Surfactants 1-hexadecylpyridinium bromid

The most frequently used ionic SDAs are again CTAB/CTAC, OTAB/OTAC as well as hexadecylpyridinium bromide/chloride (CPB/CPC), whereby the syntheses are carried out under basic conditions, and most commonly surfactants of the Pluronic and Brij type 86 are used as nonionic SDAs under acidic conditions. In rare cases also Gemini surfactants or long alkyl chained ionic liquids were applied as SDAs, whereby an ethane-bridged PMO with a Fm-3m symmetry was successfully prepared for the first time.88... 

A photoresponsive surfactant (77) containing an azobenzene moiety has been used to control micellar catalysis78). The proton abstraction from benzoin which can be monitored by the disappearance of 2,6-dichlorophenolindophenyl is catalyzed by cationic micelles such as hexadecylpyridinium bromide (HDPB). If the reaction occurs in micelles containing both (77) and HDPB, the reaction is slower than in pure... 

Over recent years the question of whether or not surfactants form aggregates similar to micelles and mesophases in other polar solvents has received considerable attention [168-191]. The solvents concerned are polar liquids such as glycerol, ethylene glycol, formamide or ethyl ammonium nitrate (a molten electrolyte at ambient temperature). The answer is yes, but the thermodynamics of the aggregation process is somewhat different. Figures 40 and 41 show measurements of EMF in hexadecylpyridinium bromide solutions where water and ethylene glycol are solvents. 

There are a variety of cationic surfactants other than quaternary alkylammonium salts. Accordingly, complex formation of 1-hexadecylpyridinium bromide (CPB) was attempted (Figure 4.44). After many trials, ten complex crystals were obtained, two of which were suitable for X-ray analysis, i.e. with guaiacol (XXXIII) and 9-anthracenecarboxylic acid (XXXTV) (Figure 4.44). The two crystals are isostructural. 

Indicator Valence change Approx. pH Effects of surfactants on JC /Kq Hexadecylpyridinium Hexadecyltrimethyl- Sodium hexadecyl bromide ammonium iodide sulfonate ... 

Hexadecylpyridinium chloride, cetylpyridinium chloride n-Hexadecyltrimethylammonium bromide (hydroxide) or cetyltrimethylammonium bromide (hydroxide) Stoichiometric concentration of surfactant (detergent) Concentration of micellized surfactant generally [D ] = [D]-cwc... 

The treatment of bentonite with hexadecylpyridinium chloride and trimethylhexadecylammonium bromide has been considered by Pal and Ghoshal, who noted that above the cation-exchange capacity adsorption of the associated form of the surfactant occurs, mainly on the external surface of the clay. 

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