Ethyl acetate is called ethyl alcohol of acetic acid, the substance is included in the group of additional substances and in international classification food additives has the index E1504.
Ethyl acetate is a volatile, colorless liquid with a pleasant odor. The formation of ethyl acetate occurs in the process of interaction and (calorizator). It has a low level of volatility and low cost, which provides the substance with a wide range of applications.
Benefits and harms of E1504
In terms of its chemical properties, Ethyl Acetate is similar to acetone, so maximum care must be taken when working with the substance. The maximum permissible level of concentration of Ethyl Acetate in indoor air has been established; it is 200 mg/m3. If this concentration level is exceeded, irritation of the eyes and mucous membranes of the respiratory tract, as well as dermatitis and eczema, may occur.
Application of E1504
In the food industry, Ethyl Acetate is used in the production of soft drinks, liqueurs, confectionery products, and is part of fruit essence.
As a solvent, ethyl acetate is used in book printing, paint and varnish production, the production of poisons, photographic films and smokeless powder. Cosmetology uses Ethyl Acetate to produce manicure products and remove nail coatings.
Use of E1504 in Russia
In the territory Russian Federation The use of E1504 Ethyl Acetate is permitted as a conditionally harmless food additive.
Organic chemistry originated as the chemistry of natural compounds isolated from organisms of animal and plant origin. The filling of various classes of substances with natural compounds is random and determined by biosynthesis (Kartsova A. A., 2005).
The first task of organic synthesis is the artificial production of useful substances by copying natural structures. This is preceded by the stage of isolating a natural compound, studying its properties and, finally, organic synthesis itself - reproducing in a research laboratory what was created in nature’s laboratory. Well, then we need to go further - to synthesize what is absent in nature.
Every day 100 thousand new ones are synthesized in the world chemical compounds, 97% of which account for organic matter.
I decided to consider the synthesis of ethyl acetate using the esterification reaction.
Ethyl acetate is an ethyl acetate that is widely used in medicine and veterinary medicine, in the printing industry; as a solvent to give the necessary consistency to paint, a hardener to fix paint, furniture varnish. It is also used as an extractant organic compounds from aqueous solutions, a gelling agent in the production of explosives; is part of industrial heat-weld adhesive. World production of ethyl acetate 0.45-0.5 million tons per year (1986) (Reed R. et al., 1982)
One of the methods in the ethyl acetate industry is the esterification of acetic acid with ethanol at 110-115 ° C in the presence of sulfuric acid.
Therefore, the goal of my work was to synthesize ethyl acetate using an esterification reaction and study its properties.
Calcium chloride
The synthesis is carried out in the device shown in the figure. Pour 2.5 ml into a 100 ml Wurtz flask equipped with a dropping funnel and connecting to a downward condenser. ethyl alcohol and then carefully add 1.5 ml of concentrated sulfuric acid while stirring. The flask is closed with a stopper into which a dropping funnel is inserted. And heated in an oil (or metal) bath to 140 ° C (the thermometer is immersed in the bath). A mixture of 2 ml of ethyl alcohol and 4.5 ml of glacial acetic acid is gradually poured into the flask from a dropping funnel. The infusion should be carried out at the same speed as the forming ether is distilled off. At the end of the reaction (after the distillation of ether has stopped), the shoulder strap is transferred to a separatory funnel and shaken with concentrated solution baking soda to remove acetic acid. Separate the upper ether layer and shake it with a saturated solution of calcium chloride (to remove alcohol, which with calcium chloride gives the crystalline molecular compound CaCl2 * C2H5OH, insoluble in ethyl acetate). Having separated the ether, it is dried with calcined calcium chloride and distilled in a water bath from a flask with a reflux condenser. At a temperature of 71-75° C, a mixture of alcohol and ethyl acetate will be distilled off; at 75-78° C, almost pure ethyl acetate is transferred. The yield is 20 g (65% theoretical) (G. V. Golodnikov, Mandelstam, 1976).
results
1. Reaction mechanism.
The production of ethyl acetate is based on the esterification reaction, as a result of which ester is formed by heating acetic acid with ethyl alcohol to 140-150 0C in the presence of a catalyst - sulfuric acid.
General reaction equation
The role of the catalyst is to protonate the carbonyl oxygen: in this case, the carbonyl carbon atom becomes more positive and more “vulnerable” to attack by the nucleophilic agent, which is the alcohol molecule. The cation formed initially adds an alcohol molecule at the expense of the unshared electrons of the oxygen atom, giving the cation:
As a result of the removal of a proton, the cation forms an ester molecule;
The use of the “labeled atoms” method made it possible to resolve the issue of where bonds are broken during the esterification reaction. It turned out that usually a water molecule is formed from the hydroxyl acid and the hydrogen of the alcohol. Consequently, in the acid molecule the bond between the acyl and the hydroxyl is broken, and in the alcohol molecule the hydrogen-oxygen bond is broken. This is exactly the conclusion that follows from the results of work on the esterification of benzoic acid with methanol containing the heavy oxygen isotope O18. The resulting ester contained the indicated oxygen isotope:
The presence of O18 was established by burning a sample of ether and analyzing the resulting combustion products (CO2 and H2O) for the presence of a heavy isotope of oxygen (Tyukavkina N.A., Baukov Yu.I., 2004).
The esterification reaction is a reversible process, therefore, in order to avoid hydrolysis of the resulting product, the ether was distilled off using a direct refrigerator.
Hydrolysis of esters is the reverse reaction of their conversion. Hydrolysis can be carried out in both acidic and alkaline environments. For the acid hydrolysis of esters, everything that was said above in relation to the esterification reaction, about the reversibility and mechanism of the process, and about methods for shifting the equilibrium is true. Alkaline hydrolysis of esters goes through the following stages:
Practically alkaline hydrolysis of esters is carried out in the presence of caustic alkalis KOH, NaOH, as well as alkaline earth metal hydroxides Ba(OH)2, Ca(OH)2. The acids formed during hydrolysis are bound in the form of salts of the corresponding metals, so the hydroxides have to be taken at least in an equivalent ratio with the ester. Typically, excess base is used. The separation of acids from their salts is carried out using strong mineral acids.
During synthesis, it is possible to establish chemical equilibrium. According to Le Chatelier's principle, in order to shift the equilibrium towards the formation of the reaction product, the addition of a mixture of ethyl alcohol and glacial acetic acid was carried out at the same rate as the forming ester was distilled off. The synthesis temperature did not exceed 150 0C.
When the temperature rises above the specified value, an intramolecular dehydration reaction may occur:
As a result of the experiment, a colorless liquid with a characteristic odor was obtained. After the ether evolution ceased, the resulting product was transferred to a separatory funnel and shaken with a concentrated soda solution to remove acetic acid.
To remove alcohol, the upper ether layer was separated and shaken with a saturated solution of calcium chloride. Ethyl alcohol with calcium chloride produces a crystalline molecular compound of the composition CaCl2*C2H5OH, insoluble in ethyl acetate. After separating the ether, it was dried with calcined calcium chloride.
2. Research results.
The yield (%) of ethyl acetate in the reaction was calculated. According to the law of conservation of mass and energy, the theoretical yield of ether is 6.3 g (7.0 ml). As a result of the synthesis, 4.5 ml (4.05 g) of ethyl acetate was obtained. The yield of the reaction product (acetic acid ethyl ester) is 64.29%.
To identify and determine the purity of the resulting ethyl acetate, the refractive angle was determined using a refractometer. According to the literature, pure ethyl acetate has a refractive angle of 1.3722 (Reed R. et al., 1982). In our case, the refractive angle of ethyl acetate was 1.3718. This value is close to the reference data, which indicates a sufficient degree of purity of the resulting product.
Ethyl acetate (ethyl acetate) 88 0.9 1.3722 1.3718 64.29
As a result of the synthesis (esterification of acetic acid with ethyl alcohol in the presence of sulfuric acid at a temperature of 140 - 150 0C), an ester was obtained - ethyl acetate, which was a transparent liquid with a characteristic odor. To identify the product, the refractive angle of ethyl acetate was measured (1.3718), which is close to the reference data. The yield of acetic acid ethyl ester was 64.29%.
is a colorless volatile liquid with a pleasant fruity odor. It dissolves in ethanol, diethyl ether, benzene, chloroform, toluene and a number of other organic solvents. It dissolves less well in water (up to 12% by weight), burns well. It has all the properties of esters and is a moderately polar solvent. It dissolves cellulose ethers, resin oil varnishes, fats, and waxes well.Density - 0.902 g/cm³. Melting point -83° C, boiling point 77° C.
Ethyl acetate is produced industrially by distilling a mixture of ethyl alcohol, acetic and sulfuric acids, as well as by treating ethyl alcohol with ketene, or by the Tishchenko reaction from acetaldehyde at 0-5 ° C in the presence of catalytic quantities of aluminum alkoxide.
Chemical formula: C 4 H 8 O 2.
Use of ethyl acetate.
As a solvent, being an active solvent of nitro- and ethylcellulose, it is widely used in the production of paints and varnishes and inks for printing machines. It is also included in the compositions of solvents for nitroglyphthalic, perchlorovinyl and epoxy enamels, various lubricating oils, waxes, polyester varnishes, paints, silicone varnishes and enamels. Up to 30% of all ethyl acetate produced is consumed for these purposes;
As a solvent in the manufacture of adhesive compositions;
At the stage of packaging various goods with flexible packaging materials - as a solvent for films and inks when applying inscriptions and images using a stencil method;
As a reagent and as a reaction medium in the production of pharmaceuticals (methoxazole, hydrocortisone, rifampicin, etc.);
As a degreasing agent in the production of aluminum foil and thin aluminum sheets;
As a cleaning and degreasing agent in the electronics industry;
In the production of film and photographic film, cellophane, various rubber products;
Mixed with alcohol as a solvent in the production of artificial leather;
As an extracting agent for various organic substances from aqueous solutions. Due to its low toxicity, ethyl acetate is used in the food industry, for example, to extract caffeine from coffee;
As a gelling agent in the manufacture of explosives;
As a component (food additive E1504) of fruit essence, which is added to soft drinks, liqueurs and confectionery.
| Indicator name | Standard for brand and variety | ||
| Grade A | Brand B | ||
| Top grade | First grade | ||
| Appearance | Transparent liquid without mechanical impurities | ||
| Color on the platinum-cobalt scale, units. Hazen, no more | 5 | 10 | 10 |
| Density at 20° C, g/cm³ | 0,898-0,900 | 0,897-0,900 | 0,890-0,900 |
| Mass fraction ethyl acetate,% | not less than 99.0 | not less than 98.0 | 91.0±1 |
| Mass fraction of acids in terms of acetic acid, %, no more | 0,004 | 0,008 | 0,010 |
| Mass fraction of non-volatile residue, %, no more | 0,001 | 0,003 | 0,007 |
| Temperature limits for distillation at a pressure of 101.3 kPa (760 mm Hg): 95% (by volume) of the product must be distilled within the temperature range, ° C |
75-78 |
74-79 |
70-80 |
| Mass fraction of water, %, no more | 0,1 | 0,2 | 1,0 |
| Mass fraction of aldehydes in terms of acetaldehyde, %, no more | 0,05 | not standardized | - |
| Relative volatility (based on ethyl ether) | 2-3 | 2-3 | 2-3 |
Safety requirements.
In terms of the degree of impact on the human body, technical ethyl acetate is classified as a low-hazard substance (hazard class 4). Ethyl acetate vapors irritate the mucous membranes of the eyes and respiratory tract. When applied to the skin it causes dermatitis and eczema. The maximum permissible concentration in the air of the working area is 200 mg/m⊃3.
Technical ethyl acetate is a flammable liquid and, when mixed with air, forms an explosive mixture of category PA, group T2 according to GOST 12.1.011.
Packaging, transportation and storage.
Technical ethyl acetate is poured into galvanized steel barrels, aluminum barrels, railway and automobile tanks.
Transportation is carried out in barrels by rail or road transport in covered vehicles, railway tanks, tank trucks in compliance with the rules for the transportation of dangerous goods in force for this type of transport.
Technical ethyl acetate is stored in warehouses or in specially equipped metal containers in compliance with the rules for storing flammable substances.
Guaranteed shelf life is six months from the date of manufacture.
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Structural formula
True, empirical, or gross formula: C4H8O2
Molecular weight: 88.106
Ethyl acetate- (ethyl ester of acetic acid) CH 3 -COO-CH 2 -CH 3 - colorless volatile liquid with a pungent odor.
Receipt
Ethyl acetate is formed by direct reaction of ethanol with acetic acid:
CH 3 COOH + C 2 H 5 OH → CH 3 COOC 2 H 5 + H 2 O
A laboratory method for producing ethyl acetate involves acetylation of ethyl alcohol with acetyl chloride or acetic anhydride:
CH 3 COCl + C 2 H 5 OH → CH 3 COOC 2 H 5 + HCl
Industrial methods for the synthesis of ethyl acetate include:
Distillation of a mixture of ethyl alcohol, acetic and sulfuric acids. Treatment of ethyl alcohol with ketene. According to the Tishchenko reaction from acetaldehyde at 0-5 °C in the presence of catalytic quantities of aluminum alkoxide:
2CH 3 CHO → CH 3 COOC 2 H 5
Physical properties
Colorless mobile liquid with a pungent odor of ether. Molar mass 88.11 g/mol, melting point −83.6 °C, boiling point 77.1 °C, density 0.9001 g/cm³, n204 1.3724. Dissolves in water 12% (by weight), in ethanol, diethyl ether, benzene, chloroform; forms double azeotropic mixtures with water (bp 70.4 °C, water content 8.2% by weight), ethanol (71.8; 30.8), methanol (62.25; 44.0), isopropanol (75.3; 21.0), CCl4 (74.7; 57), cyclohexane (72.8; 54.0) and a ternary azeotropic mixture of E: water: ethanol (bp 70.3 °C, content respectively 83.2, 7.8 and 9% by weight).
Application
Ethyl acetate is widely used due to its low cost and low toxicity, as well as its acceptable odor. In particular, as cellulose nitrates, cellulose acetate, fats, waxes, for cleaning printed circuit boards, mixed with alcohol - in the production of artificial leather. Annual world production in 1986 was 450-500 thousand tons. World production of ethyl acetate in 2014 is about 3.5 million tons per year.
One of the most popular poisons used in entomological stains to kill insects. Insects after killing in its vapors are much softer and more pliable in dissection than after killing in chloroform vapors. Used as a component of fruit essences. Registered as a food additive E1504.
Laboratory Application
Ethyl acetate is often used for extraction and for column and thin layer chromatography. Rarely used for reactions due to the tendency to hydrolysis and transesterification. Used to produce acetoacetic ester:
2CH 3 COOC 2 H 5 → CH 3 COCH 2 COOC 2 H 5
Cleaning and drying
Commercial ethyl acetate typically contains water, alcohol, and acetic acid. To remove these impurities, it is washed with an equal volume of 5% sodium carbonate, dried with calcium chloride and distilled. For higher water content requirements, phosphorus anhydride is added several times (in portions), filtered and distilled, protecting from moisture. Using a 4A molecular sieve, the water content of ethyl acetate can be reduced to 0.003%.
Safety
The LD 50 for rats is 11.6 g/kg, indicating low toxicity. Ethyl acetate vapors irritate the mucous membranes of the eyes and respiratory tract and cause dermatitis and eczema when exposed to the skin. The maximum permissible concentration in the air of the working area is 200 mg/m³. MPC in atmospheric air populated areas 0.1 mg/m³. Flash point - 2 °C, auto-ignition temperature - 400 °C, concentration limits of vapor explosion in air 2.1-16.8% (by volume). Safety during transportation. In accordance with ADR (ADR), hazard class 3, UN code 1253.
Ethyl acetate is a flammable, colorless liquid with a pleasant odor. The product is an ester of acetic acid and has all the chemical properties characteristic of this group of compounds.
Specifications
Parameters of ethyl acetate according to GOST 8981-78.
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Index |
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Top grade |
First grade |
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Appearance |
Transparent liquid without mechanical impurities |
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Density of ethyl acetate, g/cm3 |
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Chromaticity, Hazen units |
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Mass fraction of acids in terms of acetic acid, % |
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Mass fraction of the main substance, % |
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Mass fraction of non-volatile residue, % |
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Mass fraction of water, % |
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Mass fraction of aldehydes in terms of acetic acid, % |
Not marked |
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Physical properties
Ethyl acetate is miscible in any proportion with toluene, benzene, chloroform, ethanol and other organic solvents. The substance is moderately polar. Limited soluble in water. Water dissolves in ethyl acetate up to 9.7% wt. The main component of the product composition quickly hydrolyzes in an alkaline environment to acetic acid and ethanol. The formation of azeotropic mixtures of solvent with ethanol, isopropyl alcohol, carbon tetrachloride, and cyclohexane is possible. Ethyl acetate has low toxicity. Vapors in high concentrations cause irritation of mucous membranes. If the substance comes into contact with the skin, dermatitis may develop, so gloves must be used when using ethyl acetate.
Application
Ethyl acetate can be used as a solvent for resin oil paints, waxes, fats, and cellulose ethers. The substance can also be used in the following cases.
- Dissolution of film-forming substances, pigments in the production of varnishes and paints, inks for printing machines.
- Production of multicomponent adhesives.
- Dissolution of ink when applying images and inscriptions using a stencil method on packaging materials.
- Creation of a reaction environment in the production of drugs.
- Cleaning and degreasing of surfaces in the electronics industry.
- Extraction of organic components from aqueous solutions (for example, caffeine from coffee).
- Gelatinization of explosives.
- Production of fruit essences, etc.
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