Ethyl acetate preparation. Ethyl acetate (ethyl acetate)

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 chemical compounds are synthesized in the world, 97% of which are organic substances.

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 of organic compounds from aqueous solutions, a gelatinizing 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. 2.5 ml of ethyl alcohol is poured into a 100 ml Wurtz flask, equipped with a dropping funnel and connecting to a downward condenser, and then 1.5 ml of concentrated sulfuric acid is carefully added with 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 product is transferred to a separating funnel and shaken with a concentrated solution of 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 an 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 precisely 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 an ethyl ester of ethanoic acid in the form of a flammable, colorless, volatile liquid substance with a pungent odor of fruit. There are no mechanical impurities. It is a moderately polar solvent product with the properties of esters. Can be dissolved in methyl carbinol, ethyl ether, benzene, methyl trichloride, methylbenzene and some other organic solvents. As for water, the dissolution in it is weaker. It itself has a dissolving effect on cellulose ethers, oil-based resin varnishes, fats and waxes.

Molar mass – 88.11 g/mol, density – 0.902 g/cm³. Thermal properties: melting temperature – -83 °C, boiling temperature – 77 °C. Formula: C 4 H 8 O 2.

Receipt in industry scale occurs during the reaction of ethanol and acetic acid. It is also possible to treat ethanol with carbomethylene or synthesize it from acetaldehyde in the presence of an aluminum alkoxide catalyst.

Applications of ethyl acetate

The main role of this substance is dissolving (this takes up a third of all ethanoic acid ethyl ester produced). It is preferred among other solvents due to its low price, low toxicity and quite tolerable odor. It is used to dissolve nitro- and cellulose acetate, waxes and fats, nitroglyphthalic, perchlorovinyl, epoxy, polyester, silicone varnishes, paints, enamels, and also clean printed circuit boards. Thus, it is used in the production of LC materials, adhesive compositions and inks for printing equipment. When packaging goods using all kinds of flexible packaging materials, it is taken for dissolution during the stencil application of inscriptions and drawings. Together with alcohol, ethyl acetate as a solvent is used, among other things, in the manufacture of artificial leather.

It is also the most popular pesticide. It is part of entomological stains (the task is to kill insects). Compared to the same chloroform, which is used for a similar purpose, ethyl acetate softens the object of influence more and makes it more pliable in preparation.

This substance is used due to its low toxicity and as a component of fruit essences. This is a well-known food additive E1504. It is added to cooling drinks, liqueurs and various confectionery products. It is used to extract caffeine from coffee.

In laboratory practice, it is used in extraction to pull out the organ. substances from aqueous solutions and chromatography (column and thin layer). Sometimes acts as a solvent in some chemicals. reactions. The rarity of such use is explained by the tendency to solvolysis with water and transesterification.

Pharmacists use it as a reaction medium for the manufacture of a number of drugs: methoxazole, hydrocortisone, rifampicin, etc.

Ethyl acetate is a participant in the synthesis of acetoacetic acid ethyl ester.

When creating explosives, it acts as a gelatinizer. In the electronics industry, when creating aluminum foil and thin sheets of aluminum - as a cleaner and disinfectant. It is also used in the creation of photographs, films, cellophane, and all kinds of technical materials. rubber products .

Ethyl acetate in industry

Ethyl acetate, or ethanoic acid ester, is widely used in various industries. industries, performing a large list of tasks:

– in paint and varnish, glue, pulp production and the production of artificial leather, ink for typewriters acts as a solvent. The solvent also acts when applying ink drawings and inscriptions to packaging materials;

– in the pharmaceutical industry it serves as a reagent and reaction medium in the manufacture of drugs;

– in the creation of aluminum foil and thin sheets of aluminum – with a degreaser;

– in the electronics industry it is also used for degreasing and also for cleaning;

– in the food industry it is a popular extractant (for example, it helps extract caffeine from coffee). In addition, it is used in the creation of cooling drinks, liqueurs, confectionery and fruit essences;

– in the production of explosives – gelatinizer;

– in the cosmetics industry it is introduced into manicure products, in particular for removing varnish from nails.

This breadth of application is due to the relative low cost, low toxicity and efficiency in each of the above processes.

Due to its high efficiency and functionalism, taking into account its low toxicity, ethyl acetate has become so widely used.

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.

Physico-chemical characteristics of ethyl acetate GOST 8981-78:

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 of 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 mmHg): 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.

It is highly soluble in alcohol, chloroform and ether, less soluble in water, burns well, and has a maximum explosive concentration in air of 2.2 - 9%. This is a solvent that has low cost, low toxicity, and has an acceptable odor.

Ethyl acetate is obtained from:

Acetylation of ethyl alcohol with acetyl chloride or acetic anhydride. (Laboratory method)
. distillation of a mixture of ethyl alcohol, acetic and sulfuric acids. (Industrial method).
. treatment of ethyl alcohol with ketene. (Industrial method).
. according to the Tishchenko reaction from acetaldehyde at 0-5 °C in the presence of catalytic quantities of aluminum alkoxide. (Industrial method)

Technical characteristics of ethyl acetate .

The name of indicators	Norm
Appearance of ethyl acetate	colorless, transparent liquid, free of mechanical impurities
Density of ethyl acetate at 20 °C, g/cm*3	0,898-0,900
Hasen unit chromaticity	5
Mass fraction of the main substance, %, not less	99,0
Mass fraction of acetic acid, %, no more	0,004
Mass fraction of non-volatile residue, %, no more	0,001
Temperature limits for the distillation of ethyl acetate at a pressure of 760 mm. rt. Art., °С	75-78
Mass fraction of water, %, no more	0,1
Relative volatility (based on ethyl ether)	2-3
Mass fraction of ethyl alcohol	absent

Characteristics of ethyl acetate by brands and varieties.

Indicator name	Ethyl acetate
	A		B
	premium	1st grade
Appearance	Transparent liquid without mechanical impurities
Color, Halen units, max.	5	10	10
Density at 20 0C, g/cm3	0,898-0,900	0,897-0,900	0,890-0,900
Mass fraction of the main substance, %	at least 99	at least 98	91±1
Mass fraction of acids in terms ofacetic acid,%, no more	0,004	0,008	0,01
Mass fraction of non-volatile residue, %, no more	0,001	0,003	0,007
Distillation temperature limits atpressure 101.3 kPa 93% (by volume)the product must be distilled withintemperature, 0С	75-78	74-79	70-80
Mass fraction of water, % no more	0,1	0,2	1
Mass fraction of aldehydes inrecalculation onacetaldehyde, % no more	0,05	not marked	-

Ethyl acetate is used in the following industries:

As a solvent in the production of paints and varnishes and inks for printing machines;
. as a solvent in the manufacture of adhesive compositions;
. at the stage of packaging various goods with flexible packaging materials - as an ink solvent when applying inscriptions and images using a stencil method;
. as a reagent and as a reaction medium in the production of pharmaceuticals (methoxazole, 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;
. as a solvent for cellulose ethers;
. 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 gelatinizing agent in the manufacture of explosives;
. as a component of fruit essences;

$\backslash mathsf(CH\_3COCl\; +\; C\_2H\_5OH\; \backslash rightarrow\; CH\_3COOC\_2H\_5\; +\; HCl)$

Industrial methods for the synthesis of ethyl acetate include:

1. Distillation of a mixture of ethyl alcohol, acetic and sulfuric acids.
2. Treatment of ethyl alcohol with ketene.
3. According to the Tishchenko reaction from acetaldehyde at 0-5 °C in the presence of catalytic quantities of aluminum alkoxide:

$\backslash mathsf(2CH\_3CHO\; \backslash rightarrow\; CH\_3COOC\_2H\_5)$

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, n 20 4 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 as a solvent, due to its low cost and low toxicity, as well as its acceptable odor. In particular, as a solvent for cellulose nitrates, cellulose acetate, fats, waxes, for cleaning printed circuit boards, mixed with alcohol - a solvent 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.

Used as a component of fruit essences. Registered as a dietary supplement E1504 .

Laboratory Application

Ethyl acetate is often used for extraction, as well as for column and thin layer chromatography. Rarely used as a reaction solvent due to its tendency to hydrolysis and transesterification.

Used to produce acetoacetic ester:

$\backslash mathsf(2CH\_3COOC\_2H\_5\; \backslash rightarrow\; CH\_3COCH\_2COOC\_2H\_5)$

Cleaning and drying

Commercial ethyl acetate usually 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

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.

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Notes

Excerpt characterizing Ethyl Acetate

- Maybe? - she said.
The princess's face changed. She sighed.
“Yes, I guess,” she said. - Ah! It's very scary…
Lisa's lip dropped. She brought her face closer to her sister-in-law's and suddenly began to cry again.
“She needs to rest,” said Prince Andrei, wincing. – Isn’t it true, Lisa? Take her to your place, and I’ll go to the priest. What is he, still the same?
- Same, same; “I don’t know about your eyes,” the princess answered joyfully.
- And the same hours, and walks along the alleys? Machine? - Prince Andrei asked with a barely noticeable smile, showing that despite all his love and respect for his father, he understood his weaknesses.
“The same clock and machine, also mathematics and my geometry lessons,” Princess Marya answered joyfully, as if her geometry lessons were one of the most joyful experiences of her life.
When the twenty minutes that were needed for the old prince to get up had passed, Tikhon came to call the young prince to his father. The old man made an exception to his lifestyle in honor of his son’s arrival: he ordered him to be allowed into his half while dressing before dinner. The prince walked in the old fashion, in a caftan and powder. And while Prince Andrei (not with that grumpy expression and manners that he assumed in the living rooms, but with that animated face that he had when he talked with Pierre) entered his father, the old man was sitting in the dressing room on a wide, morocco upholstered chair, in a powder room, leaving his head in Tikhon’s hands.
- A! Warrior! Do you want to conquer Bonaparte? - said the old man and shook his powdered head, as much as the braided braid in Tikhon’s hands allowed. “At least take good care of him, otherwise he’ll soon write us down as his subjects.” - Great! - And he stuck out his cheek.
The old man was in good spirits after a pre-dinner nap. (He said that after lunch there is a silver dream, and before lunch there is a golden dream.) He joyfully glanced sideways at his son from under his thick, overhanging eyebrows. Prince Andrei came up and kissed his father in the place he indicated. He did not answer his father’s favorite topic of conversation - making fun of the current military people, and especially Bonaparte.
“Yes, I came to you, father, and with my pregnant wife,” said Prince Andrei, watching with animated and respectful eyes the movement of every feature of his father’s face. – How is your health?
“Unhealthy, brother, there are only fools and libertines, but you know me: busy from morning to evening, abstinent, and well, healthy.”
“Thank God,” said the son, smiling.
- God has nothing to do with it. Well, tell me,” he continued, returning to his favorite hobby, “how the Germans taught you to fight with Bonaparte according to your new science, called strategy.
Prince Andrei smiled.
“Let me come to my senses, father,” he said with a smile, showing that his father’s weaknesses did not prevent him from respecting and loving him. - After all, I haven’t settled in yet.
“You’re lying, you’re lying,” the old man shouted, shaking his braid to see if it was braided tightly, and grabbing his son’s hand. - The house is ready for your wife. Princess Marya will take her and show her and talk a lot about her. This is their woman's business. I'm glad for her. Sit and tell me. I understand Mikhelson’s army, Tolstoy too... a one-time landing... What will the Southern Army do? Prussia, neutrality... I know that. Austria what? - he said, getting up from his chair and walking around the room with Tikhon running and handing pieces of clothing. - Sweden what? How will Pomerania be transferred?
Prince Andrei, seeing the urgency of his father’s demand, at first reluctantly, but then more and more animated and involuntarily, in the middle of the story, out of habit, switching from Russian to French, began to outline the operational plan of the proposed campaign. He told how an army of ninety thousand had to threaten Prussia in order to bring it out of neutrality and draw it into the war, how part of these troops had to unite with the Swedish troops in Stralsund, how two hundred and twenty thousand Austrians, in conjunction with one hundred thousand Russians, had to act in Italy and on the Rhine, and how fifty thousand Russians and fifty thousand Englishmen would land in Naples, and how, as a result, an army of five hundred thousand had to attack the French from different sides. The old prince did not show the slightest interest in the story, as if he was not listening, and, continuing to get dressed as he walked, unexpectedly interrupted him three times. Once he stopped him and shouted:
- White! white!
This meant that Tikhon did not give him the vest he wanted. Another time he stopped and asked:
- And will she give birth soon? - and, shaking his head reproachfully, said: - Not good! Keep going, keep going.
The third time, when Prince Andrei was finishing the description, the old man sang in a false and senile voice: “Malbroug s"en va t en guerre. Dieu sait guand reviendra." [Malbroug is getting ready to go on a campaign. God knows when he will return.]
The son just smiled.
“I’m not saying that this is a plan that I approve,” said the son, “I just told you what it is.” Napoleon had already drawn up his own plan no worse than this.