1 -Butylimidazolium tetrafluoroborate

Li et al. [93] have used l-ethylimidazolium trifluoroacetate, which is a Bronsted acidic ionic liquid, as a medium for the electropolymerization of aniline. They report that in this ionic liquid the oxidation potential of aniline is lower (0.58 V compared to 0.83 V in 0.5 M H2SO4) and that the growth rate of the polymer is increased. Further, the resultant films are smooth, strongly adhered to the Pt working electrode and are very electrochemically stable. Similar results have been reported by Liu et al. [92], who found that this was the best ionic liquid for the polymerization of aniline, compared to the unsatisfactory results observed in other protic ionic liquids 1-butylimidazolium tetrafluoroborate, 1-butylimidazolium nitrate and 1-butylimidazolium p-toluenesulfonate, as well as the l-butyl-3-methylimidazolium hydrogen sulfate and l-butyl-3-methyimidazolium dihydrogen phosphate. 

A mixture of 1 mmol 6>-amino-acetophenone, 1 mmol ethyl acetoacetate, and 1 mmol 1-butylimidazolium tetrafluoroborate [Hbim]BF4 was heated at 100°C with good stirring for 3 h. The completion of reaction was monitored by TLC (EtOAc/petroleum ether, 1 4). After completion of the reaction, the reaction mixture was diluted with 25 mL water. The ethyl 2,4-dimethylquinoline-3-carboxylate was extracted with EtOAc (2 x 10 mL) and dried over Na2S04. After removal of solvent, the crude product was purified by column chromatography (EtOAc/petroleum ether, 1 4), to afford 94% ethyl 2,4-dimethylquinoline-3-carboxylate as oil. The aqueous layer consisting of the ionic liquid was distilled (80°C at 10 mmHg) for 2 h to remove water and recycle 98% of the ionic liquid [Hbim]BF4. 

Butylimidazolium Tetrafluoroborate ([Hbim]BFJ rt, good to excellent yield, aromatic and aliphatic diketones, 10-96 min, excellent yield with electron deficient aromatic diamines 104... 

Dihydropyrimin-2-(lH)-ones (DHPMs) have been synthesized in excellent yields in short reaction times at ambient temperature in the absence of any added catalyst by the reaction of aromatic or aliphatic aldehydes with ethyl acetoacetate (EAA) and urea (or thiourea) at room temperature in l- -butylimidazolium tetrafluoroborate ([Hbim][BF ]) under ultrasound irradiation (Fig. 12.39) [27]. 

Several reports have been pubhshed for the synthesis of Qx from 1,2-diones (Scheme 2.16, Table 2.5) using different ILs under different reaction conditions using room temperature Bronsted acid ILs like l-n-butylimidazolium tetrafluoroborate ([Hbim]BF [104], Heteropolyanion-based ILs [105], 1-butyl-3-methylimmidazohumtetrafluorDborate ([bmim]BF4) [106] and N, N, AA-trimeth-yl-A/ -propanesulfic acid ammonium hydrogen sulfate [TMPSA] HS04 [107]. 

Potewar TM, Ingale SA et al (2008) Efficient synthesis of quinoxalines in the ionic liquid 1-n-butylimidazolium tetrafluoroborate ([hbim]bf ) at ambient temperature. Synth Commun 38 3601-3612... 

Poly 1 - [2-(methacry loy loxy )ethy 1]-3-butylimidazolium tetrafluoroborate ... 

Poly [ 1 -(4-viny Ibenzy l)-3-butylimidazolium tetrafluoroborate] carbon dioxide carbon dioxide carbon dioxide 2005TA4 2005TA5 2007BL2... 

Poly[l-(4-vinylbenzyl)-3-butylimidazolium o-benzoic sulfimide] Poly [ 1 -(4-vinylbenzyl)-3 -butylimidazolium hexafluorophosphate] Poly [ 1 -(4-vinylbenzyl)-3 -butylimidazolium tetrafluoroborate] Poly [ 1 -(4-vinylbenzyl)-3 -butylimidazolium trifluoromethane sulfonamide]... 

Recently, Tang et al. [21] reported that poly(ionic liquid)s showed significantly enhanced and fast CO2 absorption compared to ILs. Especially, the polymers of tetraalkylammonium-based ILs have CO2 sorption capacities 6.0-7.6 times of those of room temperature ILs. Electrospinning of the poly(ionic liquid) solution was first demonstrated by Chen and co-workers [42]. Figure 10.5 shows the electrospun fibers from various concentrations of poly(l-[(2-methacryloyloxy)ethyl]-3-butylimidazolium tetrafluoroborate or MEBIm-BF4) in cosolvent 3/1 acetoni-trile/DMF. At 2.5 wt%, a concentration below the entanglement concentration, only droplets were obtained (Fig. 10.5a). Beaded fibers were observed at 5 and... 

A basic ionic liquid, l-methyl-3-butylimidazolium hydroxide ([bmIm]OH) and l-butyl-3-methyl-methylimidazolium tetrafluoroborate ([bmim]BF4), has been introduced as a catalyst and reaction medium for the Markovnikov addition of imidazoles 116 to vinyl esters 115 under mild conditions to give imidazoesters 117 <06JOC3991 06TL1555>. A series of (nitroimidazolyl)succinic esters and diacids were prepared from the Michael-type addition of the nitroimidazole to the a,P-unsaturated ester <06S3859>. 

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. 

The IL-based surfactants employed for these analyses are commonly composed of methyl- or butylimidazolium cations containing long alkyl chains in their structures between 4 and 16 carbon atoms [20,23,36,56,59-73]. The most common anion in these applications is bromide [20,23,36,56,60,62,64,67,68,71,73] followed by the tetrafluoroborate anion [65, 66, 69]. There is only one application utOizing a pyri-dinium-based IL-based surfactants [63], in which a comparison of the performance of a monocationic and a dicationic pyridinium-based IL-based surfactant was made. 

Poly [2-( 1 -butylimidazolium-3-y l)ethy 1 methacrylate tetrafluoroborate]) carbon dioxide 2005TA4... 

Safarov, J. Verevkin, S. P. Bich, E. Heintz, A. Vapor pressures and activity coefficients of n-alcohols and benzene in binary mixtures with 1-methyl-3-butylimidazolium octyl sulfate and l-mefliyl-3-octyli-midazolium tetrafluoroborate. J. Chem. Eng. Data 2006, 51, 518-525. 

Densities, Refractive Indices, and Viscosities of the Ionic Liquids l-Methyl-3-octylimidazolium Tetrafluoroborate and l-Methyl-3-butylimidazolium Perchlorate and Their Binary Mixtures with Ethanol at Several Temperatures. J.Chem.Eng.Data, 53, 3 (March. 2008) 677-682. 

---