Learn all about benzisothiazolinone, including how it's made, and why Puracy uses benzisothiazolinone in our products.
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  • Pronunciation: (Ben-ZISO-thia-ZO-li-none)
  • Type: Synthetic
  • Other names: BIT

What Is Benzisothiazolinone?

Benzisothiazolinone, also called BIT, is an off-white to yellowish liquid antimicrobial substance.[1]

What Does Benzisothiazolinone Do in Our products?

Benzisothiazolinone is a preservative, but it is also a disinfectant used in the film, fiber, leather, masonry, metalworking, and embalming industries.[1] However, it is also found in liquid hand soap and sunscreen.[2] It dissolves in water and is used in water-based solutions, such as pastes, paints, and oils.[3]

Why Puracy Uses Benzisothiazolinone

We use benzisothiazolinone in several of our products as a biodegradable preservative that is a better alternative to formaldehyde, methylisothiazolinone, and medium-chain triglycerides. The Scientific Committee on Consumer Safety considers the ingredient safe when used as a preservative up to 0.01% in cosmetics. Whole Foods has deemed the ingredient acceptable in its body care and cleaning product quality standards.[5,6,7]

How Benzisothiazolinone Is Made

There are three common methods for making BIT. The first involves reacting 2-halogenothiobenzoyl halide with a primary amine to obtain an N-substituted BIT. The 2-halogenothiobenzoyl halide is typically made by cleaving the disulphide 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 cyclising 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 disulphide 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.[4]


[1] European Commission
[2] Environmental Working Group
[3] European Commission
[5] Whole Foods Market
[6] Whole Foods Market
[7] European Commission