Quaternium (inci)

Quaternium (see also Polyquaternium) is a particularly prominent group of complex ammonium compounds, which are also called quats under the generic term "quaternary ammonium compounds".

Quaternary ammonium compounds, also called quaternium (and polyquaternium) have a quaternary nitrogen atom, i.e. a nitrogen atom in which all four hydrogen atoms are replaced by organic radicals. In contrast to polyquaternium (polymer, consists of several quats) it is a monomer.

Quats include for example:

• Benzalkonium chloride
• Cetylalkonium chloride
• Cetylpyridinium chloride
• Cetyltrimethylammonium bromide
• Denatonium benzoate
• Tetrabutylammonium hydroxide (TBA
• Quaternium
• Polyquaternium

The name "Quaternium" is quite confusing, because although the core of the compounds, the quaternary ammonium compound, is the same for all quaternium compounds, their properties, however, are quite different depending on the integrated alkyl radical (silicone radicals are also possible).

If silicone residues are incorporated into a quaternary ammonium compound, such quaternium compounds can also be addressed as "silicones". Quaternium 80, for example, is such a silicone-based quaternium compound (film former).

Of particular pharmaceutical interest are cationic surfactants, compounds which carry at least one longer (lipophilic) hydrocarbon chain on the nitrogen. Quaternium-14 (chemical name: dodecyl(ethylbenzyl)dimethylammonium chloride), for example, contains lauryl alcohol as a lipophilic hydrocarbon chain. The anion is a chloride ion. The compound is therefore cationic and therefore has a positive charge.

Quats with at least one long hydrocarbon chain have surface-active properties and are used as cationic surfactants in products such as fabric softeners, as invert soaps or as antistatic agents (e.g. in shampoos) also as anti-agents (algicides) in swimming pools.

No conclusions can be drawn from the nomenclature "Quaternium" + appended number about the underlying chemical structure of the substance, so that in case of doubt, the complicated chemical nomenclature must be used.