Flavor ingredient regulatory record
beta-Naphthyl isobutyl ether
beta-Naphthyl isobutyl ether is an ether in the fruity family, FEMA GRAS under FEMA number 3719 (CAS 2173-57-1). Its odor is sweet, fruity, floral, estery, complex.
- FEMA
- 3719
- CAS
- 2173-57-1
- JECFA
- 1259
- EU FL
- 04.054
- Formula
- C14H16O
- EC
- 218-529-2
GRAS status: FEMA GRAS, publication 13. Recorded by FDA in the Substances Added to Food inventory under CAS 2173-57-1.
Structure
Identity
Also known as: Naphthalene, 2-(2-methylpropoxy)-, Naphthalene, 2-isobutoxy-, 2-(2-Methylpropoxy)naphthalene, Isobutyl 2-naphthyl ether, 2-Isobutoxynaphthalene, β-Naphthyl isobutyl ether, 2-(2-methylpropoxy)naphthalene, nerolin fragarol, isobutyl 2-naphthyl ether, naphthalene, 2-(2-methylpropoxy)-, naphthalene, 2-isobutoxy-, isobutyl beta-naphthyl ether.
Can beta-Naphthyl isobutyl ether be labeled natural?
The process decides for beta-Naphthyl isobutyl ether. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic beta-Naphthyl isobutyl ether is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic beta-Naphthyl isobutyl ether identical-to-natural.
- 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
beta-Naphthyl isobutyl ether is FEMA GRAS under FEMA number 3719. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
Listed on the Union List of flavouring substances as FL 04.054, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 1259, evaluated at the 61st meeting in 2003. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. beta-Naphthyl isobutyl ether appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 2173-57-1, where EPA names it Naphthalene, 2-(2-methylpropoxy)-.
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, floral, estery, complex.
Where it is used
beta-Naphthyl isobutyl ether is used in beverage, confection, fruit flavors and flavoring agents, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to beta-Naphthyl isobutyl ether by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Butyl beta-naphthyl ether | 4634 | 85% | Not determined |
| o-Methylanisole | 2768 | 74% | In nature |
| beta-Naphthyl methyl ether | 4704 | 70% | Not determined |
| 6-Methoxyquinoline | 4640 | 69% | Not determined |
| Propyl cinnamate | 2938 | 67% | In nature |
More ethers in this index
Digeranyl ether · 1,1-Dimethoxyethane · sec-Butyl ethyl ether · Hydroquinone monoethyl ether · Isoamyl phenethyl ether · Methyl phenethyl ether
beta-Naphthyl isobutyl ether FAQ
Is beta-Naphthyl isobutyl ether on the FEMA GRAS list?
It is. FEMA number 3719 covers beta-Naphthyl isobutyl ether. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for beta-Naphthyl isobutyl ether?
The FEMA number for beta-Naphthyl isobutyl ether is 3719 and its CAS registry number is 2173-57-1. Its flavor category is fruity.
What is beta-Naphthyl isobutyl ether used for?
beta-Naphthyl isobutyl ether is described as sweet, fruity, floral, estery, complex. It shows up in beverage, confection, fruit flavors and flavoring agents.
What did JECFA conclude about beta-Naphthyl isobutyl ether?
JECFA evaluated beta-Naphthyl isobutyl ether at the 61st meeting in 2003 under JECFA number 1259. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is beta-Naphthyl isobutyl ether approved in the EU?
Yes. FL 04.054 is the Union List entry for beta-Naphthyl isobutyl ether, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Is beta-Naphthyl isobutyl ether natural or artificial?
Nature makes beta-Naphthyl isobutyl ether, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial beta-Naphthyl isobutyl ether, same molecule. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
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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 BETA-NAPHTHYL ISOBUTYL ETHER under CAS 2173-57-1 and carries its FEMA number, its JECFA flavor number. The inventory is searchable at FDA. FDA records its technical effect as flavor enhancer, 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.