Glycolic acid 99 related overview
Glycolic acid 99, that is, 99% purity glycolic acid, has a unique position in the chemical industry.

I. Properties
Glycolic acid 99 presents as a colorless and easily deliquescent crystal with strong hygroscopicity. Its melting point is relatively low, about 78-80 ° C. It can be miscible with various organic solvents such as water, alcohol, acetone, etc. This characteristic is derived from its molecular structure containing both carboxyl and hydroxyl groups, which makes it hydrophilic and certain hydrophilicity. In terms of chemical properties, the carboxyl group makes it acidic, which can neutralize with bases to form corresponding carboxylic salts; the hydroxyl group can participate in esterification reactions, etc., giving glycolic acid 99 a variety of chemical reaction activities.

Second, Application
1. ** Pharmaceutical field **: Because of its mild acidity and good solubility, in pharmaceutical preparations, glycolic acid 99 is often used as an excipient to adjust the pH value of drugs, enhance the stability and solubility of drugs, and help drugs to be better absorbed by the human body. In some external drugs, its slight exfoliation can promote skin metabolism, assist in the treatment of certain skin diseases, such as acne, acne, etc., and improve skin conditions.
2. ** Cosmetics Industry **: As an important fruit acid ingredient, glycolic acid 99 can effectively remove the aging keratinocytes accumulated on the surface of the skin, promote the renewal of epidermal cells, make the skin smoother and more delicate, and improve the gloss of the skin. At the same time, it also has a certain moisturizing effect, which can increase the moisture content of the skin and reduce the generation of wrinkles, so it is widely used in various skin care products, such as creams, serums, masks and other products.
3. ** Industrial Cleaning **: With its acidity and good solubility, glycolic acid 99 can be used for metal surface cleaning. It can effectively remove rust, scale and other dirt on the metal surface, and is relatively less corrosive to metals. Compared with some strong acid cleaning agents, it is milder and will not cause excessive damage to metal substrates. It is widely used in the cleaning of metal parts such as electronic components and precision instruments. In industrial circulating water systems, it can be used as a water quality stabilizer to prevent calcium and magnesium plasma in water from forming scale and ensure the normal operation of the circulating water system.

III. Production
1. ** Carboxylation of formaldehyde and carbon monoxide **: Carboxylation reaction is carried out with formaldehyde and carbon monoxide as the main raw materials under the action of a specific catalyst. This method has a relatively wide range of raw material sources, but the reaction conditions are relatively harsh, and it needs to be carried out in a high temperature and high pressure environment, which requires high reaction equipment. During the reaction process, the choice of catalyst is crucial, which not only affects the rate of reaction, but also plays a key role in the purity and yield of the product. Commonly used catalysts include metal catalysts such as palladium halide. By optimizing the composition of the catalyst and the reaction conditions, the production efficiency and product quality of glycolic acid 99 can be improved.
2. ** Hydrolysis method of chloroacetic acid **: Using chloroacetic acid as the starting material, the hydrolysis reaction is carried out under alkaline conditions. Chloroacetic acid is mixed with sodium hydroxide solution, hydrolyzed to produce sodium glycolate, and then through acidification treatment, the sodium glycolate is converted into glycolic acid, and finally the The process of this method is relatively simple, but a large amount of salt-containing wastewater is generated during the production process, which causes great pressure on the environment and requires complete wastewater treatment facilities. At the same time, the raw material chloroacetic acid has certain toxicity and corrosiveness, and strict safety protection measures are required during the production operation.

In summary, glycolic acid 99 has shown a wide range of application value in many fields due to its unique properties, and the continuous optimization of its production method is of great significance to meet market demand, improve product quality and reduce environmental impact.