Ionic liquids acidic extractant

Svetlana V. Smirnova was born in Yartsevo, Smolensk region, Russia. She graduated from MSU Chemistry Department, having specialization in analytical chemistry. She holds MS and PhD degrees from MSU. Her PhD thesis was devoted to the solvent extraction of amino acids. She works at the MSU Chemistry Department as an assistant professor (since 2002) and an associate professor (since 2005) giving the lectures and practice courses in analytical chemistry. Her scientific interests lie in the area of application of ionic liquids in extraction processes. She is the coauthor of more than 20 scientific publications. 

Ionic liquid s extraction power for DBT is not uniquely based on chemical interactions involving the acid proton Desulphurization is hardly affected by the chemical nature of the anion. The size of the anion is rather important for the extraction effect Pronounced effect of the cation s size on the extraction power of the ILs. A possible explanation for this behaviour may be that the physical solubility of DBT in the IL is dependant on stearic factors The use of halogen-free ionic liquids avoids stability and corrosion problems. Extraction is only to a small extent influenced by the degree of alkylation of the DBT derivatives, which is a major advantage compared to HDS... 

Several ionic liquid-based extraction systems for the separation of and recycling rare-earth elements (REEs) have been reviewed in this chapter. There is a great interest in applying ILs to the REE recycling process [14]. However, before IL-based extractions of REEs can be carried out on an industrial scale, there are certain IL factors that need to be considered comprehensively, such as cost, purity, acidity stability, viscosity solubility, density, electrical conductivity, electrochemical windows, extraction efficiency, selectivity, extraction mechanism, stripping ratio, and methods of recycling [14]. The continuing studies in the above areas are warranted. 

Kubota F, Shimobori Y, Baba Y, Koyanagi Y, Shimojo K, Kamiya N, Goto M (2011) Application of ionic liquids to extraction separation of rare earth metals with an effective digiycoi amic acid extractant. J Chem Eng Jpn 44 307-312... 

Flowever, information concerning the characteristics of these systems under the conditions of a continuous process is still very limited. From a practical point of view, the concept of ionic liquid multiphasic catalysis can be applicable only if the resultant catalytic lifetimes and the elution losses of catalytic components into the organic or extractant layer containing products are within commercially acceptable ranges. To illustrate these points, two examples of applications mn on continuous pilot operation are described (i) biphasic dimerization of olefins catalyzed by nickel complexes in chloroaluminates, and (ii) biphasic alkylation of aromatic hydrocarbons with olefins and light olefin alkylation with isobutane, catalyzed by acidic chloroaluminates. 

The first application involving a catalytic reaction in an ionic liquid and a subsequent extraction step with SCCO2 was reported by Jessop et al. in 2001 [9]. These authors described two different asymmetric hydrogenation reactions using [Ru(OAc)2(tolBINAP)] as catalyst dissolved in the ionic liquid [BMIM][PFg]. In the asymmetric hydrogenation of tiglic acid (Scheme 5.4-1), the reaction was carried out in a [BMIM][PF6]/water biphasic mixture with excellent yield and selectivity. When the reaction was complete, the product was isolated by SCCO2 extraction without contamination either by catalyst or by ionic liquid. 

Inorganic compound extraction, ionic liquids in, 26 875-876 Inorganic compound-hydrogen chloride-water systems, 13 817-818 Inorganic compound lubricants, 15 246 Inorganic compounds, 13 104 hydrochloric acid reaction with,... 

Several authors reported the use of ionic liquids containing protonic acid in catalysis (118-120). For example, strong Bronsted acidity in ionic liquids has been reported to successfully catalyze tetrahydropyranylation of alcohols (120). Tetra-hydropyranylation is one of the most widely used processes for the protection of alcohols and phenols in multi-step syntheses. Although the control experiments with the ionic liquids showed negligible activity in the absence of the added acids, high yields of product were obtained with the ionic liquid catalysts TPPTS or TPP.HBr-[BMIM]PF6. By rapid extraction of the product from the acidic ionic liquid phase by diethyl ether, the reaction medium was successfully reused for 22 cycles without an appreciable activity loss. A gradual loss of the catalyst and a reduced volume of the ionic liquid were noted, however, as a consequence of transfer to the extraction solvent. 

The Robinson annulation of ethyl acetoacetate and tra i -chalcone was investigated with pulverized NaOH in [BMIMjPFg as the base catalyst at 100°C 110). The mixture was neutralized before extraction with toluene. The product, 6-ethoxycarbonyl-3,5-diphenyl-2-cyclohexenone, was obtained by purification in a silica gel chromatography column. A yield of 48% was obtained (Scheme 7). The ionic liquid could be recycled and reused with no diminution of product yield. The C2 position in imidazolium cations is an acidic proton donor and may have reacted... 

An excellent demonstration of the tunability of ionic liquids for catalysis is provided by an investigation of the dimerization of 1-butene (235). A Ni(cod)(hfacac) catalyst (Scheme 23) was evaluated for the selective dimerization of 1-butene after it was dissolved in various chloroaluminate ionic liquids. Earlier work on this reaction with the same catalyst in toluene led to the observations of low activity and difficult catalyst separation. In ionic liquids of varying acidity, little catalytic activity was found. However, a remarkable activity was achieved by adding a weak buffer base to an acidic ionic liquid. The reaction took place in a biphasic reaction mode with facile catalyst separation and catalyst recycling. A high selectivity to the dimer product was obtained because of a fast extraction of the Cg product from the ionic liquid phase, with the minimization of consecutive reaction to give trimers. Among a number of weak base buffers, a chinoline was chosen. The catalyst performance was compared with that in toluene. The catalyitc TOF at 90°C in toluene was... 

Matsumoto, M., Mochiduki, K., Fukunishi, K., Kondo, K., Extraction of organic acids using imidazolium-based ionic liquids and their toxicity to Lactobacillus rhamnosus, Sep. Purif. Tech., 40,97-101, 2004. 

Martak, ]., Schlosser, S., Phosphonium ionic liquids as new, reactive extractants of lactic acid, Chem. Pap., 60, 395-398, 2006. 

Smirnova, S.V, Torocheshnikova, I.I., Formanovsky, A.A., Pletnev, I.V, Solvent extraction of amino acids into a room temperature ionic liquid with dicyclo-hexano-18-crown-6. Anal. Bioanal. Chem., 378,1369-1375,2004. 

Ionic liquids are successfully being used as replacements for hydrofluoric acid for the commercial oil exploration application discussed previously (Chauvin and Helene, 1995). As we saw in the previous chapter, ionic liquids have potential as extractants in recovery of butyl alcohol from fermentation broth (Fadeev and Meagher, 2001). 

Fig. 4 Resonant frequency changes with time due to repetitive FIA melamine injections, for the MIP-QCM chemosensor. Melamine concentration is indicated with number at each curve. Inset shows FIA calibration plots for (1) melamine and its interfering compounds, such as (2) ammeline, (3) cyanuric acid, and (4) cyromazine. Volume of the injected sample solution was 100 pL. The flow rate of the 1 mM FIC1 carrier solution was 35 pL min-1. The MIP film was prepared by electropolymerization of 0.3 mM bis(2,2 -bithienyl)-benzo-[18-crown-6]methane functional monomer and 0.3 mM 3,3 -bis[2,2 -bis(2,2 -bithiophene-5-yl)]thianaphthene cross-linking monomer, in the presence of 0.1 mM melamine, in the trihexyl(tetradecyl)phosphonium tris(pentafluor-oethy 1)-trifluorophosphate ionic liquid ACN (1 1 v/v) solution, which was 0.9 mM in trifluoroacetic acid (pH = 3.0). The melamine template was extracted from the MIP film with 0.01 M NaOH before the determinations (adapted from [134])...

Martak, J. and Schlosser,. (2007) Extraction of lactic acid by phosphonium ionic liquids. Separation and Purification Technology, 57, 483. 

Seddon and co-workers described the Friedel-Crafts acylation reaction of benzene with ace-tylchloride using acidic chloroferrate ionic liquids as catalysts [38], In contrast to the same reaction in presence of acidic chloroaluminate systems the ketone product could be separated from the ionic liquid by solvent extraction, provided that the molar ratio of FeCl3 is in the range 0.51-0.55 in the applied ionic liquid catalyst (Scheme 1). 

Whilst in some cases near-stoichiometric amounts of reagents can be used [16], the excess (5-10 equiv.) of ketone reagent is preconceived in order to ensure convenient kinetics and conversion. Reactions can be run typically at room temperature [20] in a polar aprotic solvent such as CHC13, or in THF or i-PrOH. The presence of water was noted to be beneficial in some cases [21]. In ionic liquids, such as in [bmim]BF4, a low (5 mol%) catalyst concentration can be applied, while the enantioselectivity of the alkylation is modest in this solvent [22]. The ionic liquid-derived hybrid catalyst 10, used neat with a small amount of trifluoroacetic acid (TFA) as co-catalyst, affords quantitatively 4, though in a remarkably high dr syn/anti = 99/1) and ee (99%). It should be noted that this catalyst can easily be recovered by extraction, and re-used without loss of activity. 

---