Propylene glycol (IUPAC name: propane-1,2-diol) is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. Its chemical formula is CH₃CH(OH)CH₂OH. Containing two alcohol groups, it is classed as a diol. It is miscible with a broad range of solvents, including water, acetone, and chloroform. In general, glycols are non-irritating and have very low volatility.

Propylene glycol

Names
Preferred IUPAC name Propane-1,2-diol
Other names Propylene glycol α-Propylene glycol 1,2-Propanediol 1,2-Dihydroxypropane Methyl ethyl glycol Methylethylene glycol
Identifiers
CAS Number	57-55-6 racemic Y 4254-15-3 S-enantiomer
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16997 Y
ChEMBL	ChEMBL286398 Y
ChemSpider	13835224 Y
ECHA InfoCard	100.000.307
EC Number	200-338-0
E number	E1520 (additional chemicals)
KEGG	C00583
PubChem CID	1030
RTECS number	TY6300000
UNII	6DC9Q167V3 Y 942194N4TD (S-enantiomer) Y
CompTox Dashboard (EPA)	DTXSID0021206
InChI InChI=1S/C3H8O2/c1-3(5)2-4/h3-5H,2H2,1H3 Y Key: DNIAPMSPPWPWGF-UHFFFAOYSA-N Y
SMILES CC(O)CO
Properties
Chemical formula	C3H8O2
Molar mass	76.095 g·mol−1
Appearance	colourless liquid
Odor	odorless
Density	1.036 g/cm3
Melting point	−59 °C (−74 °F; 214 K)
Boiling point	188.2 °C (370.8 °F; 461.3 K)
Solubility in water	Miscible
Solubility in ethanol	Miscible
Solubility in diethyl ether	Miscible
Solubility in acetone	Miscible
Solubility in chloroform	Miscible
log P	-1.34
Thermal conductivity	0.34 W/m-K (50% H2O @ 90 °C (194 °F))
Viscosity	0.042 Pa·s
Pharmacology
ATCvet code	QA16QA01 (WHO)
Hazards
GHS labelling:
Hazard statements	[?] Preview warning: H-phrases: "" not found
Precautionary statements	[?] Preview warning: P-phrases: "" not found
NFPA 704 (fire diamond)	0 1 0
Related glycols	Ethylene glycol, 1,3-propanediol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

It is produced on a large scale primarily for the production of polymers. In the European Union, it has E-number E1520 for food applications. For cosmetics and pharmacology, the number is E490. Propylene glycol is also present in propylene glycol alginate, which is known as E405. Propylene glycol is a compound which is GRAS (generally recognized as safe) by the US Food and Drug Administration under 21 CFR x184.1666, and is also approved by the FDA for certain uses as an indirect food additive. Propylene glycol is approved and used as a vehicle for topical, oral, and some intravenous pharmaceutical preparations in the U.S. and in Europe.