Quaternary ammonium cation. Any or all of the R groups may be the same or different alkyl groups. Also, any of the R groups may be connected.
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+ with R being alkyl groups. Unlike the ammonium ion NH4+ itself and primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH of their solution. Quaternary ammonium cations are synthesized by complete alkylation of ammonia or other amines.
Quaternary ammonium salts or quaternary ammonium compounds are salts of quaternary ammonium cations with an anion. They are used as disinfectants, surfactants, fabric softeners, antistatic agents (e.g. in shampoo), and phase transfer catalysts. In liquid fabric softeners, the chloride salts are often used. In dryer anticling strips, the sulfate salts are often used.
The synthesis of this cation from ammonia is referred to as quaternization.
See also
- Benzalkonium chloride, a common quaternary disinfectant
- Denatonium, the bitterest compound known
- Cocamidopropyl betaine, a common surfactant
- Cetyl trimethylammonium bromide (CTAB), one of the most investigated cationic surfactant compounds
- Aliquat 336, a phase transfer catalyst