Dodecyltrimethylammonium

A surfactant solution is a mixture of DTAC (dodecyltrimethylammonium chloride) and CPC (cetyl pyridinium chloride) the respective CMCs of the pure surfactants are 2 X lO M and 9 x IO M (Ref. 140). Make a plot of the CMC for mixtures of these surfactants versus the mole fraction of DTAC. 

Creme rinses are appHed to the hair after washing. Frequently used quaternaries in creme rinses are dodecyltrimethylammonium chloride [112-00-5] dimethyloctadecy1(pentaethoxy)ammonium chloride, benzyldimethyloctadecylammonium chloride [122-19-0] and dimethyldioctadecylammonium chloride... 

Dodecyltrimethylammonium bromide [1119-94-4] M 308.4, m 246°(dec). Purified by repeated crystn from acetone. Washed with diethyl ether and dried in a vacuum oven at 60° [Dearden and Wooley J Phys Chem 91 2404 1987]. 

Dodecyltrimethylammonium chloride [112-00-5] M 263.9, m 246 (dec). Dissolved in MeOH, treated with active charcoal, filtered and dried in vacuo [Waldenburg J Phys Chem 88 1655 1984], or recrystd several times from 10% EtOH in acetone. Also repeatedly crystd from EtOH/ether or MeOH. [Celia et al. 7 Am Chem Soc 74 2062 7952.]... 

Toshima et al. obtained colloidal dispersions of platinum by hydrogen- and photo-reduction of chloroplatinic acid in an aqueous solution in the presence of various types of surfactants such as dodecyltrimethylammonium (DTAC) and sodium dodecylsulfate (SDS) [60]. The nanoparticles produced by hydrogen reduction are bigger and more widely distributed in size than those resulting from the photo-irradiation method. Hydrogenation of vinylacetate was chosen as a catalytic reaction to test the activity of these surfactant-stabilized colloids. The reaction was performed in water under atmospheric pressure of hydrogen at 30 °C. The photo-reduced colloidal platinum catalysts proved to be best in terms of activity, a fact explained by their higher surface area as a consequence of their smaller size. 

The mechanism and rate of reduction of nitroarenes by cluster rhodium/cobalt carbonyls under basic conditions and catalysed by dodecyltrimethylammonium chloride has been reported [13]. 

Dodecyltrimethylammonium chloride is rapidly mineralized in fresh water after an acclimation period, and the rate is faster following the second rather than the first addition of the quaternary ammonium compound. 

At the phase boundary between water and an organic solvent immiscible with water, an electric double layer may also be formed if one of the solutions in contact contains an amphiphilic ion, i.e. an ion that contains both hydrophilic (usually electrically charged) and hydrophobic (nonpolar) groups (for example the dodecyltrimethylammonium ion). Ions with these properties are simply adsorbed on the phase boundary with the nonpolar group oriented into the organic solvent and the ionized group in the aqueous phase. 

Hong et al. applied capillary EKC with dodecyltrimethylammonium-bromide/sodium dodecylsulfate (12.7/21.1 mM) vesicles to the separation of alkylphenones (Fig. 8A) and obtained better resolution than with sodium dodecylsulfate micelles (59). The logarithms of the retention factors for 20 neutral compounds of similar structures showed an excellent linear correlation with log Poct (R2 = 0.98). Similarly, Razak et al. (60) showed that the log capacity factors for interaction between neutral and positively charged analytes and cetyltrimethylammoniumbromide/sodium octylsulfate vesicles correlated linearly with the log Poa values. 

Contrary to hydrotropes, micelle-forming surfactants spontaneously self-aggregate cooperatively above the critical micelle concentration (cmc) even in the absence of solubilizate. Typical examples of micelle-forming surfactants include sodium dode-cylsulfate (SDS), dodecyltrimethylammonium bromide (DTAB), cetyltrimethyl-ammonium bromide (CTAB), and heptaoxyethylene dodecyl ether (C12E7) (Scheme 2). 

CZE-ELD, with a An microelectrode at —0.6 V vs. SCSE and a Pt wire as auxiliary electrode, using sodium borate buffer and dodecyltrimethylammonium bromide for dynamic coating of the capillary internal surface, can be applied for separation and determination of hydroperoxides in ultra-trace amounts. Thus, various hydroperoxides derived from linoleic acid undergo total dissociation to carboxylates in borate buffer however, due to their similar molecular masses, in order to resolve the ELD signals, it is necessary to add /3 -cyclodextrin (83) to form complexes with the analytes and reduce their mobility, in accordance with the value of the complexation equilibrium constants . 

DOC (dissolved organic carbon), 606, 607-8 Dodecyltrimethylammonium bromide, 744 Domino reactions, thiyl and selenyl radicals, 221-3, 224, 225, 226-7 DOPA (3,4-dihydroxyphenylalanine), 614, 615... 

Our group [124] has used pyrene and pyrene labeled poly(acrylic acid) as a fluorescent probe to investigate the interaction between poly(acrylic acid) (PAA) and dodecyltrimethylammonium bromide (DTAB) in water. We have measured the Is /1 ratio of pyrene as a function of DTAB in the presence of 1 g/L PAA. A sharp decrease in polarity is found well below the CMC of DTAB (1.3 X 10 M, Fig. 17). The onset of this polymer-induced association is referred to as the critical aggregation concentration. The CAC has been measured at various pH and NaCl levels (Fig. 18). It was observed that the... 

Fig. 23 Schematic representation of the formation of polymer surfactant complexes for the pyrene-labeled (polyacrylic acid)-dodecyltrimethylammonium bromide system for high (high pH) and low (low pH) degrees of ionization...

Actual transfer distance along the primary DNA ds Interduplex center-to-center separation Spermine tetrahydrochloride Dodecyltrimethylammonium bromide Octadecyltrimethylammonium bromide Poly-L-lysine hydrobromide Polyethylenimine hydrochloride Ionization energy... 

Dodecyltrimethylammonium bromide [1119-94-4] M 308.4. Purified by repeated crystn from... 

Dodecyltrimethylammonium chloride [112-00-5] M 263.9. Dissolved in MeOH, treated with active... 

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