Cleansing Agents
The word detergent means cleansing agent . Actually detergent word is derived from Latin word „ detergere ‟ means “ to wipe off ”, Cleansing agents are the substance which remove dirt and have cleansing action in water . These are also called surfactants .
Detergents can be classified into two types . 1 . Soapy detergents or soaps , and 2 . Non-soapy detergents or soapless soap .
1 . Soaps Soaps are sodium or potassium salts of higher fatty acids ( containing 15-18 carbon atoms ) e . g ., stearic acid , oleic acid and palmitic acid . Sodium salts of fatty acids are known as hard soaps while the potassium salts of fatty acids are known as soft soaps .
Hard soaps are prepared by cheaper oil and NaOH while soft soaps are Jlrepared by oil of good quality and KOH . The soft soaps do not contain freealkali , produce more lather and are used as toilet soaps , shaving SOapsand shampoos .
Preparation of soaps
Soaps containing „ Sodium salts are formed by heating fat ( glyceryl ester ~ fatty acid ) with aqueous sodium hydroxide solution . This reaction is known as saponification .