glycolic acid

Glycolic acid
General
Systematic name	2-Hydroxyethanoic acid
Other names	glycolic acid, hydroxyacetic acid
Molecular formula	C2H4O3
SMILES	O=C(O)CO
Molar mass	76.05 g/mol
Appearance	colorless solid
CAS number	[79-14-1]
Properties
Density and phase	1.27 g/cm3
Solubility in water	0.1 g/mL
Other solvents	alcohols, acetone, acetic acid and ethyl acetate[1]
Melting point	75 °C
Boiling point	decomposes
Acidity (pKa)	3.83
Viscosity	? cP at ? °C
Structure
Crystal structure
Dipole moment	? D
Hazards
MSDS	External MSDS
Main hazards	Corrosive (C)
NFPA 704	1 3 0
Flash point	129 °C [2]
R/S statement	R: R22-R34 S: S26-S36/37/39-S45
RTECS number	MC5250000
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related α-hydroxy acids	lactic acid
Related compounds	acetic acid, glycerol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Glycolic acid (or hydroxyacetic acid) is the smallest α-hydroxy acid (AHA). It appears in the form of a colorless, odorless and hydroscopic crystalline solid that is highly soluble in water and related solvents. Glycolic acid is associated with sugar-crops and is isolated from sugarcane, sugar beets, pineapple, canteloupe, and unripe grapes.

Uses

Due to its excellent capability to penetrate skin, glycolic acid finds applications in skin care products, most often as a chemical peel performed by a dermatologist in concentrations of 20%-80% or at-home kits in lower concentrations of 10%. It is used to improve the skin's appearance and texture. It may reduce wrinkles, acne scarring, hyperpigmentation and improve many other skin conditions. Once applied, glycolic acid reacts with the upper layer of the epidermis, weakening the binding properties of the lipids that hold the dead skin cells together. This allows the outer skin to "dissolve" revealing the underlying skin.

Glycolic acid is also a useful intermediate for organic synthesis, in a range of reactions including: oxidation-reduction, esterification and long chain polymerization. It is used as a monomer in the preparation of polyglycolic acid and other biocompatible copolymers (e.g. PLGA). Among other uses this compound finds employment in the textile industry as a dyeing and tanning agent, in food processing as a flavoring agent and as a preservative. Glycolic acid is often included into emulsion polymers, solvents and additives for ink and paint in order to improve flow properties and impart gloss.

Preparation

Glycolic acid is isolated from natural sources and is inexpensively available. It can be prepared by the reaction of chloroacetic acid with sodium hydroxide followed by re-acidification.

Safety

Glycolic acid is a mild irritant.^[3]

See also

• (Link to external sources on chemicals.)

References

1. ^ DuPont Glycolic Acid Technical Information. Retrieved on 2006-07-06.
2. ^ Glycolic Acid MSDS. University of Akron. Retrieved on 2006-09-18.
3. ^ Glycolic Acid MSDS. ICSC:NENG1537 International Chemical Safety Cards (WHO/IPCS/ILO). Retrieved on 2006-06-08.

External links

• DuPont Glycolic Acid
• Glycolic.org Glycolic Acid
• Computational Chemistry Wiki

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