Ionic Aliquat-based

Fontas, C, Palet, C., Salvado, V. Hidalgo, M. (2000). A hollow fiber supported liquid membrane based on Aliquat 336 as a carrier for rhodium(III) transport and preconcentration. Journal of Membrane Science, 178,1-2,131-139, ISSN 0376-7388 Frade, R. F. M., Rosatella, A. A., Marques, C. S., Branco, L. C., Kulkarni, R S., Mateus, N. M. M, Afonso, C. A. M. Duarte, C. M. M. (2009). Toxicological evaluation on human colon carcinoma cell line (CaCo-2) of ionic liquids based on imidazolium, guanidinium, ammonium, phosphonium, pyridinium and pyrrolidinium cations. Green Chemistry, 11,10,1660-1665, ISSN 1463-9262 Fraser K. J. MacFarlane D. R. (2009). Phosphonium-based ionic liquids An overview. 

A number of different ionic liquids have been screened in the ruthenium-catalysed oxidation of secondary alcohols (see Scheme 5.18). Three different ruthenium compounds, RuC13, RuCl2(PPh3)3 and [RuCFl/i-cymene) were compared and best results were obtained with RuCl2(PPh3)3.[76] While imidazolium-based ionic liquids gave only poor results (anion = Cl) or suppressed the reaction completely (anion = [BF4] or [PF6] ), tetraalkylammonium-based solvents such as Aliquat 336 (tricaprylmethylammonium chloride) or tetramethylammonium hydroxide afforded much better yields. 

A further evidence on the acceleration enjoyed by a typical Pd-catalysed reaction, the Heck reaction, in an ionic phase ( V-mcthyl-Y.Y. V.-trioctylammonium chloride or Aliquat 336) is found in a triphasic protocol developed by Tundo and coworkers. 7b.The arylation of electron poor olefins is catalysed by palladium supported on charcoal (Pd/C) and is carried out in the heterogeneous isooctane/Aliquat 336/water system (Figure 27). Under this multiphasic condition, Aliquat 336 forms a third liquid phase between the organic and the aqueous phase that traps the catalyst. The use of phosphines is not necessary. As a matter of fact, Aliquat 336 incorporates the solid-supported catalyst and ensures an efficient mass transfer between the bulk phases resulting in an increase of the reaction rate of an order of magnitude compared to the reaction in the absence of the ionic liquid. A determing role is played by the base while I LN drives the reaction towards the formation of ethyl cinnamate, reaction carried out in the presence of KOH lead to formation of Ullmann dimerisation products. 

Polystyrene-based immobilized ruthenium catalysts can be used in oxidation of alcohols with NMO, TEMPO/O2, or O2 [94]. Catalytic oxidative cleavage of vicinal diols to aldehydes with dioxygen was reported with RuCl2(PPh3)3 on active carbon [95]. Ionic liquids such as tetramethyl ammonium hydroxide and Aliquat 336 can be used as the solvent for the RuCl2(PPh3)3-catalyzed aerobic oxidation of alcohols [96]. 

In recent years, the quaternary ammonium-functionalized ILs have been investigated widely because of its cheap, low toxicity properties. A kind of ILs was designed and synthesized by tricaprylmethylammonium chloride (Aliquat 336 or A336) and traditional carboxylic acid and phosphoric acid extractant [2]. Because the cation and anion of this kind of ILs are all the functional group for the REEs extraction, we called them bifunctional ionic liquid extractants (Bif-ILEs). Bif-ILEs could be synthesized by acid/base neutralization, and this reaction process was under mild condition, with easier purification and good yield (about 70-80 %). 

Chitosan, a widely used natural biopolymer, has been studied for the adsorption of various metal ions from dilute solutions. Unfortunately, the inherent properties of chitosan, such as hydrophilicity and metal-binding capability, are often insufficient to meet the requirements of a number of applications. To improve these properties, both chemical and physical modifications of chitosan are required. Thus, Aliquat 336-functionalized chitosan as adsorbent was prepared. In fact, the new chitosan adsorbent can also be described as P-SIL containing quaternary ammonium ionic liquid [23]. Unlike the previous reported structure, the Aliquat 336-functionalized chitosan, which was prepared by acid/base neutralization reaction, consists largely of cations and anions (Fig. 5.12). The structure was so flexible that the adsorption ability could be controlled precisely. Moreover, incorporation of Aliquat 336 into the chitosan backbone could significantly enhance its metal ions extraction ability. It has been shown to have much improved affinity for Pb " than pure chitosan. This may be explained in that the new strategy doesn t reduce the original amino active sites besides, the synergistic effect between cation and anion also contributes to the enhancement of adsorption capabilities. On the other hand, the effort to increase selectivity of the adsorbent for one metal ion over others is to make the adsorbent sterically efficient with that metal ion only. The new chitosan-... 

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