Cetyltrimethylammonium hydroxide

Cetyltrimethylammonium mesylate. Cetyltri-V-propylammonium hydroxide. Cetyltrimethylammonium X, X = OMs, Cetyltri-V-propylammonium hydroxide. f Cetyltri-V-butylammonium bromide. SBorohydride. 

CTABr(OH) n-Hexadecyltrimethylammonium bromide (hydroxide) or cetyltrimethylammonium bromide (hydroxide)... 

Figure 4.23 Synthesis space diagram for a ternary system composed of tetraethylorthosilicate (TEOS), cetyltrimethylammonium bromide (CTAB), and sodium hydroxide (H, hexagonal phase [MCM-41] C, cubic phase [MCM-48] L, lamellar phase [MCM-50] H20/Si02 = 100, reaction temperature 100°C, reaction time 10 days). (Reprinted from Science, Vol. 267, A. Firouzi, D. Kumar, L.M. Bull, T. Besier, R Sieger, Q. Huo, S.A. Walker, J.A. Zasadzinski, C. Glinka, J. Nicol, D.l. Margolese, G.D. Stucky, B.F. Chmelka, Cooperative Organization of Inorganic-Surfactant and Biomimetic Assemblies, pp. 1138-1143. Copyright 1995. With permission of AAAS.)...

Because of the differential partitioning of hydroxide and phenoxide anions into organic solvents by quaternary ammonium cations, the catalysts generally have little effect on the Reimer-Tiemann reaction of phenols with dihalocarbenes [15]. Cetyltrimethylammonium bromide has been used in the two-phase dichloromethyl-ation of polysubstituted phenols (Scheme 7.21, Table 7.10) under Makosza s conditions [16,17] ring expansion of the reaction products provides an effective route to tropones. The rate of the reaction is enhanced by ultrasonic radiation [16]. 

A wide choice of cationic surfactants such as CTAB (cetyltrimethylammonium bromide), CTAH (cetyltrimethylammonium hydroxide), TTAB (tetradecyltrimethylammonium bromide), TTAOH (tetradecyltrimethylammonium hydroxide), MTAB (myristyltrimethylammo-nium bromide), OFM (OFM Anion-BT, Waters, Milford, MA, USA), HDB (hexadimethrine bromide), and many others may be used to reverse the EOF. CTAH and TTAOH should be preferred to CTAB and TTAB to avoid interference from bromate contamination. The capillary coating is performed just by rinsing with the BGE containing this flow modifier or even with an additional rinse step with a solution containing this flow modifier. 

The effects of micelles of cetyltrimethylammonium bromide (CTABr), tetradecyl-trimethylammonium bromide (TTABr) and sodium dodecyl sulfate (SDS) on the rates of alkaline hydrolysis of securinine (223) were studied at a constant [HO ] (0.05 m). An increase in the total concentrations of CTABr, TTABr and SDS from 0.0 to 0.2 M causes a decrease in the observed pseudo-first-order rate constants (kobs) by factors of ca 2.5, 3, and 7, respectively. The observed data are explained in terms of pseudophase and pseudophase ion-exchange (PIE) models of micelles. Cationic micelles of CTABr speed attack of hydroxide ion upon coumarin (224) twofold owing to a concentration effect. ... 

A method for purifying certain neutral polysaccharides by precipitation in borate buffer with cetyltrimethylammonium bromide was developed by Stacey and coworkers,118 but it does not appear to have been used for the isolation of galactomannan gums. It has, however, been claimed119 that guar gum and locust-bean gum can be separated by carefully controlled precipitation of the cetylpyridinium bromide complexes by 0.1 M sodium hydroxide. Guar gum is precipitated between pH 7.0 and 8.3, and locust-bean gum between 8.6 and 9.3. 

Si02 0.0015 Ti(OEt)4 0.12 CTABr 0.26 TMAOH 24.3 H20 were CTABr is cetyltrimethylammonium bromide (from Aldrich), TMAOH is tetramethylammonium hydroxide (from Aldrich). The silica source was Aerosil-200 from Degussa and Ti(OEt)4 was supplied by Alpha Products. The crystallization was performed at 100°C for 48 hours in Teflon lined stainsteel autoclaves. The solid was recovered by filtration and exhaustive washing with distilled water until neutral pH in the filtrate was obtained. Then, the Ti-MCM-41 was dried at 60°C for 24 hours. The occluded surfactant was removed by calcination at 540°C in nitrogen for 1 hour and subsequently, for 5 hours in air. 

Thiourea dioxide (aminoiminomethanesulfinic acid) reduced diaryl ditellurium and divinyl ditellurium derivatives in tetrahydrofuran, to which an ammonium salt such as cetyltrimethylammonium chloride, serving as a phase-transfer catalyst, and 50% aqueous sodium hydroxide had been added4,5. 

Dialkyl Ditellurium (Thiourea Dioxide Method)2 A mixture of 128 mg (1.0 mmol) of elemental tellurium, 4 mg (0.01 mmol) of cetyltrimethylammonium bromide, 0.75 ml tetrahydrofuran, and 0.5 ml dimethyl sulfoxide is heated at 80° for 15 min under an atmosphere of deoxygenated nitrogen. To this mixture is added 100 mg (1.0 mmol) of thiourea dioxide, 112 mg (2.6 mmol) sodium hydroxide, and 0.75 ml water. The resulting mixture is refluxed for 1 h. The purple solution is then cooled to 15°. Alkyl halide (2.0 mmol) is added and the mixture is stirred at 20° for 1 h. After normal work-up, the dark-red oils were passed through a pad of Celite with dichloromethane as the mobile phase. 

Bis[6-(tetrahydropyran-2-yl-oxy)-l-hexyl] Tellurium2 (Thiourea Dioxide Method) Under an atmosphere of nitrogen 200 mg (2 mmol) thiourea dioxide, 112 mg (2.6 mmol) sodium hydroxide, 0.75 mt water, 0.75 ml tetrahydrofuran and 128 mg (1 mmol) tellurium are mixed. The mixture is refluxed for 1 h. Then 2 mmol of the alkyl halide and 4 mg cetyltrimethylammonium bromide are added to the pale-pink solution.The mixture is refluxed for 1 h and then worked up in the usual way. The residue is purified by column chromatography on silica gel with petroleum ether as the mobile phase. The product is isolated in 72% yield. Similarly prepared were2 ... 

An example of exchange with an oxygen-containing functional group is given which utilises a micellar system. Cationic micelles of cetyltrimethylammonium chloride and bromide, and tetradecyltrimethylammonium chloride and bromide, accelerate the reaction of 2-(4-nitro-phenoxy)quinoxaline with hydroxide ion to give quinoxalin-2(l/f)-one. ... 

The kind of counter ion of an ion-pair reagent is vitally important for selecting the appropriate detection method. If suppressed conductivity detection is applied, the ion-pair reagent is used in its hydroxide form. With direct conductivity detection, salicylate is perferred as the counter ion for tetraalkylammonium cations [19,20], since these salts exhibit a lower background conductance in aqueous solution. According to Wheals [21], eluents such as cetyltrimethylammonium bromide in combination with citric acid at pH 5.5 have proved suitable for UV-, RI-, and amperometric detection, as well as for direct conductivity detection. This example is an impressive illustration of the versatility of ion-pair chromatography. 

Hexadecylpyridinium chloride, cetylpyridinium chloride n-Hexadecyltrimethylammonium bromide (hydroxide) or cetyltrimethylammonium bromide (hydroxide) Stoichiometric concentration of surfactant (detergent) Concentration of micellized surfactant generally [D ] = [D]-cwc... 

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