Hexadecyltrimethylammonium hydroxide

Alkyltrimethylammonium surfactants, such as hexadecyltrimethylammonium chloride (HTAC) [6, 9, 38-41], hexadecyltrimethylammonium hydroxide (HTAH) [38, 42], hexadecyltrimethylammonium bromide (HTAB) [43-46], te-tradecyltrimethylammonium bromide (TTAB) [47], pentadecyltriethylammon-... 

The CAS Registry Number for hexadecyltrimethylammonium hydroxide [505-86-2] has also been widely applied to cetrimide. 

MCM-41, synthesized using hexadecyltrimethylammonium hydroxide, was ion-exchanged with tetrapropylammonium hydroxidc-MCM-41 by shaking a suspension of 2.00 g of MCM-41 in 1.22 g of 25.0 wt. % of tetrapropylammonium hydroxide solution in 1 L at room temperature overnight. The solid was recovered by centrifugation, washed in water and subjected to a hydrothermal treatment at 170°C in a 15-mL Teflon autoclave. The recrystallized MCM-41 was recovered by centrifugation, washed with deionized water and dried under vacuum at 60 °C. The template was removed by calcination in a stream of air al 500 °C for 6 h [91]. 

In the case of (Sn)MCM-48 hexadecyltrimethylammonium hydroxide (0.1 mol), filmed silica (0.035 mol) and tin tetrachloride (from 5.5T0 to 4.5-10" mol) were used. The hydrothermal synthesis (samples denoted (Sn)MCM-48/HT) was carried out in Teflon-lined stainless steel autoclaves at 135 °C for 24 h [16]. Using microwave procedure the synthesis was performed at 135 C for 2 h (samples denoted (Sn)MCM-48/MW). All solid products were filtered, washed with deionized water, dried at 100 C and calcined at 550 °C. The prepared samples are listed in Table 2. 

Inositol phosphates isomers have also been separated by micellar mobile high-performance liquid chromatography (Brando et ah, 1990). This involved addition of the surfactant hexadecyltrimethylammonium hydroxide (HDTMA+OH ) to the mobile phase to form micellar ion association complexes that were separated on a reversed-phase column. Enhanced sensitivity and selectivity can be achieved by use of high-performance liquid chromatography in con-... 

In the analysis of inorganic anions using acetonitrile-water (3-1-7) containing citric acid and hexadecyltrimethylammonium hydroxide as eluent. Wheals reported that bromide, cyanide, dithionite, ferrocyanide, iodide, metabisulfite, nitrite, perborate, peroxide, sulfide, thiocyanate and thiosulfate respond at a GCE (-1-0.75 V vs Ag/AgCl). Dou and Krull have further shown that post-column irradiation (low pressure Hg arc discharge lamp) can facilitate the EC detection of chromate, dichromate and perchlorate and give improved sensitivity for thiocyanate. Despite this work, however, the application of EC detection to the analysis of these ions in biological systems has not been reported as yet. 

CsBr = octyltrimethylammonium bromide, = dodecyltrimethylammonium bromide, C gOH = hexadecyltrimethylammonium hydroxide, C.10CI = hexadecyltrimethylammonium chloride, C gBr = hexadecyltrimethylammonium bromide, CieOH = octadecyitrimethyi-ammonium hydroxide, HEX = hexadecane, TOL = toluene, MES = mesitylene... 

Acids such as sulfuric or nitric acids or bases such as sodium hydroxide may catalyze the hydrolysis of PET. It has been demonstrated that the rate of alkaline PET hydrolysis increases in the presence of quaternary ammonium compounds.26 27 Niu et al.26 reported an increase in the rate of alkaline PET degradation in the presence of dodecylbenzyldimethylammonium chloride at 80°C. Polk et al.27 reported increases in the rate of sodium hydroxide depolymerization of PET in the presence of trioctylmethylammonium chloride, trioctyl-methylammonium bromide, and hexadecyltrimethylammonium bromide at 80° C. 

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

Quaternary ammonium periodates, prepared either from periodic acid and the quaternary ammonium hydroxide [21, 22] or by metathesis from sodium periodate and a quaternary ammonium salt [e.g. 23-25], have been used for a range of oxidations at stoichiometric levels in two-phase systems [21-33], The tetra-n-butyl-ammonium and hexadecyltrimethylammonium salts are both highly soluble in organic solvents (considerably less so in water), whereas benzyltriethylammonium periodate has a lower solubility and stability than either salt. 

The degradation of several commercial penicillin antibiotics has been reported.110-113 Thus the kinetics and mechanism of decomposition of cefazolin ester (136) in phosphate buffers110 and the effect of hexadecyltrimethylammonium bromide-based microemulsions on the decomposition of the antibiotic cephalosporin, cephaclor (137)111 have been reported. Reaction of the latter can occur intramolecularly or intermolecularly by hydroxide attack. Degradation in the solid state of cephaclor (137) has also been reported.112 The same group has looked at the decomposition under aqueous acidic conditions.113 The degradation pathways that have been recognized are... 

The reactions of a phosphate triester, p-nitrophenyl diphenyl phosphate with hydroxide and fluoride ions has been demonstrated to be catalyzed strongly by cationic surfactants and inhibited by NaLS and a non-ionic surfactant (Bunton and Robinson, 1969a Bunton et al., 1969, 1970). Hexadecyltrimethylammonium bromide (CTAB) increased the second-order rate constant for the reaction ofp-nitrophenyl diphenyl phosphate with hydroxide ion by a maximum factor of approximately 11 and that with fluoride ion by a maximum factor of approximately 33 at CTAB concentrations of 3 x 10 m and 2 x 10 m respectively. At higher detergent concentrations the catalysis became progressively less pronounced (Fig. 11). This behavior does not fit equation (10) (Bunton and Robinson, 1969a). However, a number of other micelle-catalyzed reactions between anions and neutral molecules have been found to... 

The synthesis of MCM-22 precursor and MCM-36 Is described in detail elsewhere [8,9].The following illustrates a typical MCM-36 preparation. MCM-22 precursor wet cake (150 g, 42 % solids) was reacted with 1.1 I of the swelling reagent, C,8TMA-OH (29 % aqueous solution of hexadecyltrimethylammonium chloride contacted with hydroxide-for-halide exchange resin) for 96 hours in a steambox. The solid obtained after filtration, washing and air drying contained approximately 40 % solids and 30 % surfactant. The swollen material was pillared with tetraethylorthosilicate, hydrolyzed... 

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... 

Synthesis of MCM-48 31 g of silica, 57 g of 25 % tetramethylammonium hydroxide and 165 g water are digested at 100°C. 172 g of 29 % hexadecyltrimethylammonium chloride solution is added and the mixture reacted for 12 hrs. at 150°C yielding MCM-48. The desired product is transient and upon prolonged heating slowly transforms into the lamellar MCM-50. The latter is initially difficult to observe since its most prominent XRD peak overlaps with the MCM-48 s (220) reflection. The lamellar impurity in MCM-48 can be detected and... 

Methanesulphonic acid (Na salt) Pentanesulphonic acid (Na salt) Hexanesulphonic acid (Na salt) Heptanesulphonic acid (Na salt) Oxtanesulphonic acid (Na salt) 2-Naphthalenesulphonic acid (Na salt) Dodecylsulphonic acid (Na salt) Tetrabutylammonium hydroxide Tetraethylammonium hydroxide Tetrabutylammonium phosphate Hexadecyltrimethylammonium bromide Trihexylamine Triheptylamine Trioctylamine... 

Cava and co-workers have extended this reaction to sulfoxides using 30% aqueous sodium hydroxide at 80-100°, usually in the presence of a phase-transfer catalyst (hexadecyltrimethylammonium bromide). 

Precipitate flotation was shown to remove cadmium (as the sulfide) using hexadecyltrimethylammonium bromide (HTA) at a pH of S-9. The residual cadmium concentration was approximately 0.5 mg/L. Using adsorbing colloid flotation with ferrous sulfide and HTA at pH 9 resulted in residual cadmium concentrations of 0.003 mg/L. In an effort to eliminate the use of sulfide, cadmium hydroxide was floated with ferric hydroxide and HTA. The lowest residual was 0.010 mg/L at pH 12. This system, however, was very sensitive to ionic strength variations. Other studies removed cadmium precipitates with various systems over large ranges of pH by varying the coprecipitates and surfactants. ... 

Thiourea dioxide j sodium hydroxide I hexadecyltrimethylammonium bromide <-... 

The reaction mixture was prepared as follows 0.62 g of /M(0H)3 (98%, J.T.Baker), 0.6 g of sodium hydroxide (p.a., Janssen) and 1.5 g of deionized water were put into a 250 ml glass beaker and brought to the boil. After a clear solution resulted, 18.52 g of tetraethylammonium hydroxide solution (Merck, 20 >wt % solution in water) were added and the solution was cooled. Then 22 or ca 50 g of the 25% water solution of hexadecyltrimethylammonium chloride (Fluka, as regards the amount of surfactant see Tab.2) were added. Aluminate, which precipitated at first, dissolved again on warming. In a separate 400 ml polypropylene beaker 18.42 g of Ludox AS-40 (Du Pont, 40 wt % colloidal silica in water) were agitated with a magnetic stirrer (at ca 500 rpm). 

There is little effect of micelles upon the rate of an intramolecular nucleophilic reaction. Micelles of hexadecyltrimethylammonium bromide catalyse, by factors of 10 —10, the arenesulphinate anion-induced hydrolysis of 4-tolylsulphonyl-methyl perchlorate. There is no relationship between the rate acceleration and hydro-phobicity of the sulphinate anion and catalysis is attributed to the concentration of the reactants in the micellar phase.The rate constants for the reaction of nucleophiles with carbonium ions and those for the addition of cyanide ion to the A -alkylpyridinium ions are similar in the micellar and aqueous phases, and the rate enhancement is due to the concentration of reactants in the micellar pseudophase. Similarly, although micellar catalysed dephosphorylation by nucleophiles may show rate enhancements of up to 4 x 10 -fold, the second-order rate constants may be slightly smaller in the micellar pseudophase lowing to its lower polarity. However, the reaction of fluoride ion with 4-nitrophenyldiphenyl phosphate is very rapid in micelles of cetyltrimethylammonium fluoride, but the rate constant continues to increase when the substrate is fully bound with increasing cetyltrimethylammonium fluoride or sodium fluoride. The failure of the micellar pseudophase model is also apparent in the reaction of hydroxide ion with 2,4-dinitrochlorobenzene. It is suggested that reaction occurs between reactants in the aqueous and micellar pseudophases and also between hydroxide ion in water and substrate in the micelle. ... 

PA6, nylon-6 PU, polyurethane OMT, oiganoclay modified with hexadecyltrimethylammonium bromide MPP, melamine polyphosphate MH, magnesium hydroxide RP, red phosphorus. 

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