Saponification usually refers to the reaction between alkali (usually strong alkali) and ester to produce alcohol and carboxylate, especially the reaction between oil and alkali.

Saponification is an exothermic reaction. Heating is to accelerate the movement of molecules, improve the reaction speed, and heat preservation is also to completely saponify soap. However, once the temperature is too high, the saponification reaction equation will move to the left, so that part of the oil can not be combined with sodium hydroxide, which hinders the saponification reaction, resulting in stratification and oil precipitation.

Saponification is an exothermic reaction and saponification is a slow chemical reaction. In order to speed up the reaction, we can keep the system at high temperature, constantly stir the solution by physical means to increase the number of molecular collisions or add alcohol to make the mixture more complete.