In short
Aldehyde C-11 undecylenic, 10-undecenal, is an unsaturated aliphatic aldehyde with a fresh, waxy, ozonic-floral smell, used for the sparkling, clean top of aldehydic fragrances.
What Aldehyde C-11 Undecylenic (10-Undecenal) smells like
10-Undecenal (aldehyde C-11 undecylenic) is a citrus-peel aldehyde with a green, slightly metallic edge, a fatty-waxy feel and a clean, soft floral impression. Suppliers list citrus, waxy, fatty and aldehydic with a green, soapy nuance; a chemical database notes a characteristic fatty, rose-like odour on dilution. One supplier warns that overdosed it becomes harsh, metallic and dominating. Its clean, floral impression is what gives it its laundry-fresh, 'clean linen' reading.
- Leading note
- Clean aldehydic
- Clear facets
- Citrus peel
- Supporting facets
- Green, rose, on dilution
- Faint facets
- Metallic
- Character
- Clean, waxy, bright, airy
What makes Aldehyde C-11 Undecylenic (10-Undecenal) distinctive
Its green, rosy brightness. Of the two C-11 aldehydes it is the livelier one — greener and more floral-rose than undecylic, with a faint metallic edge that becomes harsh if overdosed.
Concentration and dilution
Fatty and, overdosed, harsh and metallic; on dilution it turns rose-like and clean.
How Aldehyde C-11 Undecylenic (10-Undecenal) is used
Used for clean, aldehydic and laundry-fresh effects in florals and in soap and fabric-care fragrance; one supplier suggests pairing it with citrus, galbanum, muguet, rose, jasmine and ozonic-marine notes.
Typical role: modifier (used in small amounts to change the character of a blend); lift (adds diffusion and radiance, especially at the top).
How Aldehyde C-11 Undecylenic (10-Undecenal) differs from similar materials
- Aldehyde C-11 Undecylic (Undecanal)
- Fraterworks describes undecylenic as greener and more floral-rose than undecylic; undecylic is waxier and soapier. (compared directly by a cited source)
- Aldehyde C-12 Lauric (Dodecanal)
- Dodecanal is waxier, creamier and violet-tinged; undecenal is greener and brighter, with a rosy, citrus-peel edge.
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
Very strong; work from a dilution. Oxidises over time.
Identity and classification
- Type
- Aroma chemical
- Origin
- Synthetic
- Odour family
- Aldehydic / Floral
- Note position
- Top note
- Physical form at room temperature
- Liquid
- Also known as
- 10-Undecenal
- CAS number
- 112-45-8
- Molecular formula
- C11H20O
- Molecular weight
- 168.28 g/mol
- IUPAC name
- undec-10-enal
The CAS number, formula and molecular weight are taken from PubChem compound 8187, 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 (1,818 reports): H315 causes skin irritation (97.2% of reports); H317 may cause an allergic skin reaction (82.9% of reports); H319 causes serious eye irritation (81.6% of reports); H412 harmful to aquatic life with long lasting effects (79% of reports); H411 toxic to aquatic life with long lasting effects (13.1% of reports). 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
-
Aldehyde C-11 Undecylic (Undecanal)
Aroma chemical · Aldehydic / Floral — aldehydic, soapy, waxy, floral
-
Aldehyde C-12 Lauric (Dodecanal)
Aroma chemical · Aldehydic / Floral — aldehydic, waxy, soapy, violet
-
Aldehyde C-12 MNA
Aroma chemical · Aldehydic / Woody — aldehydic, resinous, ambergris, incense
Aldehyde C-11 Undecylenic (10-Undecenal) is also suggested as a partner on the pages for Adoxal and Ethyl Undecylenate.
Used in formulas and accords
Used in 32 published formulas
Aldehyde C-11 Undecylenic (10-Undecenal) is an ingredient in 23 perfume formulas and 9 accords in the Formula & Accord Library.
Community formulas
RUŌOD House Originals
Original compositions by RUŌOD House.
Further reading
Questions about Aldehyde C-11 Undecylenic (10-Undecenal)
Is Aldehyde C-11 Undecylenic (10-Undecenal) natural or synthetic?
Aldehyde C-11 Undecylenic (10-Undecenal) is synthetic — it is made by chemical synthesis.
What is the CAS number of Aldehyde C-11 Undecylenic (10-Undecenal)?
112-45-8. It was checked against PubChem on 19 October 2026.
Which published formulas use Aldehyde C-11 Undecylenic (10-Undecenal)?
Aldehyde C-11 Undecylenic (10-Undecenal) is used in 32 published formulas in the RUŌOD Lab Formula & Accord Library, including Birch Ghost, Blood Accord and Brined Olive Accord. Each is listed with a link under "Used in formulas and accords" on this page.
Sources
- PubChem — compound 8187, 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 — 10-undecen-1-al — odour database.
- Parchem — 10-undecen-1-al — distributor's description.
- Scent.vn — Aldehyde C-11 Undecylenic — distributor's description.
- ChemicalBook — 10-undecenal (CAS 112-45-8) — odour database.
- Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 20 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.