Chemistry Form 5
SOAP & DETERGENT
I) Definition of Soap o Soap are sodium or potassium salts of long-chain carboxylic acids o The general formula of a soap : RCOO Na / RCOO K • R is an alkyl group which contain 12 to 18 carbon atoms.
II) The history of soap manufacturing.
▪ Solvay Process - Carbon dioxide ( obtained from heating CaCo ) is passed into concentrated NaCl solution which is saturated with ammonia . NaCl +NH +H O + CO – Na HCO +NH Cl - NaHCO is then heated to obtain soda. 2NaHCO – Na CO +H O +CO .
III) Preparation of Soap by Saponification
Saponification is a process whereby the soaps are prepared by hydrolyzing fats or oils under alkaline conditions.
It is also the alkaline hydrolysis of esters using alkaline solutions.
Fats/ Vegetable oils + concentrated alkalis – soap + glycerol
(Fats- tallow from cow) ( Vegetable oils – palm oil or olive oil)
For example,
- Glyceryl tristearates ❑ is a naturally occuring esters ❑ found in fats or oils.
Example of soap, 1) sodium palmitate, C H COONa 2) Sodium oleate, C H COONa 3) Sodium stearate, C H COONa
□ To enhance the soap’s marketability,additives are used such as perfume, colouring matter and antiseptic. □ Production of soap can be precipitated by adding common salt to the reaction mixture in order to reduce the solubility of soap in water. □ Properties of soap depends on a) type of alkali used for saponification b) type of animal fats or vegetable oils used □ Potassium soap are softer, milder than sodium soap which can be used for bathing.
IV) Structure of soap molecule. • When soap is dissolved in water, it will dissociate and produce sodium ions and carboxylate ions. • The active substances in soap is
I) Definition of Soap o Soap are sodium or potassium salts of long-chain carboxylic acids o The general formula of a soap : RCOO Na / RCOO K • R is an alkyl group which contain 12 to 18 carbon atoms.
II) The history of soap manufacturing.
▪ Solvay Process - Carbon dioxide ( obtained from heating CaCo ) is passed into concentrated NaCl solution which is saturated with ammonia . NaCl +NH +H O + CO – Na HCO +NH Cl - NaHCO is then heated to obtain soda. 2NaHCO – Na CO +H O +CO .
III) Preparation of Soap by Saponification
Saponification is a process whereby the soaps are prepared by hydrolyzing fats or oils under alkaline conditions.
It is also the alkaline hydrolysis of esters using alkaline solutions.
Fats/ Vegetable oils + concentrated alkalis – soap + glycerol
(Fats- tallow from cow) ( Vegetable oils – palm oil or olive oil)
For example,
- Glyceryl tristearates ❑ is a naturally occuring esters ❑ found in fats or oils.
Example of soap, 1) sodium palmitate, C H COONa 2) Sodium oleate, C H COONa 3) Sodium stearate, C H COONa
□ To enhance the soap’s marketability,additives are used such as perfume, colouring matter and antiseptic. □ Production of soap can be precipitated by adding common salt to the reaction mixture in order to reduce the solubility of soap in water. □ Properties of soap depends on a) type of alkali used for saponification b) type of animal fats or vegetable oils used □ Potassium soap are softer, milder than sodium soap which can be used for bathing.
IV) Structure of soap molecule. • When soap is dissolved in water, it will dissociate and produce sodium ions and carboxylate ions. • The active substances in soap is