3-Hexanone, 5-mercapto-5-methyl- (CAS 851768-51-9) — Citrus Top Note Fragrance Ingredient
3-Hexanone, 5-mercapto-5-methyl-
CAS 851768-51-9
What Is 3-Hexanone, 5-mercapto-5-methyl-?
3-Hexanone, 5-mercapto-5-methyl- is a synthetic fragrance ingredient used in modern perfumery to create tropical fruit and citrus nuances. You’ll encounter it in fruity-floral fragrances and some tropical-themed body care products. This molecule matters because it delivers a powerful, diffusive effect at very low concentrations, allowing perfumers to create vibrant top notes without overwhelming compositions.
Safety Profile
USE WITH AWARENESSWhat Does 3-Hexanone, 5-mercapto-5-methyl- Smell Like?
A burst of juicy grapefruit peel with tropical undertones dominates the opening, like biting into a perfectly ripe passionfruit. As it evolves, a subtle sulfurous character emerges – not unpleasant, but reminiscent of freshly cut guava or ripe durian. The dry-down reveals a clean, slightly woody musk that anchors the brighter top notes. Exceptionally potent, even minute concentrations can transform a fragrance’s entire character.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at 0.2% to create the signature passionfruit-grapefruit accord that makes this summer fragrance instantly recognizable. The sulfurous edge prevents the fruit notes from becoming too candy-like.
Provides a modern twist on classic colognes by adding a tropical fruit nuance to the traditional bergamot-lime opening. The perfumer used it at 0.15% for optimal diffusion.
Chemistry, Properties & Perfumer Guide
The Chemistry
A sulfur-containing ketone belonging to the class of mercaptoketones. The molecule features a methyl group and thiol functionality at the 5-position of a hexanone backbone. Synthesized through nucleophilic addition of methyl mercaptan to unsaturated ketones, followed by purification to remove residual sulfur compounds. The thiol group makes it highly reactive – requiring stabilization with antioxidants in commercial preparations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Odor Threshold | Extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.05-0.3% | Up to 0.5% | Extremely powerful – use sparingly |
| Functional Fragrance | 0.01-0.1% | Up to 0.2% | For tropical fruit shower gels |
Classic Accords
Tip: Always pre-dilute to 1% or lower before incorporating into blends due to extreme potency.
Alternatives & Comparisons
Less sulfurous alternative with similar tropical fruit character but better stability in alkaline formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards (as of Amendment 49).
GHS Classification
RIFM Assessment
Under evaluation by RIFM – preliminary data suggests safe use at current industry levels.
Sustainability
Synthetic production minimizes agricultural impact. However, sulfur-containing compounds require careful waste management during manufacturing. The extreme potency means very small quantities are needed, reducing overall environmental load.
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