Citronellal (CAS 106-23-0) — Citrus Top Note Fragrance Ingredient
Citronellal
CAS 106-23-0
What Is Citronellal?
Citronellal is a fresh, lemony-smelling compound found in citronella oil and lemongrass. You’ll recognize it from natural insect repellents and citrus-scented cleaning products. This ingredient matters because it’s nature’s way of combining bright citrus with herbal depth, creating a scent that’s both uplifting and grounding.
Safety Profile
USE WITH AWARENESS
What Does Citronellal Smell Like?
Citronellal bursts with a crisp, lemony-citrus character that’s sharper than lemon but less sweet than orange. The initial blast carries metallic herbal undertones reminiscent of crushed lemongrass stalks. As it settles, the scent evolves into a warmer, rosier character with subtle woody undertones. In drydown, it leaves a clean, slightly camphoraceous trail that blends beautifully with floral notes.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Citronellal provides the bright citrus-herbal sparkle that defines this classic masculine. It bridges the bergamot top to rosemary heart, creating a refreshing aromatic effect.
Used sparingly here to enhance the natural lemon note without overpowering the delicate neroli and petitgrain heart of this historic cologne.
2D Molecular Structure
SMILES: CC(CCC=C(C)C)CC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Citronellal is a monoterpenoid aldehyde, structurally similar to citral but with a saturated carbon chain. It occurs naturally as both (+) and (-) enantiomers, with the (-) form being more common in citronella oil. Industrial production often involves the oxidation of citronellol or isolation from citronella oil. The molecule’s reactivity makes it useful as a precursor in the synthesis of other fragrance compounds like hydroxycitronellal.
Physical & Chemical Properties
| Boiling Point | 205-208 °C |
|---|---|
| Density | 0.850-0.860 g/cm³ |
| Refractive Index | 1.446-1.456 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Provides citrus lift in top notes |
| Functional Fragrance | 1-5% | Up to 10% | Used in cleaning products for fresh scent |
Classic Accords
+ Geranium + Cedarwood = Masculine Aromatic
Tip: Stabilize citronellal in alcohol-based fragrances with antioxidants to prevent oxidation to citronellic acid.
Alternatives & Comparisons
Brighter, more intense lemon character but less stable. Use when a stronger citrus impact is needed.
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 restrictions under IFRA standards. Generally recognized as safe at typical usage levels.
EU Allergen Declaration
Must be declared when present above 0.001% in leave-on products or 0.01% in rinse-off products.
GHS Classification
H317 May cause allergic skin reaction
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels. No significant systemic toxicity concerns.
Sustainability
Most commercial citronellal is derived from renewable citronella grass, primarily grown in Southeast Asia. Sustainable harvesting practices are being implemented by major producers. Synthetic production via citronellol oxidation offers a consistent alternative with lower agricultural impact.
Explore Citronellal
Browse essential oils and aroma compounds.
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Industry & Science Data
References
- Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods. International Journal of Food Microbiology. PMID 15246235
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Ingredient Data Sheet
CAS 106-23-0Physical Properties
| Molecular Weight | 154.25 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3🔬 PubChem |
| Boiling Point | 205 °C🔬 EPA CompTox |
| Vapor Pressure | 0.28 mmHg @ 25°C📊 OPERA |
| Flash Point | 73.9 °C🔬 EPA CompTox |
| Involatility Index | 0.0243💻 Calculated |
| log Kp (skin permeability) | -1.511💻 Calculated |
| SMILES | CC(CCC=C(C)C)CC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 1 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fatty• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| Citronellal has an intense, lemon-, citronella-, rose-type odor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “This aldehyde is rather unstable under exposure to air, daylight and alkali, and is therefore not much used as such in perfumes or flavors. Citronella oil is less expensive and more stable. It gives a more attractive picture of the Citronellal odor in its natural modification and composition. Citron”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0207 ppm (n=6)📖 van Gemert |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
| FEMA Number | FEMA 2307⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| IOFI Classification | Nature Identical📖 Fenaroli |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID3041790
Physical Properties
| Molecular Weight | 154.253 g/mol🔬 EPA CompTox |
| Density | 0.856 g/cm^3🔬 EPA CTX |
| Boiling Point | 206.6 °C🔬 EPA CTX |
| Melting Point | 147 °C🔬 EPA CTX |
| Flash Point | 75.275 °C🔬 EPA CTX |
| Refractive Index | 1.437 Dimensionless📊 OPERA |
| Molar Volume | 184.714 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.76 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.632 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.632 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.86 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.159 mmHg🔬 EPA CTX |
| Viscosity | 1.403 cP📊 OPERA |
| Surface Tension | 25.131 dyn/cm📊 OPERA |
| Thermal Conductivity | 132.313 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 17.07 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 48.424 cm^3/mol📊 OPERA |
| Polarizability | 19.197 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.
