Most of the commercially-available cationic surfactants are derivatives of organic nitrogen compounds, and their positive ion charges are carried by nitrogen atoms, and some new cationic surfactants have positive ion charges carried by atoms such as phosphorus, sulfur, iodine, and arsenic. According to the chemical structure of cationic surfactants, it can be divided into four types: amine salt type, quaternary ammonium salt type, heterocyclic type and rasp salt type.

Amine salt type
The amine salt type cationic surfactant is a general term for primary amine salt, secondary amine salt and tertiary amine salt surfactants. Their properties are very similar, and many products are a mixture of primary and secondary amines. Such surfactants are mainly salts of fatty amines and inorganic acids, and are only soluble in acidic solutions. Under alkaline conditions, the amine salt easily reacts with the base to form a free amine and reduce its solubility, so the range of use is limited.

Quaternary ammonium salt type
Quaternary ammonium salt type cationic surfactants are the most important cationic surfactant varieties, and their properties and preparation methods are different from amine salt types. This type of surfactant is soluble in both acidic and alkaline solutions, has a series of excellent properties, and has good compatibility with other types of surfactants. Therefore, it is widely used.

Heterocyclic
The heterocyclic ring contained in the cationic surfactant molecule is mainly nitrogen-containing morpholine ring, pyridine ring, imidazole ring, piperazine ring and quinoline ring.

Salt type
Cationic surfactants can be divided into surfactants containing elements such as N, P, As, S, and I according to different heteroatoms, but this classification method is rarely used. According to the different atoms carrying positive charges, cationic surfactants also include salt salts, sulfonium salts, iodine salt and salt compounds.