1 -hexyl-3-methylimidazolium HMIM

Emim= l-ethyl-3-methylimidazolium, Bmim= l-butyl-3-methylimidazolium, Hmim= l-hexyl-3-methylimidazolium... 

FIGURE 5.1 Electrostatic potential field around various cations as calculated at the PW91/ DNP level, (a) l-Ethyl-3-methylimidazolium (EMIM), (b) l-butyl-3-methylimidazolium (BMIM), and (c) l-hexyl-3-methylimidazolium (HMIM). 

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. 

Note DMIm 1,3-dimethylimidazolium EMIm 1-ethyl-3-methylimidazolium PrMlm 1-methyl-3-propylimida-zolium BMIm 1-butyl-3-methylimidazolium PeMlm 1-pentyl-3-methylimidazolium and HMIm 1-hexyl-3-methylimidazolium. 

Besides, Shen et al. [26] have performed comparative studies on alkylation of phenol with ferf-butyl alcohol (TBA) with liquid acids such as H PO or solid acids, for example, HZSM-5, H-(), dodecatungstophosphoric acid (HPW), and HPW/ MCM-41, in the ionic liquids [BMIM]PFg, [OMIM]BF ([OMIM] = 7-octyl-5-methylimidazolium cation), and [HMIM]BF ([HMIM] = 7-hexyl-5-methylimidazo-lium cation). The results suggested that ionic liquids improve the catalytic activity of HjPO, with the conversion of phenol increasing from 44.5% to the maximum value of 77.3% in the alkylation of phenol with TBA by H PO in different ionic liquids. This improvement effect in conversion may be attributed to the higher solubility of... 

The ionic liquid l-n-hexyl-3-methylimidazolium bis(trifiuorosulfonyl)imide, [hmim] [TfaN], was synthesized and characterized using standard procedures [17-19] at the University of Notre Dame. The ionic liquid l-(3-aminopropyl)-3-methylimidazolium bis(trifiuoromethylsulfonyl)imide, [H2NC3H5mim][Tf2N], was also synthesized and characterized at the University of Notre Dame [20]. 

The Michael-Arbuzov rearrangement is a basic reaction for the preparation of 4-coordinate species including phosphine oxides from 3-coordinate phosphorus esters, such as phosphinous esters. In most cases, the reaction requires a prolonged heating above 100 °C. Odinets et al. have now succeeded in carr5nng out the Arbuzov-reaction of ethyl diphenylphosphinite with a variety of alkyl halides in ionic liquids at or below 110 °C in short reaction times, mostly within half an hour. The best ionic liquid was l-hexyl-3-methylimidazolium bromide (Scheme 2). The recovered [hmim]Br could be recycled at least five times without a decrease in activity. 

During the syntheses of PLLA and poly(L-lactide-co-glycolide) (PLLGA) in the ionic liquid l-hexyl-3-methylimidazolium hexafluoro-phosphate [HMIM][PF6] mediated by Novozyme-435, the highest PLLA yield (63%) was obtained at 90 "C with a MW... 

The selective aerobic (O2) oxidative coupling of thiols in several imidazolium-based ionic liquids is studied in the absence of any base/metal catalysts. Disulfides are obtained from the corresponding thiols in good to excellent yields in l-hexyl-3-methylimidazolium bromide ([hmim]Br). Furthermore, a H NMR-based mechanistic study of the S-S bond formation demonstrated the cooperative role of halide anion and imidazolium cation of [hmimJBr. ... 

To date, many kinds of CO2 separation membranes have been reported, including polymeric membranes, composite membranes, and facilitated transport membranes. Further improvements in membrane performance depend on effective CO2 separation materials, and one candidate is ILs. It has been reported that ILs have good CO2 selectivity, suggesting that they may be a possibility for the development of new CO2 separation materials. Since ILs are liquid at room temperature, it is necessary to affix ILs to appropriate support materials. Supported IL membranes have been prepared by impregnation of commercial porous polymer films with 1-n-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf2N]) and have obtained good C02/He separation properties [40]. Recently, electrospun Nafion/polyethylene oxide (PEO)-supported IL membranes were fabricated for CO2 separation [41]. In this composite membrane, the electrospun Nafion/PEO material acted as a gutter layer for ILs and PEO was added to form clean nanofibrous... 

BMIm-PF l-buthyl-3-methylimidazolium hexafluorophosphate HMIm-PFg l-hexyl-3-methylimidazolium hexafluorophosphate OMIm-PFg l-octyl-3-methylimidazolium hexafluorophosphate... 

When Br0nsted acidic ILs l-hexyl-3-methylimidazolium tetrafluoroborate [HMIM]BF4 (Lu et al., 2007) and N-methyl-pyrrolidonium tetrafluoroborate [HNMP]Bp4 (Zhao et al., 2007) were used for desulfurization in the presence of H2O2, sulfur compounds can be deeply removed due to formation of hydroxyl radicals. For [HMIM]BF4the DBT remotion was 93% when a mixture of 3.2 mL of model oil and 5.0 mL of the IL were stirring at 90 °C during 6 h. In the case of [HNMP]BF4 the efficiency of sulfur extraction was 99.4% for fuel diesel (total sulfur 3240 ppm) at ratio of 1 1 and 2 h of reaction time at 60 °C. The IL was recycled 7 times without a significant decrease in desulfurization. 

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