Description

Glycolic acid is the smallest α-hydroxy acid (AHA). This colorless, odorless, and hygroscopic crystalline solid is highly soluble in water. It is found in some sugar-crops.It is one of the most well-known and widely used alpha-hydroxy acids in the skincare industry.

Properties

Glycolic acid is slightly stronger than acetic acid due to the electron-withdrawing power of the terminal hydroxyl group. The carboxylate group can coordinate to metal ions forming coordination complexes. Of particular note are the complexes with Pb2+ and Cu2+ which are significantly stronger than complexes with other carboxylic acids. This indicates that the hydroxyl group is involved in complex formation, possibly with the loss of its proton.

Applications

Glycolic acid is used in the textile industry as a dyeing and tanning agent, in food processing as a flavoring agent and as a preservative, and in the pharmaceutical industry as a skin care agent. It is also used in adhesives and plastics.Glycolic acid is often included into emulsion polymers, solvents and additives for ink and paint in order to improve flow properties and impart gloss. It is used in surface treatment products that increase the coefficient of friction on tile flooring. It is the active ingredient in the household cleaning liquid Pine-Sol.

Safety

Glycolic acid is a strong irritant depending on pH. Like ethylene glycol, it is metabolized to oxalic acid, which could make it dangerous if ingested.