The mechanism of action of KP-M27 is to act on bacterial cells, and the bactericidal mechanism is slightly different under different acidity and alkalinity. Under neutral or acidic conditions, K+ is taken out of bacterial cells and H+ is taken into bacterial cells; under alkaline conditions, K+ or Mg2+ is taken out of bacterial cells and Na+ is taken into bacterial cells. By eliminating the ionic gradient for bacteria to obtain nutrients, the cells are eventually “starved”.
Therefore, its bactericidal mechanism is not the same as many bactericides, it kills bacteria while not being consumed itself.
The process by which aromatic ketones generate active free radicals through photochemical action is actually the process in which aromatic ketones are reduced by light. Aromatic ketones can be reduced with active tertiary amines, mercaptans, ketones, ethers, etc., and all can generate active free radicals, but tertiary amines The rate of photoinduced electron transfer reaction with aromatic ketones is as high as 10°mol-1.s-order, micronized carnauba wax which is 1 to 2 orders of magnitude higher than the chlorine abstraction reaction between thiol and aromatic ketones. The direct reaction between aliphatic ketones, ethers and aromatic ketones The hydrogen abstraction reaction rate is the lowest and has almost no industrial application value. Aromatic ketone/thiol initiation system is mainly suitable for multiolefin monomers. Aromatic ketone/active tertiary amine combination is the main application mode of hydrogen abstraction photoinitiators.
Active amine supply gas
Active amine compatible with aromatic ketones is not only a necessary co-initiator for generating active free radicals, but also plays an anti-oxidant polymerization inhibitory function. The active amines that can be used as co-initiators are generally tertiary amines with at least one aH. After the nitrogen atom loses an electron, the H on the αC at the N ortho position is strongly acidic, and it is easy to leave as a proton to produce an active amine at the C center. Alkyl radicals. The structure of active amines has a greater impact on the reactivity, and tertiary amines with higher ionization potential have poor electron donating ability: most aliphatic tertiary amines have lower ionization potential. The ionization potential of primary and secondary amines is higher than that of tertiary amines, and electron transfer is relatively difficult. The resulting active free radicals are not α-aminoalkyl radicals, but amino radicals centered on N atoms . Free radicals have high addition activity to vinyl monomers and low reactivity with molecular oxygen, but their own production efficiency is too low, and overall it is still not comparable to tertiary amines. Because the N atom part of the aromatic amine is conjugated to the benzene ring, the lone pair of electrons on the N atom are separated to the benzene ring, which leads to an increase in the ionization potential of the N atom and a decrease in the electron donating ability. The active amine used in the early days was triethanolamine, which is simple and easy to obtain. Compared with tertiary amines without hydroxyl, tertiary amines with ethanolamine structure have higher reactivity with benzophenone, and finally produce amine alkyl methyl radicals with high addition activity. , And release formaldehyde at the same time. N-Methyldiethanolamine is a very active co-initiator and is widely used in research.
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