Flavor ingredient regulatory record

2-Ethyl-2-hexenal

2-Ethyl-2-hexenal is an aldehyde in the fruity family, FEMA GRAS under FEMA number 4612 (CAS 645-62-5). Its odor is sweet, fruity, green apple, floral, nutty.

FEMA
4612
CAS
645-62-5
Formula
C8H14O

GRAS status: FEMA GRAS, publication 24. Recorded by FDA in the Substances Added to Food inventory under CAS 645-62-5.

Structure

2D structure of 2-Ethyl-2-hexenal
Structure of 2-Ethyl-2-hexenal, C8H14O. Drawn from the canonical SMILES.

Identity

IUPAC name (E)-2-ethylhex-2-enal
CAS number 645-62-5
FEMA number 4612
Molecular formula C8H14O
Molecular weight 126.2 g/mol
SMILES CCC/C=C(/C=O)CC
InChIKey PYLMCYQHBRSDND-SOFGYWHQSA-N
PubChem CID 5354264
Chemical class Aldehyde
Boiling point 175 °C
Flash point 68 °C

Also known as: 2-Hexenal, 2-ethyl-, 2-Ethyl-3-propylacrolein, α-Ethyl-β-propylacrolein, 2-Ethyl-2-hexen-1-al, α-Ethyl-2-hexenal, 3-Formylhept-3-ene, CKB 1364, NSC 4787, (e)-2-ethylhex-2-enal, 2-ethyl-3-propylacrolein, (e)-2-ethyl-2-hexenal, 2-hexenal, 2-ethyl-.

Can 2-Ethyl-2-hexenal be labeled natural?

2-Ethyl-2-hexenal occurs in nature, so the label depends on the route: 2-Ethyl-2-hexenal won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 2-Ethyl-2-hexenal is artificial. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.

United States
Natural or artificial, by process
European Union and UK
Natural only from natural material
Mercosur and Mexico
Natural or identical-to-natural

How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.

Regulatory status, with citations

United States

2-Ethyl-2-hexenal is FEMA GRAS under FEMA number 4612. It is cited in the Code of Federal Regulations at 21 CFR 172.515.

21 CFR 172.515

European Union and United Kingdom

No EU FL number is on file for 2-Ethyl-2-hexenal. That is not a finding either way. The Union List covers defined flavouring substances, so natural complex materials are handled as flavouring preparations under Parts B to F and never receive a number, and substances used as additives sit under Regulation 1333/2008 instead. Confirm the position before EU or UK use.

JECFA (WHO / FAO)

2-Ethyl-2-hexenal has not been evaluated by JECFA as a flavouring agent, or no evaluation is on file.

Other US flags

Not on the California Proposition 65 list.

TSCA Inventory status

A flavor ingredient is also an industrial chemical. 2-Ethyl-2-hexenal appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 645-62-5, where EPA names it 2-Hexenal, 2-ethyl-.

Active in US commerce

EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. What active and inactive mean.

EPA publishes no regulatory flags on this listing. What the flags mean.

From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.

Odor and taste

Odor: Sweet, fruity, green apple, floral, nutty.

Where it is used

2-Ethyl-2-hexenal is used in beverage, confection, fruit flavors, bakery and dairy, typically as a fruity note.

Structurally similar flavor ingredients

Flavor ingredients with a GRAS determination closest to 2-Ethyl-2-hexenal by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.

MaterialFEMASimilarityOccurrence
5-Methyl-2-hepten-4-one376190%In nature
3-Hepten-2-one340090%In nature
2-Hepten-4-one339989%In nature
3-Heptanone254588%In nature
(E,Z)-4-Octen-3-one432881%In nature

More aldehydes in this index

2-trans,4-trans-Decadienal · 1-Methyl-1H-pyrrole-2-carboxaldehyde · Perillaldehyde propyleneglycol acetal · Valeraldehyde · Octadec-9-enal · alpha-Hexylcinnamaldehyde

2-Ethyl-2-hexenal FAQ

Does 2-Ethyl-2-hexenal have FEMA GRAS status?

2-Ethyl-2-hexenal holds FEMA GRAS status under FEMA number 4612. It is also codified at 21 CFR 172.515.

How do I cite 2-Ethyl-2-hexenal by FEMA or CAS number?

Cite 2-Ethyl-2-hexenal as FEMA 4612 or CAS 645-62-5; both point to the same entry. FEMA files it in the fruity flavor category.

Can 2-Ethyl-2-hexenal be labeled a natural flavor?

Since 2-Ethyl-2-hexenal is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 2-Ethyl-2-hexenal is synthesized. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.

What does 2-Ethyl-2-hexenal smell and taste like, and where is it used?

The odor of 2-Ethyl-2-hexenal is sweet, fruity, green apple, floral, nutty. Typical uses are beverage, confection, fruit flavors, bakery and dairy.

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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as 2-ETHYL-2-HEXENAL under CAS 645-62-5 and carries its FEMA number. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.

A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.

Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.

About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.