The ethyl acetate or ethyl ethanoate (IUPAC name) is an organic compound whose chemical formula is CH3COOCtwoH5. It consists of an ester, where the alcoholic component derives from ethanol, while its carboxylic acid component comes from acetic acid..
It is a liquid under normal conditions of temperature and pressure, presenting a pleasant fruity aroma. This property is perfectly in harmony with what is expected of an ester; which is in fact the chemical nature of ethyl acetate. For this reason it finds use in food products and alcoholic beverages..
The upper image shows the skeletal structure of ethyl acetate. Note on the left its carboxylic acid component, and on the right the alcoholic component. From a structural point of view, this compound could be expected to behave as a hybrid between vinegar and alcohol; however, it exhibits its own properties.
It is here that such hybrids called esters stand out for being different. Ethyl acetate cannot react as an acid, nor can it be dehydrated due to the absence of an OH group. Instead, it undergoes basic hydrolysis in the presence of a strong base, such as sodium hydroxide, NaOH.
This hydrolysis reaction is used in teaching laboratories for chemical kinetic experiments; where the reaction is also second order. When hydrolysis occurs, ethyl ethanoate practically returns to its initial components: acid (deprotonated by NaOH), and alcohol.
In its structural skeleton it is observed that hydrogen atoms predominate over oxygen atoms. This influences their ability to interact with species that are not as polar as fats. Likewise, it is used to dissolve compounds such as resins, colorants, and in general organic solids..
Despite having a pleasant aroma, prolonged exposure to this liquid has a negative impact (like almost all chemical compounds) on the body..
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The upper image shows the structure of ethyl acetate with a spheres and bars model. In this model, oxygen atoms are highlighted with red spheres; to its left is the fraction derived from acid, and to its right the fraction derived from alcohol (alkoxy group, -OR).
The carbonyl group is seen by the C = O bond (the double bars). The structure around this group and the adjacent oxygen is flat, due to the fact that there is a delocalization of the charge by resonance between both oxygens; a fact that explains a relatively low acidity of α hydrogens (those of the -CH group3, linked to C = O).
By rotating two of its bonds, the molecule directly favors how it interacts with other molecules. The presence of the two oxygen atoms, and the asymmetry in the structure, give it a permanent dipole moment; which in turn, is responsible for their dipole-dipole interactions.
For example, the electron density is higher near the two oxygen atoms, decreasing considerably in the -CH group.3, and gradually in the OCH grouptwoCH3.
Due to these interactions, ethyl acetate molecules form a liquid under normal conditions, which has a considerably high boiling point (77ºC)..
If you look closely at the structure, you will notice the absence of an atom capable of donating a hydrogen bond. However, oxygen atoms are such acceptors, and because of ethyl acetate it is very soluble in water, and interacts to an estimable degree with polar compounds and hydrogen bond donors (such as sugars)..
Also, this allows it to interact excellently with ethanol; reason why its presence is not missed in alcoholic beverages.
On the other hand, its alkoxy group makes it capable of interacting with certain apolar compounds, such as chloroform, CH3Cl.
-Ethyl acetate
-Ethyl ethanoate
-Ethyl acetic ester
-Acetoxyethane
C4H8ORtwo or CH3COOCtwoH5
88.106 g / mol.
Clear colorless liquid.
Colorless liquid.
Characteristic of ethers, similar to the smell of pineapple.
Pleasant when diluted, adds a fruity flavor to the beer.
3.9 ppm. 0.0196 mg / m3 (low odor); 665 mg / m3 (high odor).
Odor detectable at 7 - 50 ppm (mean = 8 ppm).
171ºF to 760mmHg (77.1ºC).
-118.5ºF (-83.8ºC).
80 g / L.
Miscible with ethanol and ethyl ether. Very soluble in acetone and benzene. Also miscible with chloroform, fixed and volatile oils, and also with oxygenated and chlorinated solvents.
0.9003 g / cm3.
3.04 (in air: 1 ratio).
It decomposes slowly with moisture; incompatible with various plastics and strong oxidizing agents. Mixing with water can be explosive.
93.2 mmHg at 25 ºC
0.423 mPoise at 25 ºC.
2,238.1 kJ / mol.
35.60 kJ / mol at 25 ºC.
24 dynes / cm at 20 ° C.
1,373 at 20 ºC / D.
2 - 8 ºC.
16 - 18 at 25 ºC.
Ethyl acetate is industrially synthesized by the Fisher reaction, in which ethanol is esterified with acetic acid. The reaction is carried out at room temperature.
CH3CHtwoOH + CH3COOH <=> CH3COOCHtwoCH3 + HtwoOR
The reaction is accelerated by acid catalysis. The equilibrium shifts to the right, that is, towards the production of ethyl acetate, through the removal of water; according to the Law of Mass Action.
Ethyl acetate is also industrially prepared using the Tishchenko reaction, conjugating two equivalents of acetaldehyde with the use of an alkoxide as a catalyst..
2 CH3CHO => CH3COOCHtwoCH3
-Ethyl acetate is synthesized as a co-product in the oxidation of butane to acetic acid, in a reaction carried out at a temperature of 175ºC and 50 atm of pressure. It is used as a catalyst for cobalt and chromium ions.
-Ethyl acetate is a co-product of the ethanolysis of polyvinyl acetate to polyvinyl alcohol..
-Ethyl acetate is also produced in industry through the dehydrogenation of ethanol, catalyzing the reaction through the use of copper at a high temperature, but below 250 ºC..
Ethyl acetate is used as a solvent and diluent, being used in cleaning circuit boards. It is used as a solvent in the manufacture of modified hop extract, and in the decaffeination of coffee and tea leaves. It is used in the inks used to mark fruits and vegetables.
Ethyl acetate is used in the textile industry as a cleaning agent. It is used in the calibration of thermometers, used in the separation of sugars. In the paint industry it is used as a solvent and thinner for the materials used..
It is used in the production of fruit flavors; for example: banana, pear, peach and pineapple, as well as grape aroma, etc..
It is used in the determination of bismuth, boron, gold, molybdenum and platinum, as well as a solvent for thallium. Ethyl acetate has the ability to extract many compounds and elements present in aqueous solution, such as: phosphorus, cobalt, tungsten and arsenic.
Ethyl acetate is used in industry as a viscosity reducer for resins used in photoresist formulations. Used in the production of acetamide, acetyl acetate, and methyl heptanone.
Ethyl acetate is used in laboratories as the mobile phase of column chromatography and as an extraction solvent. As ethyl acetate has a relatively low boiling point, it is easy to evaporate, allowing the substances dissolved in the solvent to be concentrated.
Ethyl acetate is used in entomology to suffocate insects placed in a container, allowing their collection and study. Ethyl acetate vapors kill the insect without destroying it and preventing it from hardening, facilitating its assembly for collection..
-The LDfifty of ethyl acetate in rats indicates low toxicity. However, it can irritate the skin, eyes, skin, nose and throat..
-Exposure to high levels can cause dizziness and fainting. Likewise, long-term exposure can affect the liver and kidneys..
-Inhalation of ethyl acetate at a concentration of 20,000 - 43,000 ppm can cause pulmonary edema and hemorrhage..
-The occupational exposure limit has been set by OSHA at 400 ppm in air, averaged over an 8-hour workshift..
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