Cationic surfactants are exactly the opposite structure to anionic surfactants in terms of form. The hydrophilic group on the other end of the hydrophobic group is a cation. All cationic surfactants used in industry are derivatives of organic nitrogen compounds. Most of them can be divided into two categories: one is the fatty amine itself, which can absorb hydrogen protons to form ammonium salts during use; the other is It is a quaternary ammonium salt. It has a positive charge in the molecule of the compound itself.
Cationic surfactants are rarely used for cleaning because the surfaces of many substrates have negative surface charges. In applications During the process, the positively charged cationic surfactant molecules do not dissolve the grease they encounter, but are instead adsorbed on the surface of the substrate. However, this characteristic has led to a series of special uses. The first is antistatic properties. Neutralization of dry electricity: Secondly, it is used as a fabric softener, which can be used to electrically adsorb ions on the surface of the substrate within a certain period of time and extend its hydrophobic end to the outside. In addition, it is used to prevent Mildew and sterilization. Because it can be oriented at the interface between the bacterial semipermeable membrane and water or air. The tightly packed interface molecules hinder the organism’s breathing or cut off its source of nutrients, leading to death.
Fatty Amine
Fatty primary amines and alkylpropylenediamines are commonly used corrosion inhibitors. The ammonium salts formed by fatty amines after absorbing protons in acid can be oriented and arranged on the interface between the metal or the inner wall of the pipe and the acid liquid. This closely arranged fatty chain group forms a kind of amine with a thickness of only 1 to 2 molecules. Protect the film from acid corrosion”
In addition to fatty primary amines, N-alkylpropanediamines are also widely used. Similar to this, there are ether amines. They are composed of fatty amines or alcohols. It is formed by addition with acrylonitrile and then hydrogenation reduction.
This type of fatty amines are mostly used in the construction industry as asphalt emulsifiers, waterproofing agents, etc.
Amine Oxide
Amine oxides are produced by using fatty tertiary amines as raw materials and oxidizing them with hydrogen peroxide.
Firstly, disperse the tertiary amine in water under good stirring, and then add hydrogen peroxide dropwise at 60~80℃. Because colloids will form when the concentration is too high, the concentration of amine oxide produced is usually 35%.
As can be seen from the structural formula of amine oxide, a high charge density will be formed around the oxygen atom, which can easily generate hydrogen bonds. It generates cations in acidic media and is non-centrifugal in neutral or alkaline media.
Amine oxide is stable when compounded into detergents. Although it is an organic nitrogen oxide, it does not act as an oxidant by itself.
As a characteristic of application performance, amine oxide has strong foaming ability and does not irritate the skin. Its main use is to replace fatty alcohol amides in the preparation of household dishwashing detergents. It is also used for cleaning cotton fabrics and is suitable for wetting and emulsifying under high electrolyte concentrations. In addition, it is also commonly used in the preparation of shampoos.
