Ethylammonium Nitrate EAN

Example 2, using ionic liquid ethylammonium nitrate (EAN) as solvent ... 

Using ethylammonium nitrate (EAN) as PIL ( . , =0.95, ji = 1.12, a=1.10, P = 0.46), following types of binary mixture models were selected for the analysis and quantification of the microscopic solvent properties (a) [molecular aprotic solvent with HBA ability + PIL cosolvent], (b) [molecular aprotic solvent with both HBD and HBA ability + PIL cosolvent] and (c) [molecular protic solvent + PIL cosolvent] [31]. The molecular solvents included in this analysis were dimethylsul-phoxide (DMSO) ( ., =0.44, 7r = 1.00, a=0.02 and p=0.76) as a polar aprotic HBA solvent, acetonitrile (AN) ( .,. =0.46, 7t =0.75, a=0.19, p=0.40) as polar aprotic HBA/HBD solvent and methanol ( .,. =0.76, 7t =0.60, a=0.98, p=0.66) as a protic solvent. EAN is a N-H-bond donor. In all cases, the pure component part of the mixtures was capable of forming associated species through hydrogen-bonding interactions. For the explored solvent mixtures, empirical parameters . n, a and P were calculated from the wave numbers of the absorbance maxima of the corresponding chemical probes at 25°C. 

Because of the high polarity of RTILs, self-assembly of amphiphiles in RTILs are quite similar to that observed in aqueous systems. Alkyltrimethylammonium bromides and alkyl pyridinium bromides in the RTIL ethylammonium nitrate (EAN), for example, form micelles just like in water, albeit with critical micelle concentration (CMC) values that are five to ten times larger [4,29]. Liquid crystalline phases are also observed in surfactant-RTIL... 

A mixture of aldehyde (1 6 mmol), beta-naphthol/phenol (2 1 mmol) and amide/carbamate/ urea (3 1.1 mmol) and ethylammonium nitrate (EAN 0.8 mmol) was stirred at room temperature for 1 h (the completion of reaction was monitored by TLC). On completion of reaction, the reaction mixture was extracted thrice with 10 mL ethyl acetate. The extract was dried over anhydrous sodium sulfate, evaporated under vacuum to obtain the crude product which was then purified by chromatographic column on silica gel (hexane/ethyl acetate, 70 30) to yield pure 1-amido- and 1-carbamato-alkyl naphthol/phenol 4. The recovered EAN was subjected to high vaccum at 80 °C to remove the water and then reused. All the isolated reaction products were characterized and confirmed by NMR. 

Depending on the combination of the cation and the anion, ILs can have either hydrophilic or hydrophobic character. The most frequently investigated ILs are based on imidazoliurn cations. Anions such as halides, acetate, nitrate and ethylsufate form hydrophilic ILs while anions such as bis(trifluoromethylsulfonyl)imide and hexafluorophosphate lead to hydrophobic ILs. Apart from these aprotic imidazoliurn or pyridinium based ionic liquids there was recently a growing interest in protic ionic liquids (PILs). A comprehensive overview about types and physicochemical properties of PILs was currently given in a review of Greaves Drummond (Greaves Drummond 2007). Ethylammonium nitrate (EAN), which represents the first room temperature ionic liquid described in literature, has already been reported in 1914 (Walden 1914) and is nowadays probably the most frequently studied PIL. 

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