77-Alkyltrimethylammonium bromides

V. Bergeron Disjoining Pressures and Eihn Stabflity of Alkyltrimethylammonium Bromide Foam Films. Langmuir 13, 3474 (1997). 

Candau SJ, Hirsch E, Zana R. New aspects of the behavior of alkyltrimethylammonium bromide micelles—hght-scattering and viscosimetric studies. J Phys Paris 1984 45 1263-1270. 

Alkyl (Me, Et, n-Pr, n-Bu), alkyldimethyl, and alkyltrimethylammonium bromides retard the neutral hydrolysis of 1-benzoyl-1,2,4-triazole (190) to benzoic acid and the triazole (191).162 This effect is attributed to a dominant stabilization of the initial state through hydrophobic interactions with the co-solute. The effects of cetylpyridinium bromide on the hydrolysis of 2,4-dinitrochlorobenzene by hydroxide ion in water have been reported.163... 

TABLE 2 81Br NMR parameters of n-alkyltrimethylammonium bromide salts averaged over a range of MAS frequencies 6... 

Usually they distinguish two types of complexes polyelectrolyte-ionic SAS. Firstly, complexes in which only the part of polymer units is connected with SAS iones. Such complexes are soluble in water their solubility is determined by the presence of polymer units not connected with SAS ions. Secondly, the complexes in which all or almost all units of polymer chain are connected with SAS ions. Such complexes are insoluble in water and are precipitated. Schematically soluble and non-soluble complexes of polyelectrolyte-SAS (on the example of complexes of polycarbonic acids with alkyltrimethylammonium bromides) are presented in Figure 3. 

Figure 3. Macromolecular organization of soluble (a) and non-soluble (b) complexes of polycarbonic acids with alkyltrimethylammonium bromides.

Particles of complexes of PAA and PMAA with alkyltrimethylammonium bromides include one macromolecule and micellar phase is formed as one "big" micelle (Figure 3). complexes of PSS are also formed in the volume of one macromolecule, however in contrast to complexes of polycarbonic acids micellar phase is formed as "not big" aggregates [28], Quite the contrary, the particles of complexes of PDAC with SDD are consisted of dozens of... 

Molecular mobility and order parameter of spin probes in soluble and insoluble complexes practically are not differed. This important result was obtained under investigation of complexes of PAA, PMAA with alkyltrimethylammonium bromide and also of complexes PDAC and PEYP with SDD with the use of various spin probes. This result means that local organization of micelle formed in soluble complexes is practically not changed under formation of insoluble complexes (see Figure 2). 

Comments the original cetrimide BP 1953 consisted largely of hexadecyltrimethylammonium bromide, with smaller amounts of analogous alkyltrimethylammonium bromides. It contained a considerable proportion of inorganic salts, chiefly sodium bromide, and was less soluble than the present product. 

Alkyltrimethylammonium bromides -Alkylammonium chlorides Alumina, Preparation Standardization a-Amino acids... 

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. 

D) (Cationics) Alkyltrimethylammonium bromides [49] supplied by Sigma (France) and used as received (99% purity) ... 

Figure 9. Adsorption isotherms of alkyltrimethylammonium bromides onto precipitated silica at 308 K (panel a) and those of sodium benzenesulfonates onto zirconia at 298 K (panel b).

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... 

Because of the high polarity of RTILs, self-assembly of amphiphiles in RTILs are quite similar to that observed in aqueous systems. Alkyltrimethylammonium bromides and alkyl pyridinium bromides in the RTIL ethylammonium nitrate (EAN), for example, form micelles just like in water, albeit with critical micelle concentration (CMC) values that are five to ten times larger [4,29]. Liquid crystalline phases are also observed in surfactant-RTIL... 

Figure 7.9 Binary phase diagrams of alkyltrimethylammonium bromide-polar solvent mixtures as a function of temperature and surfactant concentration. (From Ref. [60], reprinted with permission of Elsevier.)...

Kogej K, Skerjanc J. Fluorescence and conductivity studies of polyelectrolyte-induced aggregation of alkyltrimethylammonium bromides. Langmuir 1999 15 4251-4258. 

Figure 2.16 Typical nitrogen adsorption-desorption isotherms at 77K for (a) MCM-41 materials templated with alkyltrimethylammonium bromide surfactants with hydrophobic tails of different lengths as indicated (volumes adsorbed for C12, C14, C16 and C18 were incremented by 200, 400, 600 and 800 ml(STP) g, respectively) and (b) nonionic triblock copolymer templated SBA-15 silicas synthesised at different temperatures (volumes adsorbed for 353 K and 373 K were incremented by 200 and 400 ml(STP) respectively). The hysteresis loops observed in this case are typical of the larger mesopores in these materials. Desorption points are represented by closed symbols. Reprinted with permission from Morishige, K. Tateishi, M., Accurate relations between pore size and the pressure of capillary condensation and the evaporation of nitrogen in cylindrical pores, Langmuir, 22, 4165 169. Copyright (2006) American Chemical Society...

Adiarya, D.P., Hattori, K., Sakai, T., and Kunieda, H. (2003) Phase and rheological behavior of salt-free alkyltrimethylammonium bromide/ alkanoyl-nmethylethanolamide/water systems. Langmuir, 19, 9173-9178. 

Figure 20.20. The CAC is typically orders of magnitude lower than the CMC for an ionic surfactant in the presence of an oppositely charged polymer, illustrated by plotting the logarithm of the CMC and the CAC of alkyltrimethylammonium bromides in the presence of an anionic polysaccharide, sodium hyaluronate, versus the number of carbons in the alkyl chain. (Redrawn from K. Thalberg and B. Lindman, J. Phys. Chem., 93 (1989) 1478)...

---