Octanal (CAS 124-13-0) — Citrus Top Note Fragrance Ingredient

ByThe Good Scents




Citrus

Octanal

CAS 124-13-0

Origin
Synthetic
Note
Top
IFRA
Generally safe
Data as of: Mar 2026

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

Generally safeUse with awarenessProfessional use
✓ GRAS status for food use
⚠ Potential mild skin irritant at high concentrations
CAS
124-13-0
Formula
Mixture
MW
Variable
Odor Family
Citrus
Layer 1 · Enthusiast

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.

Eau Sauvage(Dior, 1966)

Octanal provides the sparkling citrus lift in this classic cologne, blending with lemon and rosemary to create its iconic fresh-chypre character.

Orange Sanguine(Atelier Cologne, 2010)

Octanal amplifies the photorealistic blood orange effect, adding peel bitterness to balance the juice sweetness.

Layer 2

2D Molecular Structure

Octanal

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

Note Position
Top
Volatility
High (30-90 min)
Blending
Excellent
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

+ Bergamot + Petitgrain = Classic Eau de Cologne
+ 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

1
Decanal CAS 112-31-2

Longer-chain (C10) aldehyde with more floral-waxy character when a less sharp citrus note is desired.

2
Citral CAS 5392-40-5

For more lemony citrus effects with greater tenacity and herbal complexity.

Layer 3

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

H315 Skin irritation
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.

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Industry & Science Data

Odor Detection Threshold
0.700 ppb
in air (orthonasal)
Ref: van Gemert, Odour Thresholds (2011)
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References

  1. Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439832279

Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.

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Ingredient Data Sheet

CAS 124-13-0

Physical Properties

Molecular Weight128.21 g/mol🔬 PubChem
LogP (Octanol-Water)2.7🔬 PubChem
Boiling Point171 °C🔬 EPA CompTox
Vapor Pressure1.18 mmHg @ 25°C📊 OPERA
Flash Point51.7 °C🔬 EPA CompTox
Involatility Index0.1123💻 Calculated
log Kp (skin permeability)-1.565💻 Calculated
SMILESCCCCCCCC=O🔬 PubChem

Volatility & Performance

Fragrance NoteTop💻 Calculated
Volatility ClassModerate💻 Calculated
Persistence Score0.5 / 5💻 Calculated

Odor & Flavor

Primary Descriptorsfattyfruity• leffingwell
Functional Groupsaldehyde💻 RDKit
“Powerful, and in undiluted state harsh-fatty, penetrating odor. In extreme dilution sweet, Orange-like, slightly fatty, Honey-like and of moderate to poor tenacity. Oxidation to Caprylic acid takes place on a perfume blotter within 24 hours, and the acid odor will influence the odor picture over a prolonged period.”📖 Arctander
n-Octanal has a fatty, citrus, honey odor on dilution.📖 Fenaroli

Flavor Notes (Arctander)

“The taste in extreme dilution is sweet, fruity, Apricot-Plum-like, but becomes fatty, It is also used extensively, but very sparingly, in flavor compositions for imitation Butter, Butterscotch, Chocolate, Apricot, Plum, Lemon-Orange, Cheese, Orange, etc. and in spice and condiment blends, e.g. Coria”📖 Arctander

Sensory Thresholds

Odor Detection Threshold0.027 ppm (n=34)📖 van Gemert

Regulatory Status

FEMA NumberFEMA 2797⚖️ FEMA GRAS
GRAS StatusGenerally Recognized as Safe⚖️ FEMA GRAS
IOFI ClassificationNature Identical📖 Fenaroli
Data Sources & Attribution
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: 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.

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