Chloride tetramethylammonium

Data reported for the protolysis constant of water in tetramethylammonium chloride (TMACl) media are listed in Table 5.9. The available data are mostly from Sipos et al. (1997), but there are supplementary data from Lucas (1967) and Capewell et a/. (1997). 

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If tetramethylammonium chloride is dissolved in hydrochloric acid, the unstable salt [(CH3)4N] [HClj], can be crystallised out here chlorine is showing weak hydrogen bonding (cf. F H—F which is stable, and Cl - H—Cl which is unstable). 

Tetramethylammonium chloride [75-57-0] is an example. Ditahowalkyldimethylammonium chloride [68783-78-8] is an example. 

Physical Properties. Most quaternary compounds are soHd materials that have indefinite melting poiats and decompose on heating. Physical properties are determined by the chemical stmcture of the quaternary ammonium compound as well as any additives such as solvents. The simplest quaternary ammonium compound, tetramethylammonium chloride [75-57-0] is very soluble ia water (163) and iasoluble ia nonpolar solvents. As the molecular weight of the quaternary compound iacreases, solubiUty ia polar solvents decreases and solubiUty ia nonpolar solvents iacreases (164—166). For example, trimethyloctadecylammonium chloride [112-03-8] is soluble ia water up to whereas dimethyldioctadecylammonium chloride [107-64-2] has... 

Tetramethylammonium chloride [75-57-0] M 109.6, m >230°(dec). Crystd from EtOH, EtOH/CHCl3, EtOH/diethyl ether, acetone/EtOH (1 1), isopropanol or water. Traces of the free amine can be removed by washing with CHCI3. 

The preparation of 2,6-difluoropyridine in 97% yield from 2,6-dichloropyridine can be accomplished at lower temperatures (150 °C) by using a catalytic amount of tetramethylammonium chloride in dimethyl sulfoxide containing less than 1% water [66]... 

The tetramethylammonium salt [Me4N][NSO] is obtained by cation exchange between M[NSO] (M = Rb, Cs) and tetramethylammonium chloride in liquid ammonia. An X-ray structural determination reveals approximately equal bond lengths of 1.43 and 1.44 A for the S-N and S-O bonds, respectively, and a bond angle characteristic bands in the IR spectrum at ca. 1270-1280, 985-1000 and 505-530 cm , corresponding to o(S-N), o(S-O) and (5(NSO), respectively. Ab initio molecular orbital calculations, including a correlation energy correction, indicate that the [NSO] anion is more stable than the isomer [SNO] by at least 9.1 kcal mol . ... 

Solvent-electrolyte tetramethylammonium chloride 0.1 m in methanol current density (start of the experiment) 22mA/cm2 reference electrode Ag/AgCl/KCl sat. (after Reference 16). 

In contrast to the behavior of 3-hexyne in trifluoroacetic acid, addition of HCl in acetic acid yields essentially rra s-3-chloro-3-hexene (48%) and 3-hexanone (52%) as products, with less than 1% of the cis chloride (31,42,43). The 3-hexanone has been shown to arise from an intermediate vinyl acetate. The kinetics are complicated, but they seem to be of first order in substrate and second order in HCl. Added tetramethylammonium chloride increases the rate of product formation and changes the product composition to >95% trans-3-chloro-3-hexene and <5% 3-hexanone. A termolecular electrophilic addition via an intermediate such as 14 has been proposed (31,42) to account for these data. 

FIG. 8 Potential oscillation at interface o/wl with SDS as surfactant with (A) no electrolyte, (B) with lOOmM NaCl, (C) lOOmM KCl, (D) lOOmM CsCl, (E) lOOmM MgClz, (F) lOOmM CaClj, (G) lOOmM BaClj, (H) lOOmM FeClj, (I) lOOmM NaF, (I) lOOmM NaBr, (K) lOOmM Nal, (L) lOOmM sodium acetate, (M) 100 mM sodium propionate, (N) 100 mM sodium -butyrate, (O) lOOmM sodium w-valerate, ( ) lOOmM tetramethylammonium chloride, (Q) 20mM tetra-ethylammonium chloride, (R) 20 mM tetrapropylammonium chloride, and (S) 20 mM tetrabutyl-ammonium chloride in phase wl. Phase w2 contains 8mM SDS and 5M ethanol and phase o contains 5mM tetrbutylammonium chloride. (Ref. 27.)... 

FIG. 9 Upper potential values, a.sds lower potential values, b.sds of the first oscillation at the interface between phases o and wl of the octanol membrane (A), interfacial potential of a two-phase octanol-water system in the absence of SDS, c.sds (B) and those in the presence of 10 mM SDS (in the case of inorganic electrolyte, 1 mM), d.sds (C)- TMACI tetramethylammonium chloride TEACI tetraethylammonium chloride TPACI tetrapropylammonium chloride TBACI tetra-butylammonium chloride AcNa sodium acetate PrNa sodium propionate, BuNa sodium n-butyrate VaNa sodium w-valerate. (Ref 27.)... 

Potential oscillation was measured in the presence of cholinergic agents (acetylcholine chloride, carbamylcholine chloride, carbamyl- d-methylcholine chloride, and acetyl-/6-methylcholine chloride) and anticholinergic agents (tetramethylammonium chloride, tetra-ethylammonium chloride, succinylcholine chloride, hexamethonium chloride, scopolamine hydrobromide, atropine sulfate, homatropine hydrochloride, and tubocurarine chloride)... 

FIG. 18 Chemical structures of (a) acetylcholine chloride, (b) carbamylcholine chloride, (c) carba-myl-y8-methylcholine chloride, (d) acetyl-/i-methylcholine chloride, (e) tetramethylammonium chloride, (f) tetraethylamonium chloride, (g) succinylcholine chloride, (h) hexamethonium chloride, (i) scopolamine hydrobromide, 0 atropine sulfate, (k) homatropine hydrochloride, and (1) tubocurar-ine chloride. 

The KB9C2H10(CH3)2 recovered from the ethanol solution is dissolved in 150 ml. of water, and a solution of 22 g. of trimethylammonium chloride in 100 ml. of water is added slowly with vigorous stirring. The precipitated salt is isolated by filtration, washed once with 50 ml. of cold water, and dried in vacuum over phosphorus(Y) oxide. The yield of (CH3)3NHB9C2Hio-(CH3)2 is 37.8 g. (98%). To purify the salt by crystallization, a boiling solution of 38 g. of the salt in 2 1. of water is allowed to cool slowly to 0°. Eighty per cent of the material is recovered in the first crop. Successive crops of the trimethylammonium salt may be obtained, or the anion may be recovered as the less soluble tetramethylammonium salt by addition of an aqueous solution of tetramethylammonium chloride to the mother liquor. The tetramethylammonium salt may be recrystallized from an ethanol-water solution. 

Tetramethylammonium chloride (2 mg) and 5 (1. Og) were placed in a vial, sealed, and heated in an oil bath at 107°C for 65 h. H-NMR analysis of the colorless, viscous grease showed the ratio of signals at 4.6 and 3.90ppm as ca. 60/1. The small amount of cyclic dimer formed (GC anlaysis) was removed by Kugelrohr distillation (up to 100°C/0.05 mm). 19F-NMR featured the internal/ terminal CF2CH20 group ratio as ca. 83/1. Size-exclusion chromatography showed the major peak with Mn, =26,700 and Mw =52,800, consistent with condensation polymer 7. 

The choice of the catalyst is an important factor in PTC. Very hydrophilic onium salts such as tetramethylammonium chloride are not particularly active phase transfer agents for nonpolar solvents, as they do not effectively partition themselves into the organic phase. Table 5.2 shows relative reaction rates for anion displacement reactions for a number of common phase transfer agents. From the table it is clear that the activities of phase transfer catalysts are reaction dependent. It is important to pick the best catalyst for the job in hand. The use of onium salts containing both long and very short alkyl chains, such as hexade-cyltrimethylammonium bromide, will promote stable emulsions in some reaction systems, and thus these are poor catalysts. 

Rate enhancements for these types of reaction have been reported to be as high as 200-fold, and the selectivity of the reaction was found to be very substrate dependent. These reactions must be conducted in dipolar aprotic solvents in the absence of water. Although tetramethylammonium chloride is too polar to find widespread application as a phase transfer agent, it has good thermal stability, and this, combined with its low cost, has resulted in its large scale industrial use in phase transfer catalysed aromatic nucleophilic fluorinations. 

The combined catalysis by 18-crown-6 and tetra-n-butylammonium bromide produces higher yields in shorter reaction times than either of the catalysts separately (Table 3.7) [21] and almost quantitative yields have been reported for solid solid liquid triphase catalysed esterification using silica impregnated with tetramethylammonium chloride [22]. 

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