Hexadecyltrimethyl ammonium bromide

Polymerization of acrylonitrile (AN) in tol uene/water was studied using hexadecyltrimethyl-ammonium bromide as the phase transfer catalyst (12). 

In another related study (using hexadecyltrimethyl ammonium bromide micelles), isopropyl benzene was solubilized, and the chemical shifts of aromatic and alkyl protons were observed. The results suggest that the isopropyl benzene molecules are oriented such that the isopropyl groups are buried more deeply in the core of the micelle, while the benzene ring is in the more hydrated palisade layer. This plus the conclusion of Item 3 is consistent with the description presented in Section 8.3, which located the benzene in a relatively polar portion of the micelle. 

Acesulfame-K, dulcin, saccharin Cl8 column Acetonitrile 50 mM a-hydroxyisobutyric acid, pH 4.5 (2.2 3.4, v/v) with 2.5 mM hexadecyltrimethyl-ammonium bromide UV—233 nm 65... 

Fig. 3. Conductivity curves of the copolymerization of 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone (0.5 mol/1) with phthalic anhydride (0.5 mol/1) in o-xylene at 120 °C initiated by various initiators.57) 1 — tri-n-hexylamine (0.025 mol/1) 2 - tri-n-hexylamine (0.025 mol/1) and cyclohexanol (0.025 mol je 1) 3 — tri-n-hexylamine (0.025 mol/1) and benzoic acid (0.025 mol/1) 4 — hexadecyltrimethyl-ammonium bromide (0.005 mol/1)...

Equation (31) allows the determination of the ratio of propagation rate constants k3/k2 by correlation of the experimental results obtained in copolymerization using equimolar ratios of monomers with the results obtained at non-equimolar monomer ratio and excess of anhydride (an excess of epoxide should not be used because of homopolymerization of the monomers at high degree of conversion). A value of k3,/k2 equal to 0.2 0.1 was found for the system 2-hydroxy-4-(2,3-epoxypropoxy) benzophenone-phthalic anhydride in nitrobenzene initiated by hexadecyltrimethyl-ammonium bromide 56). 

HTMAB = hexadecyltrimethyl ammonium bromide A HTMAB (10 mo %), H20 TMBAB = tetrabutyl ammonium bromide... 

PRP-1 styrene-divinyl-benzene (10 pm) W ater-acetonitrile-propanol (90 7 3) containing 0.45 M-KH2P04 and O.lmM-hexadecyltrimethyl ammonium bromide [2 mL/min], UV at 254 nm Limit of detection 2 pg [154]... 

The influence of sodium dodec3d sulfate, hexadecyltrimethyl-ammonium bromide and a polyoxyethylene(18) dodecylphenol on the hydrolysis of the Schiff bases p-chlorobenzylidene-l,l-dimethylethyl-amine, p-methoxybenzylidene-l,l-dimethylethylamme, and benz-hydrilidenedimethylammonium iodide (iV,iV-dimethylbenzophenone-imonium iodide) have been investigated (Behme and Cordes, 1965). The observed pseudo-first order rate constant for the hydrolysis ofp-chloro-... 

The conductometric titration of aqueous hexadecyltrimethyl-ammonium bromide-cetyl alcohol mixtures with benzene allows determination of the mechanism of emulsification. However, the shapes of the conductometric titration curves are complex the most sta-... 

The caticHiic surfactants are used infrequently in emulsion polymerization t pli-cations since they are not compatible with the anionic surfactants and with the (typically) negatively charged latex particles. These surfactants are usually of the following types salts of long chain amines, polyamines and their salts, quaternary ammonium salts (e.g., hexadecyltrimethyl ammonium bromide), polyoxyethyle-nated long-chain amines and their quatemized doivatives, and amine oxides [89]. 

In certain instances, enantioselectivity can be influenced by the addition of a second chiral additive such as alkylhydroxyalkyl cellulose [3,4], hexadecyltrimethyl ammonium bromide or cetylpyridinium chloride [3]. Extra additives, will not only introduce a different enantiomeric selectivity, but it will also increase the probability of the solute interacting with a chiral center and thus increase the selectivity. This... 

Surprisingly, almost all the applied work in MLC to date appears to have involved only ionic micellar mobile phases composed of either anionic sodium dodecyl sulfate (SDS), or cationic hexadecyltrimethyl-ammonium bromide or chloride (CTAB or CTAC), and dodecyltrimethyl-ammonium bromide (DTAB). Reports on the use of unclmrg nonionic surfactants, such as Neodol 91-6 and polyoxyethylene(23) dodecanol (Brij 35) are exceptions. 

Wu et al. [129] prepared biodegradable polyQactic acid) (PLA)/organically modified montmorillonite (m-MMT) nanocomposites by solution blending, the most critical part of this process being the modification of the MMT. The MMT was first treated with hexadecyltrimethyl-ammonium bromide (CTAB) cations, and then modified with biocompatible and biodegradable chitosan. As the chemical similarity between m-MMT and PLA was improved, the m-MMT became well separated in the PLA matrix. 

Abbreviations DLPC, dilinoleoyl phosphatidylcholine PC, phosphatidylchoUne (egg) LA, Unoleic acid SDS, sodium dodecyl sulfate HDTBr, hexadecyltrimethyl ammonium bromide. 

First-order static quadrupole effects give for the chlorine and bromine nuclei rise to spectra analogous to that shown in Fig. 7.4. First-order quadrupole splittings have been determined for Cl in the hexagonal mesophase of the dodecyltrimethylammonium chloride-water system [1Z6 405] and for Br in the hexagonal mesophase of the hexadecyltrimethyl-ammonium bromide-water system [Z21], (The hexagonal mesophase is built... 

O. R. Miranda, N. R. Dollahon and T. S. Ahmadi, Critical concentrations and role of ascorbic acid (Vitamin C) in the crystallization of gold nanorods within hexadecyltrimethyl ammonium bromide (CTAB)/tetraoctyl ammonium bromide (TOAB) micelles. Crystal Growth and Design, 6(12), 2747-2753 (2006). 

Chromatographic analysis of the vitamin Bg complex, including sample preparation and pre-TLC extraction have been reviewed (14). Separation of pyridoxine from other water-soluble vitamins in pharmaceutical preparations may be facilitated by impregnating silica gel plates with zinc acetate to provide a self-indicating system after separation (7). Impregnation of plates with hexadecyltrimethyl-ammonium bromide has been used to improve the TLC analysis of vitamin in foods (9). Overpressure layer chromatography was found to provide better separation and resolution of B( from other compounds than HPTLC (11). 

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