Benzalkonium Chloride (BZK)

Benzalkonium chloride is a cationic surface-acting agent belonging to the quaternary ammonium group. It has three main categories of use: as a biocide, a cationic surfactant, and phase transfer agent in the chemical industry. The chemical is a nitrogenous mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. Benzalkonium chloride is readily soluble in ethanol and acetone. Although dissolution in water is slow, aqueous solutions are easier to handle and are preferred. Solutions should be neutral to slightly alkaline, with colour ranging from colourless to a pale yellow. Solutions foam profusely when shaken, have a bitter taste and a faint almond-like odour which is only detectable in concentrated solutions. Benzalkonium chloride solutions are fast-acting biocidal agents with a moderately long duration of action.