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CAS 1 record

CAS 26172-55-4

CAS 26172-55-4 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 26172-55-4
CAS 26172-55-4PubChem CID 33344

5-Chloro-2-methyl-4-isothiazolin-3-one

Chloromethylisothiazolinone is a 1,2-thiazole that is 4-isothiazolin-3-one bearing a methyl group on the nitrogen atom and a chlorine at C-5. It is a powerful biocide and preservative and is the major active ingredient in the commercial product KathonTM. It has a role as an antimicrobial agent, a xenobiotic and an environmental contaminant. It is an organochlorine compound and a member of 1,2-thiazoles. It is functionally related to a methylisothiazolinone. — ChEBI

IUPAC name
5-chloro-2-methyl-1,2-thiazol-3-one
Molecular formula
C4H4ClNOS
Molecular weight
149.60 g/mol
Exact mass
148.9702126 Da
XLogP3
0.9
Topological polar surface area
45.6 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

MethylchloroisothiazolinoneCMIT5-Chloro-2-methyl-3(2H)-isothiazolone5-Chloro-2-methyl-3-isothiazoloneKathon CG 52433(2H)-Isothiazolone, 5-chloro-2-methyl-5-chloro-N-methylisothiazolone5-chloro-2-methylisothiazolin-3-one
16 more reported names
5-chloro-n-methylisothiazolin-3-oneHS 818n-methyl-5-chloroisothiazoloneDEL7T5QRPN4-ISOTHIAZOLIN-3-ONE, 5-CHLORO-2-METHYL-N-Methyl-5-chloroisothiazolin-3-one5-chloro-2-methyl-3(2H)-isothiazolinoneHS-818RefChem:818544247-500-7Chloromethylisothiazolinone5-chloro-2-methylisothiazol-3(2h)-one5-Chloro-2-methyl-2H-isothiazol-3-one5-chloro-2-methyl-isothiazol-3-one5-Chloro-2-methyl-4-isothiazolin-3-one (CMI)5-chloro-2-methyl-4-isothiazoline-3-one
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External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 26172-55-4

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No records found for this CAS number.

How CAS 26172-55-4 is used on this site

CAS 26172-55-4 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 26172-55-4 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.