L-Ethyl-3 methylimidazolium

The chloroaluminate(III) ionic liquids - [EMIM][C1-A1C13], for example (where EMIM is l-ethyl-3-methylimidazolium) - are liquid over a wide range of AICI3 concentrations [24]. The quantity of AICI3 present in the ionic liquid determines the physical and chemical properties of the liquid. When the mole fraction, X(A1C13), is below 0.5, the liquids are referred to as basic. When X(A1C13) is above 0.5, the liquids are referred to as acidic, and at an X(A1C13) of exactly 0.5 they are referred to as neutral. 

ENIM]C1 AICI31 [BP] Cl AICI3 J [BMIM] = 1-butyl-3-methylimidazolium cation [EMIM] = l-ethyl-3-methylimidazolium cation [BP] = N-l-butylpyridinium cation... 

Lipases from C. antarctica and P. cepacia showed higher enantioselectivity in the two ionic liquids l-ethyl-3-methylimidazolium tetrafluoroborate and l-butyl-3-methylimidazolium hexafluoroborate than in THE and toluene, in the kinetic resolution of several secondary alcohols [49]. Similarly, with lipases from Pseudomonas species and Alcaligenes species, increased enantioselectivity was observed in the resolution of 1 -phenylethanol in several ionic liquids as compared to methyl tert-butyl ether [50]. Another study has demonstrated that lipase from Candida rugosa is at least 100% more selective in l-butyl-3-methylimidazolium hexafluoroborate and l-octyl-3-nonylimidazolium hexafluorophosphate than in n-hexane, in the resolution of racemic 2-chloro-propanoic acid [51]. 

The microwave-assisted thionation of amides has been studied by Ley and coworkers using a polymer-supported thionating reagent [115]. This polymer-supported amino thiophosphate serves as a convenient substitute for its homogeneous analogue in the microwave-induced rapid conversion of amides to thioamides. Under microwave conditions, the reaction is complete within 15 min, as opposed to 30 h by conventional reflux in toluene (Scheme 7.95). The reaction has been studied for a range of secondary and tertiary amides and GC-MS monitoring showed that it proceeded almost quantitatively. More importantly, this work was the first incidence of the use of the ionic liquid l-ethyl-3-methylimidazolium hexafluorophosphate... 

Recently, there has been considerable interest in developing molten salts that are less air and moisture sensitive. Melts such as l-methyl-3-butylimidazolium hexa-fluorophosphate [211], l-ethyl-3-methylimidazolium trifluoromethanesulfonate [212], and l-ethyl-3-methylimidazolium tetrafluoroborate [213] are reported to be hydro-phobic and stable under environmental conditions. In some cases, metal deposition from these electrolytes has been explored [214]. They possess a wide potential window and sufficient ionic conductivity to be considered for many electrochemical applications. Of course if one wishes to take advantage of their potential air stability, one loses the opportunity to work with the alkali and reactive metals. Further, since these ionic liquids are neutral and lack the adjustable Lewis acidity common to the chloroaluminates, the solubility of transition metal salts into these electrolytes may be limited. On a positive note, these electrolytes are significantly different from the chloroaluminates in that the supporting electrolyte is not intended to be electroactive. 

Table 4.5 A comparison of the melting points of l-ethyl-3-methylimidazolium and 1 -ethyl-2,3-dimethylimidazolium salts...

Alkylimidazolinm tetraflnoroborates are, for example, ionic liquids at room-temperature that can provide an anion to stabilize an intermediate cation-radical with no possibility of nucleophilic attack on it. Ionic liquids have a huge memory effect, and their total friction is greater than that of conventional polar solvents. Thus, the total friction of l-ethyl-3-methylimidazolium hexafluoro-phosphate is about 50 times greater than that of AN (Shim et al. 2007). The solvent effects of ionic liquids on ion-radical ring closures deserve a special investigation. The ring closure reactions can be, in principal, controlled by solvent effects. 

Interestingly, catalyst 3a showed higher racemization activities in ionic liquids such as [EMlm]BF4 and [BMlm]PF,5 ([EMlm]=l-ethyl-3-methylimidazolium, [BMlm]=l-butyl-3-methyl-imidazolium) [19]. The DKR in ionic liquids has one big... 

The combination of quaternary ammonium chloride salt, such as l-ethyl-3-methylimidazolium chloride (EMIC), with... 

Voltammetry at a glassy carbon (GC) electrode was used to study of the electrochemical deposition of CdTe from the Lewis basic l-ethyl-3-methylimidazolium chloride/tetrafluoroborate room temperature ionic liquid [208]. 

The electrochemistry of Cd(II) was investigated at different electrodes (GC, polycrystalline tungsten, Pt, Ni) in a basic l-ethyl-3-methylimidazolium chloride/tet-rafluoroborate, at room temperature molten salt [312], and in acidic zinc chloride-l-ethyl-3-methylimidazolium [284]. 

Formation of several successive layers of bulk intermetallic compounds has been shown. Also, Lee et al. [480] have detected, during Al UPD, the formation of two alloys on polycrystalline Au electrodes from acidic l-ethyl-3-methylimidazolium chloroaluminate that melt at room temperature. Moreover, in the Al UPD region, fast phase transition between these two intermetallic compounds has been evidenced. Later, the same group of researchers [481] has performed EQCM studies on Al deposition and alloy formation on Au(lll) in ambient temperature molten salts/benzene mixtures. 

Generally in cycloalkanes, solubility is very similar to that in alkanes. The solubility of imidazolium IL, l-ethyl-3-methylimidazolium tosylate, [C2Cilm][TOS] in cyclohexane and cycloheptane displays a very large miscibility gap in the liquid phase (close to its melting temperature) [101,102]. Ammonium IL, [(Ci)2C4HOC2N]Br, has shown lower solubility in cyclohexane than in heptane and the immiscibility gap was from Xjl = 0.02 to 0.90 [53]. 

Zhang, S. et al.. Determination of physical properties for the binary systems of l-ethyl-3-methylimidazolium tetrafluoroborate + H2O, /. Chem. Eng. Data, 49, 760,2004. 

Hofman, T. et al.. Densities, excess volumes, isobaric expansivity, and isothermal compressibility of the (l-ethyl-3-methylimidazolium ethylsulfate + methanol) system at temperatures (298.15 to 333.15) K and pressures from (0.1 to 35) MPa, /. Chem. Thermodyn., 40, 580, 2008. 

Arce, A., Rodriguez, O., and Soto A., A comparative study on solvents for separation of ferf-amyl ethyl ether and ethanol mixtures. New experimental data for l-ethyl-3-methylimidazolium ethyl sulfate ionic liquid, Chem. Eng. Set., 61, 6929, 2006. 

Selvan, M.S. et al.. Liquid-liquid equilibria for toluene -I- heptane + l-ethyl-3-methylimidazolium triodide and toluene -I- heptane -I- l-butyl-3-methylimid-azolium triodide, /. Ghem. Eng. Data, 45, 842, 2000. 

Arce, A. et al.. Separation of aromatic hydrocarbons from alkanes using the ionic liquid l-ethyl-3-methylimidazolium bis (trifluoromethyl)sulfonyl amide. Green Ghem., 9, 70, 2007. 

Takahashi, S., Suzuya, K., Kohara, S., Koura, N., Curtiss, L.A., and Saboungi, M.-L., Structure of l-ethyl-3-methylimidazolium chloroaluminates Neutron diffraction measurements and ab initio calculations, Z. Phys. Chem., 209, 209-221, 1999. 

Fletcher, K. A., and Pandey, S., Surfactant aggregation within room-temperature ionic liquid l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, Langmuir, 20, 33-36, 2004. 

Figure 5.3 Chromatograms of amines with mobile phases containing (a) water adjusted to pH 3 with HCl and (b) 30 mmol/L l-ethyl-3-methylimidazolium tetra-fluoroborate. Chromatographic conditions C18 column (5 pm, 150 X 4.6 mm ID) rate flow 1.0 mL/min detection at 254 nm. Peaks (1) benzylamine (2) benzidine (3) N,N-dimethylaniline and (4) N-ethylaniline. (Adapted from Xiaohua, X., Liang, Z., Xia, L., and Shengxiang, Anal. Chim. Acta, 519, 207-211, 2004.)...

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