Toilet soap and Laundry soap

In our daily life, we often hear people say that after washing clothes with detergent, if you use soap to wash the easily dirty places such as collar cuffs, it will reduce its decontamination ability. Because detergent is acidic and soap is alkaline, the acid-base neutralization will certainly reduce its decontamination ability. It sounds quite scientific, but it is actually a misunderstanding.

We know that the main component of soap is the sodium salt of higher fatty acids, in addition to fillers such as flavors, bactericides, and active agents. Strong alkali needs to be added during the production process, as well as its own hydrolysis:

RCOO-＋H 2O≒RCOOH ＋OH -

So the solution is alkaline when used. Since it is neutralized by acid during production, the alkalinity of soap is generally small. There are many types of synthetic detergents, which can be divided into three types according to their structure: anionic, cationic and non-ionic. Among them, the detergent widely used in daily life is anionic.

Since strong alkali is added during neutralization and the hydrolysis itself is alkaline, most of the shampoos and shower gels used in daily life are non-ionic, which are neither ionized nor hydrolyzed in water, so their aqueous solutions are neutral. Only cationic detergents are weakly acidic when hydrolyzed in aqueous solution, but their hydrophilic and hydrophobic groups will not react with soap, so the activity of the groups is not reduced. Therefore, in daily life, when you are washing clothes or taking a bath, you don’t have to worry about this. While enjoying the pleasure brought by cleaning, you might as well add a hint of fragrance to add color to your life.