Citronellyl 3-methyl-2-butenoate (CAS 20770-40-5) — Citrus Top to middle Note Fragrance Ingredient
Citronellyl 3-methyl-2-butenoate
CAS 20770-40-5
What Is Citronellyl 3-methyl-2-butenoate?
Citronellyl 3-methyl-2-butenoate is a synthetic fragrance ingredient often found in perfumes and body care products. It contributes a fruity, floral character reminiscent of citrus and berries. This ester is valued for its ability to enhance freshness in fragrances while adding subtle sweetness and complexity to floral compositions.
Safety Profile
GENERALLY SAFEWhat Does Citronellyl 3-methyl-2-butenoate Smell Like?
Citronellyl 3-methyl-2-butenoate opens with a bright burst of citrusy bergamot and juicy raspberry notes, quickly settling into a heart of soft floral rose with a hint of tropical lychee. The dry-down reveals a clean, slightly woody-musky base that adds tenacity without heaviness. Like biting into a perfectly ripe peach on a summer morning, this material brings both freshness and subtle sweetness to fragrance compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to enhance the fruity-floral character of this iconic summer fragrance, adding juicy brightness to the citrus top notes and smooth transition to the floral heart.
Provides subtle fruity facets to this delicate floral, helping bridge the grapefruit top notes with the jasmine-hyacinth heart accord.
2D Molecular Structure
SMILES: CC(CCOC(=O)C=C(C)C)CCC=C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Citronellyl 3-methyl-2-butenoate is an ester formed from citronellol and 3-methyl-2-butenoic acid. As a synthetic material, it’s typically produced via acid-catalyzed esterification under controlled conditions. The ester linkage gives this compound its characteristic fruity-floral odor profile while maintaining good stability in formulations. Its molecular structure allows for both volatility as a top note and sufficient tenacity to carry through to the middle phase of fragrance development.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~250°C (estimated) |
| Density | ~0.89 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Adds fruity-floral freshness |
| Body Care | 0.5-3% | Up to 5% | Provides subtle fruity nuances |
Classic Accords
Tip: Use in citrus-floral compositions to add naturalistic fruity facets without candied sweetness.
Alternatives & Comparisons
For a brighter, more citrusy effect with less floral character. Lacks the berry nuances of the 3-methyl-2-butenoate ester.
When more rosy-floral character is desired while maintaining similar fruity aspects. Has greater tenacity in the dry-down.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards. No usage limits specified.
RIFM Assessment
Currently under review by RIFM with preliminary data showing no significant safety concerns at typical usage levels.
Sustainability
As a synthetic material, citronellyl 3-methyl-2-butenoate offers consistent quality without natural sourcing variability. Production from petrochemical precursors raises some environmental concerns, though newer green chemistry routes using bio-based citronellol are being developed to improve sustainability.
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Physicochemical Properties
DTXSID: DTXSID40864961
Physical Properties
| Molecular Weight | 238.371 g/mol🔬 EPA CompTox |
| Density | 0.888 g/cm^3📊 OPERA |
| Boiling Point | 289.198 °C📊 OPERA |
| Melting Point | 3.302 °C📊 OPERA |
| Flash Point | 134.629 °C📊 OPERA |
| Refractive Index | 1.46 Dimensionless📊 OPERA |
| Molar Volume | 266.827 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.097 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 5.097 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 5.097 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.55 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.006 mmHg📊 OPERA |
| Surface Tension | 28.076 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 | 7 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 73.076 cm^3/mol📊 OPERA |
| Polarizability | 28.97 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.
