Benzisothiazolinone (BIT) Biocide, Benzisothiazolin


Benzisothiazolinone (BIT) biocide has a good bactericidal capacity. Benzisothiazolin is an important bactericide and antiseptic. It can restrain microbes (fungi, germs, algae, etc.) from growing in an organic medium.

The BIT biocide can resolve any problem caused by microbes growing in organic products. Such as mildewing, degeneration, and go bad. It is stable over a broad pH range of 4-12 and a broad temperature range.

1,2-Benzisothiazolin-3-One is miscible in water and most of the low alcohols and glycols.

CAS No.:


Molecular Formula:


Molecular Weight:


Structure Formula:

benzisothiazolinone structure formula

Benzisothiazolinone (BIT) Synthesis:

There are three methods to make 1,2-Benzisothiazolin-3-One.

The first involves reacting 2-halogenothiobenzoyl halide with a primary amine to obtain an N-substituted Benzisothiazolin. The 2-halogenothiobenzoyl halide is typically made by cleaving the disulfide bond of 2,2′-dithio-bis-benzoic acid with halogen and simultaneously or sequentially converting the carboxylic acid groups to acid halides.

A second method involves cyclizing 2-halogenothiobenzamide in the presence of acid or alkali. The 2-halogenothiobenzamide typically comes from converting 2,2′-dithio-bis- benzoic acid to bisamide and then cleaving the disulfide bond with halogen.

The third method is to heat 2,2′-dithio-bis-benzamides in the presence of a sodium hydroxide solution. Another method is to disproportion bisamide in alkali in the presence of oxygen or an oxygen-release agent.


AppearanceSlight yellow powder
Purity (HPLC)98% Min.
Water15% Max.
Melting Point155-158 deg. C
pH (1% solution)  8.0-10.0


Benzisothiazolin (BIT) biocide can control the growth of microorganisms in emulsion paints, adhesives, concrete additives, and other water treatment formulations.

Using quantum: 0.03~0.3% (w/w).

1,2-Benzisothiazolin-3-One has a microbicide and a fungicide mode of action. Mainly, BIT is used as a preservative, just like below.

  • Emulsion paints, caulks, varnishes, adhesives, inks, and photographic processing solutions.
  • Home cleaning and car care products; laundry detergents, stain removers, and fabric softeners.
  • Industrial settings include textile spin-finish solutions, leather processing solutions, and the preservation of fresh animal hides and skins.
  • Agriculture in pesticide formulations.
  • Gas and oil drilling in muds and packer fluids preservation.

It is commonly used alone or as a mixture with methylisothiazolinone in paints. Typical product concentrations are 200–400 ppm depending on the application area and the combination with other biocides.

According to a study in Switzerland, 19% of the paints, varnishes, and coatings contained BIT in 2000. The fraction in adhesives, sealants, plasters, and fillers was shown at that time as 25%. However, a later study in 2014 showed a dramatic rise in usage to 95.8% of house paints.

Packing and Storage:

25 kg fiber drum.

fiber drum


Low toxicity. No irritation to the eyes and skin.

1,2-Benzisothiazolin-3-One can cause sensitization and allergy if the skin is exposed to this chemical for a long time. And also, Benzisothiazolinone is classified as an irritant for the skin and eyes. Therefore, people need good protection when they use it.


Proxel bd20; 1,2-benzisothiazolin-3-one; Benzisothiazolinone; Bioban 200.


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