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Template:Short description Template:Chembox

Ethyl acetate (systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound with the formula Template:Chem2, simplified to Template:Chem2. This flammable, colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, and the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent.[1]

Production and synthesis

Ethyl acetate was first synthesized by the Count de Lauraguais in 1759 by distilling a mixture of ethanol and acetic acid.[2]

In 2004, an estimated 1.3 million tonnes were produced worldwide.[1][3] The combined annual production in 1985 of Japan, North America, and Europe was about 400,000 tonnes. The global ethyl acetate market was valued at $3.3 billion in 2018.[4]

Ethyl acetate is synthesized in industry mainly via the classic Fischer esterification reaction of ethanol and acetic acid. This mixture converts to the ester in about 65% yield at room temperature:

Template:Chem2

The reaction can be accelerated by acid catalysis and the equilibrium can be shifted to the right by removal of water.

It is also prepared in industry using the Tishchenko reaction, by combining two equivalents of acetaldehyde in the presence of an alkoxide catalyst:

Template:Chem2

Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene:[5]

Template:Chem2

Uses

Ethyl acetate is used primarily as a solvent and diluent, being favored because of its low cost, low toxicity, and agreeable odor.[1] For example, it is commonly used to clean circuit boards and in some nail varnish removers (acetone is also used). Coffee beans and tea leaves are decaffeinated with this solvent.[6] It is also used in paints as an activator or hardener. Ethyl acetate is present in confectionery, perfumes, and fruits. In perfumes it evaporates quickly, leaving the scent of the perfume on the skin.

Ethyl acetate is an asphyxiant for use in insect collecting and study.[7] In a killing jar charged with ethyl acetate, the vapors will kill the collected insect quickly without destroying it. Because it is not hygroscopic, ethyl acetate also keeps the insect soft enough to allow proper mounting suitable for a collection. However, ethyl acetate is regarded as potentially doing damage to insect DNA, making specimens processed this way less than ideal for subsequent DNA sequencing.[8]

Laboratory uses

In the laboratory, mixtures containing ethyl acetate are commonly used in column chromatography and extractions.[9] Ethyl acetate is rarely selected as a reaction solvent because it is prone to hydrolysis, transesterification, and condensations.

Occurrence in wines

Ethyl acetate is the most common ester in wine, being the product of the most common volatile organic acidacetic acid, and the ethyl alcohol generated during the fermentation. The aroma of ethyl acetate is most vivid in younger wines and contributes towards the general perception of "fruitiness" in the wine. Sensitivity varies, with most people having a perception threshold around 120 mg/L. Excessive amounts of ethyl acetate are considered a wine fault.

Reactions

Ethyl acetate is only weakly Lewis basic, like a typical carboxylic acid ester.

Ethyl acetate hydrolyses to give acetic acid and ethanol. Bases accelerate the hydrolysis, which is subject to the Fischer equilibrium mentioned above. In the laboratory, and usually for illustrative purposes only, ethyl esters are typically hydrolyzed in a two-step process starting with a stoichiometric amount of a strong base, such as sodium hydroxide. This reaction gives ethanol and sodium acetate, which is unreactive toward ethanol:

Template:Chem2

In the Claisen condensation, anhydrous ethyl acetate and strong bases react to give ethyl acetoacetate:[10]

Preparation of ethyl acetoacetate.
Preparation of ethyl acetoacetate.
Template:Clear

Properties

Physical properties

Vapor pressure of ethyl acetate
Heat of evaporation of ethyl acetate

Under normal conditions, ethyl acetate exists as a colorless, low-viscosity, and flammable liquid. Its melting point is −83 °C, with a melting enthalpy of 10.48 kJ/mol. At atmospheric pressure, the compound boils at 77 °C. The vaporization enthalpy at the boiling point is 31.94 kJ/mol. The vapor pressure function follows the Antoine equation

log10(p)=ABT+C,

where

p is the vapor pressure in bars,
T is the absolute temperature in kelvins, and
A=4.22809, B=1245.702, C=55.189 are constants.

This function is valid within the temperature range of Template:Cvt.

The enthalpy of vaporization in kJ/mol is calculated according to the empirical equation by Majer and Svoboda[11]

ΔHvap=Aexp(βTr)(1Tr)β,

where

Tr=T/Tc is the reduced temperature, and Tc = 523.2 K is the critical temperature.
A = 54.26 kJ/mol and β = 0.2982 are constants.

The following table summarizes the most important thermodynamic properties of ethyl acetate under various conditions.

Compilation of key thermodynamic properties
Property Type Value Remarks References
Standard enthalpy of formation ΔfHliquid0
ΔfHgas0
−480.57 kJ/mol
−445.43 kJ/mol
as liquid
as gas
[12]
Standard entropy Sliquid0
Sgas0
259.4 J/(mol·K)
362.75 J/(mol·K)
as liquid
as gas
[13][14]
Combustion enthalpy ΔcHliquid0 −2235.4 kJ/mol [15]
Heat capacity (25 °C) cp 168.94 J/(mol·K)
1.92 J/(g·K)
113.64 J/(mol·K)
1.29 J/(g·K)
as liquid

as gas
[16][14]
Critical temperature Tc 523.2 K [11]
Critical pressure pc 38.82 bar [17]
Critical density ρc 3.497 mol/L [18]
Acentric factor ωc 0.36641 [19]

Safety

The Template:LD50 for rats is 5620 mg/kg,[20] indicating low acute toxicity. Given that the chemical is naturally present in many organisms, there is little risk of toxicity.

Overexposure to ethyl acetate may cause irritation of the eyes, nose, and throat. Severe overexposure may cause weakness, drowsiness, and unconsciousness.[21] Humans exposed to a concentration of 400 ppm in 1.4 mg/L ethyl acetate for a short time were affected by nose and throat irritation.[22] Ethyl acetate is an irritant of the conjunctiva and mucous membrane of the respiratory tract. Animal experiments have shown that, at very high concentrations, the ester has central nervous system depressant and lethal effects; at concentrations of 20,000 to 43,000 ppm (2.0–4.3%), there may be pulmonary edema with hemorrhages, symptoms of central nervous system depression, secondary anemia and liver damage. In humans, concentrations of 400 ppm cause irritation of the nose and pharynx; cases have also been known of irritation of the conjunctiva with temporary opacity of the cornea. In rare cases exposure may cause sensitization of the mucous membrane and eruptions of the skin. The irritant effect of ethyl acetate is weaker than that of propyl acetate or butyl acetate.[23]

References

Template:Reflist

Template:Esters

  1. 1.0 1.1 1.2 Template:Ullmann
  2. Template:Cite journal
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  6. ico.org Template:Webarchive
  7. Template:Cite journal
  8. Template:Cite journal
  9. Template:OrgSynth
  10. Template:Cite journal
  11. 11.0 11.1 V. Majer, V. Svoboda: Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation. Blackwell Scientific Publications, Oxford 1985, ISBN 0-632-01529-2.
  12. K. B. Wiberg, L. S. Crocker, K. M. Morgan: Thermochemical studies of carbonyl compounds. 5. Enthalpies of reduction of carbonyl groups. In: J. Am. Chem. Soc. 113, 1991, pp. 3447–3450. doi:10.1021/ja00009a033.
  13. G. S. Parks, H. M. Huffman, M. Barmore: Thermal data on organic compounds. XI. The heat capacities, entropies and free energies of ten compounds containing oxygen or nitrogen. In: J. Am. Chem. Soc. 55, 1933, S. 2733–2740, doi:10.1021/ja01334a016.
  14. 14.0 14.1 D. R. Stull, Jr.: The Chemical Thermodynamics of Organic Compounds. Wiley, New York, 1969.
  15. M. E. Butwill, J. D. Rockenfeller: Heats of combustion and formation of ethyl acetate and isopropyl acetate. In: Thermochim. Acta. 1, 1970, pp. 289–295. doi:10.1016/0040-6031(70)80033-8.
  16. Template:Cite journal
  17. D. Ambrose, J. H. Ellender, H. A. Gundry, D. A. Lee, R. Townsend: Thermodynamic properties of organic oxygen compounds. LI. The vapour pressures of some esters and fatty acids. In: J. Chem. Thermodyn. 13, 1981, S. 795–802. doi:10.1016/0021-9614(81)90069-0.
  18. S. Young, G. L. Thomas: The vapour pressures, molecular volumes, and critical constants of ten of the lower esters. In: J. Chem. Soc. 63, 1893, S. 1191.
  19. J. Schmidt: Auslegung von Sicherheitsventilen für Mehrzweckanlagen nach ISO 4126-10 Template:In lang. In: Chem. Ing. Techn. 83, 2011, pp. 796–812. doi:10.1002/cite.201000202.
  20. Hazard Ethyl Acetate MSDS Template:Cite web
  21. Template:Cite book
  22. Template:Cite book
  23. Template:Citation