Citronellyl nitrile (CAS 51566-62-2) — Citrus Top to middle Note Fragrance Ingredient
Citronellyl nitrile
CAS 51566-62-2
What Is Citronellyl nitrile?
Citronellyl nitrile is a synthetic fragrance ingredient that mimics the fresh, citrusy-rosy scent of citronella. It’s commonly found in household cleaners, soaps, and functional fragrances where a long-lasting citrus note is desired. This molecule matters because it provides citronella-like freshness without the volatility of natural citronella oil, making products smell cleaner for longer periods.
Safety Profile
GENERALLY SAFEWhat Does Citronellyl nitrile Smell Like?
Citronellyl nitrile opens with a sharp, green citrus burst reminiscent of crushed lemongrass leaves, quickly settling into a rosy-herbaceous heart. Over hours, it reveals a clean, slightly metallic undertone like wet stones near a citrus grove. Unlike citronellol, it lacks sweetness, instead offering a crisp, almost antiseptic clarity that works exceptionally well in modern functional fragrances.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a synthetic alternative to citrus top notes, providing freshness that survives the shower in this aquatic classic.
The nitrile’s crispness complements the green tea accord, creating a unisex freshness that defined 90s minimalism.
2D Molecular Structure
SMILES: CC(CCC=C(C)C)CC#N
Chemistry, Properties & Perfumer Guide
The Chemistry
An unsaturated nitrile derived from citronellal, citronellyl nitrile belongs to the class of terpenoid nitriles. Industrially produced via hydrocyanation of citronellal followed by dehydration, this achiral molecule offers superior oxidative stability compared to its aldehyde precursor. The nitrile group (-C≡N) contributes to both longevity and its characteristically dry citrus odor profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | 220-225 °C (estimated) |
| Density | 0.86-0.88 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Functional Fragrances | 1-3% | Up to 5% | Provides persistent freshness in detergents |
| Fine Fragrance | 0.5-1.5% | Up to 3% | Adds crispness to citrus florals |
Classic Accords
Tip: Use with ionones to soften the metallic edge while maintaining projection.
Alternatives & Comparisons
When a sweeter, more natural rosy-citrus character is desired, though less stable.
For a greener, sharper citrus profile with similar chemical stability.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (as of 2023 Amendment 51).
EU Allergen Declaration
Not listed in EU allergen regulation (EC) No 1223/2009 Annex III.
GHS Classification
RIFM Assessment
RIFM safety assessment confirms safe use at current industry levels (2021).
Sustainability
As a synthetic material, citronellyl nitrile reduces pressure on natural citronella oil production. Modern catalytic synthesis routes have improved atom economy compared to older methods, though energy-intensive purification steps remain an environmental consideration.
Explore Citronellyl nitrile
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References
- Brenna et al. (2012). Nitrile Fragrance Ingredients. Flavour and Fragrance Journal. DOI:10.1002/ffj.1234
- PubChem Compound Summary for Citronellyl nitrile PubChem
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 51566-62-2Physical Properties
| Molecular Weight | 151.25 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.2🔬 PubChem |
| Boiling Point | 230 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0361 mmHg @ 25°C📊 OPERA |
| Flash Point | 103 °C🔬 EPA CompTox |
| Involatility Index | 0.0032💻 Calculated |
| log Kp (skin permeability) | -1.351💻 Calculated |
| SMILES | CC(CCC=C(C)C)CC#N🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.6 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | citrusgreen• leffingwell |
| Functional Groups | alkene💻 RDKit |
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: DTXSID7052155
Physical Properties
| Molecular Weight | 151.253 g/mol🔬 EPA CompTox |
| Density | 0.845 g/cm^3🔬 EPA CTX |
| Boiling Point | 229.538 °C🔬 EPA CTX |
| Melting Point | -19.459 °C📊 OPERA |
| Flash Point | 103 °C🔬 EPA CTX |
| Refractive Index | 1.445 Dimensionless📊 OPERA |
| Molar Volume | 180.779 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.325 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.171 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.171 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.01 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.036 mmHg🔬 EPA CTX |
| Viscosity | 1.423 cP📊 OPERA |
| Surface Tension | 28.238 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.992 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 23.79 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 48.15 cm^3/mol📊 OPERA |
| Polarizability | 19.088 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.
