Tetradecyltrimethylammonium bromide TTAB

Other cationic surfactants such as TTAB, DTAB, DODAB, STAC, CEDAB, and DDDAB have been used in CL reactions with less frequency. Thus, tetradecyltrimethylammonium bromide [TTAB] has been used to increase the sensitivity of the method to determine Fe(II) and total Fe based on the catalytic action of Fe(II) in the oxidation of luminol with hydrogen peroxide in an alkaline medium [47], While other surfactants such as HTAB, hexadecylpiridinium bromide (HPB), Brij-35, and SDS do not enhance the CL intensity, TTAB shows a maximum enhancement at a concentration of 2.7 X 10 2 M (Fig. 11). At the same time it was found that the catalytic effect of Fe(II) is extremely efficient in the presence of citric acid. With regard to the mechanism of the reaction, it is thought that Fe(II) forms an anionic complex with citric acid, being later concentrated on the surface of the TTAB cationic micelle. The complex reacts with the hydrogen peroxide to form hydroxy radical or superoxide ion on the... 

Fig. 8 The effect of the addition of the cationic surfactant tetradecyltrimethylammonium bromide (TTAB) in the separation buffer for the separation of ion complexes with the chelating agent EDTA. TTAB, 0.5 mM, was added to the separation buffer for the separation of N03 (1), Cu-EDTA, Pb-EDTA, EDTA (2), Cr-EDTA (3), and Fe-EDTA (4). (For details of experimental conditions, see Ref. 341.)...

Micellar media are formed from tensioactive molecules in aqueous solution. Mi-cellization is a manifestation of the strong self-association of water and water-like solvents [95]. Micelles are known to increase the solubilization of weakly polar substances in water and, as a consequence, their presence determines the magnitude of hydrophobic interactions. Micelles aggregate spontaneously in aqueous solution beyond a critical concentration which is a function of pressure [96]. As a result, pressure may induce an extra kinetic effect on the rate of organic reactions carried out in aqueous micellar systems. Representative ionic micelles are sodium dodecyl sulfate (SDS) and tetradecyltrimethylammonium bromide (TTAB). Recent examples demonstrate the beneficial effect of the presence of surfactants in Lewis acid-catalyzed reactions, a kind of biactivation [97]. 

Lopez-Leon T, Santander-Ortega MJ, Ortega-Vinuesa JL, Bastos-Gonzalez D (2008) Hofmeister effects in colloidal systems influence of the surface namre. J Phys Chem C 112 16060-16069 Lyklema J (2009) Simple Hofmeister series. Chem Phys Lett 467 217-222 Maiti K, Mitra D, Guha S, Moulik AP (2009) Salt effect on self-aggregation of sodium dodecylsulfate (SDS) and tetradecyltrimethylammonium bromide (TTAB) physicochemical correlations and assessment in the light of Hofmeister (lyotropic) effect. J Mol Liq 146 44-51 Marcus Y (1997) Ion properties. Dekker, New York... 

Figure 20.22. Phase separation in mixtures of a polyelectrolyte and an oppositely charged surfactant changes from associative (a,b), to no phase separation (c) and finally to segregative (d,e) as electrolyte is added. This example shows mixtures of a cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and an anionic polysaccharide, sodium hyaluronate (NaHy). (Redrawn from B. Lindman and K. Thalberg, in Interactions of Surfactants with Polymers and Proteins E. D. Goddard and K. P. Ananthapadmanabhan (Eds), CRC Press, Boca Raton, FL, 1993, p. 254)...

Figure 1 shows the changes of cmc and ionization degree a near the cmc, for tetradecyltrimethylammonium bromide (TTAB) in mixtures... 

X-ray scattering (SAXS) have yet been done. The interaction of L64 with three different cationic surfactants was investigated by Mahajan et al. using SANS [67]. These authors employed the surfactants hexadecyltrimethylammonium bromide (HDTAB), tetradecyltrimethylammonium bromide (TTAB), and dodecyltrimethy-lammonium bromide (DTAB). For all studied cationic surfactants and all ratios of L64 to surfactant, the authors report ellipsoidal micelles. Since this is the preferred shape of the micelles of the pure cationic surfactants, they conclude that in this case the shape is dominated by the surfactant [67]. 

Figure 7.2 shows plots of the Pt4/peaks of tetradecyltrimethylammonium bromide (TTAB)-capped nanoparticles before and after 2 h of UV-ozone cleaning. The Pt4/7/2 core level is fitted at 70.9 eV and the chemical shifts of the Pt4/core level of the natural oxidation states (PF from PtO and PP" from Pt02) relative to pure Pt are about 1.2 and 3.0 eV. As shown in Fig. 7.2a, the Pt4/peak of bare TTAB-capped nanoparticles exhibits an oxidation state of PP. After UV-ozone cleaning, the XPS Pt4/ peak reveals higher oxidation states, which indicate the formation of PP". In accordance with the XPS results above, the turnover rate also... 

As an example, Pt nanopartides with various shapes such as cubes or tetrahedrons can be synthesized using acrylic add [46], polyacrylate [47] and sodium polyacrylate [48-50] as capping molecules. Tetradecyltrimethylammonium bromide (TTAB) is an effective capping agent for preparing cubic and cubo-octahedral Pt nanopartides [4, 5]. Cubic Pt nanopartides can also be prepared in organic solutions in the presence of oleic acid and oleylamine [51-53]. 

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