Ingredient Dictionary

PENTANEDIONE

Acetylacetone is a beta-diketone that is pentane in which the hydrogens at positions 2 and 4 are replaced by oxo groups.

Definition

Acetylacetone is a beta-diketone that is pentane in which the hydrogens at positions 2 and 4 are replaced by oxo groups. It is a conjugate acid of an acetylacetonate.

Source: PubChem

US FDA substance register · UNII 46R950BP4J · registered name ACETYLACETONE · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Pentanedione is the organic compound that conforms to the formula

Cosmetic roles

Helps it stick to skin or surfacesADHESIVE

Safety & regulatory references

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

More data — names, identifiers, properties, test records, literature

Names & identifiers

PENTANEDIONEINCI2,4-PentanedioneSynonym

CAS No.chemical registry number: 123-54-6
EC No.EU chemical inventory number: 204-634-0
DTXSIDUS EPA chemical ID: DTXSID4021979
DTXCIDUS EPA compound ID: DTXCID601979

IUPAC: Pentane-2,4-dione
Molecular formula: C5H8O2
Molecular weight: 100.117 g/mol

Measured properties

Appearance: 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. · Liquid, CBI
Odour: Pleasant odor · Mild ketone-like odor
Boiling point: 284.7 °F at 760 mmHg (USCG, 1999) · 138 °C
Melting point: -10.3 °F (USCG, 1999) · -23 °C
Solubility: In water, 166,000 mg/L at 20 °C · One part dissolves in about 8 parts water
Density: 0.975 at 68 °F (USCG, 1999) - Less dense than water, will float · 0.9721 at 25 °C/4 °C
Stability: Stable under recommended storage conditions.
Viscosity: 0.6 mPa.s at 20 °C
Dissociation constant: pKa = 8.93
Colour: colourless
Odour threshold: 0.01 ppm
Melting/freezing point: -23 ℃
Initial boiling point and range: 139~140 ℃
Flash point: 34 ℃(c.c.)
Evaporation rate: 0.75
Upper/lower flammability or explosive limits: 11.6 / 2.4 %
Vapour pressure: 0.93 ㎪ (20℃)
Water solubility: 16.6 g/100㎖ (20℃)
Vapour density: 3.5
Relative density: 0.9721 (25℃)
n-Octanol/water partition coefficient (Kow): 0.4
Auto-ignition temperature: 340 ℃
Molecular weight: 100.12

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 22 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

No specific technical function6
Solvent4
Chemical reaction regulator4
Processing aids not otherwise specified3
Corrosion inhibitor2
Surface modifier1
Hardener1
Intermediate1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

5 skin studies and 4 eye studies are on record.

Classed as moderate1Classed as low2

The studies disagree (the most common conclusion covers 33%), so they do not establish that this ingredient is irritating. These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 9 studies

Classification not possible
Skin Sensitization · Screening
Not likely to be sensitizing
skin sensitisation: in vivo (LLNA) · Screening · according to OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Not classified
Skin Irritation · Screening
Moderate or Mild Irritation
skin irritation: in vivo · Screening · other guideline: as stated in report according to
Category 6.3B (Category 3)
Skin Irritation · Read Across
Category 2B
Eye Irritation · Screening
Category 6.4A (Category 2A)
Eye Irritation · Read Across
Moderate or Mild Irritation
eye irritation: in vivo · Screening · other guideline: as stated in report according to
Moderate or Mild Irritation
eye irritation: in vivo · Screening · EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion) equivalent or similar to