Cetyltrimethylammonium halides

Michael reactions. The addition of amines to chalcones can be accomplished in aqueous suspensions of the reactants in the presence of cetyltrimethylammonium halides, i.e., organic solvents are not required. 

Micellar and microemulsion effects on reactivity in aquation and base hydrolysis reactions of iron(II)-diimine complexes have been much studied/ The latest contribution deals with the effects of added potassium chloride or bromide to micelles of the respective cetyltrimethylammonium halides. Effects on base hydrolysis of [Fe(phen)3] and its 4,7-diphenyl and 3,4,7,8-tetramethyl derivatives can be interpreted in terms of competitive binding to the micelles in a pseudophase-ion exchange model. In connection with these secondary effects of added halides it should be mentioned that further studies of kinetics of aquation of [Fe(bipy)3] and of [Fe(phen)3] in strong aqueous solutions of chlorides have been interpreted in terms of water and of chloride attack, with the postulation of transient diimine-chloride-iron(II) intermediates. ... 

Cuccovia, I.M., da Silva, I.N., Chaimovich, H., Romsted, L.S. New method for estimating the degree of ionization and counterion selectivity of cetyltrimethylammonium halide micelles chemical trapping of free counterions by a water soluble arenediazonium ion. Langmuir 1997,13(4), 647-652. 

The reductive coupling of allyl halides to 1,5-hexadiene at glassy C electrodes was catalyzed by tris(2, 2,-bipyridyl)cobalt(II) and tris(4,4 -dimethyl-2, 2/-bipyridyl)cobalt(II) in aqueous solutions of 0.1 M sodium dodecylsulfate (SDS) or 0.1 M cetyltrimethylammonium bromide (CTAB).48 An organocobalt(I) intermediate was observed by its separate voltammetric reduction peak in each system studied. This intermediate undergoes an internal redox reaction to form 1,5-hexadiene... 

Synthesis of MCM-41 with Additives. The hydrothermal crystallization procedure as described earlier [10] was modified by adding additional salts like tetraalkylammonium (TAA+) bromide or alkali bromides to the synthesis gel [11]. Sodium silicate solution ( 14% NaOH, 27% Si02) was used as the silicon source. Cetyltrimethylammonium (CTA) bromide was used as the surfactant (Cl6). Other surfactants like octadecylltrimethylammonium (ODA) bromide (C,8), myristyltrimethylammonium (MTA) bromide (C,4) were also used to get MCM-41 structures with different pore diameter. Different tetralkylammonium or alkali halide salts were dissolved in little water and added to the gel before addition of the silica source. The final gel mixture was stirred for 2 h at room temperature and then transferred into polypropylene bottles and statically heated at 100°C for 4 days under autogeneous pressure. The final solid material obtained was washed with plenty of water, dried and calcined (heating rate l°C/min) at 560°C for 6 h. 

The Co reagent 192, prepared by the reaction of Co2(CO)8 with sodium, is reactive, and the acylcobalt complex 193 is formed by the reaction of acyl halides. Insertion of butadiene at the Co-acyl bond generates the 7r-allylcobalt complex 194, from which the acylbutadiene 195 is formed by deprotonation with a base [82]. Based on this reaction, various acyldienes are prepared by Co2(CO)8-catalysed reaction of active alkyl halides, conjugated dienes and CO. The Co-catalysed reaction can be carried out smoothly under phase-transfer conditions. For example, 6-phenyl-3,5-hexadien-2-one (197) was prepared in 86% yield by the reaction of Mel, 1-phenylbutadiene (196) and CO in the presence of cetyltrimethylammonium bromide [83]. 

RX — RCN.4 Nitriles are obtained in 75-93% yield by heating a suspension of an alkyl halide, NaCN (2 equiv.), and cetyltrimethylammonium bromide (1.5 mole %) in water (26 mole %) at 100° overnight. 

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 ... 

Using distribution between chloroform and water, Jones and asso-ciates have separated an acetylated mixture of neutral polysaccharide, which dissolved in the chloroform, and an acidic polysaccharide, which formed an emulsion between the two phases. Such mixtures were shown by Scott < to be easily separated by precipitation of the acidic component with such quaternary ammonium salts as cetyltrimethylammonium (Cetavlon) or cetylpyridinium halides. Polysaccharides which differ in acidity can also be separated by this method, and, as the solubility of the precipitate increases with increasing ionic strength, the separation can also be done as... 

Aliphatic and aromatic nucleophilic substitution reactions are also subject to micellar effects, with results consistent with those in other reactions. In the reaction of alkyl halides with CN and S Oj in aqueous media, sodium dodecyl sulfate micelles decreased the second-order rate constants and dodecyltrimethylammonium bromide increased them (Winters, 1965 Bunton, 1968). The reactivity of methyl bromide in the cationic micellar phase was 30 to 50 times that in the bulk phase and was negligible in the anionic micellar phase a nonionic surfactant did not significantly affect the rate constant for n-pentyl bromide with S2O3-. Micellar effects on nucleophilic aromatic substitution reactions follow similar patterns. The reaction of 2, 4-dinitrochlorobenzene or 2, 4-dinitrofluorobenzene with hydroxide ion in aqueous media is catalyzed by cationic surfactants and retarded by sodium dodecyl sulfate (Bunton, 1968, 1969). Cetyltrimethylammonium bromide micelles increased the reactivity of dinitrofluorobenzene 59 times, whereas sodium dodecyl sulfate decreased it by a factor of 2.5 for dinitrochlorobenzene, the figures are 82 and 13 times, respectively. A POE nonionic surfactant had no effect. 

Sulfides are readily formed from thioli syl halides) or epoxides " in the present micelles of cetyltrimethylammonium broa generates symmetrical sulfides. Alkynj trophiles for 5-alkylation of (9,0 -dialkyl C-Alkylations. The alkylation of et neous application of microwave radiation from alkylation because secondary reacti drolysis take place. 

Sulfides are readily formed from thiols on reaction with halides (including glyco-syl halides) or epoxides in the presence of a phase-transfer catalyst. In aqueous micelles of cetyltrimethylammonium bromide the reaction of Na2S with haloalkanes generates symmetrical sulfides. Alkynyl phenyliodonium salts are suitable electrophiles for S-alkylation of O.O -dialkyl phosphorodithiolates. ... 

Calix[n]arenes 1-3 were used as inverse PT catalysts in the alkylation of active methylene compounds with alkyl halides in aqueous NaOH solutions,and in aldol-type eondensation and Michael addition reactions. In the aikylation of phenylacetone with octyl bromide, the IPTC procedure enhanced the alkylation versus hydrolysis and C versus O alkylation selectivities with respect to those observed xmder classical PTC reactions in the presence of tetrabutylammonium bromide (TBAB) or hexadecyltributylammonium bromide (HTPB). Moreover, the aqueous catalyst solution was easily separated from the organic phase eontaining the products, and no organic solvent was required. In the case of the aldol-type condensation of benzaldehyde with indene or acetophenone in aqueous NaOH (Fig. 9), IPTC reaetions eatalyzed by I were compared with those conducted in aqueous micelles in the presence of cetyltrimethylammonium bromide (CTAB) as the sufactant. Although selectivities and yields were similar, the IPTC proeedure avoided the formation of emulsions, thus faciUtating product separation and catalyst recovery. In the light of the results obtained, water-soluble calix[ ]arenes 1-3 were proposed... 

The successful homocouphng of aryl and heteroaryl bromides and chlorides was achieved by using palladium on charcoal in the presence of sodium hydroxide, sodium formate, and a surfactant (cetyltrimethylammonium bromide, etc.) (Scheme 6). The advantage of this procedure is that the homocoupling of aryl and heteroaryl halides can be successfully achieved (Table... 

CTAB = cetyltrimethylammonium bromide, usually 10-20 mol% to aryl halide... 

Cationic sm-factants such as tetradecyltrimethyl-ammonium bromide (TTAB), cetyltrimethylammoni-um bromide (CTAB), and cetyltrimethylammonium chloride (CTAC) have also been useful for MEKC analysis. Most cationic sm-factants have an alkyltri-methylammonium group, and their counterions are halides. The addition of cationic surfactants to the backgroimd electrolytes (BGE) caused the reversal of electroosmotic flow (EOF) owing to a positively charged capillary wall on account of the adsorption of cationic sm-factants. As a result of the reversed EOF, the polarity of the electrodes has to be reversed in order to detect the analytes. 

Sodium telluride and ditelluride are readily generated in situ from Te by reduction with thiourea dioxide, and subsequent treatment with alkyl halide provides the corresponding dialkyl tellurides and ditellurides. E Thiourea dioxide and NaOH in 1 1 water/THF added to Te under N2, the mixture refluxed for 1 h, n-octyl halide and a little cetyltrimethylammonium bromide in THF added, and refluxing continued for 1 h - dioctyl telluride. Y 85%. The method is cheap, simple and does not require very dry conditions. F.e. and sym. ditellurides s. J.T.B. Ferreira et al., Synth. Commun. 19, 239-44 (1989) prepn. of Na2Te from ultra-pure Te-ingots/Na-naphthalenide, or from Te/Na and a little naphthalene, s. K.T. Higa, D.C. Harris, Organometallics 8, 1674-8 (1989). 

Monoalkyltrimethylammonium salts, e.g. cetyltrimethylammonium bromide. Monoalkyldimethylbenzylammonium chloride, e.g. benzalkonium chloride. Dialkyldimethylammonium salts, e.g. didecyldimethylammonium halides. 

Hel and CO by a Co2(C0)g/cetyltrimethylammonium bromide/MaOH (aqu.) system290 or from benzyl halides and Mel in the presence of Fe(CO)5.291 Rh/I-catalysts convert PhCH2Br, HCOOR and CO into carboxylic esters.282 phBr,... 

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