The typical chemical equation for the formation of sodium stearate, for example, from neutralization of sodium hydroxide and stearic acid (fatty acid) as given below:
(C18H35O2)3C3H5(l) + 3NaOH(aq) → C3H5(OH)3(l) + 3CH3(CH2)16COONa(aq)
Many cops are made from vegetable oils, such as olive oil, palm oil, rice bran oil coconut oil, and palm oil, other made of animal fats (tallows - beef fat or lard – pig fat).
Soaps made from potassium hydroxide tend to be more soft and more soluble in water.
In households, soaps are mainly used as surfactants, which has both hydrophilic and hydrophobic parts, for washing, bathing, and cleaning. When soap, such as sodium stearate, dissolves in water, carboxylate anions and metal cations are produced:
CH3(CH2)16COONa((s) + water → CH3(CH2)16COO-(aq) + Na+(aq)
Where the hydrophobic parts part with long hydrocarbon chain attaches to non-polar grease and grime , while, the hydrophilic part, carboxylate anion end, is attached to polar water compounds by interaction of ion-dipole.
As a cleaning agent, soap suffers from two major disadvantages during washing. It will function well either in acidic water or in hard water with high mineral content of calcium and magnesium cations because of the following chemical reactions:
CH3(CH2)16COONa((s)
+ HCl(aq) → CH3(CH2)16COOH(aq)
+ Na+(aq) + Cl-(aq)
2CH3(CH2)16COONa((s) + Ca2+ (aq) → Ca[CH3(CH2)16COO](s) + 2Na+(aq)
There are many types of soaps, depending upon the usage, which can be characterised as:
● Hard and soft soaps, everything in-between;
● Transparent soaps, which are made with some different ingredients, usually some form of alcohol to modify the process;
● Glycering soaps, which are made with addition of glycerine, which acts as a humectant, in them tend to make your skin feel moister;
● Medicated soaps, which are made with addition of compounds such as triclosan or triclocarban to have antibacterial and disinfectant functions;
● Scouring soaps, which are made with addition of sand or pumice to remove dead cells from the skin surface being cleaned
● Liquid soaps - which are actually very difficult to produce and are just in fact commercial detergents (see Chemistry in daily life - detergents).
2CH3(CH2)16COONa((s) + Ca2+ (aq) → Ca[CH3(CH2)16COO](s) + 2Na+(aq)
There are many types of soaps, depending upon the usage, which can be characterised as:
● Hard and soft soaps, everything in-between;
● Transparent soaps, which are made with some different ingredients, usually some form of alcohol to modify the process;
● Glycering soaps, which are made with addition of glycerine, which acts as a humectant, in them tend to make your skin feel moister;
● Medicated soaps, which are made with addition of compounds such as triclosan or triclocarban to have antibacterial and disinfectant functions;
● Scouring soaps, which are made with addition of sand or pumice to remove dead cells from the skin surface being cleaned
● Liquid soaps - which are actually very difficult to produce and are just in fact commercial detergents (see Chemistry in daily life - detergents).