Octanal (CAS 124-13-0) — Citrus Top Note Fragrance Ingredient
Octanal
CAS 124-13-0
What Is Octanal?
Octanal is a citrusy-smelling compound found naturally in orange peels and other citrus fruits. It’s widely used in perfumes, flavorings, and household products to create fresh, zesty aromas. This aldehyde adds sparkling top notes to fragrances and enhances fruity accords in everything from fine perfumery to laundry detergents.
Safety Profile
GENERALLY SAFE
What Does Octanal Smell Like?
Octanal bursts with an intense, zesty orange peel character – like freshly grated citrus zest with a slightly waxy, aldehydic edge. The initial brightness evolves into a cleaner, soapier aroma reminiscent of fine French milled soap. Unlike simpler citrus notes, octanal carries depth into the heart phase with subtle floral undertones before fading to a faintly green, slightly fatty dry-down. Its aldehydic nature gives it more tenacity than limonene but less than decadent C-12 MNA.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Octanal provides the sparkling citrus lift in this classic cologne, blending with lemon and rosemary to create its iconic fresh-chypre character.
Octanal amplifies the photorealistic blood orange effect, adding peel bitterness to balance the juice sweetness.
2D Molecular Structure
SMILES: CCCCCCCC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Octanal is an 8-carbon aldehyde (C8H16O) belonging to the fatty aldehyde family. While occurring naturally in citrus oils, most commercial octanal is produced synthetically via oxidation of 1-octanol or hydroformylation of 1-heptene. Its straight-chain structure lacks chirality centers, making stereoisomerism irrelevant. The aldehyde functional group (-CHO) is responsible for its reactivity and characteristic odor profile.
Physical & Chemical Properties
| Boiling Point | 171-173 °C |
|---|---|
| Density | 0.821 g/cm³ |
| Flash Point | 54 °C |
| Vapor Pressure | 1.6 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Citrus top note enhancer |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Cleaning product brightener |
Classic Accords
+ Aldehyde C-10 + Citral = Hyperreal Citrus
+ Galbanum + Violet Leaf = Green Citrus Chypre
Tip: Stabilize with antioxidants to prevent oxidation to octanoic acid which smells cheesy.
Alternatives & Comparisons
Longer-chain (C10) aldehyde with more floral-waxy character when a less sharp citrus note is desired.
For more lemony citrus effects with greater tenacity and herbal complexity.
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 IFRA restrictions. Listed on IFRA Transparency List.
GHS Classification
H319 Eye irritation
RIFM Assessment
RIFM assessment confirms safe use at current industry levels.
Sustainability
Synthetic production from petrochemical feedstocks dominates the market, though some natural isolates exist. Production has relatively low environmental impact compared to citrus oil extraction which requires large land and water resources.
Explore Octanal
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Industry & Science Data
References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439832279
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Physicochemical Properties
DTXSID: DTXSID3021643
Physical Properties
| Molecular Weight | 128.215 g/mol🔬 EPA CompTox |
| Density | 0.823 g/cm^3🔬 EPA CTX |
| Boiling Point | 171 °C🔬 EPA CTX |
| Melting Point | -10.242 °C🔬 EPA CTX |
| Flash Point | 51.863 °C🔬 EPA CTX |
| Refractive Index | 1.412 Dimensionless📊 OPERA |
| Molar Volume | 157.908 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.2 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.006 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.006 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.36 Log10 unitless🔬 EPA CTX |
| Water Solubility | 0.005 mol/L🔬 EPA CTX |
| Henry's Law Constant | 427.385 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.093 mmHg🔬 EPA CTX |
| Viscosity | 1.231 cP📊 OPERA |
| Surface Tension | 26.03 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.745 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 | 6 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 39.299 cm^3/mol📊 OPERA |
| Polarizability | 15.579 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.
