2,6-Nonadienal

What 2,6-Nonadienal smells like

2,6-Nonadienal is the essence of cucumber and one of the keys to violet leaf: an intensely powerful, greasy green with cucumber, violet-leaf and melon notes. Bedoukian describes a powerful cucumber and violet-leaf odour in dilution with a hint of melon; Parchem lists green, cucumber, melon, fatty and vegetative. It occurs in cucumber, freshly cut watermelon and bread crust. It is so strong that it is sold diluted in dipropylene glycol, and De Hekserij describes its concentrated smell as an intense, greasy green.

Leading note

Cucumber

Clear facets

Violet leaf

Supporting facets

Fatty, melon

Faint facets

Vegetative

Character

Green, fatty, intense, watery

• cucumber
• green
• violet leaf
• watery

What makes 2,6-Nonadienal distinctive

It is the cucumber molecule — the aggressive, fatty-green aldehyde behind the cucumber and violet-leaf effect, harsher and leafier than its alcohol, nonadienol.

Concentration and dilution

Overwhelmingly greasy and green when concentrated; only in dilution does it read clearly as cucumber and violet leaf with a hint of melon.

How 2,6-Nonadienal is used

Used in traces as an indispensable component of violet-leaf accords and their substitutes, and for cucumber, melon and watery-green effects, alongside fruits such as melon, pear and apple and florals such as violet and linden.

Typical role: modifier (used in small amounts to change the character of a blend).

How 2,6-Nonadienal differs from similar materials

2,6-Nonadienol*

Givaudan describes the alcohol as fruitier and less leafy, and Fraterworks as softer and more floral than the aggressive aldehyde; it is also more stable. (compared directly by a cited source)

Methyl Heptine Carbonate

Methyl heptine carbonate is violet foliage first, vegetal and hay-like; nonadienal is cucumber first, fattier and more aggressive.

Violet Leaf Absolute

The absolute owes much of its cucumber-green to nonadienal and related compounds, but adds an earthy, waxy, metallic natural complexity.

An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

Extremely potent; work from 0.1% or weaker dilutions.

Identity and classification

Type

Aroma chemical

Origin

Occurs in nature

Odour family

Green / Aquatic

Note position

Top note

Physical form at room temperature

Liquid

Also known as

Cucumber aldehyde, Violet leaf aldehyde

CAS number

557-48-2

Molecular formula

C9H14O

Molecular weight

138.21 g/mol

IUPAC name

(2E,6Z)-nona-2,6-dienal

The CAS number, formula and molecular weight are taken from PubChem compound 643731, whose own record lists this CAS number; checked 19 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (1,526 reports): H317 may cause an allergic skin reaction (92.7% of reports); H315 causes skin irritation (90.5% of reports). 105 of the reports find it does not meet the hazard criteria. A skin sensitiser classification concerns handling the neat material and the dose in a finished product; the IFRA Standards, where they apply, set the limits. Unless it is harmonised, this is the notifiers' own classification, not a binding one.

This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.

Materials it works with

• Violet Leaf Absolute

  Absolute · Green / Aquatic — green, leafy, cucumber, watery

• Melonal

  Aroma chemical · Aquatic / Fruity — melon, watery, green, fresh

• Calone

  Aroma chemical · Aquatic / Metallic — marine, watermelon, ozonic, watery

• 2,6-Nonadienol

  Aroma chemical · Green / Fruity — cucumber, violet leaf, green, melon

2,6-Nonadienal is also suggested as a partner on the pages for cis-6-Nonenal, cis-6-Nonenol, Methyl Heptine Carbonate, Methyl Octine Carbonate and Violiff.

Used in formulas and accords

Used in 3 published formulas

2,6-Nonadienal is an ingredient in 2 perfume formulas and 1 accord in the Formula & Accord Library.

Community formulas

• Pumpkin Accord

  Community Formula · Accord · listed as “Trans-2, Cis-6-Nonenal 1%”, at 1%

RUŌOD House Originals

Original compositions by RUŌOD House.

• Lime Bruise

  RUŌOD House Original · listed as “2,6-Nonadienal 1% DPG”, at 1% in DPG

• Violet Static

  RUŌOD House Original · listed as “2,6-Nonadienal 1% DPG”, at 1% in DPG

Further reading

• Green Notes in Perfumery: Leaf, Galbanum and Violet Leaf

  The green palette — cis-3-hexenol, galbanum, violet leaf, styrallyl acetate — what green notes do, dosage, restrictions and pairings.

• How to Dilute Aroma Chemicals and Raw Materials for Formulating

  Why perfumers keep materials at 10%, 1% or 0.1%, how to make a dilution by weight, which solvent to choose, and how to account for it in a formula.

Questions about 2,6-Nonadienal

Sources

• PubChem — compound 643731, checked 19 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• The Good Scents Company — (E,Z)-2,6-nonadienal (with Bedoukian's description) — odour database.
• Parchem — (E,Z)-2,6-nonadien-1-al specification — distributor's description.
• Fraterworks — trans-2-cis-6-nonadienal — distributor's description.
• De Hekserij — 2,6-nonadien-1-al — distributor's description.
• Wikipedia — trans,cis-2,6-Nonadienal — published perfumery reference.
• Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 20 October 2026. Evidence: several independent published descriptions, which agree. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.