HISTORY AND PREPARATION OF SOAP AND DETERGENT

The history of soap manufacturing

Soaps can be prepared through saponification. What is saponification?

therefore,

general equation,

What is fat?

What happen to the fat during saponification?

Consider this reaction;

                                                        hydrolysis reaction

Fats/oil in concentrated sodium hydroxide   à Fatty acid +  glycerol    

                 

Fatty acid + alkali/sodium ion à sodium salt fatty acid/soap + water

Overall:  Fats/oil  +  alkali/sodium ion à   soap  +  glycerol

Preparation of soap by saponification

Procedure :

1.   10 cm³ of palm oil is measured with measuring cylinder 10ml and poured into a beaker 250ml.

2.   50 cm³ of concentrated sodium hydroxide solution 5 mol dm^-3 measured with measuring cylinder 50ml and poured in the beaker.

3.   The mixture is heated and stirred with glass rod until its boiling for 5 minutes. Then, the flame is turned off and the mixture is left to cool.

4.   50 cm³ water and a few spatulas of sodium chloride was added to the mixture and boiled again for 5 minutes. Then, the flame is turned off and the mixture is left to cool.

[white precipitate is formed and floats].

5.   The mixture is filtered with filter paper, and the residue (soap) is washed by distilled water.

Example-->

Soap                     Chemical formula

Sodium palmitate        CH3(CH2)14COONa

Sodium stearate          CH3(CH2)16COONa

        Sodium oleat     CH3(CH2)CH=CH(CH2)COOK

• Potassium soap is usually used for bathing because its more softer and milder than sodium. 

BARAKALLAHUFIKUM