Isothiazolinones iis composed of 5-chloro-2-methyl-4-thiazoline-3-ketone (CMI) and 2-methyl-4- thiazoline-3-ketone(MI). Isothiazolinones’ bactericidal effect is carried out by breaking the bond between bacteria and algae protein. When contacted with microbes, isothiazolinones can quickly inhibit their growth. Thus leading to the death of these microbes.

CAS No.:

26172-55-4, 2682-20-4

Molecular Weight:


Structure Formula:



Isothiazolinones have strong inhibition and biocidal effects on ordinary bacteria, fungi, and alga. And it has many advantages, such as high biocidal efficiency, good degradation, no residual, safety in operation, good compatibleness, good stabilization, and low cost in operation.

Isothiazolinones can mix with chlorine and most cation, anion, and non-ionic surfactants. However, its bio-sludge stripping effect is excellent when used at high dosages.

Isothiazolinones are fungicidal with broad spectrum properties, high efficiency, low toxicity, and non-oxidative. It is the ideal biocidal in the industrial circulating cool water system. Also, in wastewater treatment, the oilfield, papermaking, pesticide, cutting oil, leather, detergent, cosmetics, etc.

Isothiazolinones have a high inhibitory effect on various fungi and algae, such as green algae, brown algae, fungi, and bacteria. At the same time, it also controls the growth of slime in water.

Isothiazolinones also have certain effects on silt’s peeling, dispersing, and infiltration. As a result, it can protect the water quality and ensure the normal operation of the equipment.

The performance of isothiazolinones is very stable. And the applicability is strong. Just put a small number of isothiazolinones in the area that water treatment is needed. Moreover, this bactericide is non-toxic. It does not cause a bad toxic effect on the water itself and can be used with confidence.


ItemGrade IGrade II
AppearanceAmber transparent liquidLight yellow or light green transparent liquid
Active content, %14.0~15.01.5~1.8
pH (as it)2.0~4.02.0~5.0
Density(20℃, g/cm31.26~1.321.02~1.05
CMI/MI (weight), %2.5~3.42.5~3.4


When used as a sludge stripper for grade II, 150~300 mg/L is preferred. When used as a biocide, 80~100 mg/l is preferred. And charges every 3~7 days. The isothiazolinones can’t be used together with oxidative fungicides like chlorine. And isothiazolinones can’t be used in cooling water systems containing sulfur. When used together with a quaternary amine, the effect will be better. When used as an industrial fungicide, 0.05~0.4% is preferred.

Based on the excellent characteristics of bactericidal algaecide, isothiazolinones are quickly recognized by various industries. For example, it is widely used in industrial circulating cooling water systems, such as chemical, textile, power plants, industrial storage tanks, cooling towers, swimming pools, fountain landscape water, and other industrial projects.

Packing and storage:

200L plastic drum, IBC(1000L), customers’ requirement.

200L plastic drum 1000L IBC

Storage for ten months in a shady room and dry place.

Safety Protection:

Isothiazolinone is corrosive to the skin. It can cause skin burns and cause allergic dermatitis. The impact will last for hours.

Do not touch your skin and eyes. Protective equipment such as protective glasses and rubber gloves should be provided during operation.

If you accidentally touch the skin, immediately remove contaminated clothing and shoes. Rinse with plenty of water for at least 15 minutes. Then, immediately apply urea acetate ointment or scald cream to the affected area and seek medical advice.