ESTER

 

BASIC CHEMICAL PRACTICAL REPORT

ESTER

AIM
1. Synthesize at least 3 ester types.
2. Determine the effect of alcohol concentration on equilibrium reaction on ester manufacture.
3. Determine the effect of carboxylic acid on the reaction.
4. balance the preparation of esters.
5. Know the typical smell of several kinds of esters.
6. Using ester as a material for making soap.
7. Knowing the principle of saponification.
8. Make various soaps for washing and cosmetics.
9. Testing the working power of soap in a container water.

THEORETICAL BASIS

Esters are prepared from carboxylic acids and l-ester by esterification reaction with the aid of concentrated H 2 SO 4 catalyst. The esterification reaction is actually an equilibrium reaction.

The esterification reaction is reversible. In order to obtain a high yield of the ester, the equilibrium should be slid towards the ester side. A technique for achieving this is to use one of the cheaper reagents excessively. Another technique is to remove one product from within the reaction mixture (eg by azeotropic distillation).

(Hiskia, ahmad, 2001: 76)

Uses of Esther

1) Short chain ester compounds (esters derived from carboxylic acids and lower ethnic alcohols) are present in fruits that give rise to the aroma of the fruit, which is called the fruit ester. This ester compound is widely used as flavoring or essences.

The aroma of bananas on food or drink can be obtained by adding amyl acetate ester. Benzil Acetate gives a strawberry scent on food or beverage. In addition it is also used as a solvent on the manufacture of paint, nail polish, and adhesive.

2) Amyl acetate is widely used as a solvent for resins and lacquers.

3) Esterification of ethylene glycol with 1.4 dicarboxylic bensen acid to produce polyester used as fabric material.

4) Esters derived from glycerol with low or high-carboxylic acid (oils and fats). Used as raw material for making soap and butter (margarine).

5) Esters of high ethnic alcohols and high ethoxylated carboxylic acids, these esters are called waxes, these waxes are different from hydrocarbon waxes (paraffin wax). Its purpose is to polish car and floor.

(The drafting team, 2012: 75-76)

Esters or alkyl alkanoates, are alkane derived compounds with functional groups -COO- and CnH2nO2 general formula. Esther is one of the special compounds because

General formula of a carboxylate ester

Can be found both in fruits, candles, and fats. Esther also has a fragrant smell so much used by humans in various fields. Esters are named alkyl alkanoates, wherein the alkyl is a carbon group attached to the O (R ') and alkanoate is the R-COO-group.

The formula for determining the ester nomenclature is based on several things:

1. The parent chain is the longest chain containing alkanoate groups.

2. Numbering starts from the first C atom bound to the O atom.

The formula for determining the nomenclature of ester compounds in general is:

(No.cabang) (branch name) (the name of the parent chain)

Example:

CH3-CH2-COO-CH2-CH3: ethyl propanoate

CH3-CH2-CH2-CH2-COO-CH 3: methyl pentanoate

CH3-CH2-COO-CH2-CH (CH3) -CH 3: 2-methyl propyl propanoate

Esther has several properties, namely:

1. Physical Properties

· More polar than ether but less polar than alcohol

· The longer the chain, the more insoluble the ester in water

In hydrogen bonding, the ester acts as a hydrogen acceptor, but can not act as a hydrogen donor

· More volatile than carboxylic acids of the same molecular weight

2. Chemical Properties

· Can experience hydrolysis

· Can experience a sapling reaction

Ester reactions:

1. Hydrolysis

Esters are hydrolyzed in acidic atmosphere to form alcohols and carboxylic acids. This hydrolysis reaction is the inverse of esterification / ester formation. The reactions can be written as:

CH3-COO-C2H5 + H2O → CH3COOH + C2H5OH

3. Saponification / sapling

Esters, especially fat and oil esters, may react with strong bases such as NaOH or KOH resulting in soap. This reaction is called saponification or saponification. The side product of this reaction is glycerol.

Based on the type of acid and the constituent alcohol, the esters can be grouped into 3 groups, ie fruit esters, waxes, and fats and oils. Here are the three groups:

1. Fruit Ester

Esters of low-grade carboxylic acids with low-tribal alcohols will form esters with 10 or less C.sub.E. at these room temperatures will be in the form of a volatile liquid and have a distinctive aroma. Because many are found in fruits or flowers, this type of ester is called a fruit ester.

2. Candles

Candles or waxes are esters of long chain carboxylic acids with long chain alcohols as well. Some types of candles are example:

Beeswax from honeycomb has the formula C22,25H47,51 COOC32,34H65,69

Spermacet from the whale's head cavity has the formula C15H31COOC16H33

Carnacauba from Brazilian palm leaves has the formula C25,27H51,55 COOC30,32H61,65

However, it should be noted that the wax is not a candle that is often used when the lights are off, because the candle belongs to the paraffin hydrocarbon group, not the ester.

3. Fat and oil

Fat is an ester of glycerol with high ethoxylated carboxylic acids. Fats are one of the most abundant ester groups in nature. For example, fat is cow's fat, whereas oil examples are corn oil and coconut oil. What distinguishes fats and oils? The fat at room temperature has a solid form while the oil is liquid, and the fat comes from animals while the oil comes from plants.

(Sukardjo, 1983: 45-46)

Esters are functional isomers of carboxylic acids with functional groups -COOH-

The general formula of ester acid is CnH2NO2.

Esters are relatively polar compounds (soluble in water). The special properties of esters that have a distinctive aroma that is not owned by another derivative is the aroma. The smaller the molecular weight or the shorter the carbon chain, the ester will give a distinctive aroma.

The ester compounds, among others, have the following characteristics:

1. Generally has a fragrant odor, resembling the smell of fruits.

2. Esters may experience hydrolysis to carboxylic acids and alcohols.

3. Because the smell is delicious then esters are widely used as essence in food.

(Raymond Chang, 2004: 256)

Properties of Esther

A. Physical Properties

1) Esters have a boiling point and a freezing point lower than the point

Boiling and freezing of the carboxylic acid of origin.

2) Low tribal esters are liquids that smell good (flavorful

fruits).

B. Chemical Properties

1) Esther is neutral and does not react with sodium metal

     or PCl3.

2) Esters may experience hydrolysis to carboxylic acids and

     alcohol.

3) Hydrolysis of high ester ethers with NaOH or KOH results

     Soap and glycerol (sapling reaction).

4) Esters can be reduced to alcohol at low temperatures.

Uses of Esther

Short chain ester compounds (esters derived from low-tension carboxylic acids with low ethnic alcohols) are present in fruits that arise from the fruit, which is called fruit ester.

This ester compound is widely used as a condiment or essence.

1) Banana scent on food or drink can be obtained by adding amyl acetate ester. Benzilacetate gives

    aromastrawberry to food or drink. In addition it is also used as a solvent in the manufacture of

    paints, nail polish, and adhesive.

2) Esters derived from glycerol with low or high-carboxylic acid (oils and fats). Used as raw material

    for making soap and butter (margarine).

3) Esters of high ethnic alcohols and high ethyl carboxylic acids. This ester is called wax (wax), this

    candle is different from hydrocarbon wax (paraffin wax). Its usefulness is to polish car and floor.

(4) Esters can be reduced to alcohol at low temperatures. 

Another uses of Esther

1) Eesters derived from low tribal carboxylic acids with low ethnic alcohols are found in fruits that

    give rise to the aroma of the fruit, so called fruit ester. This ester compound is widely used as

    flavoring or essence.

2) As a solvent on the manufacture of paints, nail polish, and adhesives.

3) Esters derived from glycerol with low or high-carboxylic acid (oils and fats). Used as raw material

    for making soap and butter (margarine).

4) Esters of high ethnic alcohols and high ethoxylated carboxylic acids. This ester is called a candle

    (wax), this candle is different from hydrocarbon wax (paraffin wax). Its usefulness is for car polish

     and floor.

(Respati, 1976: 155-156)

MATERIAL TOOLS

· Tools

1. Reaction Tubes

2. Pipette Drops

3. Glass Watch

4. Watershed

5. Lakmus

6. 500mm Cup Cups

7. Thermometer

8. Mixer Stem

· Material

1. 1ml glacial acetic acid

2. 1ml Isoamel alcohol

3. H2SO4 6M

4. Mitanol 3ml

5. Benzanoic acid 250ml

6. 1ml butifat acid

7. NaOH 10%

8. Coconut Oil

9. HCL 10%

10. NaCL solution

11. CaCL2 1M

12. MgSO41M

13. Lead Nitrate 1M

WORK PROCEDURES

A. Synthesis and identification of esters

Test tube

=>  Included 1ml CH3COOH + 1ml Isoamil alcohol

Watershed

=>  Add 10 drops of H2SO4

=>  Heat ± 10 minutes to form 2 layers
=>  Moved the top layer formed into the watch glass using dropper drops

Observation result

=>  Identified the substance by smell it

B. Esterification with excess alcohol

3 test tubes

=>  Included in each 3 ml CH3COOH tube

=>  Within each tube 2m, 3ml and 4ml ethanol were added

=>  Added 10 drops of H2SO4

Watershed

Heated ± 10 minutes

Observation result

C. Synthesis of several esters

Test tube

=>  Included 1ml CH3COOH + 1 ml n-butanol

Watershed
=>  Add 10 drops of H2SO4

=>  Heat ± 10 minutes to form 2 layers

=>  Moved the top layer formed into the watch glass using dropper drops

Observation result
=>  Identified the substance by smell it

D. Esterification with excess acid

3 Test tubes
=>  Included 4ml, 6ml, 8ml CH3COOH

=>  Added 3 ml of ethanol to each tube

=>  Added 15 drops of H2SO4 into each test tube

=>  Shake evenly and heated

Watershed

=>  Observation result

E. Saponification of esters

Test tube

=>  Included 1ml NaOH 10%

Penang iar

=>  In enter 3 ml esters made in experiment C

=>  Added to the water bath until the odor of the ester disappears, then heated the reaction tube ± 25 minutes

Test tube

=>  Cooled the test tube under the cold water stream

=>  Added to 1ml 10% HCl that has been cold and then stirred

=>  Examined its acidity with litmus paper

=>  Observation result

F. Making soap
 Glass of 500ml cup

=>  Included in 5ml coconut oil + 15ml NaOH 3M + 20ml Ethanol. Heated

=>  At ± 90 ° C for 20 minutes and cooled

Cup glass
=>  After forming solids taken a little solid that formed and put into a test tube, then dissolved with hot water and shake strongly

=>  Added 2ml hot saturated NaCl solution then tested in flame various solutions

=>  Observation result

RESULTS AND DISCUSSION 

RESULT

A. Synthesis and Identification of Esters

* Write down the esterification reaction equation

Answer: C2H5OH + CH3COOH + H2SO4 CH3COOC2H5 + H2SO4 + H2O

* Does the reaction go as it is written?

Answer: yes, as written

* Evidence of the reaction?

Answer: formed 2 layers

* Esther produced what does it smell like?

Answer: smell of rubber balloon

B. Esterification with excess alcohol

Conclusion: the more alcohol is added the thicker the ester layer is formed and the smell of the ester becomes more stinging.

 C. Reactions of some Esters

D. Esterification with excess acid

Conclusion: the more acidic volume of the ester layer is thicker and the odor smells more stinging

E. Saponification of esters

* Draw a formula for building methyl salicylate and make the reaction equation with NaOH

Answer: CH3COOH + NaOH CH3COONa + H2O

* Write down the reaction equation of product A with HCl!

Answer: CH3COOH + HCl CH3COOCl + H2O

* How does the examination result with litmus paper?

Answer: acid

F. Soap Making

Observation of soap work power

DISCUSSION

A. Synthesis and Identification of esters

This time trial about the synthesis and identification of ester, praktikan will know about equation of esterification reaction. Whether the reaction can go perfectly and evidence of reactions and odor generated.

The first stage that praktikan do is insert 1ml of acetic acid glasiat and 1ml ethanol into 1 test tube. Then carefully add 10 drops of 6 M sulfuric acid. The solution is stirred and the test tube inserted into the water bath for about 10 minutes and note the formation of the coating. Note that the top layer is an ester.

Once the layer is formed, carefully remove a few drops and identify the smell by smelling the resulting odor.

Equations of esterification reactions

C2H5OH + CH3COOH + H2SO4 CH3COOC2H5 + H2SO4 + H2O

Evidence of the reaction

Evidence of the reaction between acetic acid with ethanol is the emergence of ester layer is two layers and the solution produces a rubber balloon odor.

The resulting esters smell like rubber balloons.

From the above data can be seen that the synthesis and identification will produce equations.

It can be concluded that the experiment reacted perfectly and can be proven in the presence of two layers and the solution produces a rubber balloon odor.

B. Esterification With Excess Alcohol

In esterification experiments with excess alcohol, praktikan will observe about the thickness of the ester layer of the compounds used and the odors produced. Praktikan will see whether the difference in volume will produce a thick layer of different ester.

The first step that practitioners do is to put 3 ml acetic acid into 3 test tubes, then each tube is added ethanol 2 ml, 3 ml and 4 ml respectively.

Then add 10 drops of H2SO4 6 M carefully and heat over the water bath for 10 minutes.

From the table it is clear that the different volumes on each tube produce different thickness of the ester layer. Can be seen at 2 ml butanol volume yields thickness of large ester layer that is 0,9 cm. While the volume of 3 ml butanol to produce a thick layer of ester is 1.4 while for the volume of butanol 4 ml yield 1.4 cm thick layer of ester.

From this experiment it can be concluded that if the volume of acid remains but the solution of ethanol volume is different then it will still produce the same odor that is the smell of rubber balloon. What can be used as a difference, however, is the thickness of the ester layer and the odor that stings more or less.

The more ethanol used thicker ester layer thicker and smelly more, and vice versa the smaller the volume of ethanol, the thicker the resulting ester layer is getting smaller and the smell is no more stinging.

C. Synthesis of some esters

            In the synthesis experiments some of these esters will be thorough about the compounds that can react or not in mixing some compounds and physical characteristics or odor generated. The first thing to do is prepare some compounds to be used here there are 3, the compounds used are: benzoic acid, acetic acid, and butyric acid. Each of these compounds is reacted with butanol but with different volumes. However, since the material to be used in the laboratory is limited, so the practitioner only experiments on acetic acid with n-butanol with the volume of H2SO4 used is 10 drops. The experimental steps were carried out in accordance with the A trial procedure.

The prepared material is inserted into the test tube and shaken, then heated for about 10 minutes and the result reacts and produces a clear color, and smells the ink of a stinging marker.

D. Esterification with excess acid

This experiment requires apparatus and materials such as the reaction tabug, stirrer and water bath and the ingredients are ethanol, H2SO4 and CH3COOH. The first step in this experiment, praktikan prepare 3 pieces of reaction tube each of which contain 4 ml, 6 ml, and 8 ml of acetic acid, then added 3 ml of ethanol into each of the reaction tube. Then drop H2SO4 as much as 3 drops into each test tube, shake slowly, then warmed to the water.

The result obtained is that the mixture reacts in the presence of a precipitate which amongst the top layer is an ester layer and the bottom layer is a water layer. The esters formed in this experiment are called ethyl acetate and each tube smells of rubber balloons all but there are things that distinguish between one tube with another tube that is the thickness of the ester's precipitate layer, the ester of which 4 ml of alcohol has the thickness of the ester 2 precipitate , 2 cm, 6 ml alcohol 2.4 cm, and 8 ml of alcohol have a thickness of 3.8 cm.

The data that the practitioner gets has been in line with the theory that the more the volume of acid and alcohol is added, the thicker the ester layer is formed and the smell of the ester becomes more intense.

E. Saponofikasi ester

In the experiment of saponification of the ester, praktikan will examine the formula of wake of methyl salicylate and its reaction equation with NaOH and HCl and the results of examination with litmus paper. The thing that praktikan do is enter 3 ml salicylic acid and 2 drops 10% NaOH into the test tube. Then put the solution into the water bath until the odor of the ester disappears as the ester layer diminishes. The heating takes approximately 25 minutes of the reaction tube then cooled under a cold stream. Only after cold is added 10 drops 10% HCl and can be identified by using litmus acidity. To test it, add 10% HCl as much as a few drops until the solution is acidic until the new can be recorded the results. And below is the experimental data:

· The formula of waking methyl salicylate

   CH3COOH + NaOH CH3COONa + H2O

· The reaction equation of product A with HCl

   CH3COOH + HCl CH3COOCl + H2O

· Inspection results with litmus paper

"After being examined with litmus paper we obtained the result that the solution was acidic.

From the data above can be seen that the formula of wake can be known after the experiment and can be written equation of the reaction that occurs both with NaOH and HCl.

F. Soap formers

In the experiment of making this soap, the first thing that praktikan do is prepare the tools and materials that will be praktikan need in making this soap. First prepared a 500 ml measuring cup, incorporating coconut oil therein, added with 15 ml of NaOH and 20 ml of Ethanol, heated at an adjusted temperature of ± 90 ° C to 20 minutes. The resulting precipitate, from the precipitate, is taken more or less as a tip of a spoon inserted into the test tube, dissolved by hot water, shaken until foam or foam occurs. However, the results we get from experiments that have been praktikan do is the resulting foam is not good because in the solution or soap solids still contain fatty acids. This is reinforced by Theory which explains that if solids dissolved by using hot water then shaken with a strong it will produce a good foam or foam means that in the solid soap does not contain fatty acids.

CONCLUSION

Based on experiments that have been done, it is concluded that:

  1. Praktikan able to synthesize at least 3 kinds of esters.

  2. Praktikan can know know the influence of alcohol concentration to equilibrium reaction on ester

      manufacture.

  3. Praktikan able to know the effect of carboxylic acid concentration to equilibrium reaction on ester

      manufacture.

  4. Praktikan be able to recognize the typical smell of some kinds of esters.

  5. Praktikan able to use ester as a material of soap making.

  6. Praktikan can know the principle of saponification.

  7. Praktikan can make various kinds of soap for washing and cosmetics.

  8. Praktikan able to test the work of soap in the water of the container.

BIBLIOGRAPHY

Ahmad, Hiskia. 2001. Chemical Kinetics. Bandung: ITB

Change, Raymond. 2004. Basic Chemistry Volume IV. Bandung: ITB

Rangke, Tobing. 1978. Basic Chemistry Volume II.Jakarta: Erland

Respati. 1976. Basic Chemistry. Jakarta: Erland

Sukardjo. 1983. Chemistry. Jakarta. Your bail

Drafting team. 2012. Basic Chemical Practical Guide. Jambi: UNJA