Synthesis of Ester

1.TITLE:
To prepare isopentyl acetate (isoamyl acetate)

2. AIM:

To make an ester referred to as banana oil from acetic acid and isopentyl alcohol

3.THEORY: This ester is often referred to as banana oil, since it has the familiar odor of this fruit

O O CH3 H+ CH3 CH3C OH + CHCH2CH2OH CH3C O CH2CH2CH + H2O CH3 CH3 Acetic acid Isopentyl alcohol Isopentyl acetate (excess) (alcohol) (ester) (vinegar)

Isopentyl acetate is prepared by the direct esterification of acetic acid with isopentyl alcohol. Since the equilibrium does not favor the formation of the ester, it must be shifted to the right, in favor of the product , by using an excess of one of the starting materials. Acetic acid is used in excess because it is less expensive than isopenthyl alcohol and more easily removed from the reaction mixture

In the isolation procedure, much of the excess acid and the remaining isopenthyl alcohol are removed by extraction with water. Any remaining acid is removed by extraction with aqueous sodium bicarbonate. The ester is purified by distillation

4.APPARATUS AND REAGENTS:

1. Isopenthyl alcohol(also called isoamyl alcohol or 3-methyl-1- buthanol)
2. Glacial acetic acid
3. Concentrated sulphuric acid
4. Round bottom flask
5. Reflux apparatus
6. Heating mantle
7. Cold water
8. Conical flask
9. Aqueous sodium bicarbonate
10. Red litmus paper
4.APPARATUS AND REAGENTS:

11. Saturated aqueous sodium chloride
12. Anhydrous