L-Ethyl-3 methylimidazolium tetrafluoroborate

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]. 

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. 

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. 

The imidazolium ions present in the CE BGE coat the capillary walls, generating an anodic EOF at low pH values (see Figure 6.5). The direction and magnitude of EOF essentially depend on pH of BGE. The change of direction of EOF fakes place befween pH 7.5 and 8 in fhe case of l-ethyl-3-methylimidazolium tetrafluoroborate ([C2Cjlm][BFJ) [44]. 

The ILs interact with surfaces and electrodes [23-25], and many more studies have been done that what we can cite. As one example, in situ Fourier-transform infrared reflection absorption spectroscopy (FT-IRAS) has been utilized to study the molecular structure of the electrified interphase between a l-ethyl-3-methylimidazolium tetrafluoroborate [C2Qlm][BF4] liquid and gold substrates [26]. Similar results have been obtained by surface-enhanced Raman scattering (SERS) for [C4Cilm][PFg] adsorbed on silver [24,27] and quartz [28]. 

The electrodeposition of silver from chloroaluminate ionic liquids has been studied by several authors [45-47], Katayama et al. [48] reported that the room-temperature ionic liquid l-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4) is applicable as an alternative electroplating bath for silver. The ionic liquid [EMIM]BF4 is superior to the chloroaluminate systems since the electrodeposition of silver can be performed without contamination of aluminum. Electrodeposition of silver in the ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) and l-butyl-3-methylimidazoliumhexafluorophosphate was also reported [49], Recently we showed that isolated silver nanoparticles can be deposited on the surface of the ionic liquid Tbutyl-3-methylimidazolium trifluoromethylsulfonate ([BMIMJTfO) by electrochemical reduction with free electrons from low-temperature plasma [50] (see Chapter 10). This unusual reaction represents a novel electrochemical process, leading to the reproducible growth of nanoscale materials. In our experience silver is quite easy to deposit in many air- and water-stable ionic liquids. 

Naphthol (0.35 mmol) was dissolved in 2 ml l-ethyl-3-methylimidazolium tetrafluoroborate containing benzyl bromide (1.5 eq) and KOH (2eq). The mixture was reacted in a microwave apparatus at 200°C 2 minutes, the product extracted with diethyl ether, and isolated in quantitative yield. 

Fuller J, Carlin R T, Osteryoung R A. The room temperature ionic liquid l-ethyl-3-methylimidazolium tetrafluoroborate Electrochemical couples and physical properties. J. Electrochem. Soc. 1997. 144, 3881-3886. 

The use of ion-supported [bis(acyloxy)iodo]arene in the ionic liquid [emim]+[BF4] (l-ethyl-3-methylimidazolium tetrafluoroborate) in the presence of bromide anion or ion-supported TEMPO for the oxidation of primary and secondary alcohols is discussed in Section 5.3.3 [52,53],... 

Kurig, H., A. Janes, and E. Lust. 2010. Electrochemical characteristics of carbide-derived carbon vertical bar l-ethyl-3-methylimidazolium tetrafluoroborate supercapacitor cells. Journal of the Electrochemical Society 157 A272-A279. 

Pahn et al. [34] employed the CV method to investigate the effect of the concentration of the addition of l-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] [BFJ) in l-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) electrolyte on the electrochemical characteristics for electrical double-layer capacitors (EDLCs). They found the concentration of [BM1M][BF4] has little influence on the... 

FIGURE 4.33 Reaction schemes at (a) —2.4 V and (b) at E >2V. (Reprinted from Electrochimica Acta, 125, Romann, T. et al., Snrface chemistry of carbon electrodes in l-ethyl-3-methylimidazolium tetrafluoroborate ionic tiqnid— An in situ infrared stndy, 183-190, Copyright 2014, with permission from Elsevier.)... 

Katayama Y, Toshimitsu Y, Miura T (2013) Electrode kinetics of tris(2,2 -bipyridine)ruthe-nium complexes in l-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid. J Electrochem Soc 160 H219-H228... 

BmimHFP and BmimPF l- -butyl-3-methylimidazolium hexafluorophosphate BmiBF l-butyl-3-methyliniidazo-Uum tetrafluoroborate BmimPF l-n-butyl-3-methylimidazolium hexafluorophosphate CjmimNTFj and EmiraNTF l-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide EmimBF polyethylene-supported l-ethyl-3-methylimidazolium tetrafluoroborate EmiraNTF l-ethyl-3-methyUmidazolium bis(trifluoromethylsulfonyl)imide Source Data from Stetter et al. (2011)... 

E-3MI-TFB = l-ethyl-3-methylimidazolium tetrafluoroborate-based ionic liquid... 

The compounds l-ethyl-3-methylimidazolium tetrafluoroborate ([EMlm][BF4]), l-butyl-3-methylimidazolium tetrafluoroborate ([B-Mlm][BF4]), l-hexyl-3-methylimidazolium tetrafluoroborate ([H-Mlm][BF4]) and l-butyl-3-methylimidazolium bromide ([BMlm]-[Br]) were used as ionic liquids. Some of these compounds are shown in Figure 1.7. Some properties are summarized in Table 1.3. 

The use of l-ethyl-3-methylimidazolium tetrafluoroborate as mobile phase additive has been evaluated for the analysis by HPLC with fluorescence detection for seven basic fluoroquinolone antibiotics, i.e., fleroxacin, ciprofloxacin, lomefloxacin, danofloxac-... 

---