Benzalkonium chloride (Alkyldimethylbenzylammonium chloride) is a cationic surface-acting agent containing the quaternary ammonium group. It has three main categories of use: as a cationic surfactant, a biocide, and phase transfer agent in the chemical industry. This compound is a heterogeneous mixture of alkylbenzyldimethylammonium chlorides of multiple even-numbered alkyl chain lengths.