Ethoxyquin

CAS 91-53-2

Ethoxyquin is an antioxidant permitted in the United States for chilli powder, paprika and ground chilli, where it protects the colour. It is far better known as an antioxidant in animal feed and fish meal, and its food uses are narrow.

Where it is and isn’t permitted

Status of Ethoxyquin by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted, with conditions21 CFR 172.140retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

What it is made from

Produced by chemical synthesis from aniline derivatives.

  • Vegan
  • Vegetarian
CAS registry number
91-53-2
InChIKey
DECIPOUIJURFOJ-UHFFFAOYSA-N
PubChem
CID 3293

Every name it appears under

62 recorded names. A label may use any of them.

E number

  • E0237
  • E324
  • E7329

CAS registry number

  • 91-53-2

As it appears in regulation

  • Ethoxyquin

Other names

  • 1,2,4-trimethyl-6-ethoxyquinoline
  • 1,2-Dihydro-2,2,4-trimethyl-6-ethoxyquinoline
  • 1,2-DIHYDRO-2,2,4-TRIMETHYLQUINOLIN-6-YL ETHYL ETHER
  • 1,2-Dihydro-6-ethoxy-2,2,4-trimethylquin oline
  • 1,2-Dihydro-6-ethoxy-2,2,4-trimethylquinoline
  • 2,2,4-Trimethyl-6-ethoxy-1,2-dihydroquinoline
  • 2,4-Trimethyl-6-ethoxy-1,2-dihydroquinoline
  • 6-(ethyloxy)-2,2,4-trimethyl-1,2-dihydroquinoline
  • 6-Ethoxy-1,2,4-trimethylquinoline
  • 6-Ethoxy-1,2-dihydro-2,2,4-trimethyl-Quinoline
  • 6-Ethoxy-1,2-dihydro-2,2,4-trimethylquinoline
  • 6-Ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, 9CI, 8CI
  • 6-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline
  • 6-ethoxy-2,2,4-trimethyl-1H-quinoline
  • 6-Ethoxy-2,4-trimethyl-1,2-dihydroquinoline
  • 6-ETMDQ
  • Alterungsschutzmittel EC
  • Amea 100
  • Antage AW
  • Antioxidant EC
  • Aries Antox
  • CAS-91-53-2
  • Caswell No. 427D
  • CCRIS 2513
  • Dawe's nutrigard
  • EMQ
  • EPA Pesticide Chemical Code 055501
  • Ethoxychin
  • Ethoxyquin
  • Ethoxyquin (Standard)
  • Ethoxyquin, >=75% (capillary GC)
  • Ethoxyquin, PESTANAL(R), analytical standard
  • Ethoxyquin, Vetec(TM) reagent grade, 75%
  • Ethoxyquine
  • Ethyl 2,2,4-trimethyl-1,2-dihydro-6-quinolinyl ether
  • Ethyl 2,2,4-trimethyl-1,2-dihydro-6-quinolinyl ether #
  • HMS500J05
  • HSDB 400
  • Niflex
  • Niflex D
  • Nix-Scald
  • Nocrac AW
  • Nocrack AW
  • Permanax 103
  • Quinol ED
  • Quinoline, 6-ethoxy-1,2-dihydro-2,2,4-trimethyl-
  • Santoflex
  • Santoflex A
  • Santoflex AW
  • Santoquin
  • Santoquine
  • Santoquine (VAN)
  • SantoquinEQ
  • Stop-Scald
  • Usaf B-24
  • WLN: T66 BM CHJ C1 C1 E1 HO2

Systematic names

  • 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/ethoxyquin.json