Tetraethylammonium bromide

Fig. V-5. The repulsive force between crossed cylinders of radius R (1 cm) covered with mica and immersed in propylene carbonate solutions of tetraethylammonium bromide at the indicated concentrations. The dotted lines are from double-layer theory (From Ref. 51).

Tetraethylammonium bromide [71-91-0] M 210.2, m 269 (dec), 284 (dec). Recrystd from EtOH, CHCI3 or diethyl ether, or, recrystd from acetoniuile, and dried over P2O5 under reduced pressure for several days. Also recrystd from EtOH/diethyl ether (1 2), EtOAc, water or boiling MeOH/acetone (1 3) or by adding equal volume of acetone and allowing to cool. Dried at 100 in vacuo for 12 days, and stored over P2O5. 

TBAP, tetrabutylammonium perchlorate TEAB, tetraethylammonium bromide TBAI, tetrabutylammonium iodide. 

In DMF, with 0.1m tetraethylammonium bromide. In 50% ethanol, with 0.1m tetraethylammonium bromide. ... 

Ga-MOR was hydrothermally synthesized by using tetraethylammonium bromide as a template. Ga content was controlled by removing Ga through HCl treatment in the same way as the dealumination of zeolite [1], The numeral at the end of catalyst name stands for Si02/Ga203 ratio in Ga-MOR thus prepared. Ga203/Ga-M0R catalyst was prepared by... 

A route to a-glycosides involves treatment of a 2,3,4,6-tetra-O-benzyl-a-D-glucopyranosyl bromide with an alcohol, tetraethylammonium bromide, and diisopropylethylamine in CH2C12. Explain the stereoselectivity of this reaction. 

Tetraethylammonium bromide, 2 549t Tetraethyldibismuthine, 4 30 Tetraethylene glycol, 42 654, 655, 660, 40 665... 

Pairs of platinum plate (2x5 cm) were set in a cell with 1 mm spacing as the working and the auxiliary electrode (Figure 2). Reference electrode was Ag/AgCl. The solution (50 ml) of phenol (0.005 mol) and electrolyte (0.01 mol) such as tetraethylammonium bromide and tetraethylammonium perchrolate was kept under nitrogen atmosphere in the cell. The electrolysis was carried out with constant potential or current density (10 mA/cm2) which was supplied by a potentiogalva-... 

Onium salts, such as tetraethylammonium bromide (TEAB) and tetra-n-butylammonium bromide (TBAB), were also tested as PTCs immobilized on clay. In particular, Montmorillonite KIO modified with TBAB efficiently catalyzed the substitution reaction of a-tosyloxyketones with azide to a-azidoketones, in a biphasic CHCI3/water system (Figure 6.13). ° The transformation is a PTC reaction, where the reagents get transferred from the hquid to the solid phase. The authors dubbed the PTC-modified catalyst system surfactant pillared clay that formed a thin membrane-hke film at the interface of the chloroform in water emulsion, that is, a third liquid phase with a high affinity for the clay. The advantages over traditional nucleophilic substitution conditions were that the product obtained was very pure under these conditions and could be easily recovered without the need for dangerous distillation steps. 

These authors, using a horn system, also noted less striking but still significant switches towards the one-electron products in other sonoelectrochemical reductions [66] including dimethylmaleate at a lead cathode in an aqueous mixed-phosphate buffer, and benzyl bromide at a lead cathode in methanolic tetraethylammonium bromide solution (Tab. 6.16). 

Aptotic solvents can be used for the reduction of aromatic hydrocarbons, particularly the condensed ring systems. Solvents used for the conversion of benzene to cyclohexa-1,4-diene at a mercury cathode under constant current conditions include dimethoxyethanc [45] and N-medtylpyrrolidone [46]. Each solvent contained water as a proton source and tetraethylammonium bromide as supporting electro-... 

In dry aprotic solvents such as acetonitrile [28] with tetraethylammonium bromide as supporting electrolyte or dimethylformamide [29] with sodium perchlorate as supporting electrolyte, the ( ) / rneso ratio for pinacols rises substantially in favour of the ( )-form. Reduction of acetophenone in dimethylformamide in the presence of europium(ni) chloride leads to the ( )-pinacol only. Under these reaction conditions, europium(ii) is formed and dimerization occurs with the involvement of this ion and the ketone in a complex [30]... 

Initiation by hydroperoxides may be intensified by anions capable of reducing other compounds. The formation of radicals in the reaction between tert-butyl hydroperoxide and tetraethylammonium bromide was studied at 55° to 77°C. in the presence of oxygen with 1-propanol as solvent. The rate of initiation was measured by consumption of a-naph-thol that acted as acceptor of free radicals. Naphthol was determined colorimetrically. Two radicals were suggested to react with one molecule of a-naphthol. The rate of initiation was found to be (Figure 3). 

Jacobsen and Pedersen153 confirmed the generation of benzoxonium ion 126 by treatment of compound 125 with triphenylmethyl fluoroborate in acetonitrile, but they treated it with tetraethylammonium bromide, obtaining a 3 2 mixture of the a and /3 anomers of methyl 2,5-di-0-benzoyl-3-bromo-3-deoxy-D-xylofuranoside (134) in a yield of 74%. This mixture could be anomerized to give the pure )8 anomer (overall yield 60%) by treatment with hydrogen bromide followed by the action of methanol. 

Ph3P(CH=CH)2PPh3 2Br" (dashed line)) in acetonitrile-water containing 0.1 M tetraethylammonium bromide. Reproduced by permission of Pergamon Press from Reference 36... 

The salt effects of potassium bromide and a series office symmetrical tetraalkylammonium bromides on vapor-liquid equilibrium at constant pressure in various ethanol-water mixtures were determined. For these systems, the composition of the binary solvent was held constant while the dependence of the equilibrium vapor composition on salt concentration was investigated these studies were done at various fixed compositions of the mixed solvent. Good agreement with the equation of Furter and Johnson was observed for the salts exhibiting either mainly electrostrictive or mainly hydrophobic behavior however, the correlation was unsatisfactory in the case of the one salt (tetraethylammonium bromide) where these two types of solute-solvent interactions were in close competition. The transition from salting out of the ethanol to salting in, observed as the tetraalkylammonium salt series is ascended, was interpreted in terms of the solute-solvent interactions as related to physical properties of the system components, particularly solubilities and surface tensions. 

An examination of Figures 1-6 indicates that Equation 1 is valid under conditions of constant x for potassium, ammonium, and tetramethylammonium bromides in ethanol-water mixtures. All three salts show an ability to salt out ethanol from these mixtures (i.e., increase its concentration in the equilibrium vapor) which is verified by their k values shown in Table XVIII. Also, the results for tetra-n-propylammonium bromide and tetra-n-butylammonium bromide in ethanol-water mixtures reveal that Equation 1 can be used to predict the salt effects of these systems however, these two salts demonstrate a propensity to salt in ethanol (i.e., decrease its vapor concentration) in ethanol-water mixtures. On the other hand, Figures 7-9 and the data in Table XVIII reveal that Equation 1 cannot be used to correlate the salt effects of tetraethylammonium bromide in ethanol-water. For this system, a linear dependence of log aja vs. z is observed initially however, a gradual levelling off occurs at higher concentrations. 

Table X. Isobaric Vapor—Liquid Equilibrium Data for the Tetraethylammonium Bromide—Ethanol—Water System at x = 0.206 (758 3 Torr)...

IV-Sulfinylbenzamide, produced by the reaction of benzamide and thionyl chloride, reacts with styrene oxide in the presence of tetraethylammonium bromide to give the 1,4,3,5-oxathiadiazepine (616) as the major product (71BCJ2836). 

---