Ammonium salts tetraoctylammonium bromide

A quaternary ammonium salt, tetraoctylammonium bromide (TOABr) and doco-sane were used as solutes and toluene was used as the solvent. The membrane used in this study was again the solvent-resistant polyimide membrane, STAR-MEM 122. A dual-cell crossflow filtration rig, similar to the one described in Section 4.3.1 was used in all the experiments with an effective membrane area of 78 cm. The stage cut was between 0.01 and 0.3% over the whole concentration and pressure range. Ideal mixing is assumed throughout the system. 

Alkynes.10 Alkynes can be prepared by double dehydrobromination of pic-dibromides in petroleum ether by use of powdered KOH and catalytic amounts of a phase-transfer catalyst. Tetraoctylammonium bromide, 18-crown-6, or even Aliquat 336 are much more effective than more hydrophilic quarternary ammonium salts, such as tetrabutylammonium hydrogen sulfate, previously used (7, 354-355)." Isolated yields are 80-98%. Yields are generally lower when mc-dichlorides are used as the starting material. 

The metal colloid preparations arc mostly based on reduction of metal ions in the presence of bulky anions (e.g. citrate and mercaptoethanesulfonatc), but also quaternary ammonium salts (e.g. tetraoctylammonium bromide) or polymers (e.g. poly(iV-vinylpyr-rolidone (PVP)) are used as stabilizers (Figure 7.2). Ionic species involved in the NP synthesis play a dual role of stabilizers for the metal particles and dopants for the polymer material. In some cases the synthesis of the metal NPs occurs under y-irradiation in the presence of the monomer, which stabilizes the metal particles [64—66,68]. A two-phase approach for the preparation of the monomer or eventually oUgomer-stabUized metal particles has been also suggested in the case of octylthiophen [57] and 3,4-ethylenediox-ythiophene (EDOT) [70,71]. 

As a matter of fact, various tetraalkylammonium salts, the most famous one being the commercial Aliquat 336 (a 2 1 mixture of methyl trioctyl and methyl tridecylammonium chloride), are used as synergistic agents for Ln (III) extraction in traditional solvents (Atanassova, 2009 Atanassova and Dukov, 2010), and we would like to recall that many tetraalkylammonium salts are, in fact, ILs for example, tetraoctylammonium bromide melts at ca. 95 °C. On the other hand, new routes for the synthesis of ammonium-type ILs have been proposed (Mikkola et al., 2006 Sun et al., 1998). However, it is out of the scope of this work to review all literature involving Aliquat salts, especially because, being commercial mixtures, their chemical and physical properties are difficult to determine. Therefore, we will restrict ourselves to systems in which the additive was clearly considered by the authors as an IL. 

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