Ingredient Dictionary

DIACETYL

Butane-2,3-dione is an alpha-diketone that is butane substituted by oxo groups at positions 2 and 3.

Definition

Butane-2,3-dione is an alpha-diketone that is butane substituted by oxo groups at positions 2 and 3. It is a metabolite produced during the malolactic fermentation. It has a role as a Saccharomyces cerevisiae metabolite and an Escherichia coli metabolite.

Source: PubChem

US FDA substance register · UNII K324J5K4HM · registered name Diacetyl · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Gives the product a scentPERFUMING

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

DIACETYLINCI2,3-ButanedioneSynonym

CAS No.chemical registry number: 431-03-8
EC No.EU chemical inventory number: 207-069-8
DTXSIDUS EPA chemical ID: DTXSID6021583
DTXCIDUS EPA compound ID: DTXCID701583

IUPAC: Butane-2,3-dione
Molecular formula: C4H6O2
Molecular weight: 86.09 g/mol

Measured properties

Appearance: Diacetyl appears as a clear colorless liquid with a strong chlorine-like odor. Flash point 80 °F. Less dense than water. Vapors heavier than air. · Clear liquid with a chlorine-like odor, [CAMEO]
Odour: Quinone odor, vapors have a chlorine-like odor · Very strong buttery odor in dilute solution
Boiling point: 190 °F at 760 mmHg (NTP, 1992) · 87.5 °C
Melting point: 27.7 °F (NTP, 1992) · -1.2 °C
Solubility: greater than or equal to 100 mg/mL at 72 °F (NTP, 1992) · In water, 200 g/L at 20 °C
Density: 0.99 at 59 °F (NTP, 1992) - Less dense than water, will float · 0.990 at 15 °C/15 °C
Stability: Stable under recommended storage conditions.
Melting/freezing point: -1.2 ℃
Initial boiling point and range: 88 ℃
Flash point: 6 ℃
Vapour pressure: 56.8 ㎜Hg
Water solubility: (200 g/ℓ at 15 ℃)
Vapour density: 3.00 ( /Air = 1/)
Relative density: 0.99 (at 15 ℃)
n-Octanol/water partition coefficient (Kow): -1.34
Auto-ignition temperature: 365 ℃
Molecular weight: 86.09

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 6 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.

Flavouring and nutrient3
Fragrance3

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

4 skin studies and 2 eye studies are on record.

Classed as moderate1

The study conclusions largely agree (100%). These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 6 studies

Category 2
Skin Irritation · Screening
Category 1
Skin Sensitization · Screening
Sh
Skin Sensitization · Authoritative
Category 6.3A (Category 2)
Skin Irritation · Read Across
Category 1
Eye Irritation · Screening
Category 6.4A (Category 2A)
Eye Irritation · Read Across