Quaternary ammonium bactericides have the properties of ionic compounds, are very soluble in water but not in non-polar solvents, and have stable chemical properties. The mechanism of action of this kind of bactericides is mainly through electrostatic force, hydrogen bonding force and hydrophobic binding between surfactant molecules and protein molecules, etc., to adsorb negatively charged bacteria and cause them to gather on the cell wall, causing lysis and production. The room obstructive effect causes the growth of bacteria to be inhibited and death. At the same time, its hydrophobic alkyl group can also interact with the hydrophilic group of bacteria to change the permeability of the membrane, and then undergo lysis, destroy the cell structure, and cause cell dissolution and death. This kind of fungicides has high efficiency, low toxicity, no accumulation, moderate toxicity to fish, is not easily affected by pH changes, is convenient to use, has a strong peeling effect on the mucus layer, and has stable chemical properties, dispersion and corrosion inhibition Good function and other characteristics.

Since the discovery of the bactericidal effect of cationic surfactants in 1935, 4 to 6 generations of quaternary ammonium salt bactericide products have been developed so far. The first generation is alkyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium chloride, etc.; the second generation is the first generation derivative, which is carried out on the benzene ring or quaternary nitrogen of the quaternary ammonium salt Obtained by substitution reaction: the third generation product is dialkyl dimethyl ammonium chloride, such as didecyl dimethyl ammonium chloride, etc.; the fourth generation is a compound product of the first and third generations; Substituted as double quaternary ammonium salts such as: ethylene bis (dodecyl dimethyl ammonium bromide), they belong to gemini or dimeric surfactants.

The quaternary ammonium bactericide not only has a bactericidal effect, but also has a strong peeling effect on the slime. It can kill the sulfate-reducing bacteria that grow under the slime. It also has a corrosion-inhibiting and synergistic effect when used with other agents. Common ones are 1227 (dodecyl dimethyl benzyl ammonium chloride), 1231 (dodecyl trimethyl ammonium chloride), trimethoate (dodecyl dimethyl benzyl ammonium bromide), 1427 (Tetradecyl dimethyl benzyl ammonium chloride), ethylene bis (dodecyl dimethyl ammonium bromide), ethylene bis (tetradecyl dimethyl ammonium chloride), etc.

There are two hydrophobic groups, two hydrophilic groups and one linking group in the double quaternary ammonium salt molecule. Its novel structure makes the performance more excellent; the low critical micelle concentration can effectively reduce the surface tension of water and significantly increase the aqueous solution It also has the functions of scale inhibition and pH adjustment. For double quaternary ammonium salts, the more asymmetric molecules, the more concentrated the positive charge, and the more ideal the sterilization effect. If the molecular structure has strong symmetry, the surface activity will increase and the bactericidal effect will decrease. Double quaternary ammonium salt has better bactericidal peeling effect. The high-efficiency fungicide MQA developed by Nanjing University of Technology, the fungicide metronidazole modified by the Huazhong University of Science and Technology synthesized with metronidazole as the parent, MBQA, Tianjin Chemical Research The asymmetric double quaternary ammonium salts developed by the institute are all.