N/A — synthetic aldehyde (also found naturally in citrus oils)
Appearance
colorless to pale yellow clear liquid
Odor Strength
High
Producing Countries
China, Germany, United States
Pyramid
Top
Fresh, citrus-aldehydic with a waxy, slightly fatty quality. Octanal smells like orange peel zested onto a cutting board — sharp, bright, with a soapy-clean edge.
Fresh, citrus-orange, aldehydic. Waxy and slightly fatty at concentration, bright and clean at dilution. Less green than hexanal, less waxy than decanal, more orange-like than nonanal. The typical 'fatty aldehyde' duality — sharp and pungent up close, clean and sparkling at a distance.
Evolution over time
Immediately
Immediately
Sharp, citrus-orange burst. Aldehydic and bright.
After a few hours
After a few hours
Waxy-clean heart. Orange character persists. Soapy undertone.
After a few days
After a few days
Quick fade. High volatility. Faint waxy-citrus residue.
The Full Story
CAS 124-13-0. An 8-carbon straight-chain aldehyde. Octanal is one of the 'fatty aldehydes' — a series of linear aliphatic aldehydes (C6-C12) that collectively define the 'aldehydic' effect in perfumery. Each member has a characteristic citrus-fatty-soapy quality that varies with chain length.
Octanal specifically has a fresh, citrus-orange character with a waxy, slightly fatty undertone. It is brighter and more citrus-like than the longer-chain aldehydes (decanal, undecanal) and less aggressively green than the shorter ones (hexanal). It contributes to the natural aroma of orange peel and various citrus fruits.
The fatty aldehydes are famously difficult materials — pungent at concentration, beautiful at dilution. The aldehydic bouquet that defines certain classic perfumes is built from combinations of C8-C12 aldehydes balanced against florals and musks.
The famous 'aldehydic' effect — the sparkling, soapy-fresh quality — was not discovered by a chemist but by a perfumer. Ernest Beaux, creating a legendary fragrance in 1921, reportedly overdosed the aldehydes in his formula by accident, and the resulting sparkling freshness became an imitated effects in perfumery history.
Extraction & Chemistry
Extraction method: Produced synthetically by oxidation of octanol, or by hydroformylation of 1-heptene. Found naturally in citrus peel oils but not commercially isolated from natural sources. Inexpensive, large-scale production.
Molecular Formula
C8H16O
CAS Number
124-13-0
Botanical Name
N/A — synthetic aldehyde (also found naturally in citrus oils)
IFRA Status
No known restrictions
Synonyms
CAPRYLIC ALDEHYDE · OCTANALDEHYDE · OCTANAL
Physical Properties
Odor Strength
High
Lasting Power
7 hour(s) at 100.00 %
Appearance
colorless to pale yellow clear liquid
Boiling Point
171.00 to 173.00 °C. @ 760.00 mm Hg
Flash Point
125.00 °F. TCC ( 51.67 °C. )
Specific Gravity
0.81000 to 0.83000 @ 25.00 °C.
Refractive Index
1.41700 to 1.42500 @ 20.00 °C.
Melting Point
12.00 to 15.00 °C. @ 760.00 mm Hg
In Perfumery
Top-note modifier in aldehydic, citrus, and fresh compositions. Octanal contributes orange-citrus brightness to the aldehydic bouquet. It is used alongside C9-C12 aldehydes to build the shimmering, 'soapy-clean' effect that defines aldehydic perfumery. Also used in citrus accords to enhance orange-peel character. Must be dosed carefully — excess creates an unpleasant rancid-fatty impression.
