l-Limonene (CAS 5989-54-8) — Citrus Top Note Fragrance Ingredient
l-Limonene
CAS 5989-54-8
What Is l-Limonene?
l-Limonene is a citrusy molecule found in the peels of oranges, lemons, and other citrus fruits. It’s commonly encountered in cleaning products, air fresheners, and citrus-based perfumes. This ingredient matters because it provides a fresh, uplifting scent that energizes spaces and compositions while being biodegradable and derived from renewable resources.
Safety Profile
GENERALLY SAFEWhat Does l-Limonene Smell Like?
l-Limonene bursts with a bright, zesty orange peel aroma – like freshly grated citrus zest with a slightly sweet, green undertone. The initial impression is intensely fresh and cheerful, evolving into a cleaner citrus note with a faintly herbal, almost minty facet as it dries. Unlike its d-isomer counterpart, the l-form has a sharper, more bitter citrus character that lacks the round sweetness of orange juice, instead recalling the pithy, slightly resinous quality of lemon rind. In drydown, it leaves a subtle woody-herbal trace that blends well with other top notes.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used alongside bergamot to create a crisp, natural citrus opening that avoids excessive sweetness. The l-isomer provides a sharper citrus counterpoint to the floral heart.
Employed in the citrus top note accord to give a fresh, unisex character. Its slightly bitter edge prevents the composition from becoming too sweet or feminine.
Blended with other citrus oils to create an authentic Italian citrus cologne effect. The l-isomer adds realism to the citrus peel impression.
Used in the top note to enhance the Sicilian lemon theme, contributing a slightly green, tart citrus nuance that pairs well with the apple note.
The l-isomer provides a bitter orange peel facet that balances the sweeter blood orange notes, creating a more complex citrus accord.
2D Molecular Structure
SMILES: CC(=C)[C@H]1CCC(C)=CC1
Chemistry, Properties & Perfumer Guide
The Chemistry
l-Limonene is a monocyclic monoterpene hydrocarbon, specifically the (4S)-enantiomer of limonene. Unlike the more common d-limonene which has an orange-like odor, l-limonene exhibits a sharper, more resinous citrus character. Industrially, it’s obtained through fractional distillation of citrus peel oils or by chromatographic separation of racemic limonene. The molecule’s chirality significantly impacts its olfactory properties – the l-form lacks the sweet roundness of its mirror image molecule. Its double bond makes it reactive, prone to oxidation to carveol and carvone over time.
Physical & Chemical Properties
| Boiling Point | 176 °C |
|---|---|
| Density | 0.84 g/cm³ |
| Refractive Index | 1.472 |
| Flash Point | 48 °C |
| Vapor Pressure | 1.5 mmHg at 20°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 2-5% | Up to 10% | Citrus top note component |
| Household Products | 1-3% | Up to 5% | Fresh citrus impression |
| Flavorings | 0.1-0.5% | Up to 1% | Citrus flavor enhancer |
Classic Accords
Tip: Combine with terpenes like pinene to enhance freshness and extend evaporation time.
Alternatives & Comparisons
The more common isomer with sweeter orange character. Use when a rounder, less bitter citrus note is desired.
For a stronger lemon note with more tenacity, though more prone to oxidation and skin sensitivity.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Considered safe at all concentrations for fragrance use.
EU Allergen Declaration
Not listed as an EU allergen, though oxidized limonene derivatives may cause sensitization.
GHS Classification
RIFM Assessment
RIFM considers l-limonene safe for use in fragrance when properly purified and stored to prevent oxidation.
Sustainability
l-Limonene is considered environmentally friendly as it’s biodegradable and can be derived from citrus processing byproducts. Most commercial l-limonene is obtained through fractional distillation of citrus oils or resolution of racemic limonene, requiring careful energy management. Synthetic production routes exist but are less common due to the availability of natural sources.
Explore l-Limonene
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
- Fenaroli’s Handbook of Flavor Ingredients (6th ed.). CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 5989-54-8Physical Properties
| Molecular Weight | 136.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 175.8 °C🔬 EPA CompTox |
| Vapor Pressure | 1.44 mmHg @ 25°C📊 OPERA |
| Flash Point | 48 °C🔬 EPA CompTox |
| Involatility Index | 0.133💻 Calculated |
| log Kp (skin permeability) | -1.117💻 Calculated |
| SMILES | CC1=CCC(CC1)C(=C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | herbalorange• leffingwell |
| Functional Groups | alkene💻 RDKit |
| “l-Limonene has a refreshing, light, very clean odor, not reminiscent of Citrus fruits in particular, and not recalling any specific Pine or Mint. This could be due to the fact that the samples of l-Limonene available have been of purely synthetic origin.”📖 Arctander | |
Sensory Thresholds
| Odor Detection Threshold | 1.3261 ppm (n=9)📖 van Gemert |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
| EU Annex III | Listed (restricted)⚖️ IFRA 51 |
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: DTXSID6047078
Physical Properties
| Molecular Weight | 136.238 g/mol🔬 EPA CompTox |
| Density | 0.84 g/cm^3🔬 EPA CTX |
| Boiling Point | 175.875 °C🔬 EPA CTX |
| Melting Point | -73.98 °C🔬 EPA CTX |
| Flash Point | 49.5 °C🔬 EPA CTX |
| Refractive Index | 1.468 Dimensionless📊 OPERA |
| Molar Volume | 163.264 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.57 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 4.457 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.457 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.31 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.027 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.456 mmHg🔬 EPA CTX |
| Viscosity | 1.256 cP📊 OPERA |
| Surface Tension | 25.939 dyn/cm📊 OPERA |
| Thermal Conductivity | 118.647 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 45.355 cm^3/mol📊 OPERA |
| Polarizability | 17.98 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.
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