[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods, glycolic acid chemical formula

Glycolic acid properties

Glycolic acid (Glycolic Acid), also known as glycolic acid, is the simplest alpha-hydroxy acid, chemical formula C2H4O3. It is a colorless, odorless crystal and is highly hygroscopic. Soluble in water, methanol, ethanol and acetone, acidic, pH range is usually between 0.5 and 2.0. Glycolic acid has good permeability and high chemical activity, which makes it perform well in many chemical reactions.

Glycolic Acid Physicochemical Properties

Glycolic acid has a molecular weight of 76.05g/mol, a melting point of about 75-80°C and a boiling point of 112°C (upon decomposition). Due to its small molecular structure and high solubility, it can quickly penetrate the skin and exert keratolytic effect. The acidic strength of glycolic acid, measured in pKa value, is about 3.83, which means that it can be partially ionized in water to form a strong acidic environment.

Glycolic acid main use

Glycolic acid is widely used in the cosmetics industry, mainly as an exfoliant and moisturizer in skin care products. It promotes the shedding of aging skin cells by weakening the connections between keratinocytes, making the skin look smoother and younger. Glycolic acid is used as a dyeing and finishing agent in the textile industry, as a cleaning and pickling agent in the metal industry, and in the food industry for the preservation of fruits and vegetables.

Cosmetics Industry Applications

In the cosmetics industry, glycolic acid is a common active ingredient and is widely used in facial care products such as facial cleansers, masks and lotions. Its exfoliating action helps to improve skin texture and tone, reducing the appearance of fine lines and wrinkles. Low concentrations (usually less than 10%) of glycolic acid products are suitable for daily use, while high concentrations are used for professional skin care and need to be used under the guidance of a doctor.

Industrial Applications

Industrially, glycolic acid is used for metal cleaning and pickling. Its strong acidity and good solubility, so that it can effectively remove the metal surface oxide and rust, improve the surface of the metal finish and the effect of subsequent treatment. Glycolic acid can be used as a dyeing assistant and fiber modifier in the textile treatment process, which can improve the hydrophilicity and dyeing uniformity of fibers.

Glycolic acid upstream and downstream raw materials

The production of glycolic acid relies primarily on two upstream feedstocks: formaldehyde and carbon monoxide. In industrial production, glycolic acid is usually prepared by oxidation of glyoxylic acid or hydrolysis of chlorohydrin. Formaldehyde and carbon monoxide through catalytic oxidation reaction to produce glyoxylic acid, and then further oxidation to produce glycolic acid. Alternatively, the chloroethanol is hydrolyzed directly to glycolic acid.

Production process

Industrial processes for the production of glycolic acid include glyoxylic acid oxidation and chlorohydrin hydrolysis. Glyoxylic acid oxidation method is the oxidation reaction of glyoxylic acid in the presence of an appropriate catalyst to generate glycolic acid. Chloroethanol hydrolysis law is through the chloroethanol and water under acidic conditions of hydrolysis reaction, directly generate glycolic acid. The two methods have their own advantages and disadvantages, the former cost is higher but the yield is higher, the latter process is simple but need to deal with by-products.

Glycolic Acid Storage Method

Due to the strong hygroscopicity and acidity of glycolic acid, special attention should be paid during storage. Glycolic acid should be stored in a dry, cool environment, away from direct sunlight and high temperature. It should be stored in acid-resistant containers, such as glass or special plastic containers, and avoid contact with metal containers to prevent corrosion. The storage environment should be kept ventilated to prevent caking or dissolution caused by moisture absorption.

Storage Security Considerations

Safety precautions must be taken when storing and handling glycolic acid. Glycolic acid is a strong irritant to the skin and eyes. Appropriate protective equipment such as gloves, protective glasses and protective clothing should be worn when handling. In the event of a leak, it should be cleaned up quickly and appropriate absorbent materials, such as sand or activated carbon, should be used to avoid its spread. The storage area shall be equipped with emergency spray and eyewash equipment to deal with emergencies.

Glycolic Acid Environmental Impact and Disposal

Glycolic acid has a certain impact on the environment, especially in the case of high concentration emissions. Its high acidity may cause harm to aquatic organisms, so special attention should be paid to disposal. The glycolic acid contained in industrial wastewater should be neutralized to reduce its acidity and avoid direct discharge. Wastes shall be disposed in accordance with hazardous chemical treatment procedures to ensure environmental safety.

Market Prospects

There is a growing demand for glycolic acid in various application areas, especially in the cosmetics and personal care market. With the improvement of consumers' requirements for the efficacy of skin care products, products containing glycolic acid are gradually favored. In metal cleaning, textile treatment and other industrial fields, glycolic acid also shows broad application prospects. It is expected that in the next few years, with the continuous advancement of technology and the expansion of application fields, the glycolic acid market will continue to grow.

Conclusion

As an important chemical raw material and additive, glycolic acid has broad application prospects and market demand. Its unique physical and chemical properties make it perform well in many fields. In the process of production and use, it is necessary to pay attention to safety protection and environmental protection to ensure its sustainable development. In the future, with the continuous progress of technology, the application field and market scale of glycolic acid will be further expanded, bringing more opportunities and challenges to related industries.