Oils and Fats
Oils and fats form an important class of compounds of biological importance. By chemical composition, these are triesters of glycerol with fatty acids. Plants and animals are the principal sources of fats and oils. Oils are liquids at room temperature while fats are solids. Soaps are salts or fatty acids. Detergents are manufactured chemically from materials other than animal fats.
Formula, the nature and the source of same fatty acids
Name
| Formula
| Nature
| Source of fatty acid
|
|---|---|---|---|
Lauric acid
| C11H23 COOH
| Saturated
| Coconut oil, butter
|
Stearic acid
| C17H35COOH
| Saturated
| Butter animal fat
|
Oleic acid
| C17H33COOH
| Unsaturated
| Butter, cotton-seed oil, Soya-bean, corn, linseed, animal fat.
|
Linoleinic
| C17H29COOH
| Unsaturated
| Linseed
|
Uses of Oils and Fats
1. Oil such as groundnut oil, coconut oil, sunflower oil ... etc are used in cooking.
2. Coconut oil, castor oil are used for cosmetic purposes.
3. These are useful in the manufacture of soap, varnished, fatty acids, leather and jute and in plastic industries.
4. Various fish liver oils have medicinal value.
Hydrogenation of Oils
Oil is a substance that exists in liquid state at room temperature. Fat exists in solid state.
e.g.: Fat - Ghee, Oil - Groundnut oil
Unsaturated and Saturated Oils:
1. Oils containing fatty acids with one or more 'C = C' double bonds are called unsaturated oils.
2. The unsaturated oils can be converted to saturated oils by hydrogenation.
3. Hydrogenation of oils is a chemical reaction carried out in the presence of nickel catalyst.
H2 + Oil (Unsaturated) ----Ni------> Fat(Saturated)
Soap
1. Soap is a Sodium or Potassium Salt of fatty acids of long Carbon chains.
2. Soaps can be directly obtained from oils or fats by hydrolysis in the presence of a base.
3. This process is called saponification of oils.
(C17H33COO)3C3H5+3NaOH ----->3C17H33COONa (Soap) + CH2OH-CH(OH)-CH2OH (Glycerol)
Process of Soap manufacture:
Soap manufacture involves three steps.
1) Hydrolysis of fat into fatty acids
2) Separation of fatty acids and
3) Neutralization of fatty acids by bases.
Some Soaps - Uses
Salts of fatty acid
| Uses
|
|---|---|
K+ salt
| Toilet soap
|
Na+ salt
| Laundry soap
|
Ca2+, Al3+
| Water proof texture
|
Mg2+
| Face powder
|
Li+ salt
| Greases
|
Triethanol Ammonium salt
| Dry cleaning and cosmetics
|
Detergents and Uses
1. Detergents differ from soap in their action with hard water.
2. Soap form insoluble compounds with Ca2+ and Mg2+ ions present in hard water and precipitate out.
3. This reduces the foaming and cleansing action.
4. Detergents also react with Ca2+ and Mg2+ ions in hard water but the products are still soluble and do not effect the Lathering and cleaning action
