5-Chloro-2-methyl-4-isothiazolin-3-one
[CAS# 26172-55-4]

Identification

• Classification: Chemical pesticide >> Fungicide >> Other fungicides
• Name: 5-Chloro-2-methyl-4-isothiazolin-3-one
• Synonyms: 5-Chloro-2-methyl-3(2H)-isothiazolone; 5-Chloro-2-methylisothiazolone; Kathon IXE
• Molecular Formula: C₄H₄ClNOS
• Molecular Weight: 149.59
• CAS Registry Number: 26172-55-4
• EC Number: 247-500-7
• SMILES: CN1C(=O)C=C(S1)Cl

Properties

• Density: 1.25 (14% aq.)
• Melting point: 52 °C
• Refractive index: 1.378

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07;GHS09 Danger
• Risk Statements: H300-H301+H311-H301-H310-H311-H314-H317-H318-H330-H331-H335-H400-H410
• Safety Statements: P260-P261-P262-P264-P264+P265-P270-P271-P272-P273-P280-P284-P301+P316-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P320-P321-P330-P333+P317-P361+P364-P362+P364-P363-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Skin corrosion	Skin Corr.	1B	H314
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	3	H301
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	3	H311
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute toxicity	Acute Tox.	2	H330
Acute toxicity	Acute Tox.	2	H310
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	3	H331
Acute toxicity	Acute Tox.	2	H300
Skin sensitization	Skin Sens.	1A	H317
Skin corrosion	Skin Corr.	1C	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Flammable liquids	Flam. Liq.	3	H226
Specific target organ toxicity - single exposure	STOT SE	1	H370
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Respiratory sensitization	Resp. Sens.	1	H334
Skin sensitization	Skin Sens.	1B	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin corrosion	Skin Corr.	1	H314
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	1	H310
Acute toxicity	Acute Tox.	1	H300
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	1	H330

Discovery and Applications

5-Chloro-2-methyl-4-isothiazolin-3-one, commonly abbreviated as CMIT, is a powerful biocide that was discovered in the mid-20th century during the development of industrial preservatives. CMIT belongs to the isothiazolinone family, which is known for its strong antimicrobial properties. The advent of this compound stems from the need for effective solutions to control microbial growth in various industrial and consumer products.

The molecular formula of CMIT is C4H4ClNOS. It has a chlorine-substituted isothiazolinone ring, which contributes to its biocidal activity. This structure enables CMIT to effectively disrupt the metabolic processes of microorganisms, making it a highly effective preservative. CMIT is often combined with other isothiazolinones, such as methylisothiazolinone (MIT), to enhance its antimicrobial efficacy.

One of the main applications of CMIT is as a preservative in industrial products. It is often used in paints, adhesives, and coatings to prevent microbial contamination, which can cause product deterioration and degradation. The presence of CMIT ensures the longevity and stability of these products by inhibiting the growth of bacteria, fungi, and algae.

CMIT is also used in personal care and cosmetic products such as shampoos, conditioners, and lotions. It acts as a preservative to prevent microbial growth, extending the shelf life of these products and ensuring they are safe for consumers. Due to its powerful biocidal properties, only low concentrations of CMIT are required for effective preservation.

In water treatment applications, CMIT is used to control microbial growth in cooling towers, pulp and paper mills, and petroleum extraction systems. Its ability to eliminate a wide range of microorganisms makes it valuable in maintaining water quality and preventing biofouling, which can lead to operational inefficiencies and equipment damage.

CMIT is found in a variety of household cleaning products and disinfectants. It helps ensure that these products effectively eliminate bacteria and other pathogens on surfaces, creating a hygienic environment. Including CMIT in these formulations enhances their antimicrobial properties, making them more effective at maintaining cleanliness.

In the paint and coatings industry, CMIT is added to formulations to prevent microbial contamination during storage and application. This use helps maintain product quality and prevent deterioration that can result in financial losses and compromised performance. CMIT ensures that paints and coatings remain effective and beautiful for a long time.

Although CMIT is highly effective as a biocide, its use is regulated due to the potential health risks associated with exposure. Regulatory agencies, such as the Environmental Protection Agency (EPA) and the European Chemicals Agency (ECHA), have established safe concentration guidelines for CMIT in various applications to minimize adverse effects on human health and the environment.

References

1986. Zur Analytik mikrobiocider Isothiazolone. Fresenius' Zeitschrift für Analytische Chemie.
DOI: 10.1007/bf00498177

2024. Trends in Patch-Test Positivity to Methylchloroisothiazolinone and Methylisothiazolinone Based on Regulatory Status: A Systematic Review. Dermatitis.
DOI: 10.1089/derm.2023.0186

2024. Metabolite analysis of 14C-labeled chloromethylisothiazolinone/methylisothiazolinone for toxicological consideration of inhaled isothiazolinone biocides in lungs. Chemosphere.
DOI: 10.1016/j.chemosphere.2024.142666