Acetylacetone

Athanor · official

C₅H₈O₂ · 100.12 g/mol

IUPAC name: pentane-2,4-dione

Also called acac, pentane-2,4-dione, ligand, beta-diketone

Reagents

Open in Athanor

Drawn from its SMILES with RDKit

WarningFlammable liquid and vapor · Harmful if swallowed

Names and identifiers

IUPAC name: pentane-2,4-dione
Synonyms: acac, pentane-2,4-dione, ligand
+ 38 more
beta-diketone, 2,4-Pentanedione, Pentane-2,4-dione, 2,4-Dioxopentane, Acetoacetone, Diacetylmethane, ACAC, Pentanedione, ACETYL ACETONE, Pentan-2,4-dione, Pentanedione-2,4, Acetyl 2-propanone, Acetone, acetyl-, Hacac, 2-Propanone, acetyl-, DTXSID4021979, 46R950BP4J, NSC-5575, DTXCID601979, CHEBI:14750, RefChem:5511, 204-634-0, 2,4-Pentadione, 2,4-Pentandione, acetylaceton, acetyl-acetone, NSC 5575, CH3COCH2COCH3, MFCD00008787, 4-Hydroxy-3-penten-2-one, CH3-CO-CH2-CO-CH3, CCRIS 3466, HSDB 2064, EINECS 204-634-0, UN2310, BRN 0741937, UNII-46R950BP4J, AI3-02266
Molecular formula: C₅H₈O₂
Empirical formula: C₅H₈O₂
Molecular weight: 100.12 g/mol
Exact mass: 100.05243
CAS number: 123-54-6
PubChem CID: 31261
Canonical SMILES: CC(=O)CC(=O)C
Isomeric SMILES: CC(=O)CC(=O)C
InChI: InChI=1S/C5H8O2/c1-4(6)3-5(2)7/h3H2,1-2H3
InChIKey: YRKCREAYFQTBPV-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Mobile, colorless or yellowish liquid; when cooled, solidifies to lustrous, pearly spangles. The liquid is affected by light, turning brown and forming resins.[5]
5 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Pentane-2,4-dione appears as a colorless or yellow colored liquid. Less dense than water. Vapors are heavier than air. Used as a solvent in paints and varnishes. [1] CAMEO Chemicals
– Liquid; CBI [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– A colorless or yellow colored liquid. [4] Occupational Safety and Health Administration (OSHA)
–shown Mobile, colorless or yellowish liquid; when cooled, solidifies to lustrous, pearly spangles. The liquid is affected by light, turning brown and forming resins. [5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 12
Odor: Mild ketone-like odor[5]
Melting point: -23.2 °C[6]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
−23.5 °C -10.3 °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.
−23 °C -23 °C [5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
−23 °C -23 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−23.5 °C -10.3 °F [4] Occupational Safety and Health Administration (OSHA)
−23.2 °Cshown -23.2 °C [6] PAC Chemical Database, U.S. Department of Energy
Boiling point: 139 °C @760 [mmHg][6]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
140.4 °C 284.7 °F at 760 mmHg (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.
138 °C 138 °C [5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
140 °C 140 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
140.4 °C 284.7 °F [4] Occupational Safety and Health Administration (OSHA)
139 °Cshown 139 °C @760 [mm Hg] [6] PAC Chemical Database, U.S. Department of Energy
Density: 0.9721 at 25 °C/4 °C[5]
5 values
Only one source reports it.
Value As written Source
– 0.975 at 68 °F (USCG, 1999) - Less dense 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.
0.9721 g/mLshown 0.9721 at 25 °C/4 °C [5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
– Relative density (water = 1): 0.98 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.975 [4] Occupational Safety and Health Administration (OSHA)
– 0.9721 @25 °C [6] PAC Chemical Database, U.S. Department of Energy
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Solubility in water: Solubility in water, g/100ml: 16[3]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– In water, 166,000 mg/L at 20 °C [5] Hazardous Substances Data Bank (HSDB)cites Riddick, J.A., W.B. Bunger, Sakano T.K. Techniques of Chemistry 4th ed., Volume II. Organic Solvents. New York, NY: John Wiley and Sons., 1985., p. 359
– Fairly soluble in neutral water [5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 12
– For more Solubility (Complete) data for Acetyl acetone (7 total), please visit the HSDB record page. [5] Hazardous Substances Data Bank (HSDB)
–shown Solubility in water, g/100ml: 16 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: log Kow = 0.40[5]
pKa: pKa = 8.93[5]
Vapor pressure: Vapor pressure, kPa at 20 °C: 0.93[3]
Flash point: 34 °C c.c.[3]
6 values
4 of 4 sources agree on it (most common value).
Value As written Source
34 °C 93 °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.
38 °C 38 °C (100 °F) - closed cup [5] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Safety Data Sheet for Acetylacetone, Product Number: P7754, Version 5.9 (Revision Date 02/15/2018). Available from, as of September 27, 2018: https://www.sigmaaldrich.com/safety-center.html
41 °C 105 °F - open cup [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 37
34 °C 93 °F (34 °C) (Closed cup) [5] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-95
34 °Cshown 34 °C c.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
34 °C 93 °F [4] Occupational Safety and Health Administration (OSHA)
Autoignition temperature: 340 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
340 °C 644 °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.
340 °C 644 °F (340 °C) [5] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-95
340 °Cshown 340 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity: 0.6 mPa.s at 20 °C[5]
Refractive index: Index of refraction: 1.4494 at 20 °C/D[5]

Value	As written	Source
–	Pentane-2,4-dione appears as a colorless or yellow colored liquid. Less dense than water. Vapors are heavier than air. Used as a solvent in paints and varnishes.	[1] CAMEO Chemicals
–	Liquid; CBI	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	A colorless or yellow colored liquid.	[4] Occupational Safety and Health Administration (OSHA)
–shown	Mobile, colorless or yellowish liquid; when cooled, solidifies to lustrous, pearly spangles. The liquid is affected by light, turning brown and forming resins.	[5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 12

Value	As written	Source
−23.5 °C	-10.3 °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.
−23 °C	-23 °C	[5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
−23 °C	-23 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−23.5 °C	-10.3 °F	[4] Occupational Safety and Health Administration (OSHA)
−23.2 °Cshown	-23.2 °C	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
140.4 °C	284.7 °F at 760 mmHg (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.
138 °C	138 °C	[5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
140 °C	140 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
140.4 °C	284.7 °F	[4] Occupational Safety and Health Administration (OSHA)
139 °Cshown	139 °C @760 [mm Hg]	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	0.975 at 68 °F (USCG, 1999) - Less dense 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.
0.9721 g/mLshown	0.9721 at 25 °C/4 °C	[5] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3857
–	Relative density (water = 1): 0.98	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.975	[4] Occupational Safety and Health Administration (OSHA)
–	0.9721 @25 °C	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	In water, 166,000 mg/L at 20 °C	[5] Hazardous Substances Data Bank (HSDB)cites Riddick, J.A., W.B. Bunger, Sakano T.K. Techniques of Chemistry 4th ed., Volume II. Organic Solvents. New York, NY: John Wiley and Sons., 1985., p. 359
–	Fairly soluble in neutral water	[5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 12
–	For more Solubility (Complete) data for Acetyl acetone (7 total), please visit the HSDB record page.	[5] Hazardous Substances Data Bank (HSDB)
–shown	Solubility in water, g/100ml: 16	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
34 °C	93 °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.
38 °C	38 °C (100 °F) - closed cup	[5] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Safety Data Sheet for Acetylacetone, Product Number: P7754, Version 5.9 (Revision Date 02/15/2018). Available from, as of September 27, 2018: https://www.sigmaaldrich.com/safety-center.html
41 °C	105 °F - open cup	[5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 37
34 °C	93 °F (34 °C) (Closed cup)	[5] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-95
34 °Cshown	34 °C c.c.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
34 °C	93 °F	[4] Occupational Safety and Health Administration (OSHA)

Value	As written	Source
340 °C	644 °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.
340 °C	644 °F (340 °C)	[5] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-95
340 °Cshown	340 °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: 7
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.6
H-bond donors: 0
H-bond acceptors: 2
Rotatable bonds: 2
TPSA (Å²): 34.1
Formal charge: 0
XLogP3: 0.4 PubChem
Complexity: 82 PubChem
Stereocenters: None
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

C59.98%
H8.05%
O31.96%

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: 0.55 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.68 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.17 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 100.12
log P ≤ 5 (Crippen): 0.55
H-bond donors ≤ 5: 0
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

Warning

Harmonized EU classification (CLP Annex VI). Source [7].

Flammable
Harmful or irritant

NFPA 704[5]

H226Flammable liquid and vapor
H302Harmful if swallowed

Precautionary statements: P210, P233, P240, P241, P242, P243, P264, P270, P280, P301+P317, P303+P361+P353, P330, P370+P378, P403+P235, P501

View all classifications (3)

[7] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · WarningH226, H302
[8] European Chemicals Agency (ECHA) · 1,190 reports · DangerH226, H302, H311+H331, H311, H331
[5] Hazardous Substances Data Bank (HSDB) · DangerH226, H302, H311, H331

Exposure limits

TLV: 25 ppm as TWA; (skin).[3]
MAK (Maximale Arbeitsplatz Konzentration): 83 mg/m[3]

First aid

Inhalation: Remove to fresh air; if victim is not breathing, give artificial respiration and then oxygen; call a physician. EYES or skin: Flush with water. (USCG, 1999)[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[9]
Fresh air, rest. Artificial respiration may be needed. Refer for medical attention.[3]
Remove contaminated clothes. Rinse and then wash skin with water and soap.[3]

Storage

Fireproof. Separated from strong oxidants. Keep in the dark.[3]
Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Storage class (TRGS 510): 3: Flammable liquids.[5]
Store in a flammable liquid storage area or approved cabinet away from ignition sources and corrosive and reactive materials. Prior to working with this chemical you should be trained on its proper handling and storage. Before entering confined space where this chemical may be present, check to make sure that an explosive concentration is not a danger. Store in stainless steel containers away from oxidizers, reducing agents, bases. Where possible, automatically pump liquid from drums or other storage containers to process containers.[5]

Incompatibilities

Incompatible materials: Strong oxidizing agents, reducing agents, strong bases, metals.[5]
Incompatibilities: Oxidizing material, bases, reducing agents, halogens, aliphatic amines, alkanolamines, organic acids, isocyanates. Light may cause polymerization.[5]

Safety data sheets on the supplier’s page: Aladdin Scientific, Quality Control Solutions (QCS Standards), Thermo Fisher Scientific.

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]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[8]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[9]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[10]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[11]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[12]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[13]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[14]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[15]MassBank Europe · 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.