What Is Glycolic Acid?
Glycolic acid, also known as hydroxyacetic acid, is a naturally occurring α-hydroxy acid found in sugar crops. Its chemical formula is C2H4O3, and it is a colorless crystal with hygroscopic properties. Glycolic acid can be produced by hydrolyzing chloroacetic acid with barium carbonate and is soluble in water, ethanol, and ether.
Uses of Glycolic Acid
Glycolic acid is used extensively in the beauty industry as a peeling agent due to its exfoliating properties. It is also used as a raw material for organic synthesis, as a sanitizing and exfoliating agent, in biodegradable resin production, and the leather industry as a dyeing and tanning agent. It serves as a pH adjuster and has applications in cleaning agents for surfaces like concrete and metals. In the medical field, polyglycolic acid, a derivative, is used as a suture material.
Properties of Glycolic Acid
Glycolic acid has a melting point of 167°F (75°C) and forms glycolic acid anhydride when heated to 212°F (100°C). At temperatures above 392°F (200°C), it forms glycolide and polyglycolide. It can be irritating to skin and mucous membranes and is metabolized into toxic oxalic acid when ingested.
Structure of Glycolic Acid
With the IUPAC name 2-Hydroxyethanoic acid, glycolic acid is a carboxylic acid with a hydroxy group. It has a molar mass of 76.05 g/mol and a density of 1.27 g/cm3.
Other Information on Glycolic Acid
1. Glycolic Acid in Nature
Found in sugarcane, pineapple, sugar beets, unripe grapes, and cantaloupe, glycolic acid is a key component in various natural sources.
2. Applications of Glycolic Acid
In organic synthesis, glycolic acid is used as an intermediate in esterification and redox reactions, and as a monomer for biocompatible copolymers. Polyglycolic acid, a biodegradable thermoplastic, is derived from condensation polymerization of glycolic acid.
3. Related Compounds of Glycolic Acid
Glycolic acid is part of the α-hydroxy acid family, which also includes β-hydroxy acids, γ-hydroxy acids, and δ-hydroxy acids. These hydroxy acids are more acidic than common carboxylic acids and are synthesized from corresponding keto acids by the action of various dehydrogenases.