Diacetyl (CAS 0431-03-08) — Sweet Top Note Fragrance Ingredient
Diacetyl
CAS 0431-03-08
What Is Diacetyl?
Diacetyl is a synthetic compound commonly found in butter-flavored foods and some fragrances. It gives a rich, creamy aroma reminiscent of butter or caramel. While it enhances flavor and scent profiles, its inhalation safety has been scrutinized in industrial settings, leading to regulated use in consumer products.
Safety Profile
USE WITH AWARENESSWhat Does Diacetyl Smell Like?
Diacetyl bursts with an intense, buttery richness that evolves into a creamy, slightly sweet heart. The dry-down reveals a subtle caramel-like warmth, making it a favorite for gourmand and dairy accords. Its volatility ensures it remains a top note, but its impact lingers subtly in the background.
Chemistry, Properties & Perfumer Guide
The Chemistry
Diacetyl (2,3-butanedione) is a diketone with a simple four-carbon structure. It is synthesized via fermentation or chemical oxidation of 2,3-butanediol. Its planar structure and carbonyl groups make it highly reactive, contributing to its strong aroma and potential for forming derivatives.
Physical & Chemical Properties
| Boiling Point | 88 °C |
|---|---|
| Density | 0.99 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used sparingly for butter nuances |
| Food Flavoring | 5-10 ppm | Up to 20 ppm | Enhances dairy profiles |
Classic Accords
Tip: Use in trace amounts to avoid overpowering the blend.
Alternatives & Comparisons
A milder alternative with similar buttery notes, less intense and safer for inhalation.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted by IFRA, but use is cautioned in aerosolized forms.
EU Allergen Declaration
Not listed as an EU allergen.
GHS Classification
RIFM Assessment
RIFM has flagged for respiratory safety assessment.
Sustainability
Diacetyl is primarily synthetic, reducing environmental impact compared to natural extraction. Its production is energy-efficient but requires careful handling to minimize workplace exposure.
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References
- PubChem: Diacetyl CID 650
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
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