DDAC Arquad® 2.10-80 is a quaternary ammonium compound - Didecyldimethylammonium chloride. Functions. Biocide,; Dispersing Agent,; Algicide/algistat,; Bactericide Didecyldimethylammonium chloride is a quaternary ammonium compound used as detergent/disinfectant in hospitals, as algicide in swimming pools,