Alkyltrimethylammonium bromide, structure

Ryoo[189] found that the structural order of MCM-41 can be improved remarkably if mixed surfactants of n-alkyltriethylammonium bromides (CrcTEAB, n = 12,14,16,20 and 22), and n-alkyltrimethylammonium bromides (CrcTMAB) are used. The optimum mixing ratio can be tuned according to the length of the alkyl groups. 

Empirical Equations Many investigators have developed empirical equations relating the CMC to the various structural units in surface-active agents. Thus, for homologous straight-chain ionic surfactants (soaps, alkanesulfonates, alkyl sulfates, alkylammonium chlorides, alkyltrimethylammonium bromides) in aqueous medium, a relation between the CMC and the number of carbon atoms N in the hydrophobic chain was found (Klevens, 1953) in the form... 

Alonso, B., Massiot, D., Florian, R, Paradies, H. H., Gaveau, R, and Mineva, T. (2009). N and Br. Quadrupolar nuclei as sensitive NMR probes of n-alkyltrimethylammonium bromide crystal structures. An experimental and theoretical study. J. Phys. Chem. B. 113, 11906-11920. 

Five n-alkyltrimethylammonium bromide C H2 +i(CH3)3N Br salts (x=l, 12, 14, 16, 18) were characterized by and Br MAS SSNMR in order to determine their NMR parameters and provide insight into their crystal structures (Table 21) [44]. Diffraction data and computations were also used in a complementary manner. The combined use of both and Br NMR data proved to be useful for structure refinement due to the fact that the NMR parameters were found to be strongly dependent on the chain packing among the five samples, more specifically variations in C-N-C angles and in the spatial positioning of the cations and anions. 

Complexation has frequently been correlated with the hydrophobic character of one (or both) of the interacting ions [273-279]. Details of the interaction between a series of dyes and alkyltrimethylammonium bromides have been published [277], The structure of the dyes used, tartrazine (XXVI) amaranth (XXVII) carmoisine (XXVIII) and erythrosine (XXIX) are shown below. These are all important colours used in the food, drug and cosmetic industries. Phase separation diagrams were constructed to indicate the relationship between surfactant concentration and the anisotropic solution-coacervate boundary. Differences between the interactions of a hydrophilic dye, tartrazine and amaranth, carmoisine and erythrosine which have both hydrophobic and hydrophilic moieties were exhibited. Tartrazine appears to behave like a simple electrolyte interacting simply with the charged groups at the micellar surfaces while the other dyes complexed and were solubilized as a complex in addition to interacting with the micelle surface [277]. These dyes also induced the formation... 

In a paper on the self-bodying action of alkyltrimethylammonium bromide-cetostearyl alcohol mixed emulsifiers, Barry and Saunders [100] discuss the sequence of events in the preparation of liquid paraffin-in-water emulsions containing these components. The gel structure in the continuous phase is clearly responsible for the self-bodying. During mixing of a ternary system the... 

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