Organic Synthesis : Formation Of An Ester Lab Report Page 1

TABLE OF CONTENT

Title Page

1 Abstract……………………………………… 2

2 Objectives……………………………………. 3

3 Material & Apparatus……………………….. 4

4 Procedures…………………………………… 5

5 Data & Results………………………………. 6

6 Discussions………………………………….. 7 – 9

7 Conclusion…………………………………... 10

8 Reference…………………………………….. 11

9 Appendix……………………………………. 12

Organic Synthesis : Formation Of An Ester Lab Report Page 2

1.0 ABSTRACT

In chemical engineering or in chemical subject, there is a chemical compound named

esters. Esters are derived from an acid (organic or inorganic) in which at least one –OH

(hydroxyl) group is replaced by an alkyl group. Usually, esters are derived from a carboxylic

acid and alcohol. Esters with low molecular weight are commonly used as fragrances and

found in essential oils too. Esters used in fragrances because it can produce a really good

smell.

Ester names are derived from the parent alcohol and the parent acid, where the latter

may be organic or inorganic. Esters named came from the simplest carboxylic acids are

commonly used. Esters are more polar than ethers but less polar than alcohols. They

participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond

donors, unlike their parent alcohol. Consequently esters are more volatile than carboxylic

acids ot similar molecular weight.

Esters are widespread in nature and are widely used in industry. Esters are responsible

for the aroma of many fruits, including apples, pears, bananas, pineapples and strawberry.

The reaction to complete esters are alcohol and carboxylic acid. It is common in organic

chemistry and biological materials, and often have the characteristic pleasant, fruity odor. It

also used in flavouring and as polymers.

The example of esters name are, Allyl hexanoate, benzyl acetate, butyl acetate and the

odor or occurrence are pineapple,(pear,strawberry,jasmine) and (apple,honey) respectively.

Organic Synthesis : Formation Of An Ester Lab Report Page 3

2.0 OBJECTIVES

1) To synthesise the ester compound.

2) To differentiate between alcohol, carboxylic acid, and ester compounds by identifying

the functional groups for each.

3) To understand the process of esterification.

4) To learn how to name the ester compounds.

5) To find out the applications of the ester.

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3.0 MATERIAL AND APPARATUS

Apparatus :-

1) 250 mL beaker

2) 400 mL beaker

3) Test tube

4) Spatula

5) Dropper

6) Hot Plate

7) Stopwatch

Material :-

1) Distilled Water.

2) Acetic Acid ( Ethanoic Acid )

3) Propanoic Acid ( Propionic Acid )

4) Methanol

5) Ethanol

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4.0 PROCEDURES

1) 400 mL beaker are filled about half full with water to prepare the hot water bath. Heat

the water to boiling and then turn off the hot plate.

2) The ester are prepared. The table data at the backside are used as guide. For each

ester, 10 drops of the organic acid are placed in a dry test tube. Then 10 drops of the

appropriate alcohol and 2 drops of concentrated sulphuric acid are added in the test

tube respectively. The test tube was placed into the beaker of hot water and let stand

for five minutes.

3) The odour of the ester is more easily detected when the ester is mixed in some water.

Never try to directly smell the ester while it is still hot. About 100 mL of water was

added in a 250 mL beaker. The contents of the test tube was poured into the beaker

and swirl it to mix the contents by using the spatula. The odour of the ester was

carefully smell after it is mixed with water by waving some of the vapors toward your

nose. This action is refer as wafting. The odour was identified. Observations were

recorded on the table.

4) Steps 2 and 3 are repeated to prepare the 4 esters in total.

5) All waste solutions was poured down to the organic waste tank.

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5.0 DATA AND RESULTS

Trial Acid Alcohol Ester name and

Structure name

Odour

1 Acetic Acid

(Ethanoic Acid)

CH3COOH

Ethanol

CH3CH2OH

Ethyl Ethanoate

CH3COOCH2CH3

Vinegar-like

odour, Not too

strong.

2 Acetic Acid

(Ethanoic Acid)

CH3COOH

Methanol

CH3OH

Methyl Ethanoate

CH3COOCH3

Odourless

3 Propanoic Acid

(Propionic Acid)

CH3CH2COOH

Ethanol

CH3CH2OH

Ethyl Propanoate

CH3CH2COOCH2CH3

The most

pungent, very

sharp smell

4 Propanoic Acid

(Propionic Acid)

CH3CH2COOH

Methanol

CH3OH

Mthyl Propanoate

CH3CH2COOCH3

Mild smell,

Smell like fruit

Table 1

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6.0 DISCUSSIONS

Lewis Structure of Propanoic Acid: Formula of Propanoic Acid:

H H O CH3CH2COOH

H C C C OH

H H

Propanoic Acid Methanol Methyl Propanoate

Reaction of Propanoic Acid and Methanol

H H O H H H O H

H – C – C – C – O – H + H – C – O – H → H – C – C – C – O – C – H + H2O

H H H H H H

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A Carboxylic acid (-COOH group) can react with an Alcohol (-OH group) to form a

new product, Ester (-COOR). From above Lewis structure diagram, a Propanoic Acid is

reacted with a Methanol, a type of alcohol to produce a Methyl Propanoate and water.

Propanoic acid is a carboxylic acid with a chemical formula C3H5COOH and functional

group –COOH while Methanol is an alcohol with a chemical formula CH3OH and functional

group –OH. When this reaction is occur, Propanoic acid will lose it OH- and Methanol will

lose H+

ion. An ester, Methyl Propanoate, CH3CH2COOCH3 will become a product and water

will form as a side product. The water, H2O is formed from the OH- ion from the Propanoic

Acid and the H+ ion from the Methanol. This reaction can be used to synthesis an Ester.

Methyl Propanoate is an ester with a sweet and fruity odor. It also usually use as a solvent

for cellulose nitrate and as a raw material for production of varnishes, paint and other

chemicals. Besides that, it is also used as a flavouring and fragrances.

An ester has a different solubility in water for each kind, but a small esters are fairly

soluble in water. Due to the increase length in chain, the solubility is decreasing. For an

example, a Methyl Methanoate, HCOOCH3, is more soluble in water than Ethyl Ethanoate,

CH3COOHCH2CH3.

The reason for this is that although an esters cannot form a hydrogen bond with each

other, they can form a hydrogen bond with the water molecules. One of a partially-positive

hydrogen atoms in water molecules can be attracted to one of the lone pairs of oxygen in the

esters thus, a hydrogen bond is formed. This intermolecular attraction will release enough

energy sufficiently to solvate the ester. As for the ester with longer chain, the hydrocarbon

portion forces itself between the water molecules and break the hydrogen bonds between the

water molecules. This makes the solubility decreases.

Based on the report from the experiment, the solubility of the ester can be rank based on

their number of hydrocarbon and their length. It was shown in the table 2 below.

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Ester and The Structured Formula Solubility in water

Methyl Ethanoate

CH3COOCH3

Higher

Lower

Ethyl Ethanoate

CH3COOCH2CH3

Methyl Propanoate

CH3CH2COOCH3

Ethyl Propanoate

CH3CH2COOCH2CH3

Table 2

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7.0 CONCLUSION

Esters also produce some other smell like souring smell like alcohol and acid because

esters are produce from alcohol and acid. Example of the alcohol were methanol and ethanol.

It produced two different power of smell. The smell is like the same, but the power of the

smell make them different. Methanol and ethanol are reacted with acid to produce esters.

Esters can be smell easily when we mix it with water and never to try smell directly the esters

while it still hot. Waving some vapors to your nose to smell it correctly. We must use esters

correctly because it can make air pollution to our environment and also our nature. The

wasted esters, alcohol or acid must be thrown it in the right way. We cannot dump it into the

pond, river or sea. It can affect the habitat in the water. The fishes may die easily because of

our bad manners. For this experiment, the solution produce two types of smell and one is

odorless.

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8.0 REFERENCE

1) 2006, ORGANIC CHEMISTRY, McGraw Hill Inter. Edittion.

2) Web , ChemWIKI

a. http://chemwiki.ucdavis.edu/Organic_Chemistry/Esters/Properties_of_Esters

3) Web, Wikipedia

a. http://en.wikipedia.org/wiki/Ester