- Solubilization of some Tetramethylammonium Salts and of Ethyltrimethylammonium Bromide by their Homologues in Chloroform
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The solubilities of tetramethylammonium chloride, bromide, thiocyanate and perchlorate and of ethyltrimethylammonium bromide in chloroform at 25 +/- 0.2 deg C have been determined.The solubilities of these salts increase markedly in the presence of a variety of higher homologues of common co-ions.It is suggested that this phenomenon involves the cooperative formation of reversed micelles.
- Czapkiewicz, Jan
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- An Efficient One-Pot, Four-Component Synthesis of Pyrazolo[3,4-b]pyridines Catalyzed by Tetrapropylammonium Bromide (TPAB) in Water
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A novel and one-pot pseudo-four-component reaction between a series of arylglyoxals, malononitrile, 3-methyl-1-phenyl-1H-pyrazol-5-amine, and acetone in the presence of tetrapropylammonium bromide (TPAB) has been developed to synthesize a series of new substituted pyrazolo[3,4-b]pyridines, using water as an environmentally friendly solvent, in high to excellent yields.
- Ezzati, Mahnaz,Khalafy, Jabbar,Marjani, Ahmad Poursattar,Prager, Rolf H.
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- Preferential orientations of structure directing agents in zeolites
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The local structure of as-synthesised silicalite-1 zeolites is modified using asymmetric R(Pr)3N+ structure directing agents. Using multi-nuclear NMR (1H, 13C, 14N, 19F, 29Si), we show for the first time the ability of these cations to adopt preferential orientations at the zeolite channels' crossing.
- Dib, Eddy,Gimenez, Antoine,Mineva, Tzonka,Alonso, Bruno
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supporting information
p. 16680 - 16683
(2015/10/05)
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- NMR study of the complex formation between tert-butyl hydroperoxide and tetraalkylammonium bromides
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The interaction between tert-butyl hydroperoxide and tetraalkylammonium bromides was studied by NMR spectroscopy in acetonitrile-d 3 at 298 K. The complex formation between the hydroperoxide molecule and corresponding quaternary ammonium salt w
- Turovskij, Nikolaj A.,Berestneva, Yulia V.,Raksha, Elena V.,Zubritskij, Mikhail Yu.,Grebenyuk, Serhiy A.
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p. 1443 - 1448
(2014/11/27)
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- Effects of charge separation, effective concentration, and aggregate formation on the phase transfer catalyzed alkylation of phenol
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The factors that influence the rate of alkylation of phenol under phase transfer catalysis (PTC) have been investigated in detail. Six linear, symmetrical tetraalkylammonium cations, Me4N+, Et 4N+, (n-Pr)4N+, (n-Bu) 4N+, (n-Hex)4N+, and (n-Oct) 4N+, were examined to compare the effects of cationic radius and lipophilicity on the rate of alkylation. Tetraalkylammonium phenoxide·phenol salts were prepared, and their intrinsic reactivity was determined from initial alkylation rates with n-butyl bromide in homogeneous solution. The catalytic activity of the same tetraalkylammonium phenoxides was determined under PTC conditions (under an extraction mechanism) employing quaternary ammonium bromide catalysts. In homogeneous solution the range in reactivity was small (6.8-fold) for Me4N+ to (n-Oct) 4N+. In contrast, under PTC conditions a larger range in reactivity was observed (663-fold). The effective concentration of the tetraalkylammonium phenoxides in the organic phase was identified as the primary factor influencing catalyst activity. Additionally, titration of active phenoxide in the organic phase confirmed the presence of both phenol and potassium phenoxide aggregates with (n-Bu)4N+, (n-Hex)4N+, and (n-Oct)4N+, each with a unique aggregate stoichiometry. The aggregate stoichiometry did not affect the PTC initial alkylation rates.
- Denmark, Scott E.,Weintraub, Robert C.,Gould, Nathan D.
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supporting information; experimental part
p. 13415 - 13429
(2012/09/25)
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- Method for producing tetrapropylammonium bromide
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A method for producing tetrapropylammonium bromide by reacting tripropylamine with propyl bromide in a polar solvent at a temperature between 60° and 160° C.
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