There are many synthetic methods of ethyl acetate, for example, it can be prepared by the reaction of acetic acid or its derivatives with ethanol, or it can be synthesized by the reaction of sodium acetate with haloethane. Among them, the most commonly used method is the direct esterification of acetic acid and ethanol catalyzed by acid.

Keywords: acetic acid, ethanol, concentrated sulfuric acid, ethyl acetate.

Introduction: Ethyl acetate is also called ethyl acetate. Pure ethyl acetate is a colorless, transparent and pungent liquid, and it is a fine chemical product with a wide range of uses. It is a very important organic chemical raw material and an excellent industrial solvent, and is widely used to produce acetate fiber, ethyl fiber, chlorinated rubber, vinyl resin, acetate fiber resin, synthetic rubber, coatings and paints. Its main uses are: as an industrial solvent, used in coatings, adhesives, ethyl cellulose, artificial leather, linoleum colorants, artificial fibers and other products; As an adhesive, it is used to produce printing ink and artificial pearls; As an extractant, it is used to produce drugs, organic acids and other products; As a spice raw material, it is used as the main raw material of pineapple, banana, strawberry and other fruit flavors and whiskey, cream and other spices. The old wine we are talking about tastes good because it contains ethyl acetate. Ethyl acetate has a fruity taste. Because wine contains a small amount of acetic acid, it reacts with ethanol to produce ethyl acetate. Because this is a reversible reaction, it takes a long time to accumulate ethyl acetate and lead to the aroma of aged wine.

First, the experimental principle

The esterification reaction is reversible, and the measures to improve the yield are: on the one hand, adding excessive ethanol, on the other hand, constantly steaming out products and water during the reaction process, so as to promote the equilibrium to move towards esterification.

The temperature should be controlled between 1 10 ~ 120℃ and not too high, because both ethanol and acetic acid are volatile.

This is a reversible reaction, and the ethyl acetate produced is hydrolyzed into acetic acid and ethanol under the same conditions. In order to obtain higher ester yield, it is usually done by increasing the amount of acid or alcohol and continuously removing ester or water from the product. In this experiment, reflux device and excessive ethanol were used to improve the yield of ester.

After the reaction is completed, the incompletely reacted CH3COOH CH3CH2OH and H2O produced in the reaction are removed by saturated Na2CO3, saturated Cacl2 and anhydrous Na2SO4 (solid) respectively.

Second, the process flow

Feeding → reflux → distillation → washing → extraction → drying → rectification → calculation of yield.

Third, instruments and reagents

1. Instruments: iron frame, round bottom flask, distillation flask (with branch pipe), spherical condenser tube, straight condenser tube, rubber tube, thermometer, separating funnel, small triangular flask and beaker.

2. Reagents: glacial acetic acid, 95% ethanol, saturated Na2CO3 solution, saturated Nacl solution, solid anhydrous Na2SO4, zeolite and saturated Cacl2 solution.

Fourth, the experimental steps

1, ready

Add 19 ml absolute ethanol, 12 ml glacial acetic acid and 2 ml concentrated sulfuric acid into a 50 ml round-bottomed flask, add a few grains of zeolite, shake well, install a spherical condenser tube, heat it on an electric heating jacket with low fire, reflux for 30 minutes, stop heating, cool, remove the spherical condenser tube, install a distillation head, modify the instrument into a common distillation device, and heat and distill until.

Step 2 purify

The distillate contains ethyl acetate and a small amount of ethanol, ether, water and acetic acid. After shaking for 30 minutes, slowly add about 10ml saturated sodium carbonate solution until no carbon dioxide gas overflows, then move it into a separating funnel, shake it fully (pay attention to timely venting), stand still, separate the lower water phase, wash the ester layer with 10ml saturated salt solution, then wash it twice with 10ml saturated calcium chloride solution respectively, and discard the lower layer.

Filtering the dried ethyl acetate into a clean distillation bottle, adding zeolite, distilling on an electric heating jacket, and collecting fractions at 73-78 DEG C..

The boiling point of pure ethyl acetate is 77.06℃, and the refractive index is 1.3723.

1 2 3 4

Ethanol (ml)19191212

Acetic acid (ml)12121912

Concentrated sulfuric acid (ml) 2 2 2 2

Reaction time (minutes) 45 30 30 30

Five, the experimental device

Experimental results of intransitive verbs

Ethanol (ml)19191212

Acetic acid (ml)12121912

Reaction time (minutes) 45 30 30 30

Ethyl acetate (ml)11.3013.0312.07 9.43

Yield (%) 52.87 60.96 60.05438+0 44.5438+02.

The refractive index is1.37021.37301.37321.4647.

Calculate output output = or output =

Seven. abstract

The method of preparing ethyl acetate by direct esterification of ethanol and acetic acid catalyzed by acid is relatively simple and easy. But the esterification reaction is reversible, so it is necessary to find a better design scheme to improve the yield.

We can adopt the following measures to improve the yield: on the one hand, adding excessive ethanol, on the other hand, constantly steaming out products and water during the reaction process, and promoting the balance to move towards the direction of ester formation. But the boiling point of ester and water or ethanol is close to that of ethanol. In order to distill ester and water, and to distill ethanol as little as possible, a long fractionator can be used for fractionation. However, due to the limited laboratory conditions, no fractionator was used in the experiment, which left some shortcomings for the experiment.