Benzisothiazolinone, also called BIT, is an off-white to yellowish liquid antimicrobial substance.
Benzisothiazolinone is a preservative, but it is also a disinfectant used in the film, fiber, leather, masonry, metalworking, and embalming industries. However, it is also found in liquid hand soap and sunscreen. It dissolves in water and is used in water-based solutions, such as pastes, paints, and oils.
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.
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] In addition, research shows the ingredient is not a strong skin irritant in skin cream up to 100ppm.