Decyltrimethylammonium bromide

In a typical experiment, Israelachvili deposited monolayers of surfactants onto cleaved mica sheets, and evaluated the surface energies using the JKR equation. Fig. 11 contrasts results for mica coated with monolayers of (a) L-a-dipalmitoyl-phosphatidylethanolamine (DMPE) where j/a = = 27 mJ/m and (b) hexa-decyltrimethylammonium bromide (CTAB) where = 20 mJ/m and = 50 mJ/m. ... 

Sierra, M.B., Morini, M.A., Schulz, P.C. and Ferreira, M.L. (2005) Unusual volumetric and hydration behavior of the catanionic system sodium undecenoate sodium decyltrimethylammonium bromide. Colloid and Polymer Science, 283 (9), 1016-1024. 

Surfactants that form micelles have also been shown to accelerate the formation of nitrosamlnes from amines and nitrite (33.) A rate enhancement of up to 80 0-fold was observed for the nitrosation of dihexylamine by nitrite in the presence of the cationic surfactant decyltrimethylammonium bromide (DTAB) at pH 3.5. A critical micelle concentration (CMC) of 0.08% of DTAB was required to cause this effect, which was attributed to a micelle with the hydrocarbon chains buried in the interior of the micelle. The positively-charged ends of the micelle would then cause an aggregation of free nitrosatable amine relative to protonated amine and thus lead to rate enhancements. Since surfactants are commonly used in water-based fluids (25-50% lubricating agent or 10-2 0% emulsifier in concentrates), concentrations above the CMC of a micelle-forming surfactant could enhance the formation of nitrosamines. 

Electroporation [250] in synthetic unilamellar dioleoylphosphatidyl-choline vesicles of 178nm diameter has been utilized for the preparation of PbS QDs. 3-10 A sized QDs are prepared by initiation of the opening of the pores between the Pb ions originally entrapped in the vesicles and S ions placed in the bulk [251]. 2.7 to 5 nm CdS nanoparticles have been prepared in a mixed vesicle dispersion formed using ionic surfactants, i.e., decyltrimethylammonium bromide and sodium 10-undecenoate [252]. The particle formation was achieved by exposing the vesicles containing the Cd (as a Cd complex of EDTA) to H2S. 

Decyltrimethylammonium bromide [2082-84-0] M 280.3. Crystd from 50% (v/v) EtOH/ethyl ether, or from acetone and washed with ether. Dried under vacuum at 60°. Also recrystd from EtOH and dried over silica gel. [Dearden and Wooley JPC 91 2404 1987]. 

The effects of micellization on reactivity have been investigated for a wide variety of ionic organic reactions other than those discussed previously in Sections IV and V, e.g. the Cannizzaro reaction, racemiza-tion, acid catalyzed enolization, base catalyzed hydrolysis of a,]8-un-saturated ketones, and coupling of quinonediimines with phenols. In the case of the Cannizzaro reaction of benzaldehyde (equation 43), the cationic surfactants eicosanyltrimethylammonium bromide and octa-decyltrimethylammonium bromide increased and the anionic surfactant... 

Lee, E. M., Thomas, R. K., Penfold, J. and Ward, R. C. (1989). Structure of aqueous decyltrimethylammonium bromide solutions at the air/water interface studied by the specular reflection of neutrons. J. Phys. Chem. 93 381-388. 

SYNS ACETOQUAT CTAB BROMAT CEE DEE CENTIMIDE CETAB CETAROL CETAVLON CETRIMIDE CETRIMONIUM BROMIDE CETYL- MINE CETY LTRIMETHYLAMMONIUM BROMIDE N-CETYLTRIMETHYLAMMONIUM BROMIDE CIRRASODOD CTAB CYCLOTON V N-HEXA-DECYLTRIMETHYLAMMONIUM BROMIDE N-HEXADECYL-N,NNI-TRIMETHYL. MMONIUM... 

ULTRASONIC RELAXATION STUDY OF FAST EXCHANGE PROCESSES IN MIXED MICELLE SYSTEMS OF ALCOHOL-DECYLTRIMETHYLAMMONIUM BROMIDE-WATER... 

The surfactant used in this study is decyltrimethylammonium bromide (DTAB). It was chosen because it has the longest hydrocarbon chain length for which the fast monomer exchange between the micelle and bulk phases can be monitored by ultrasonic techniques. 

Effects of addition of n-tetradecyltrimethylammonium bromide (C14TAB) on the micelle-monomer exchange processes of /f-decyltrimethylammonium bromide (CioTAB) were investigated by the ultrasonic relaxation method. The relaxation frequency increased and the relaxation strength decreased with increasing amount of CuTAB added. The dependence of the relaxation frequency on the amount of CuTAB added was in fair agreement with the relaxation theory of Annianson for mixed micelle... 

Figure 1. Conductometric titration at 63°C of 25 cc water containing 0.15 g hexa-decyltrimethylammonium bromide and 0.10 g cetyl alcohol (1 1 molar ratio) with benzene at a constant rate of 1 cc/min. Key 1, no cetyl alcohol 11, 0.10 g cetyl alcohol. (Reproduced, with permission, from Ref. 2. Copyright 1980, Plenum...

The electron microscopic investigation showed that rodlike particles l-2pm in length and 0.1-0.2ym in diameter were formed at hexadecyltrimethylammonium bromide-cetyl alcohol ratios of 1 3 to 1 1 (Figure 3). These rodlike particles showed an electron diffraction pattern (Figure 4) that was not shown by either hexa-decyltrimethylammonium bromide or cetyl alcohol alone. Moreover, heating these particles in the transmission electron microscope showed transitions near the melting points of both cetyl alcohol and hexadecyltrimethylammonium bromide. 

Figure 7. Conductometric titration at 63°C of 25 cc water containing 0.15 g hexa-decyltrimethylammonium bromide and 0.10 g cetyl alcohol (1 1 molar ratio) with...

The actual solute and micellar concentrations of hexadecyltrimethylammonium bromide should be lower than the calculated values because the rodlike particles and micellar aggregates are assumed to be non-conducting. The negative value calculated for the concentration in rodlike particles for the 1 0.33 hexadecyltrimethylammonium bromide-cetyl alcohol molar ratio is essentially zero. Figure 2 shows that the benzene conductometric titration curve for the 1 0.33 hexadecyltrimethylammonium bromide-cetyl alcohol ratio is very close to that for the same concentration of hexa-decyltrimethylammonium bromide without cetyl alcohol (Figure 1). 

The results of Table V are consistent with those of Table IV. The values of P(1) were in reasonable agreement with the initial conductances of the titration curves, and the values of P(2) increased with increasing emulsifier concentration at the 1 3 molar ratio, and decreased slightly at the less efficient 1 1 ratio (there are no values of P(l) and P(2) for 0.4% emulsifier at the 1 3 molar ratio because of the absence of a descending leg). At both the 1 3 and 1 1 molar ratios, the values of P(2) were smaller for the 0.6% emulsifier than for the 0.8% and 0.4% emulsifier, respectively, which suggests a better balance between the hexa-decyltrimethylammonium bromide and cetyl alcohol in the rodlike particles, despite the increase in micellar emulsifier with increasing emulsifier concentration. 

Using this approach Jang and coworkers166 have reported the synthesis of PPy nanoparticles at the 2 nm scale. Typical surfactants used in the preparation of these sub-5-nm particles were quaternary ammonium-based cations such as octyltrimeth-ylammonium bromide or decyltrimethylammonium bromide. Reactions at room temperature produced nanoparticles with diameters on the order of 10 nm, whereas at 70°C ca. 50 nm diameter particles were observed. 

---