Thermodynamics of cesium complexes formation with 18-crown-6 in ionic liquids

Formation of Complexes in RTIL and Ion Separations

“…Some of the logK values for RTILs are presented in Tables 3-5 along with the stability of the same complexes in some molecular solvents (Ruas et al, 2006;Ikeda et al, 2008;Danil de Namor et al, 1995;ArnaudNeu et al, 2003;Bessiere & Lejaille , 1979;Ernst & Jezowska-Trzebiatowska, JezowskaTrzebiatowska & Chmielowska, 1961;Chmielowska, 1961;Kikuchi & Sakamoto, 2000). As could be seen from (Vendilo et al, 2010). At the same time, the logK 1 values for an alkali metal cation with crown ether in molecular solvents is correlated (Mei et al, 1977;Smetana & Popov, 1980) with donor number (DN) of the solvent (Reichardt, 2005), Table 5, although some exceptions for [Cs(18C6)] + are known (pyridine: DN 33.1; logK 1 =5.7 (Mei et al, 1977)).…”

“…At the same time, the logK 1 values for an alkali metal cation with crown ether in molecular solvents is correlated (Mei et al, 1977;Smetana & Popov, 1980) with donor number (DN) of the solvent (Reichardt, 2005), Table 5, although some exceptions for [Cs(18C6)] + are known (pyridine: DN 33.1; logK 1 =5.7 (Mei et al, 1977)). In this sense, the log K 1 value presented in (Georg et al, 2010); b (Ruas et al, 2006); c (Ikeda et al, 2008); d logK2 = 3.67 (Ernst &JezowskaTrzebiatowska, 1966) and3.4 (Jezowska-Trzebiatowska &Chmielowska, 1961); e (Lewandowski et al, 2005); f (Bessiere & Lejaille, 1979); j (Danil de Namor et al, 1995); h (Vendilo et al, 2010) ; i (Arnaud-Neu et al, 2003); all data for 23-30 o C. There is also some qualitative agreement of the logK 1 values and a solvent polarity derived from E N T scale (Reichardt, 2005) (empirical scale based on solvatochromic pyridinium Nphenolate betaine dye), Table 5. An examination of Table 5 reveals that the polarity of RTILs with a range of 0.60 -0.65 fits well into the existing empirical solvent polarity scale for molecular solvents characterizing them not as "superpolar", but as quite normal polar solvents (Reichardt, 2005).…”

“…However, the number of reports on the complex composition, equilibrium constants and thermodynamics of complex formation is surprisingly small relative to that of conventional molecular solvents, Table 2. The data on ΔH and ΔS of complex formation are even less common (Vendilo et al, 2010a;2010c;2009a). It should be noted that all the constants mentioned in Table 2 represent co-called "conditional" equilibrium constants defined as:…”

“…Room temperature ionic liquids (RTILs) are gaining an increasing interest as a unique medium for a complex formation and development of new inorganic materials (Cocalia et al, 2006;Billard et al, 2003;Yan et al, 2010;Vendilo et al, 2010;Nockemann et al, 2009;Nockemann et al, 2008;Murding & Tang, 2010;Billard & Gaillard, 2009;Taubert, 2004;Tang et al, 2008). Among the most promising fields the RTIL-based lithium batteries (Lewandowski & SwiderskaMocek, 2009;Rosol et al, 2009) and recent applications of ionic liquids in the separation technology (Dundan & Kyung, 2010;Dietz, 2006) can be considered as a "hot" research topic.…”

Supramolecular Structures in the Presence of Ionic Liquids

“…(Yuan et al, 2008(Yuan et al, , 2009 Besides, stability constants of metal ion complexes with crown ethers in IL aqueous solutions were obtained (Popov et al, 2007) and the solubilization of the ILs [C n mim][Tf 2 N] by the presence of crown ether was studied (Rickert et al, 2007). It is also reported that the stability of cesium complexed with 18C6 in ILs is affected by the nature of both cation and anion of ILs (Vendilo et al, 2009;Vendilo et al, 2010b). Moreover, the complex stability is important for the extraction process (Vendilo et al, 2010a).…”