Isothiazolinones is composed of 5-chloro-2-methyl-4-thiazoline-3-ketone (CMI) and 2-methyl-4- thiazoline-3-ketone(MI). The bactericidal effect of isothiazolinones is carried out through 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 has 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. When used at high dosage, its bio sludge stripping effect is excellent.

Isothiazolinones is a kind of fungicidal with properties of broad spectrum, 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, and cosmetics, etc.

Isothiazolinones has 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 has certain effects on peeling, dispersing and infiltration of slime. 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 sludge stripper for grade II, the dosage of 150-300 mg/L is preferred. when used as a biocide, the dosage of 80-100 mg/l is preferred. and charges every 3-7 days. The isothiazolinones can’t be used together with oxidative fungicidal, such as chlorine. And isothiazolinones can’t be used in cooling water system containing sulfur. When used together with a quaternary amine, the effect will be better. When used as an industrial fungicide, the dosage of 0.05-0.4% is preferred.

Based on the excellent characteristics of bactericidal algaecide, isothiazolinones is 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 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. Apply urea acetate ointment or scald cream to the affected area and seek medical advice immediately.