Experiment # 4:

Preparation of Ethyl

acetate

Date: 19-10-10

Muhammad Usman

(2008-chem-02-B)

1. Ethanol:

Harmful: Pure Ethanol will irritate the skin and eyes. Nausea, vomiting and intoxication

are symptoms of ingestion. Long term use by ingestion can result in serious liver

damage. Death from Ethyl alcohol consumption is possible when blood alcohol

level reaches 0.4%.

A blood level of 0.5% or more is commonly fatal. Levels of even less than 0.1%

can cause intoxication, with unconsciousness often occurring at 0.3–0.4%

Highly flammable: It has a flash point of 13

oC. It can readily catch fire. So care should be taken

while handling it because its combustion products include Acetaldehyde which

is a strongly carcinogenic substance. However, ethanol itself is not cancer

causing.

Properties of Ethanol:

IUPAC Name Ethanol

Other names

Absolute alcohol

Drinking alcohol

Ethyl alcohol

Ethyl hydrate

Grain alcohol

Hydroxy-Ethane

Appearance Colorless liquid

Structure

Molecular formula C2H6O

Molar mass 46.07 g mol-1

Density 0.789 g cm-3

Melting point -114.3 oC

Boiling point 78.4 oC

Solubility in water Miscible

Acidity (Pka) 15.9

Flash point 13 oC

Auto-ignition temperature 422 oC

2. Sulphuric acid:

Corrosive:

It is a strongly corrosive compound as it readily oxidizes anything.

Dangerous to Environment:

Although sulfuric acid is non-flammable, contact with metals in the event of a

spillage can lead to the liberation of hydrogen gas. The dispersal of acid aerosols

and gaseous sulfur dioxide is an additional hazard of fires involving sulfuric acid.

Very toxic:

Sulfuric acid is not considered toxic besides its obvious corrosive hazard, and the

main occupational risks are skin contact leading to burns and the inhalation of

aerosols. Exposure to aerosols at high concentrations leads to immediate and severe irritation of the eyes,

respiratory tract and mucous membranes.

Properties of sulfuric acid:

IUPAC name Sulfuric acid

Other names Oil of vitriol

Structure

Molecular formula H2SO4

Molar mass 98.06 g/gmol

Appearance

Density 1.84 g/cm3 (liquid)

Melting point 10 oC

Boiling point 337 oC

Solubility in water Miscible

Acidity (Pka) -3

Viscosity 26.7 cP (20 oC)

Flash point Non- flammable

3. Sodium Carbonate:

Irritant:

Skin Contact:

Excessive contact may cause irritation with blistering and redness. Solutions may

cause severe irritation or burns.

Eye Contact:

Contact may be corrosive to eyes and cause corneal destruction. Risk of serious

injury increases if eyes are kept tightly closed. Other symptoms may appear from

absorption of sodium carbonate into the bloodstream via the eyes.

Toxic:

Sodium carbonate is only slightly toxic, but large doses may be corrosive to the

gastro-intestinal tract where symptoms may include severe abdominal pain,

vomiting, diarrhea, collapse and death.

Inhalation:

Inhalation of dust may cause irritation to the respiratory tract. Symptoms from

excessive inhalation of dust may include coughing and difficult breathing.

Properties of Na2CO3:

IUPAC name Sodium Carbonate

Other names

Soda ash

Washing soda

Soda crystals

Structure

Molecular formula Na2CO3

Molar mass 105.9884 g/mol (anhydrous)

Appearance

Density 2.54 g/cm3 (anhydrous)

Melting point 851 oC (anhydrous)

Boiling point 1600 oC (anhydrous)

Solubility in water 22 g/100 ml (20 oC)

Basicity (Pkb) 3.67

Solubility Insoluble in Alcohol , Ethanol

Flash point Non-Flammable

4. Glacial Acetic acid:

Harmful:

Dilute acetic acid, in the form of vinegar, is harmless.

However, ingestion of stronger solutions is dangerous to human and animal life.

It can cause severe damage to the digestive system, and a potentially lethal

change in the acidity of the blood.

Flammable:

Concentrated acetic acid can be ignited with difficulty in the laboratory. It

becomes a flammable risk if the ambient temperature exceeds 39 °C (102 °F),

and can form explosive mixtures with air above this temperature (explosive

limits: 5.4–16%).

Corrosive:

Concentrated acetic acid is corrosive and must be handled with appropriate care,

since it can cause skin burns, permanent eye damage, and irritation to the

mucous membranes. These burns or blisters may not appear until hours after

exposure. Latex gloves offer no protection, so especially resistant gloves, such

as those made of nitrile rubber, are worn when handling the compound.

Properties of Glacial Acetic acid:

Glacial acetic acid is a trivial name for water-free acetic acid.

IUPAC name Acetic acid

Other names Acetyl hydroxide, Ethylic acid, Hydrogen

acetate, Methane-carboxylic acid

Structure

Molecular formula CH3COOH

Molar mass 60.05 g mol-1

Appearance Colorless liquid

Density 1.049 g/cm

3 (l)

1.266 g/cm3 (s)

Melting point 16.5 °C, 290 K, 62 °F

Boiling point 118.1 °C, 391 K, 245 °F

Solubility in water Fully miscible

Acidity (Pka) 4.76 at 25oC

Viscosity 1.22 mPa.S at 25oC

Flash point 43 °C

Preparation of ethyl acetate

Chemicals Required:

1. C2H5OH 2. CH3COOH

3. H2SO4 (Concentrated) 4. Na2CO3 (30%)

Apparatus:

1. Round Bottom Flask 2. Condenser

3. Knee tube 4. Adopter

5. Separating funnel 6. Beaker

7. Conical flask 8. Wire gauze

Chemical Reaction:

C2H5OH + CH3COOH CH3COOC2H5 + H2O

Procedure:

1. Mix 25 ml of Ethanol & 25 ml of Glacial acetic acid thoroughly in a round bottom flask.

2. Add slowly with cooling & shaking 15 ml of concentrated H2SO4. Ensure that the liquid is

homogenous.

3. Fit the flask with a heat flux water condenser & boil the mixture gently over wire gauze for 10

minutes.

4. Now alter the position of the condenser & distill of about 2/3 of mixture. Then transfer the

distillate to a separating funnel.

5. Add about 12.5 ml of 30% Na2CO3 solution in separating funnel.

6. Cork the funnel & shake carefully in order to neutralize the free acetic acid & H2SO4.

7. Due to the addition of Na2CO3, CO2 will be formed which should be removed by removing the

cork at frequent intervals.

8. Two layers will be formed. Allow the two layers to separate & carefully run off & eject the lower

aqueous layer.

Uses of ethyl acetate:

1. Commercial uses:

In the field of Entomology, ethyl acetate is an effective chemical for use in insect collecting and study. In

a killing jar charged with ethyl acetate, the vapors will kill the collected (usually adult) 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.

2. Laboratory uses:

In the laboratory, mixtures containing ethyl acetate are commonly used in column chromatography and

extractions.

Industrial production of Ethyl acetate:

Industrially Ethyl acetate is prepared from following procedure.

Feed tank:

The raw materials are first blended in correct proportion in a vessel called feed tank.

Pre-heater:

Raw materials in the form of a steady stream are fed to the esterifying column through a pre-heater unit.

Here the temperature of feed is increased.

Esterification column:

Feed is introduced into the column from side. Here via chemical reaction feed is converted into products

i.e. ethyl acetate along with some higher esters due to the presence of other acids as impurities along with

acetic acid.

From the top of the column the mixture is taken off whose composition is following.

Ester……………………….20%

Water……………………...10%

Alcohol……………………70%

Separating column:

The ternary mixture taken off passes to the separating column at point “B” here it is rectified by the

closed steam.

Part of the condensate is

1. Reflux back to top of column

2. Take off goes to the proportional mixing device

Proportional mixing device:

Mixture is blended with about an equal volume of water which causes a separation into two layers.

Separating tank:

These layers are separated out in separator tank. Watery portion overflows back to the lower portion of

the separating column where it is blended with alcohol and water accumulating in the base of the column.

The watery portion through a pipe “D” is fed to the Esterification column. On the lower plates of column,

the alcohol is exhausted and distills upward as vapor while the slop water goes to waste at “E”.

Product recovery section:

1. Drying column:

The washed ester, containing a little dissolved water and alcohol, overflows from the separator and enters

a drying column in which a sufficient amount is distilled off to carry with it water and alcohol.

Dry ethyl acetate is collected at the bottom of the column.

2. Cooler:

Here the product ethyl acetate is cooled to bring it at required temperature.

3. Storage tank

Finally prepared ethyl acetate is stored into this tank.

References:

1. Unit processes in organic synthesis by P.H. Groggins

5th edition, page 729-730

2. Wikipedia

http://en.wikipedia.org/wiki/ethyl_acetate/