Ethylpyridinium bromide

Protolytic reactions can also occur in fused salts. The solvent participates in these reactions provided that at least one of its ions has protogenic and/or protophilic character. An example of a solvent in which the cation is aprotic and the anion protophilic is ethylpyridinium bromide (m.p. 114°C). The acid HA is protolysed in this solvent (HA -I- Br HBr + A"). Hydrogen bromide acts as a solvated proton and the acidity is expressed as... 

In many ways, chloroaluminate molten salts are ideal solvents for the electrodeposition of transition metal-aluminum alloys because they constitute a reservoir of reducible aluminum-containing species, they are excellent solvents for many transition metal ions, and they exhibit good intrinsic ionic conductivity. In fact, the first organic salt-based chloroaluminate melt, a mixture of aluminum chloride and 1-ethylpyridinium bromide (EtPyBr), was formulated as a solvent for electroplating aluminum [55, 56] and subsequently used as a bath to electroform aluminum waveguides [57], Since these early articles, numerous reports have been published that describe the electrodeposition of aluminum from this and related chloroaluminate systems for examples, see Liao et al. [58] and articles cited therein. 

Pacholec, F., and Poole, C.F., Stationary phase properties of the organic molten salt ethylpyridinium bromide in gas chromatography, Chromatographia, 17, 370-374,... 

Fig. 3.6 Sedimentation velocity profiles for PS-poly(4-vinyl-Af-ethylpyridinium bromide) (Mw = 33 kg mol 8% PS) in methanol/34% water/LiBr mixtures at different LiBr concentrations (a) 0.01 M (b) 0.015 M (c) 0.02 M (d) 0.1 M. From Selb and Gallot (1981b).

Ethylpyridine N-oxide, AK98 N-Ethylpyridinium bromide, AK98 Ethyl 2-(4-pyridy1)acrylate, AR63... 

A major breakthrough was achieved in 1951 with the report of Hurley and Wier. They noticed that a mixture of N-ethylpyridinium bromide (EtPyBr) and AICI3 with a eutectic composition of 1 2 X(AlCh) = 0.66 h of EtPyBr to AICI3 became liquid at unusually low temperatures [2], They investigated these melts with regard to their potential use in the electrodeposition of aluminum at ambient temperature [3]. Several studies were carried out on this system, however, its use was very limited since it is only liquid at a mole fraction of X(A1C13) = 0.66 and the ease of oxidation of the bromide ion limits the electrochemical stability. In the following years the main interest in ionic liquids was focused on electrochemical applications [4—6]. 

Thesing and Festag (26) condensed a quaternary salt of gramme with A-phenacyl-3-ethylpyridinium bromide to yield XXIXa from which the benzoyl group was removed by the action of alcoholic alkali forming XXIXb. The latter was hydrogenated to a tetrahydropyridine compound which spontaneously cyclized to XXX and this in turn was dehydrogenated to fiavopereirine. 

In acetonitrile electrochemical reduction gives iron(I) and iron(O) spedes.557b In this solvent ligand oxidation reactions are almost absent, but they are not completely avoided due to the presence of small amounts of water.558 This problem was overcome by using a totally anhydrous low temperature (25 °C) molten salt comprising aluminum chloride and ethylpyridinium bromide (2 1 mole ratio). In this medium, reversible one-electron electrochemical oxidations take place559 with [Fe(37a)3]2+, [Fe(37b)3]2+ and a number of related complexes.560 Here the iron(III) form is thermodynamically more stable than is iron(II), whereas in aqueous solutions the reverse is true. 

The exchange reactions between salts of polymer adds (bases) and weak polybases (polyadds) in aqueous solutions are accompanied by considerable pH changes and also by the appearance of turbidity, particularly if the components are mixed in equivalent quantities. The copredpitation of polymeric adds and polybases was described first by Fuoss and Sadek This behavior of the mixture of two oppositely charged polyelectrolytes can be explained by the formation of a polyelectrolyte complex, this reaction being accompanied by elimination of a low-molecular weight acid or base. Thus, the exchange reaction between poly(acrylic add) and pdly(4-vinyl-ethylpyridinium bromide) was shown by potentiometry and turbidimetry to result in the precipitation of an insoluble macromolecular product, i.e. the ionic comj ex, and... 

C7H10BrN 1-ethylpyridinium bromide 1906-79-2 25.00 1.3691 2 11384 C7H12N20 cis-2-amino-4-cyclohexene-1-carboxamide 111302-96-6 25.00 1.0278 2... 

Molten salts hold promise in generating species that require highly acidic media for stability. Benzene in AlClj-ethylpyridinium bromide, melting at RT, acts to dissolve organometallics without changing the conducting nature of the melt . Such melts are applied in organoiron and metal-carbonyP oxidations. 

In another study, Selb and Gallot investigated the conformational properties of poly(styrene-g-4-vinyl-N-ethylpyridinium bromide) in water/methanol/LiBr mixtures [306]. The graft copolymers did not show intermolecular association in contrast to the linear block copolymers. Viscometric results showed that these graft copolymers also form compact, star-like monomolecular micelles with polystyrene cores and poly(4-vinyl-V-ethylpyridinium bromide) coronas, which resemble the polymolecular micelles of diblock materials. 

The electrochemistry of the iron carbonyls is complex and in some respects ill defined. The pentacarbonyl [Fe(CO)s] is oxidized in most common, non-aqueous electrochemical solvents in an irreversible but diffusion-controlled process (4, 154,155). The monocation [Fe(CO)5] + shows some stability in a mixture of benzene and molten AlCl3-ethylpyridinium bromide (43), and the oxidation is reversible in CF3COzH at fast cyclic voltametric scan rates (42). 

Figure 6. Effect of C12 content on reduced viscosity of polyelectrolytes. Key 1, polyivinyl-N-ethylpyridinium bromide) 2, 6.75% polysoap 3, 13.6% poly soap 4, 28.5% poly soap 5, 37.9% polysoap. Reproduced from ref. 8. Copyright 1954 American Chemical Society.)...

Another report by Koch [486] describes a rechargeable aluminum battery based on AlCls/A-ethylpyridinium bromide or AlCls/A-etiiyl-A-methyl imidazol-ium chloride melts and a TiS2 cathode. It has been reported that A1 can intercalate reversibly into a number of sulfides, including TiS2, FeSs and TaS2. 

The early work mainly used alkylammonium and alkylphosphonium salts dispersed on commercially available packing materials such as chromosorb [25-27]. These packed SILP columns had two major drawbacks, namely, low thermal stability (Tjjjjx < 200 °C) and poor separation efficiency. One of the first examples of an IL overcoming these limitations was 1-ethylpyridinium bromide ([EPy]Br)... 

The electrochemical behaviour of metal carbonyls in aprotic solvents was investigated by Pickett et al (1) and Seurat et al (2). The electrochemical oxidation of several metal carbonyls was also described in a mixture of the high Lewis acid, room temperature molten salt, composed of aluminium chloride and ethylpyridinium bromide (2 1 molar ratio) and benzene (50% v/v) (3). In these studies Cr(CO)6 was found to be reversibly oxidised, at a potential of 1.53 V vs SCE, to the seventeen electron cation Cr(CO)6" which is stable on the time scale of many seconds. The cyclic voltammogram of C r(CO)6 shows a second oxidation peak at a potential of 2.06 V for further oxidation of the cation Cr(CO)5 and the proposed mechanism is (1) ... 

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