Hydroxynonanoic acid, delta-lactone (CAS 3301-94-8) — Sweet Middle Note Fragrance Ingredient
Hydroxynonanoic acid, delta-lactone
CAS 3301-94-8
What Is Hydroxynonanoic acid, delta-lactone?
Hydroxynonanoic acid, delta-lactone is a synthetic fragrance ingredient used to add creamy, coconut-like nuances to perfumes. It’s found in tropical-inspired fragrances and some gourmand scents. This lactone contributes a subtle richness that enhances other ingredients without overpowering them.
Safety Profile
GENERALLY SAFEWhat Does Hydroxynonanoic acid, delta-lactone Smell Like?
This lactone delivers a soft, creamy coconut-milk character with hints of warm butter and faint tropical fruit. Unlike sharper gamma-lactones, it evolves smoothly into a skin-like muskiness during drydown. The effect is reminiscent of sun-warmed skin after applying coconut oil – subtle, comforting, and slightly sweet without being cloying.
2D Molecular Structure
SMILES: CCCCC1CCCC(=O)O1
Chemistry, Properties & Perfumer Guide
The Chemistry
Hydroxynonanoic acid, delta-lactone belongs to the lactone class of cyclic esters. Unlike the more common gamma-lactones, its ring structure contains five atoms (including the oxygen). It’s produced synthetically through intramolecular esterification of hydroxynonanoic acid precursors. The delta-lactone configuration contributes to its softer, more diffusive character compared to gamma variants.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Background enhancer |
| Functional Fragrance | 0.1-1% | Up to 3% | Creamy modifier |
Classic Accords
Tip: Use to soften harsh woody notes and add natural creaminess to floral compositions.
Alternatives & Comparisons
Stronger coconut character with more pronounced sweetness, suitable when a bolder lactone effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply.
RIFM Assessment
Not currently assessed by RIFM.
Sustainability
As a synthetic ingredient, hydroxynonanoic acid delta-lactone has minimal environmental impact from sourcing. Production typically uses petrochemical feedstocks, though bio-based routes may become available. Its efficiency in formulations (requiring low usage levels) contributes to sustainable fragrance development.
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Physicochemical Properties
DTXSID: DTXSID70863149
Physical Properties
| Molecular Weight | 156.225 g/mol🔬 EPA CompTox |
| Density | 0.983 g/cm^3🔬 EPA CTX |
| Boiling Point | 273.05 °C🔬 EPA CTX |
| Melting Point | -28.8 °C🔬 EPA CTX |
| Flash Point | 132 °C🔬 EPA CTX |
| Refractive Index | 1.44 Dimensionless📊 OPERA |
| Molar Volume | 164.58 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.4 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.291 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.291 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.87 Log10 unitless📊 OPERA |
| Water Solubility | 0.017 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.004 mmHg🔬 EPA CTX |
| Viscosity | 2.312 cP📊 OPERA |
| Surface Tension | 29.752 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 43.387 cm^3/mol📊 OPERA |
| Polarizability | 17.2 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
