Azelaic Acid (CAS 123-99-9) — Woody Base Note Fragrance Ingredient
Azelaic Acid
CAS 123-99-9
What Is Azelaic Acid?
Azelaic acid is a naturally occurring dicarboxylic acid found in wheat, rye, and barley. It’s commonly used in skincare for its antibacterial and anti-inflammatory properties. While not typically used for fragrance, it appears in some functional perfumes where skin benefits are desired alongside scent.
Safety Profile
GENERALLY SAFEWhat Does Azelaic Acid Smell Like?
Azelaic acid is nearly odorless, making it unique among fragrance ingredients. Its neutral scent profile allows it to be used as a functional carrier or base in formulations where active skincare benefits are desired without interfering with the fragrance composition. In high purity, it may exhibit a faint waxy, fatty character reminiscent of candle wax or unscented soap.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used in medicated or therapeutic fragrances where skin benefits are desired. Its odor neutrality makes it ideal for carrying active ingredients without scent interference.
2D Molecular Structure
SMILES: OC(=O)CCCCCCCC(O)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Azelaic acid (nonanedioic acid) is a saturated dicarboxylic acid with a straight-chain structure. Naturally produced by Malassezia furfur yeast, it can also be synthesized through ozonolysis of oleic acid. The industrial process typically involves nitric acid oxidation of oleic acid. As a C9 dicarboxylic acid, it bridges the gap between shorter chain acids (like adipic) and longer chain acids (like sebacic). The molecule lacks chiral centers, existing as a single stereoisomer.
Physical & Chemical Properties
| Boiling Point | 286.5 °C at 100 mmHg |
|---|---|
| Melting Point | 106.5 °C |
| Flash Point | 210 °C (closed cup) |
| Density | 1.225 g/cm³ at 25 °C |
| Vapor Pressure | 0.00000001 mmHg |
| Refractive Index | 1.4303 at 111 °C |
| Solubility | 2400 mg/L at 20 °C |
| Appearance | Monoclinic prismatic needles |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Functional Fragrances | 1-5% | Up to 10% | As active carrier base |
| Skincare Perfumes | 0.5-3% | Up to 5% | For therapeutic benefits |
Classic Accords
Tip: Use as a neutral base for active ingredients in functional perfumery where scent interference must be minimized.
Alternatives & Comparisons
Shorter chain dicarboxylic acid with similar neutral properties but higher solubility.
Longer chain alternative with slightly more waxy character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
No IFRA restrictions. Not classified as a fragrance allergen.
RIFM Assessment
RIFM considers azelaic acid safe for use in fragrances at current levels.
Sustainability
Azelaic acid can be sourced sustainably from cereal grains or produced through green chemistry approaches. The synthetic route from oleic acid (derived from vegetable oils) offers consistent quality and reduces agricultural land use compared to direct plant extraction. Biodegradable and non-persistent in the environment.
Explore Azelaic Acid
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References
- PubChem Compound Summary for CID 2266 PubChem 2266
- Breathnach A.S. (1996). Azelaic acid: potential as a general antitumoural agent. Medical Hypotheses. PMID 8676762
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID8021640
Physical Properties
| Molecular Weight | 188.223 g/mol🔬 EPA CompTox |
| Density | 1.16 g/cm^3🔬 EPA CTX |
| Boiling Point | 317.067 °C🔬 EPA CTX |
| Melting Point | 109.108 °C🔬 EPA CTX |
| Flash Point | 200.567 °C🔬 EPA CTX |
| Refractive Index | 1.475 Dimensionless📊 OPERA |
| Molar Volume | 166.348 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.57 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | -0.023 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -2.477 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.93 Log10 unitless📊 OPERA |
| Water Solubility | 0.013 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0 mmHg🔬 EPA CTX |
| Viscosity | 15.261 cP📊 OPERA |
| Surface Tension | 41.209 dyn/cm📊 OPERA |
| Thermal Conductivity | 161.126 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 74.6 Ų💻 Computed |
| H-Bond Donors | 2 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 8 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 46.874 cm^3/mol📊 OPERA |
| Polarizability | 18.582 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.
