Propylene glycol

Athanor · official

C₃H₈O₂ · 76.09 g/mol

IUPAC name: propane-1,2-diol

Also called propane-1,2-diol, E1520, PG

Solvents

Open in Athanor

Drawn from its SMILES with RDKit

Names and identifiers

IUPAC name: propane-1,2-diol
Synonyms: propane-1,2-diol, E1520, PG
+ 37 more
1,2-propanediol, 1,2-Propylene glycol, 1,2-dihydroxypropane, 2-Hydroxypropanol, Isopropylene glycol, Dowfrost, Sirlene, Methylethyl glycol, Methylethylene glycol, Monopropylene glycol, Trimethyl glycol, Propylene Glycol USP, Solar Winter BAN, Solargard P, alpha-Propyleneglycol, dl-Propylene glycol, DL-1,2-Propanediol, Methyl glycol, Ucar 35, Sentry Propylene Glycol, (RS)-1,2-Propanediol, FEMA No. 2940, (+-)-Propylene glycol, 1,2-Propylenglykol, PG 12, alpha-Propylene glycol, (+-)-1,2-Propanediol, Kilfrost ABC-S, Kollisolv pg, DTXSID0021206, Propyleneglycolum, 1,2-(RS)-Propanediol, Ins no.1520, Propylene glycol (solvent), 1,2 Propanediol, NSC-69860, Ins-1520
Molecular formula: C₃H₈O₂
Empirical formula: C₃H₈O₂
Molecular weight: 76.09 g/mol
Exact mass: 76.05243
CAS number: 57-55-6
PubChem CID: 1030
Canonical SMILES: CC(CO)O
Isomeric SMILES: CC(CO)O
InChI: InChI=1S/C3H8O2/c1-3(5)2-4/h3-5H,2H2,1H3
InChIKey: DNIAPMSPPWPWGF-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Colorless viscous liquid[5]
5 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Thick odorless colorless liquid. Mixes with water. (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
– Large Crystals; CBI; Liquid; Wet Solid; Other Solid; Liquid; Liquid; Other Solid [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS ODOURLESS HYGROSCOPIC VISCOUS LIQUID. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Thick odorless colorless liquid. [4] Occupational Safety and Health Administration (OSHA)
–shown Colorless viscous liquid [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1050
Odor: Practically odorless[5]
Melting point: -59 °C[3]
4 values
4 of 4 sources agree on it (most common value).
Value As written Source
−60 °C -76 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−59 °Cshown -59 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−60 °C -76 °F [4] Occupational Safety and Health Administration (OSHA)
−60 °C -60 °C [6] PAC Chemical Database, U.S. Department of Energy
Boiling point: 188.2 °C[3]
4 values
4 of 4 sources agree on it (most common value).
Value As written Source
188.2 °C 370.8 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
188.2 °Cshown 188.2 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
188.2 °C 370.8 °F [4] Occupational Safety and Health Administration (OSHA)
187.6 °C 187.6 °C @760 [mm Hg] [6] PAC Chemical Database, U.S. Department of Energy
Density: 1.0361 @ 20°C[6]
4 values
4 of 4 sources agree on it (most common value).
Value As written Source
– 1.04 at 68 °F (USCG, 1999) - Denser than water [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
– Relative density (water = 1): 1.04 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 1.04 [4] Occupational Safety and Health Administration (OSHA)
–shown 1.0361 @ 20°C [6] PAC Chemical Database, U.S. Department of Energy
Solubility in water: Solubility in water: miscible[3]
3 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– greater than or equal to 100 mg/mL at 70 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– In water, 1X10+6 mg/L at 20 °C /miscible/ [5] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992)
–shown Solubility in water: miscible [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: -0.92[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = -0.92 [5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 7
–shown -0.92 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa: pKa = 14.8 at 25 °C[5]
Vapor pressure: Vapor pressure, Pa at 20 °C: 10.6[3]
4 values
2 of 3 sources agree on it (most common value).
Value As written Source
0.08 mmHg 0.08 mmHg at 68 °F [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
0.13 mmHg 0.13 mmHg at 77 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
0.13 mmHg 0.13 mm Hg at 25 °C /Extrapolated/ [5] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
0.08 mmHgshown Vapor pressure, Pa at 20 °C: 10.6 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Flash point: 99 °C (210 °F) (Closed cup)[5]
6 values
3 of 4 sources agree on it (most common value).
Value As written Source
99 °C 210 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
104 °C 104 °C Pensky-Martens closed cup [5] Hazardous Substances Data Bank (HSDB)cites Martin AE, Murphy FH; Glycols, Propylene Glycols. Kirk-Othmer Encyclopedia of Chemical Technology (1994). John Wiley & Sons, Inc. Online Posting Date: December 4, 2000
99 °Cshown 210 °F (99 °C) (Closed cup) [5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-102
107 °C 225 °F (Open cup) [5] Hazardous Substances Data Bank (HSDB)cites U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.
101 °C 101 °C c.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
99 °C 210 °F [4] Occupational Safety and Health Administration (OSHA)
Autoignition temperature: 371 °C (700 °F)[5]
3 values
2 of 3 sources agree on it (most common value).
Value As written Source
371 °C 700 °F (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
371 °Cshown 700 °F (371 °C) [5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-102
420 °C 420 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity: 0.581 cP at 20 °C[5]

Value	As written	Source
–	Thick odorless colorless liquid. Mixes with water. (USCG, 1999)	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–	Large Crystals; CBI; Liquid; Wet Solid; Other Solid; Liquid; Liquid; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS ODOURLESS HYGROSCOPIC VISCOUS LIQUID.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Thick odorless colorless liquid.	[4] Occupational Safety and Health Administration (OSHA)
–shown	Colorless viscous liquid	[5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1050

Value	As written	Source
−60 °C	-76 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−59 °Cshown	-59 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−60 °C	-76 °F	[4] Occupational Safety and Health Administration (OSHA)
−60 °C	-60 °C	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
188.2 °C	370.8 °F at 760 mmHg (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
188.2 °Cshown	188.2 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
188.2 °C	370.8 °F	[4] Occupational Safety and Health Administration (OSHA)
187.6 °C	187.6 °C @760 [mm Hg]	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	1.04 at 68 °F (USCG, 1999) - Denser than water	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–	Relative density (water = 1): 1.04	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	1.04	[4] Occupational Safety and Health Administration (OSHA)
–shown	1.0361 @ 20°C	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	greater than or equal to 100 mg/mL at 70 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	In water, 1X10+6 mg/L at 20 °C /miscible/	[5] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992)
–shown	Solubility in water: miscible	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = -0.92	[5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 7
–shown	-0.92	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
0.08 mmHg	0.08 mmHg at 68 °F	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
0.13 mmHg	0.13 mmHg at 77 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
0.13 mmHg	0.13 mm Hg at 25 °C /Extrapolated/	[5] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
0.08 mmHgshown	Vapor pressure, Pa at 20 °C: 10.6	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
99 °C	210 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
104 °C	104 °C Pensky-Martens closed cup	[5] Hazardous Substances Data Bank (HSDB)cites Martin AE, Murphy FH; Glycols, Propylene Glycols. Kirk-Othmer Encyclopedia of Chemical Technology (1994). John Wiley & Sons, Inc. Online Posting Date: December 4, 2000
99 °Cshown	210 °F (99 °C) (Closed cup)	[5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-102
107 °C	225 °F (Open cup)	[5] Hazardous Substances Data Bank (HSDB)cites U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.
101 °C	101 °C c.c.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
99 °C	210 °F	[4] Occupational Safety and Health Administration (OSHA)

Value	As written	Source
371 °C	700 °F (USCG, 1999)	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
371 °Cshown	700 °F (371 °C)	[5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-102
420 °C	420 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 5
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 1
H-bond donors: 2
H-bond acceptors: 2
Rotatable bonds: 1
TPSA (Å²): 40.5
Formal charge: 0
XLogP3: -0.9 PubChem
Complexity: 20 PubChem
Stereocenters: 0 defined, 1 undefinedCIP: C2: undefined
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C47.35%
H10.60%
O42.05%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -0.64 Crippen (Wildman and Crippen 1999)
log S (water solubility): 0.16 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.6 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 76.09
log P ≤ 5 (Crippen): -0.64
H-bond donors ≤ 5: 2
H-bond acceptors ≤ 10: 2

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

This chemical does not meet GHS hazard criteria for 98% (6762 of 6899) of all reports.[7]

NFPA 704[5]

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
Fresh air, rest.[3]
Remove contaminated clothes. Rinse skin with plenty of water or shower.[3]
Rinse with plenty of water (remove contact lenses if easily possible).[3]

Storage

Separated from strong oxidants and alkalis. Dry. Well closed. Ventilation along the floor.[3]
Propylene glycol is hygroscopic and should be stored in a well-closed container, protected from light, in a cool, dry place.[5]
Propylene glycol, dipropylene glycol, and tripropylene glycol are stable materials that require no special handling procedures. They are noncorrosive and can be transported or stored in stainless steel, aluminum, and lined steel containers. Carbon steel is also acceptable, although slight iron contamination may occur upon extended periods of storage. U.S.P.-grade propylene glycol is typically stored in stainless steel.[5]

Incompatibilities

Reacts with strong oxidants, causing fire hazard.[5]
Propylene glycol is incompatible with oxidizing reagents such as potassium permanganate.[5]
No significantly dangerous substances are produced after contact with light, humidity or commonly available chemicals. Propylene glycol may react with hydrofluoric acid + nitric acid + silver nitrate to form the explosive silver fulminate.[5]
A chemical polishing mixture (of hydrofluoric acid, propylene glycol, and silver nitrate) was put into a closed glass bottle which burst 30 min later, and formation of silver fulminate was suggested. However, in absence of the silver salt such mixtures evolve gas and should not be stored in any event, especially after use for metal polishing, when the dissolved metal(s) tend to further destabilize the mixture.[5]

Safety data sheets on the supplier’s page: AbaChemScene, Sigma-Aldrich, CAPOT.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[6]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[8]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[9]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[10]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[11]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.