The effect of water on hydrolysis of N methyl pyrrolidone

At room temperature, due to the formation of hydrogen bonds between N-Methyl-2-Pyrrolidone and water, the hydrolysis rate of NMP is about 1%, and at high temperatures due to the destruction of hydrogen bonds, the hydrolysis rate of NMP remains at about 2.5%, so when only water is present in NMP The hydrolysis rate is small at both high temperature and room temperature. After adding NaOH, in the NMP containing NaOH solution at room temperature, water inhibits the hydrolysis of NMP to a certain extent, but after a certain amount, due to dissolution Partially non-ionized NaOH, the alkaline environment reduces the activation energy required for NMP to break the C-N bond, thereby intensifying the hydrolysis of NMP.

Through orthogonal experiments, it was found that because NMP hydrolysis needs to break the C-N bond to open the ring and needs to absorb energy, the temperature has the greatest impact on NMP hydrolysis.Secondly, the activation energy of NMP hydrolysis is reduced due to the alkaline environment caused by NaOH. NMP can achieve a higher hydrolysis rate at lower temperatures; the smallest factor that affects NMP hydrolysis is water.The formation of hydrogen bonds between water and NMP at low temperatures plays a role in protecting NMP, but at the high temperature, the presence of NaOH solution Under the influence of hydrogen bonds, the hydrolysis rate of NMP rises.

Application of poly vinyl pyrrolidone in cosmetics

In addition to being used in hair cosmetics, poly vinyl pyrrolidone can also be used in skin care moisturizers, cream-based hair dye dispersants, and foam stabilizers in cosmetics. Because of its good moisturizing properties, it is widely used in the manufacture of skin care agents, cleansing agents, shampoos, toothpaste, etc. 

The skin care agent made of Polyvinylpyrrolidone can kill the virus and prevent wrinkles. It can effectively extend the penetration and retention time in cosmetics, which can be used for skin moisturizing and skin care. PVP is used in lipsticks, eye shadows, and mascara to reduce skin irritation caused by pigments and certain ingredients. PVP used in soaps can improve the sticking strength of bar soap. In sanitary soaps, Polyvinylpyrrolidone (PVP) can form complexes with fungicides to reduce skin irritation. PVP is used in liquid detergents to prevent cross-coloring and anti-redeposition, and to prevent skin irritation caused by synthetic detergents. For example, a liquid detergent formulation is: sodium alkylbenzene sulfonate 10.0% (mass fraction, the same below); surfactant 5.6; PVP 0.7%; sodium tripolyphosphate 12.0; Potassium silicate 4. O%; potassium xylene sulfonate 5. O%; water 62.7%. In addition, PvP used in enzyme-based laundry detergents, as both an adjuvant and a binding agent and stabilizer, can prevent the enzyme from being damaged by moisture and sodium percarbonate.