L- -3-methylimidazolium

Bradley, A.E., Hardacre, C., Holbrey, J.D., Johnston, S., McMath, S.E.J. and Nieuwenhuyzen, M., Small-angle X-ray scattering studies of liquid crystalline l-allq l-3-methylimidazolium salts, Chem. Mater. 14, 629-635 (2002). 

Shi, W. and Maginn, E.J., Molecular simulation and regular solution theory modelling of pure and mixed gas absorption in the ionic liquid l-n-hejq l-3-methylimidazolium bis(Trifluoromethylsulfonyl)amide ([hmim][Tf2N]), J. Phys. Chem. B112,16710-16720 (2008). 

El Seoud, O. A Pires, P. A R. Abdel-Moghny, T. Bastos, E. L. (2007). Synthesis and micellar prop>erties of surface-active ionic liquids l-All l-3-methylimidazolium chlorides.. Colloid Inter free Sci., 313,296-304. 

In general, isotopic exchange is both expensive and difficult. In the case of many room-temperature ionic liquids, however, the manufacture of deuterated ionic liquids is relatively easily achievable. For example, the general synthesis of l-allcyl-3-methylimidazolium salts is shown in Scheme 4.1-1 [2]. This methodology allows maximum flexibility in the deuteration on the imidazolium cation that is, it can be either ring or side chain deuteration or both. 

Figure 4.2-1 shows the calculated ab initio molecular structure of the ionic liquid [BMIM][PFg] (l-butyl-3-methylimidazolium hexafluorophosphate). 

Davis and co-workers have carried out the first examples of the Knoevenagel condensation and Robinson annulation reactions [61] in the ionic liquid [HMIM][PFg] (HMIM = l-hexyl-3-methylimidazolium) (Scheme 5.1-33). The Knoevenagel condensation involved the treatment of propane-1,3-dinitrile with a base (glycine) to generate an anion. This anion added to benzaldehyde and, after loss of a water molecule, gave l,l-dicyano-2-phenylethene. The product was separated from the ionic liquid by extraction with toluene. 

The first successful hydrogenation reactions in ionic liquids were studied by the groups of de Souza [45] and Chauvin [46] in 1995. De Souza et al. investigated the Rh-catalyzed hydrogenation of cyclohexene in l-n-butyl-3-methylimidazolium ([BMIM]) tetrafluoroborate. Chauvin et al. dissolved the cationic Osborn complex [Rh(nbd)(PPh3)2][PFg] (nbd = norbornadiene) in ionic liquids with weakly coordinating anions (e.g., [PFg] , [BFJ , and [SbF ] ) and used the obtained ionic catalyst solutions for the biphasic hydrogenation of 1-pentene as seen in Scheme 5.2-7. 

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. 

Anionic surfactants like alkanesulfonates can also be determined by poten-tiometric titration with ion-selective electrodes. Recently, a special PVC electrode was offered as a high-sense surfactant electrode in combination with the new titrant l,3-didecyl-2-methylimidazolium chloride [20]. This one-phase... 

A new class of solvents called ionic liquids has been developed to meet this need. A typical ionic liquid has a relatively small anion, such as BF4, and a relatively large, organic cation, such as l-butyl-3-methylimidazolium (16). Because the cation has a large nonpolar region and is often asymmetrical, the compound does not crystallize easily and so is liquid at room temperature. However, the attractions between the ions reduces the vapor pressure to about the same as that of an ionic solid, thereby reducing air pollution. Because different cations and anions can be used, solvents can be designed for specific uses. For example, one formulation can dissolve the rubber in old tires so that it can be recycled. Other solvents can be used to extract radioactive waste from groundwater. 

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

Based on the properties of ionic hquids in high-temperature microwave-enhanced reactions, the authors chose l-butyl-3-methylimidazolium tetraflu-orophosphate ([bmimjPFe) as the suitable ionic liquid (Scheme 23). The addition of 0.15 mmol of [bmimjPFe to a reaction in 2.0 mL of DCF was found to increase the reaction rate dramatically and a set-temperature of 190 °C was reached in a mere 1 min, while the reactions programmed at 190 °C, in the absence of the ionic liquid, reached only 170 °C in 10 min. The reactions were finished in a mere 18-25 min of irradiation time, including the hydrolysis of the sensitive imidoyl chloride moiety with water. The formed bis-lactams were isolated in good yield and purity. 

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]. 

Glycidyl methacrylate (purity 98 %) was purchased fiom Aldrich. Ionic liquids based on 1-n-ethyl-3-methyliinidazolium (EMIm), l-n-butyl-3-methylimidazolium (BMhn), 1-n-hexyl-3-methylimidaJ5Dlium (HMhn) with dififeent anions such as CT, BF4", PFg wo e prepared according to the procedures reported previously. Copolymerization of glycidyl methacrylate (GMA) and CO2 were carried out in a 50 mL stainless steel autoclave equipped with a... 

Cull and co-authors reported a microbe-mediated transformation of benza-mide from benzonitrile in a mixed solvent of IL, l-butyl-3-methylimidazolium... 

The dehydration of fructose 40 or glucose into 5-hydroxymethylfurfural 41 is a process which has been exploited to convert biomass into higher value products. The reaction has been achieved using a chromium NHC complex, formed in situ from CrCl and the NHC 42 (Scheme 11.10) [16], The reaction is performed in the ionic liquid BMIM+Cl (l-butyl-3-methylimidazolium chloride). 

When the same [NiI (NHC)2] complexes are employed as alkene dimerisation catalysts in ionic liquid (IL) solvent [l-butyl-3-methylimidazolium chloride, AICI3, A-methylpyrrole (0.45 0.55 0.1)] rather than toluene, the catalysts were found to be highly active, with no evidence of decomposition. Furthermore, product distributions for each of the catalyst systems studied was surprisingly similar, indicating a common active species may have been formed in each case. It was proposed that reductive elimination of the NHC-Ni did indeed occur, as outlined in Scheme 13.8, however, the IL solvent oxidatively adds to the Ni(0) thus formed to yield a new Ni-NHC complex, 15, stabilised by the IL solvent, and able to effectively catalyse the dimerisation process (Scheme 13.9) [25-27],... 

Recently several pubhcations have examined replacing aqueous solvents with ionic liquids. Since simple and complex sugars are soluble in many imidazolium hahdes, water is not required as a co-solvent and degradation of HMF is minimal. Lansalot-Matras et al. reported on the dehydration of fmctose in imidazolium ionic liquids using acid catalyst (6). Moreau et al. reported that l-H-3-methylimidazolium chloride has sufficient acidity to operate without added acid (7). And we reported that a 0.5 wt% loading (6 mole% compared to substrate) of many metal halides in 1-ethyl-3-methylimidazohum chloride ([EMIM]C1) result in catalytically active materials particularly useful for dehydration reactions (8). 

For conversion of the more reactive l-arylsulfonyl-3-methylimidazolium triflate (trifluoromethane sulfonate) with alcohols or phenols, no base is required 175... 

In this reaction the l-arylsulfonyl-3-methylimidazolium triflate was prepared in situ. Table 10-1 reveals the broad scope of this reaction. 

The 3-methylimidazolium-3-amino-2-propen-l-one compounds can also be considered as vinylogous azolides, as the following reactions with nucleophiles demonstrate ... 

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