Ethyl acetate

Ethyl acetate 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.<ref name=Ullmann>Template:Ullmann</ref>

Production and synthesis

Ethyl acetate was first synthesized by the Count de Lauraguais in 1759 by distilling a mixture of ethanol and acetic acid.<ref>Template:Cite journal</ref>

In 2004, an estimated 1.3 million tonnes were produced worldwide.<ref name=Ullmann/><ref>Template:Cite journal</ref> 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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Ethyl acetate is produced 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:

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The reaction can be accelerated by acid catalysts 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:

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Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene:<ref name=Misono>Template:Cite journal</ref>

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Uses

Ethyl acetate is used primarily as a solvent and diluent, being favored because of its low cost, low toxicity, and agreeable odor.<ref name=Ullmann/> 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.<ref name="ico.org">ico.org Template:Webarchive</ref> 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.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref>

Laboratory uses

In the laboratory, mixtures containing ethyl acetate are commonly used in column chromatography and extractions.<ref>Template:OrgSynth</ref> 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 acid – acetic 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:

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In the Claisen condensation, anhydrous ethyl acetate and strong bases react to give ethyl acetoacetate:<ref>Template:Cite journal</ref>

Preparation of ethyl acetoacetate.

Properties

Physical properties

File:Vapour pressure ethyl acetate.svg

Vapor pressure of ethyl acetate

File:Heat of evaporation ethyl acetate.svg

Heat of evaporation of ethyl acetate

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

<math>\log_{10}(p) = A - \frac{B}{T + C},</math>

where

<math>p</math> is the vapor pressure in bars,

<math>T</math> is the absolute temperature in kelvins, and

<math>A = 4.22809</math>, <math>B = 1245.702</math>, <math>C = -55.189</math> 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<ref name="Majer Svoboda">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.</ref>

<math>\Delta H_\text{vap} = A\exp(-\beta\,T_\text{r})\,(1 - T_\text{r})^\beta,</math>

where

<math>T_\text{r} = T/T_\text{c}</math> is the reduced temperature, and <math>T_\text{c}</math> = 523.2 K is the critical temperature.

<math>A</math> = 54.26 kJ/mol and <math>\beta</math> = 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	<math>\Delta_f H^0_\text{liquid}</math> <math>\Delta_f H^0_\text{gas}</math>	−480.57 kJ/mol −445.43 kJ/mol	as liquid as gas	<ref name="Wiberg">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.</ref>
Standard entropy	<math>S^0_\text{liquid}</math> <math>S^0_\text{gas}</math>	259.4 J/(mol·K) 362.75 J/(mol·K)	as liquid as gas	<ref name="Parks">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.</ref><ref name="Stull">D. R. Stull, Jr.: The Chemical Thermodynamics of Organic Compounds. Wiley, New York, 1969.</ref>
Combustion enthalpy	<math>\Delta_c H^0_\text{liquid}</math>	−2235.4 kJ/mol		<ref name="Butwill">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.</ref>
Heat capacity (25 °C)	<math>c_p</math>	168.94 J/(mol·K) 1.92 J/(g·K) 113.64 J/(mol·K) 1.29 J/(g·K)	as liquid as gas	<ref name="Pintos">Template:Cite journal</ref><ref name="Stull" />
Critical temperature	<math>T_\text{c}</math>	523.2 K		<ref name="Majer Svoboda"/>
Critical pressure	<math>p_\text{c}</math>	38.82 bar		<ref name="Ambrose">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.</ref>
Critical density	<math>\rho_\text{c}</math>	3.497 mol/L		<ref name="Young">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.</ref>
Acentric factor	<math>\omega_c</math>	0.36641		<ref>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.</ref>

Safety

The Template:LD50 for rats is 5620 mg/kg,<ref>Hazard Ethyl Acetate MSDS {{#invoke:citation/CS1|citation |CitationClass=web }}</ref> indicating low acute toxicity. Given that the chemical is naturally present in many organisms, there is little risk of toxicity.

World Health Organization(WHO) has assessed the Acceptable Daily Intake(ADI) of Ethyl Acetate at 25mg per kg of body weight.<ref>WHO Evaluations {{#invoke:citation/CS1|citation |CitationClass=web }}</ref> This is similar to the ADI of other artifcial sweeteners that are friendly and have been commonly used for a long time.<ref>FDA Information {{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite journal</ref> According to European Food Safety Authority(EFSA), Ethyl Acetate taken orally is rapidly metabolized and broken down. The half-life in blood after ingestion exposure is known to be appproximately 35 seconds.<ref>Template:Cite journal</ref>

Overexposure to ethyl acetate may cause irritation of the eyes, nose, and throat. Severe overexposure may cause weakness, drowsiness, and unconsciousness.<ref>Template:Cite book</ref> 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.<ref>Template:Cite book</ref> 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.<ref>Template:Citation</ref>

External links

• https://pubchem.ncbi.nlm.nih.gov/compound/ethyl_acetate#section=Toxicity
• NIOSH Pocket Guide to Chemical Hazards
• International Chemical Safety Cards
• Material safety data (MSDS) for ethyl acetate
• National Pollutant Inventory – Ethyl acetate fact sheet
• Ethyl Acetate: Molecule of the Month
• Purpose of Using Concentrated Sulfuric Acid in Esterification for Catalysis
• Basic facts and contact SEKAB [1] SEKAB ethyl acetate
• A Techno Commercial Profile of Ethyl Acetate in India
• Calculation of vapor pressure, liquid density, dynamic liquid viscosity, surface tension of ethyl acetate