Monochloroacetic acid

CAS 79-11-8

Listed as a preservative by the US.

Listed as preservatives (US)
Chemical structure of Monochloroacetic acid, from PubChem compound 300
Structure from PubChem CID 300 (National Library of Medicine, public domain). A depiction of one compound: where a listing covers a family, or a substance has no single structure, this page shows none.

Monochloroacetic acid was formerly used as a preservative. It is prohibited from use in human food in the United States.

Where it is and isn’t permitted

Status of Monochloroacetic acid by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
CanadaHealth CanadaNo listing matchedHealth Canada’s lists name additives without E or INS numbers, so this site matches them by exact name. A substance listed there under a name this site does not recognise has no row here.
European UnionEuropean Commission / EFSANo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
Great BritainFood Standards Agency / Food Standards ScotlandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
JapanConsumer Affairs AgencyNo listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance.
South KoreaMinistry of Food and Drug SafetyNo listing matchedThis site imports Part III of South Korea’s Standards and Specifications for Food Additives, matched by CAS number, then INS number, then exact name. Mixed preparations and sanitisers are not imported, and an entry whose identifiers disagreed with a page’s is held for review, so an empty row does not show that South Korea does not permit the substance.
United StatesFood and Drug AdministrationProhibited21 CFR 189.155retrieved 2026-10-17
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 industrially by chlorinating acetic acid. It remains an important industrial chemical intermediate outside food use.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
79-11-8
InChIKey
FOCAUTSVDIKZOP-UHFFFAOYSA-N
PubChem
CID 300

Every name it appears under

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

CAS registry number

  • 79-11-8

As it appears in regulation

  • Monochloroacetic acid

Other names

  • .alpha.-Chloroacetic acid
  • 2-chloro-acetic acid
  • 2-chloro-ethanoic acid
  • 2-chloroacetic acid
  • 4-02-00-00474 (Beilstein Handbook Reference)
  • Acetic acid, 2-chloro-
  • Acetic acid, chloro-
  • Acetocaustin
  • Acetocaustin (TN)
  • Acide chloracetique
  • Acide chloroacetique
  • Acide monochloracetique
  • Acidomonocloroacetico
  • alpha-chloro-acetic acid
  • alpha-Chloroacetic acid
  • BRN 0605438
  • C2H3ClO2
  • CAS-79-11-8
  • Caswell No. 179B
  • CCRIS 2117
  • CH2ClCOOH
  • Chloracetic acid
  • chloro acetic acid
  • chloro-acetic acid
  • Chloroacetic
  • chloroacetic acid
  • Chloroacetic acid (80% or less)
  • CHLOROACETIC ACID CRYSTALLINE
  • Chloroacetic acid, 99%
  • Chloroacetic acid, >=99%
  • CHLOROACETIC ACID, ACS
  • Chloroacetic acid, ACS grade
  • Chloroacetic acid, ACS reagent, >=99.0%
  • Chloroacetic acid, analytical standard
  • Chloroacetic acid, for synthesis, 99.0%
  • Chloroacetic acid, liquid
  • Chloroacetic acid, molten
  • Chloroacetic acid, puriss., >=99.0% (T)
  • Chloroacetic acid, purum, >=97.0% (T)
  • Chloroacetic acid, solid
  • Chloroacetic acid, solid (dot)
  • CHLOROACETIC-ACID
  • Chloroethanoic acid
  • ClCH2COOH
  • cloroacetic acid
  • EPA Pesticide Chemical Code 279400
  • FOCAUTSVDIKZOP-UHFFFAOYSA-
  • HSDB 939
  • Kyselina chloroctova
  • MCAA
  • MKhUK
  • Monochloorazijnzuur
  • Monochloracetic acid
  • Monochloracetic acidacide monochloracetique
  • Monochloressigsaeure
  • monochloro acetic acid
  • monochloro-acetic acid
  • Monochloroacetic acid
  • Monochloroethanoic acid
  • sJPhLQDIKTp@
  • WLN: QV1G

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 rather than machine-read, and none has been written for this substance yet.

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is Monochloroacetic acid?
Monochloroacetic acid was formerly used as a preservative. It is prohibited from use in human food in the United States.
What is Monochloroacetic acid used for in food?
It is listed as a preservative — the role the US assigns it. This page shows every function each regulator records, with the citation for each.
Is Monochloroacetic acid vegan?
Yes. Monochloroacetic acid is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • ecfr retrieved 2026-10-17

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

Machine-readable: a JSON record of this additive is given on request —how to ask for access.

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