d,l-Limonene (isomer unspecified) (CAS 7705-14-8) — Citrus Top Note Fragrance Ingredient
d,l-Limonene (isomer unspecified)
CAS 7705-14-8
What Is d,l-Limonene (isomer unspecified)?
d,l-Limonene is a fresh, citrusy-smelling compound found in the peels of oranges, lemons, and other citrus fruits. It’s widely used in household cleaners, air fresheners, and fragrances for its bright, uplifting aroma. This versatile ingredient creates an instant association with cleanliness and freshness, making it a staple in many consumer products.
Safety Profile
USE WITH AWARENESSWhat Does d,l-Limonene (isomer unspecified) Smell Like?
d,l-Limonene bursts with a vibrant, zesty citrus character reminiscent of freshly peeled oranges. The initial impression is intensely fresh and slightly sweet, like biting into a ripe tangerine. As it evolves, it reveals a cleaner, more terpenic quality with subtle woody undertones. The dry-down retains a faint citrusy freshness, though less sweet than the opening, with a dry, slightly resinous edge.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Limonene provides the sparkling citrus top note that defines this classic cologne, combining with rosemary and basil for a crisp, aromatic opening.
Used alongside other citrus notes to create the vibrant, sun-drenched Mediterranean citrus accord that makes this fragrance so instantly recognizable.
2D Molecular Structure
SMILES: CC(=C)C1CCC(C)=CC1
Chemistry, Properties & Perfumer Guide
The Chemistry
Limonene is a monocyclic monoterpene hydrocarbon with the molecular formula C10H16. It exists as two enantiomers: d-limonene (more common in nature) and l-limonene (found in some citrus and conifer oils). The racemic mixture (d,l-limonene) is commonly produced synthetically. Industrial production typically involves fractional distillation of citrus peel oils or catalytic isomerization of α-pinene from turpentine.
Physical & Chemical Properties
| Boiling Point | 176 °C |
|---|---|
| Flash Point | 48 °C |
| Density | 0.841 g/cm³ |
| Vapor Pressure | 1.5 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Fresh citrus top notes |
| Household Products | 5-15% | Up to 30% | Clean, fresh character |
Classic Accords
Tip: Stabilize in ethanol-based formulations to prevent oxidation to carvone and limonene oxide.
Alternatives & Comparisons
A similar terpene mixture containing limonene isomers, often used interchangeably but with slightly less citrusy character.
For more lemony citrus notes when a stronger, more defined citrus character is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
IFRA 49: No restrictions, but recommended max 20% in leave-on products due to sensitization potential.
EU Allergen Declaration
EU Allergen: Must be declared when concentration exceeds 0.001% in leave-on and 0.01% in rinse-off products.
GHS Classification
RIFM Assessment
RIFM assessment confirms sensitization potential at high concentrations but safe at typical usage levels in fragrances.
Sustainability
While naturally occurring in citrus, most commercial limonene is derived as a byproduct of the orange juice industry or synthesized from pine chemicals. Synthetic production has lower environmental impact than citrus oil extraction when considering land and water use.
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References
- PubChem Compound Summary for Limonene PubChem CID 22311
- IFRA Standards Library IFRA 49th Amendment
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID2029612
Physical Properties
| Molecular Weight | 136.238 g/mol🔬 EPA CompTox |
| Density | 0.841 g/cm^3🔬 EPA CTX |
| Boiling Point | 176.764 °C🔬 EPA CTX |
| Melting Point | -54.262 °C🔬 EPA CTX |
| Flash Point | 45.482 °C🔬 EPA CTX |
| Refractive Index | 1.468 Dimensionless📊 OPERA |
| Molar Volume | 163.264 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.452 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 | 0.029 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.633 mmHg🔬 EPA CTX |
| Viscosity | 1.256 cP📊 OPERA |
| Surface Tension | 25.913 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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