Glycolic acid is the smallest alpha-hydroxy acid with the chemical formula C2H4O3. This hygroscopic crystalline solid is colorless and odorless as well as highly soluble in water. Glycolic acid is relatively stronger than acetic acid, owing to its greater electron withdrawing power of the terminal OH group.

History

Glycolic acid was first named by French Chemist Auguste Laurent in 1848. Glycolic acid was first prepared by German chemist Adolph Strecker and Russian chemist Nikolai Nikolaevich Sokolov in 1851.

They produced glycolic acid by forming ester of glycolic acid by treatment of hippuric acid with nitrogen dioxide and nitric acid. The ester was boiled with dilute sulfuric acid for days, which ultimately resulted in glycolic acid.

Preparation

Glycolic acid can be prepared through numerous ways. The main methods involve a low-cost catalyzed reaction of formaldehyde with synthesis gas. This chemical compound can also be prepared by the reaction of sodium hydroxide with chloroacetic acid, which is followed by re-acidification.

Other methods include hydrolysis of cyanohydrin and hydrogenation of oxalic acid. Enzymatic biochemical process is also used to prepare glycolic acid. Glycolic acid is produced during the photorespiration of plants, such as pineapple, cantaloupe, sugarcane, grapes and sugar beets. 

Applications

Glycolic acid finds applications in numerous industries. It is used as a dyeing and tanning agent in the textile industry. In the food processing industry, it is used as a preservative and a flavoring agent.

This chemical compound is used in plastics, adhesives, solvents, emulsion polymers, additives of paint and ink. Glycolic acid is an important active ingredient in floor cleaning products such as pine-sol.

In the pharmaceutical industry, glycerol finds applications in skin care products like chemical peel. It is an important intermediate for organic synthesis and a wide range of reactions such as long chain polymerization, esterification and oxidation-reduction.
Glycolic acid is used as a monomer for the preparation of copolymers like polyglycolic acid.

Safety

This chemical compound is a strong irritant, which varies according to the ph. Ingestion of glycol can be lethal due to its metabolization to oxalic acid.