Phenol cation

Disinfectants come from various chemical classes, including oxidants, halogens or halogen-releasing agents, alcohols, aldehydes, organic acids, phenols, cationic surfactants (detergents) and formerly also heavy metals. The basic mechanisms of action involve de-naturation of proteins, inhibition of enzymes, or a dehydration. Effects are dependent on concentration and contact time. 

Hygienic and surgical hand disinfection The former is required after a suspected contamination, the latter before surgical procedures. Alcohols, mixtures of alcohols and phenols, cationic surfactants, or acids are available for this purpose. Admixture of other agents prolongs duration of action and reduces flammability. 

In aqueous solutions, the phenol cation radical has pKa = -2 (Dixon Murphy 1978 Holton Murphy 1979). Surprisingly, the pKa value of the 2,4,6-triphenylphenol cation radical is equal to 5 only (Land et al. 1961 Land Porter 1963). A natural question arises Why does the stabilization of the phenoxyl radical with the shielding phenyl groups result in such a small increase in acidity ... 

S. Re and Y. Osamura, Size-dependent hydrogen bonds of cluster ions between phenol cation radicals and water molecules a molecular orbital study, J. Phys. Chem. A, 102 (1998) 3798-3812. 

Whereas 2-naphthol is attacked at position 1, 1-naphthol is substituted in the 4-position. The phenolic cations thus obtained... 

The dissociative proton transfer of the solvated phenol cation corresponding to process VIII (scheme 1),... 

Carbomers are discolored by resorcinol and are incompatible with phenol, cationic polymers, strong acids, and high levels of electrolytes. Certain antimicrobial adjuvants should also be avoided or used at low levels, see Section 11. Trace levels of iron and other transition metals can catalytically degrade carbomer dispersions. Intense heat may be generated if a carbomer is in contact with a strong basic material such as ammonia, potassium or sodium hydroxide, or strongly basic amines. 

Although the ketene ring 30 is found to be only 53 kJmoC above 21 and by far more stable than acetyl ion 29, it turns out that the CO loss from an indirect process, finally giving the five-membered ion 31, namely 29 30 —> (CO - - 31), constitutes a substantially more difficult route. It is apparent from Figure 32 that the cyclic isomer 29 could be a possible intermediate in the CO-eliminative process of phenol cation 21. Nevertheless,... 

It may be noted that the energy amount involved in the CO-loss process is by far smaller than that needed for a deprotonation of phenol cation as mentioned above, namely 857 kJmoC. This suggests that the ease with which a deprotonation of phenol radical cations occurs in different solutions was likely to arise from either a specific participation of the solvent molecules in the supermolecule or a strong continuum effect. 

As already indicated in Scheme 2, fragmentation of ionized phenol and its simple derivatives is quite complex, certainly more complex than that of higher alkylphenols under El-MS conditions. Therefore, the gas-phase ion chemistry of simple phenolic cations is of major importance for a sound understanding of mass spectrometry of phenols. A... 

The ionization potential (IP) of phenols is a measure of how readily an electron can be donated from the OH group to yield the phenolic cation. As pointed out before, the IP... 

It contributes no off-taste and may mask the undesirable taste of the famulation Incompatible with phenols, cationic polymers, high concentrations of electrolytes, and resorcinol... 

The dissociation of the styrene ion involves a transition state very similar to the reactant. The large negative entropy of activation results from the fact that the internal energy content of the transition state is reduced, compared to the reactant ion, by an amount equal to the critical energy. The transition state structure for the CO loss from the phenol cation is also close to the precursor but some vibrational modes loosen up, resulting in a slightly positive activation entropy. 

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