Benzalkonium salts are widely used as disinfectants, biocides and detergents, among a variety of other applications. The cationic surface-activity of these salts determines their potential to act as a biocide on both target and non-target organisms.
Quaternary compounds, including the benzalkonium salts, constitute an economically important class of industrial chemicals that are widely distributed among a diverse array of products and users from an industrial to the household sector. Because of their strong cationic surface activity, quaternary compounds are used primarily as disinfectants, biocides, and detergents, but also as anti-electrostatics, and as phase transfer catalysts .
Very important features of benzalkonium salts are their bactericidal and antimicrobial properties. The antimicrobial activity depends on a changing length of the side n-alkyl chain. It is well known that the C12-homolog is most effective against yeast and fungi, the C14-homologue against gram-positive bacteria and C16-homolog against gram-negative bacteria . For these reasons they are widely used as preservatives for ophthalmic, nasal and parenteral products. They are also used as topical antiseptics and disinfectants for medical equipment .
These compounds are not generally used as single components, but rather as mixtures composed of two or three benzalkonium members differing only in the length of the alkyl chains . Such mixtures are produced on a large-scale in industry. However, a targeted synthesis of pure individuals could be of interest because of the above-mentioned specificity of each salt against different pathogens.