Room-temperature ionic liquids complexes

Theoretical and applied aspects of microwave heating, as well as the advantages of its application are discussed for the individual analytical processes and also for the sample preparation procedures. Special attention is paid to the various preconcentration techniques, in part, sorption and extraction. Improvement of microwave-assisted solution preconcentration is shown on the example of separation of noble metals from matrix components by complexing sorbents. Advantages of microwave-assisted extraction and principles of choice of appropriate solvent are considered for the extraction of organic contaminants from solutions and solid samples by alcohols and room-temperature ionic liquids (RTILs). 

So far, there have been few published simulation studies of room-temperature ionic liquids, although a number of groups have started programs in this area. Simulations of molecular liquids have been common for thirty years and have proven important in clarifying our understanding of molecular motion, local stmcture and thermodynamics of neat liquids, solutions and more complex systems at the molecular level [1 ]. There have also been many simulations of molten salts with atomic ions [5]. Room-temperature ionic liquids have polyatomic ions and so combine properties of both molecular liquids and simple molten salts. 

Much emphasis has been placed in recent times on easily recoverable liquid bi-phasic catalysts, including metal clusters in nonconventional solvents. For instance, aqueous solutions of the complexes [Ru3(CO)12.x(TPPTS)x] (x=l, 2, 3 TPPTS = triphenylphosphine-trisulfonate, P(m-C6H4S03Na)3) catalyze the hydrogenation of simple alkenes (1-octene, cyclohexene, styrene) at 60°C and 60 bar H2 at TOF up to 500 h 1 [24], while [Ru i(CO)C (TPPMS) >,] (TPPMS = triphenylphos-phine-monosulfonate, PPh2(m-C6H4S03Na) is an efficient catalyst precursor for the aqueous hydrogenation of the C=C bond of acrylic acid (TOF 780 h 1 at 40 °C and 3 bar H2) and other activated alkenes [25]. The same catalysts proved to be poorly active in room temperature ionic liquids such as [bmim][BF4] (bmim= Tbutyl-3-methylimidazolium). No details about the active species involved are known at this point. 

In none of the above cases has a reaction been performed whilst taking the EXAFS data. Hamill et al. [50] have investigated catalysis of the Heck reaction by palladium salts and complexes in room-temperature ionic liquids. On dissolution of palladium ethanoate in [BMIMj and N-butylpyridinium ([BP] ) hexafluorophos-phate and tetrafluoroborate ionic Hquids, and triethyl-hexyl ammonium bis(trifluo-romethanesulfonyl)imide, a gradual change from ethanoate coordination to the formation of palladium metal was observed in the Pd K-edge EXAFS, as shown in Figure 4.1-13. 

Youngs, T.G.A., Del Popolo, M.G., and Kohanoff, J., Development of complex classical forcefields through force matching to ab initio data Application to a room-temperature ionic liquid, /. Phys. Chem. B, 110, 5697-5707, 2006. 

Appleby, D., Hussey, C.L., Seddon, K.R., Turp, J.E., Room-temperature ionic liquids as solvents for electronic absorption spectroscopy of halide complexes. Nature, 323,614-615,1986. 

Nikitenko, S.I., Moisy, Ph., Formation of higher chloride complexes of Np(IV) and Pu(IV) in water-stable room-temperature ionic liquid [BuMeIm][Tf2N], Inorg. Chem., 45,1235-1242,2006. 

A study of the use of room temperature ionic liquids as a new class of nonaqneous solvents for 2-phase catalytic hydrocarbon transformations. The liquids investigated were mixtures of quartemary ammonium salts and organo-aluminum componnds. They were found to be very effective solvents for metal-catalyzed olefin dimerization and metathesis reactions. Their complexing ability and acidity can be tuned as re-... 

Examples of these reactions are the reduction of the non-hydrated form of formaldehyde or that of acetic acid in aqueous solution at a mercury electrode [9] as well as the reduction of many inorganic ions in their complexed forms [49], Among organic species there are also many examples of this reaction scheme like the reduction of benzoic acid at room temperature ionic liquids [50] or that of the oxidation of ferrocenecarboxylate in the presence of a p-cyclodextrin host (see Fig. 3.21) [51]. 

SIMULATIONS OF THE DYNAMICS OF 18-CROWN-6 AND ITS COMPLEXES FROM THE GAS PHASE TO AQUEOUS INTERFACES WITH SC-C02 AND A ROOM-TEMPERATURE IONIC LIQUID... 

Chaumont, A., Wipff, G. (2004), M3+ Lanthanide Chloride Complexes in "Neutral" Room-Temperature Ionic Liquids. A Theoretical Study, J. Phys. Chem A 108, 3311-3319. 

Ionic liquids can be used as replacements for many volatile conventional solvents in chemical processes see Table A-14 in the Appendix. Because of their extraordinary properties, room temperature ionic liquids have already found application as solvents for many synthetic and catalytic reactions, for example nucleophilic substitution reactions [899], Diels-Alder cycloaddition reactions [900, 901], Friedel-Crafts alkylation and acylation reactions [902, 903], as well as palladium-catalyzed Heck vinylations of haloarenes [904]. They are also solvents of choice for homogeneous transition metal complex catalyzed hydrogenation, isomerization, and hydroformylation [905], as well as dimerization and oligomerization reactions of alkenes [906, 907]. The ions of liquid salts are often poorly coordinating, which prevents deactivation of the catalysts. 

In fact, the majority of functionalized onium salts are solids, very viscous or waxy at room temperature, which makes them difficult to use as such. This is even truer for salts bearing complex substituents. Since non-functional room temperature ionic liquids can usually easily dissolve other salts, they can be used as solvents to make low viscosity solutions of high melting point TSOSs, resulting in mixtures... 

Ionic liquids with anions containing transition metal complexes were among the earliest developed room temperature ionic liquids [60], Transition metal based ionic liquids have been synthesized either by reaction of phosphonium or imidazolium halides with the corresponding metal halides, or by metathesis with alkali salts of the metal-based anions. Among the metal containing ionic liquids, ionic liquid-crystals are excluded in this section as they were reviewed thoroughly in 2005 [61], Synthesis of metal based salts can be divided in to three groups (1) transition metal salts, (2) p-block metal salts and (3)/-block metal salts. 

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