What is the soap recipe? The authoritative answer is here!

Soap is a daily chemical product that people often use at home. Soap has many uses in life. For example, many people wash their hands with soap, which can remove bacteria on their hands and achieve better cleaning effects. Especially when hands are particularly dirty, it is recommended that you wash your hands with soap. Soap contains sodium stearate. When this chemical substance comes into contact with water, it will be dissolved in water to form stearate ions and sodium ions. So you will find that if you put soap in water, there will usually be no precipitation, and the water is usually transparent. In fact, soap contains many other ingredients. If you make soap yourself, you must understand the correct formula so that the soap you make can play its due role.

Making of soap:

1. Principle

Oil and sodium hydroxide are boiled together and hydrolyzed into sodium and glycerol, the higher fatty acids. The former becomes soap after processing and forming.

2. Supplies

One 150 ml beaker and one 300 ml beaker, glass rod, alcohol lamp, asbestos mesh, tripod, lard (or other animal or plant fat or oil), NaOH, 95% alcohol, and saturated salt water.

3. Operation

(1) In a 150ml beaker, add 6g of lard and 5ml of 95% alcohol, then add 10ml of 40% NaOH solution. Stir with a glass rod to dissolve (heat over low heat if necessary).

(2) Place the beaker on an asbestos net (or in a water bath), heat over low heat, and stir continuously with a glass bowl. During the heating process, if the alcohol and water are reduced by evaporation, they should be replenished at any time to maintain the original volume. For this purpose, 20 ml of a mixture of alcohol and water (1:1) can be prepared in advance for addition.

Take out a few drops of sample with a stick and put them into a test tube. Add 5-6 ml of distilled water into the test tube and heat and shake. When left standing, oil separates out, indicating that saponification is incomplete. Alkaline solution can be added to continue saponification.

(4) Slowly add 20 ml of hot distilled water to the completely saponified viscous liquid and stir to make them dissolve. Then slowly pour the viscous liquid into 150 ml of hot saturated salt solution while stirring. After standing, the soap will salt out and float up. After all the soap has precipitated and solidified, you can take it out with a glass rod and the soap is ready.

4. Description

(1) Fats and oils are not easily soluble in alkaline water. Alcohol is added to increase the solubility of fats and oils in the alkaline solution and accelerate the saponification reaction.

(2) If heating is not done in a water bath, use low heat.

(3) During the saponification reaction, the original volume of the mixed liquid must be maintained and the mixed liquid in the beaker must not be allowed to boil dry or spill out of the beaker.