Butylene glycol

• USP–NFButylene Glycol

1,3-butanediol; 1,3-butylene glycol; β-butylene glycol; 1,3-dihydroxybutane; methyltrimethylene glycol

Butane-1,3-diol · [107-88-0]

UNII 3XUS85K0RA · PubChem CID 7896

C4H10O2 · 90.12

Solvent, humectant

Typical concentrations: — · Dosage forms: Semi-solid

Butylene glycol is a water-miscible solvent, humectant and co-solvent used mainly in topical pharmaceutical and cosmetic products such as creams, lotions, gels and hair products. It is commonly used at a few per cent up to about 10% as a humectant and solvent; it also enhances the efficacy of preservative systems and has antimicrobial activity of its own at high concentrations. It is used as a solvent for flavourings in foods.

A clear, colourless, viscous and hygroscopic liquid with a slight odour and a sweetish taste with a bitter aftertaste.

Boiling point

about 207 °C

Density

about 1.005 g/cm³ at 20 °C

Solubility

miscible with water, acetone, ethanol and ether; practically insoluble in aliphatic hydrocarbons

Hygroscopicity

hygroscopic; absorbs water from the atmosphere

Refractive index

about 1.440 at 20 °C

Stable under normal storage conditions. Because it is hygroscopic it should be stored in a well-closed container in a cool, dry place.

Incompatible with strong oxidising agents.

Produced by catalytic hydrogenation of 3-hydroxybutanal (acetaldol), which is obtained by aldol condensation of acetaldehyde.

Of low toxicity by the oral and dermal routes and widely used in cosmetics. It may cause mild skin and eye irritation, and occasional cases of allergic contact dermatitis have been reported.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended; the liquid is combustible and should be kept away from sources of ignition.

Included in the FDA Inactive Ingredient Database (topical preparations). Permitted in the USA as a solvent for natural and synthetic flavourings in foods, and widely used in cosmetics.

Propylene glycol; glycerol; pentylene glycol; hexylene glycol.

Butylene glycol is often chosen in place of propylene glycol in skin products because it has a lighter, less tacky feel. As a chiral diol it exists as two enantiomers; the commercial material is the racemate.