillation to remove , unreacted , and , achieving yields exceeding 95% based on acrylic acid conversion. This process benefits from the low cost and availability of as a feedstock, making it economically dominant for large-scale operations. An alternative industrial route, the Reppe carbonylation process developed in the , involves the reaction of , , and using a nickel carbonyl catalyst under high pressure (up to 100 atm) and elevated temperatures (150–200°C) to directly form ethyl acrylate. However, this method became less common after the 1950s due to the high cost and safety risks associated with acetylene production and handling, as well as the rise of cheaper propylene-based routes. The propylene-based esterification method has been the dominant approach since the 1960s, largely replacing earlier acetylene-derived processes and enabling significant scale-up in production. Global production capacity for ethyl acrylate reached approximately 790 kilotons per year in 2021, with major producers including Dow (around 220 kilotons capacity), BASF, and Arkema; in the United States, production capacity stands at about 300 kilotons annually. In recent years, sustainability efforts have led to the adoption of bio-based production methods. In 2024, transitioned to producing ethyl acrylate entirely from bioethanol derived from at its facility in Carling, , achieving 40% bio-carbon content and up to 30% reduction in product compared to fossil-based equivalents. Similarly, announced a full transition to bio-based ethyl acrylate using bio-ethanol at its Ludwigshafen site in in 2024, with the product featuring 14C-traceable bio-content to verify claims and lower . To prevent unwanted during storage and transport, ethyl acrylate is stabilized with 10–15 ppm of or monomethyl ether hydroquinone (MEHQ), which act as radical scavengers, allowing safe handling under inert atmospheres or at controlled temperatures below 25°C.

Alternative syntheses

One alternative synthesis of ethyl acrylate involves laboratory-scale Fischer esterification of with , catalyzed by . The reaction mixture is refluxed at temperatures around 140°C under , followed by to isolate the product with yields up to 97%. This method is suitable for small-scale preparation due to its simplicity and use of readily available reagents, though it requires careful control to minimize side reactions. Another route employs sulfuric acid-catalyzed addition-elimination between and to form ethyl acrylate. The process involves reacting with in the presence of concentrated at elevated temperatures, leading to an intermediate that decomposes to the desired product upon heating and ; this 1985 patented method achieves high selectivity under optimized conditions. Oxidative esterification represents a modern variant explored at pilot scale, utilizing , oxygen, and over a palladium-based catalyst supported on alumina with promoter. The vapor-phase reaction proceeds at 125°C and atmospheric to moderate pressure (up to 75 psi), yielding ethyl acrylate with conversions around 22% based on and selectivities favoring the ester over byproducts like . This approach leverages direct C-C bond formation from lower-cost feedstocks but remains niche due to catalyst deactivation challenges. A rare synthetic pathway for ethyl acrylate, particularly suited for isotopically labeled variants, starts from propargyl alcohol via partial followed by . The step reduces the triple bond to a double bond using selective catalysts like , yielding allylic intermediates, which then undergo Pd-catalyzed with CO to incorporate labels and form the acrylate skeleton; this multi-step process is low-yield but valuable for tracer studies in applications. Post-synthesis purification of ethyl acrylate typically involves under reduced pressure (e.g., 70–135 mm Hg) to separate it from unreacted acids, alcohols, and oligomers while minimizing thermal polymerization. Stabilizers such as 10–20 ppm monomethyl ether hydroquinone are added immediately after to inhibit during storage.

Reactivity

Polymerization reactions

Ethyl acrylate undergoes free radical primarily through a chain-growth mechanism involving the addition of the vinyl . The is typically initiated by such as benzoyl peroxide or azo compounds like 2,2'-azobisisobutyronitrile (AIBN), which decompose to generate radicals that add to the monomer's electron-deficient , forming a propagating radical. Light-induced via photoinitiators is also employed, particularly for controlled processes. The chain growth proceeds by successive addition of units, represented as: nCH2=CHCO2C2H5→[−CH2−CH(CO2C2H5)−]nn \mathrm{CH_2=CHCO_2C_2H_5} \rightarrow \left[ -\mathrm{CH_2-CH(CO_2C_2H_5)}- \right]_n This results in a tactic poly(ethyl acrylate) with predominantly atactic stereochemistry due to the radical nature of the process. Polymerization conditions vary by method: bulk polymerization is straightforward but prone to heat buildup; solution polymerization uses solvents like benzene or toluene for better temperature control; emulsion polymerization employs water with surfactants for latex production. Typical temperatures range from 50–80 °C to balance initiation rate and avoid excessive side reactions, with AIBN concentrations around 0.1–1 wt% relative to monomer. Molecular weight is controlled by chain transfer agents such as thiols (e.g., n-dodecyl mercaptan) or solvents like alcohols, which abstract hydrogen from the propagating radical, terminating one chain and initiating another, yielding number-average molecular weights from 10^4 to 10^6 g/mol depending on agent concentration. Copolymerization of ethyl acrylate with other vinyl monomers is common to tailor properties, following the Mayo-Lewis mechanism where reactivity ratios dictate composition drift. With styrene, the reactivity ratio for ethyl acrylate (r_EA) is approximately 0.15–0.25 at 50–60 °C, indicating a for styrene addition to ethyl acrylate radicals, while r_styrene ≈ 0.8 favors alternation. For , r_VAc ≈ 0.02–0.05 and r_EA ≈ 4.5–6.0 at 60–70 °C, leading to preferential incorporation of ethyl acrylate and composition drift. With , the ratios are close to unity, enabling random copolymers. An example is the terpolymerization in acrylonitrile-styrene-acrylate (ASA) resins, where ethyl acrylate enhances flexibility and weather resistance akin to ABS plastics. Anionic polymerization of ethyl acrylate is less common due to the sensitivity of the group to nucleophilic attack, which can lead to or elimination, but it enables living polymerization for block copolymers. Organolithium initiators such as , often ligated with crown ethers or phosphazenes to moderate reactivity, are used in apolar solvents like at low temperatures (–78 to 0 °C) to produce narrow molecular weight distributions (PDI < 1.2). This method is particularly suited for synthesizing styrene-ethyl acrylate block copolymers with defined architectures. Polymerization is inhibited by oxygen, which forms relatively stable peroxo radicals that terminate propagating chains, necessitating inert atmospheres or deoxygenation. Commercial ethyl acrylate contains stabilizers like hydroquinone (10–100 ppm) to prevent premature polymerization during storage. At high conversions (>30–50%), the Trommsdorff-Norrish effect causes autoacceleration: increasing reduces termination rates more than , leading to rapid exotherms and potential runaway reactions, which is mitigated by semi-batch feeding or cooling. Poly(ethyl acrylate) homopolymer exhibits a glass transition temperature of –24 °C, rendering it rubbery and flexible at room temperature, ideal for soft segments in adhesives and coatings.

Addition reactions

Ethyl acrylate undergoes nucleophilic addition reactions as a Michael acceptor due to its α,β-unsaturated ester structure, where nucleophiles add to the β-carbon, followed by protonation at the α-carbon to yield β-substituted propanoate derivatives. The general mechanism involves conjugate addition, represented as: \ceCH2=CHCO2C2H5+NuH−>Nu−CH2−CH2CO2C2H5\ce{CH2=CHCO2C2H5 + NuH -> Nu-CH2-CH2CO2C2H5} This reaction is facilitated by bases such as NaOH or solid bases like Na/NaOH/Al₂O₃, which deprotonate the nucleophile to enhance its reactivity. For instance, primary amines participate in aza-Michael additions, as seen in the reaction of benzylamine with ethyl acrylate, producing high yields of the β-amino ester product under mild conditions. Ammonia can also serve as a nucleophile, forming ethyl 3-aminopropanoate, though multiple additions may occur with excess ammonia. Secondary amines readily undergo aza-Michael addition to ethyl acrylate, yielding tertiary β-amino esters that function as intermediates in , including the preparation of betaines and pharmaceuticals. A representative example is the addition of , producing ethyl 3-(dimethylamino)propanoate, which has been employed in the synthesis of cilomilast, a phosphodiesterase 4 inhibitor. These reactions typically proceed efficiently without additional catalysts due to the nucleophilicity of the amine, though Lewis acids like LiClO₄ can accelerate the process. Thiols also act as nucleophiles in Michael-type additions to ethyl acrylate, often via a radical-mediated rather than base-catalyzed conjugate addition. The reaction involves hydrogen abstraction from the by a , generating a thiyl radical that adds to the β-carbon: \ceRSH+CH2=CHCO2C2H5−>[radical]RS−CH2CH2CO2C2H5\ce{RSH + CH2=CHCO2C2H5 ->[radical] RS-CH2CH2CO2C2H5} Common include azo compounds like AIBN or photoinitiators for UV-triggered processes, enabling rapid and efficient additions. This is particularly valuable in the formulation of coatings, where it provides uniform network formation, low shrinkage, and enhanced durability through thioether linkages. Electrophilic additions of hydrogen halides (HX, where X = Cl or Br) to ethyl acrylate across the yield 3-halopropanoate esters, with the halogen attaching to the β-carbon. Under radical conditions induced by peroxides, the addition follows anti-Markovnikov , as exemplified by: \ceCH2=CHCO2C2H5+HBr−>[peroxides]BrCH2CH2CO2C2H5\ce{CH2=CHCO2C2H5 + HBr ->[peroxides] BrCH2CH2CO2C2H5} This regiochemistry arises from the radical mechanism, where a radical adds to the less substituted β-carbon, forming a stable α-carbon radical stabilized by the group, followed by hydrogen abstraction. Even without peroxides, acrylates often exhibit this anti-Markovnikov orientation due to the electron-withdrawing carbonyl influencing the . The radical pathway lacks , producing achiral products without diastereoselectivity concerns in this linear system.

Cycloaddition reactions

Ethyl acrylate functions as an electron-deficient dienophile in Diels-Alder reactions due to the electron-withdrawing group, which activates the toward with conjugated dienes to form substituted products. A representative example is its reaction with , yielding ethyl cyclohex-3-ene-1-carboxylate as the derivative bearing the substituent at the 1-position. These reactions typically proceed under thermal conditions at 150–200 °C, often requiring high pressure for gaseous dienes like butadiene, though yields can reach up to 93% under optimized high-pressure setups similar to those for unactivated analogs. Lewis acids such as AlCl₃ catalyze the process by coordinating to the carbonyl oxygen, lowering the and accelerating the reaction at milder temperatures. The substituent influences , favoring the endo in concerted cycloadditions, as secondary orbital interactions between the and the carbonyl stabilize the transition state. For instance, the reaction of ethyl acrylate with (a more reactive proxy for ) produces an endo:exo ratio of approximately 82:18 under uncatalyzed conditions at ambient temperature, shifting to nearly 99:1 endo with AlCl₃·OEt₂ catalysis. In cases involving unsymmetrical dienes, such as piperylene, adheres to the ortho-para rule, where the electron-withdrawing orients para to electron-donating groups on the , yielding predominant "para" isomers (e.g., 95:5 ratio in the piperylene-methyl acrylate analog). These regioselective adducts, such as carboxylates, serve as key intermediates in pharmaceutical synthesis, enabling access to complex carbocycles for drug candidates. Less commonly, ethyl acrylate undergoes photochemical [2+2] cycloadditions with alkenes under UV irradiation to generate cyclobutane derivatives, often requiring photosensitizers for efficient triplet-state involvement, though such reactions are limited by competing side processes like polymerization. The Diels-Alder adducts of ethyl acrylate exhibit synthetic utility through thermal retro-Diels-Alder decomposition, typically at elevated temperatures above 200 °C, which cleaves the cyclohexene ring to regenerate the diene and dienophile for stepwise assembly in total synthesis. Overall, these cycloadditions afford high yields of 80–95% with activated dienes like cyclopentadiene, but efficiency diminishes with sterically hindered substrates due to increased activation barriers.

Applications

Polymer production

Ethyl acrylate (EA) is primarily utilized in the industrial production of various , where it serves as a key to impart flexibility and adhesion properties due to its low temperature (Tg) of -24 °C. This characteristic enables the resulting materials to remain soft and elastic at , enhancing their performance in applications requiring durability and pliability. Global demand is estimated at approximately 175,000 metric tons as of 2025, predominantly for coatings and adhesives. Homopolymers of ethyl acrylate, known as poly(ethyl acrylate), are synthesized to produce flexible materials used as softening agents in and in paints for improved film formation. These homopolymers exhibit excellent compatibility with other monomers, allowing seamless integration into broader formulations, and are applied in textile finishing for crease-resistant fabrics and in paper coatings for enhanced saturation and strength. C copolymers incorporating EA are more common in industrial settings, often combined with butyl acrylate or methyl methacrylate to form acrylic emulsions suitable for water-based adhesives and coatings, providing superior tack and weather resistance. EA-acrylic acid copolymers are essential in superabsorbent polymers (SAPs), which absorb large volumes of water for use in hygiene products like diapers. These copolymers leverage EA's flexibility to balance absorbency with structural integrity in end-use applications. Industrial polymerization of EA typically employs processes for producing water-based paints and adhesives, where monomers are dispersed in water with and initiators to yield stable, low-viscosity dispersions. is used to generate bead-like particles for specialized coatings and finishes, offering control over for uniform application. The mechanisms of these polymerizations, involving free-radical initiation, are detailed in related reactivity discussions.

Organic synthesis

Ethyl acrylate functions as a key in , particularly as a Michael acceptor in conjugate additions and as a dienophile in cycloadditions, enabling the construction of complex carbon frameworks for fine chemicals and pharmaceuticals. Its α,β-unsaturated ester structure facilitates regioselective reactions under mild conditions, making it suitable for multi-step syntheses where high selectivity is essential. Unlike its dominant role in large-scale , applications here emphasize targeted small-molecule assembly with stringent purity requirements to minimize side products. In pharmaceutical synthesis, ethyl acrylate undergoes Michael addition with nucleophiles such as to generate intermediates for bioactive compounds. For instance, treatment of nor-morphine derivatives with ethyl acrylate yields N-carboxyethylated products that serve as haptens or precursors for analgesics, enhancing and receptor affinity. Similar additions contribute to certain PDE4 inhibitors via amine conjugation to the moiety. These reactions typically proceed in protic solvents at ambient temperatures, yielding β-substituted esters with >90% efficiency in optimized protocols. For , ethyl acrylate can act as a dienophile in Diels-Alder cycloadditions with dienes, forming adducts that serve as intermediates for certain herbicides and pesticides. These [4+2] reactions provide stereocontrolled access to bicyclic structures, as seen in routes employing palladium-catalyzed couplings with acrylates for agrochemical intermediates. Yields often exceed 80% under thermal or , supporting scalable synthesis of active ingredients with defined . As a precursor to fine chemicals, ethyl acrylate reacts with via Michael addition to produce , a non-proteinogenic used in nutritional supplements and as a building block for . The process involves heating ethyl acrylate with excess aqueous at 100–200°C, achieving conversions up to 95% while suppressing . Additionally, with higher alcohols converts it to esters employed in fragrance formulations, imparting fruity or green notes through subsequent derivatization. A representative reaction sequence demonstrates its role in peptide analog synthesis: Michael addition of ethyl to ethyl acrylate generates diethyl 2-(2-ethoxy-2-oxoethylamino)succinate, which upon and yields γ-carboxyglutamic acid derivatives or constrained peptide mimics for . This alkylation step, often base-promoted, proceeds with high (>95%) and serves as an acyl equivalent for α-amino elaboration. Such sequences link to broader addition mechanisms discussed in reactivity sections. Organic synthesis applications operate on a smaller scale than polymer production, typically in kilogram-to-tonne batches, necessitating >99% purity to avoid impurities affecting downstream yields or bioactivity. Recent developments (post-2020) integrate ethyl acrylate into variants, such as regioselective aza-Michael additions with dihydropyrimidinones for efficient small-molecule ligation. Biocatalytic approaches, including enzyme-mediated additions to acrylates, further enhance by enabling asymmetric transformations under aqueous conditions.

Other industrial uses

Ethyl acrylate serves as a key comonomer in the production of pressure-sensitive adhesives (PSAs), often copolymerized with to enhance tackiness and properties in applications such as tapes, labels, and stickers. These adhesives benefit from ethyl acrylate's ability to form flexible, water-based emulsions that provide strong bonding while maintaining low emissions. In the textiles and leather industries, ethyl acrylate is incorporated into impregnation formulations to impart water repellency to fabrics and s, as well as serving as a binder in non-woven materials for improved and cohesion. These applications leverage its reactivity to create coatings that enhance resistance to moisture and mechanical stress without compromising fabric flexibility. For and production, ethyl acrylate contributes to surface coatings that boost , printability, and abrasion resistance, particularly in high-quality and papers. Its use in these formulations allows for the development of water-resistant finishes that improve the longevity and aesthetic appeal of printed materials. In , ethyl is utilized in acrylate copolymers for sprays and nail products, where it helps form flexible films that provide hold and shine, though its application is restricted by regulatory limits due to potential risks. These copolymers are formulated at low concentrations to balance performance with safety compliance in personal care items. Ethyl acrylate is also employed in the synthesis of soil-release polymers for detergents, typically as copolymers with , which attach to synthetic fabrics during washing to facilitate easier removal of oily and particulate soils. These polymers, with an ester-to-acid around 70:30, enhance in formulations by promoting hydrophilic surfaces on hydrophobic fibers. Notable growth in bio-based alternatives has occurred since 2020, driven by demands in adhesives and coatings. As of 2024, companies like and have introduced bioethanol-derived variants, reducing reliance on feedstocks and aligning with goals.

Occurrence

Natural sources

Ethyl acrylate occurs naturally as a volatile compound in several fruits, including pineapples, where it is present at concentrations up to approximately 0.077 mg/100 g and contributes to the fruit's characteristic aroma. It has also been detected in passion fruit, raspberries, and at trace levels, typically below 1 ppm, as part of the natural flavor profile in these tropical and berry fruits. In dairy products, ethyl acrylate is found as a in , a Gruyère-type variety produced in the through microbial processes involving . These low concentrations, generally under 1 ppm, arise during the cheese ripening stage as a result of enzymatic esterification in the . The compound's presence in natural sources is typically analyzed using gas chromatography-mass spectrometry (GC-MS) techniques in food volatile profiling, confirming its role as a minor aroma contributor without significant accumulation.

Flavoring applications

Ethyl acrylate imparts a fruity, pineapple-like flavor profile at low concentrations, typically ranging from 0.1 to 1 ppm, making it suitable for enhancing tropical and rum-like in food products. This sensory characteristic arises from its volatile nature, contributing subtle sweetness and fruitiness without overpowering other ingredients when used sparingly. The compound's detectability is notably sensitive, with a sensory threshold of 0.15 ppb in , allowing it to influence flavor even in trace amounts. Historically, ethyl acrylate served as a synthetic flavoring additive in various foods and beverages, such as candies, baked goods, and , where it was recognized as (GRAS) by the Flavor and Extract Manufacturers Association (FEMA) under reference number 2418 until its withdrawal in 2018. In the United States, the (FDA) permitted its use as a direct in accordance with current good manufacturing practices until October 9, 2018, when it was banned due to emerging data indicating potential genotoxic risks. In contrast, it remains authorized in the for use in certain flavorings, as affirmed by the (EFSA) in evaluations confirming no safety concerns at estimated intake levels under intended conditions. For flavoring applications, ethyl acrylate requires high-purity grades that are inhibitor-free to avoid and ensure stability in formulations, distinguishing it from industrial variants used in polymers. Following regulatory changes, alternatives such as pineapple extracts or safer ester compounds like have been adopted to replicate similar fruity profiles without the associated risks. This shift emphasizes the compound's occurrence in as a minor volatile component, though synthetic forms were preferred for their consistency in controlled .

Safety and environmental impact

Health hazards

Ethyl acrylate is a potent irritant to the skin, eyes, and upon acute exposure, causing severe burns, lacrimation, and of mucous membranes. of vapors at concentrations around 1350 ppm for 4 hours results in an LC50 in rats, leading to respiratory distress and mortality. yields an LD50 of approximately 1020 mg/kg in rats, while dermal exposure has an LD50 of 3,049 mg/kg in rats, indicating moderate through these routes. Symptoms from low-level include , drowsiness, and , with concentrations as low as 25 ppm causing irritation that may not be tolerated for extended periods. Chronic exposure to ethyl acrylate can lead to sensitization, resulting in , particularly among workers handling or paints containing acrylates. Occupational cases of have been reported in painters and adhesive workers due to repeated contact. is classified as possibly carcinogenic to humans (Group 2B) by the International Agency for Research on Cancer, based on sufficient evidence of forestomach tumors in following at high doses. Its toxicity mechanism involves spontaneous Michael addition reactions with and sulfhydryl groups in proteins, depleting cellular antioxidants and causing , particularly in epithelial tissues. Regulatory exposure limits reflect these hazards: the OSHA (PEL) is 25 ppm (100 mg/m³) as an 8-hour time-weighted average with skin notation, while NIOSH considers it a potential occupational without a numerical . The Acute Exposure Guideline Level-1 (AEGL-1) for notable and discomfort is 8.3 ppm across exposure durations from 10 minutes to 8 hours. Additionally, uncontrolled of ethyl acrylate can generate and , posing risks that exacerbate dangers in confined or heated environments.

Environmental effects

Ethyl acrylate exhibits moderate acute toxicity to aquatic organisms. The 96-hour LC50 for (Pimephales promelas) is 2.5 mg/L, indicating potential harm to fish populations at low concentrations. For invertebrates, the 48-hour for Daphnia magna is 7.9 mg/L, suggesting sensitivity in crustacean species. It is also an irritant to , with growth inhibition observed at similar concentrations, potentially disrupting in aquatic ecosystems. Ethyl acrylate is readily biodegradable in aquatic environments. The BOD5/COD ratio is 0.74, demonstrating high relative to . In standardized tests, it achieves >70% degradation within 28 days according to 301 guidelines, confirming rapid microbial breakdown. Under aerobic conditions in water, the half-life is less than 1 day, limiting long-term persistence. Bioaccumulation potential is low due to its hydrophilic nature and rapid degradation. The log Kow value is 0.73, and the factor (BCF) is <10, indicating minimal uptake in aquatic organisms. It hydrolyzes to and , further reducing accumulation risk. In the atmosphere, ethyl acrylate degrades primarily through reaction with hydroxyl (OH) radicals, with a of 9.6 hours, preventing significant transport or buildup. It has low , posing negligible risk to stratospheric . Soil mobility is high, with a Koc value of approximately 10, allowing easy leaching into . However, quick in mitigates contamination risks. Spills of ethyl acrylate are toxic to aquatic life, necessitating immediate to prevent damage. Remediation typically involves to enhance volatilization and using microbial consortia to accelerate degradation.

Regulatory status

Ethyl acrylate is classified under the European Union's Classification, Labelling and Packaging (CLP) Regulation as Category 4 (oral and inhalation), Skin Irritation Category 2, Eye Irritation Category 2, Skin Sensitisation Category 1, Category 2, and Aquatic Acute Category 1. This harmonized classification, updated through the 21st Adaptation to Technical Progress (ATP 21) in 2023 and further revisions post-2020, requires specific labeling, safety data sheets, and risk management measures for handlers. Under the REACH Regulation, ethyl acrylate is registered for manufacture and import volumes exceeding 100,000 tonnes per annum in the , with no authorization requirements under Annex XIV as it is not a (SVHC); however, it faces restrictions for specific applications, including prohibition in cosmetic products per Annex II of the Cosmetics Regulation (EC) No 1223/2009 and limitations in toys under Annex II, Section III of the Directive. In the United States, the FDA withdrew authorization for ethyl acrylate as a synthetic substance and adjuvant in food in 2018, following petitions citing carcinogenic risks observed in animal studies. For transportation, ethyl acrylate is designated UN 1917 (ethyl acrylate, stabilized), Hazard Class 3 ( with a packing group II), under the UN Model Regulations, DOT, ADR/RID, and IATA; it is classified as a marine pollutant under the IMDG Code due to its aquatic toxicity. Occupationally, the American Conference of Governmental Industrial Hygienists (ACGIH) sets a (TLV) of 5 ppm (21 mg/m³) as an 8-hour time-weighted average, with a (STEL) of 15 ppm (61 mg/m³); it is listed on the U.S. TSCA inventory, requiring reporting for significant new uses, and on Canada's Domestic Substances List (DSL). Environmentally, the U.S. EPA has not established an IRIS oral reference dose for ethyl acrylate, though provisional peer-reviewed values (PPRTV) derive a chronic p-RfD of 0.02 mg/kg-day based on forestomach effects in rats. Under REACH, it does not meet criteria for persistent, bioaccumulative, and toxic (PBT) or very persistent and very bioaccumulative (vPvB) substances. 's 2024 screening assessment under the Chemicals Management Plan concludes that ethyl acrylate is unlikely to pose an unacceptable risk to human health or the environment at current exposure levels in .

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