Thermophysical Properties of Dual Functionalized Imidazolium-Based Ionic Liquids

Abstract

In this work, some new dual functionalized imidazolium-based ionic liquids 3-(3-butyl-1H-imidazol-3-ium-1-yl)propanenitrile chloride [C2CNBim]Cl, 3-(3-allyl-1H-imidazol-3-ium-1-yl)propanenitrile chloride [C2CNAim]Cl, 3-[3-(2-hydroxyethyl)-1H-imidazol-3-ium-1-yl]propanenitrile chloride [C2CNHEim]Cl, and 3-(3-benzyl-1H-imidazol-3-ium-1-yl)propanenitrile chloride [C2CNBzim]Cl have been synthesized and characterized by 1H NMR, FTIR, and elemental analysis. Their thermophysical properties such as viscosity and density were measured for a temperature range of (293.15 to 353.15) K at atmospheric pressure, and their refractive indices were measured in the range of (293.15 to 333.15) K. The effect of functionalized side chains on their thermophysical properties was studied. The thermal expansion coefficient values were calculated using experimental density values. Thermal behavior of these ionic liquids was investigated using a thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC).

Synthesis and Structure of Ionic Liquids Containing the ­[Al(OC6H4CN)4]– Anion

“…The introduction of a nitrile group in the cation leads to a lower thermal stability compared to imidazolium aluminates containing only alkyl chains as shown for compounds 20 and 21 . The thermal stability of the corresponding halides ( 18 and 19 ) are similar to the reported values in the literature [decomposition temperatures of 1‐(2‐cyanoethyl)‐3‐allyllimidazolium chloride ([C 8 H 12 N 3 ]Cl): 218 °C and 1‐(2‐cyanoethyl)‐3‐cyanomethyl‐imidazolium salts: [C 8 H 9 N 4 ]Cl: 196 °C, [C 8 H 9 N 4 ][N(CN) 2 ]: 176 °C] 11c,32…”

Density and excess molar volume of binary mixture of thiocyanate-based ionic liquids and methanol at temperatures 293.15–323.15K

“…The apparatus was calibrated with ultra-pure water and validated with ILs for which the density values are already established [28]. The temperature was controlled to within ±0.01 K, and the densimeter was capable of measuring density to ±0.00001 g cm −3 where the uncertainty of the results was measured 0.00001 g cm −3 .…”

“…Then, [C 1 = C 2 )C 1 im][SCN] was prepared by metathesis reaction between [C 1 = C 2 )C 1 im]Cl and sodium thiocyanate (NaSCN). 3-(3-Butyl-1H-imidazol-3-ium-1-yl)propanenitrile chloride ([(NC) 2 C 2 C 4 im]Cl) was synthesized using previously reported method [28]. Further, the chloride anion of the aforementioned was exchanged with SCN of NaSCN salt to obtain 3-(3-butyl-1H-imidazol-3-ium-1-yl)propanenitrile thiocyanate [(NC) 2 …”

Cholesteryl-containing ionic liquid crystals composed of alkylimidazolium cations and different anions

“…3c suggesting formation of imidazolium tetrachloroaluminate. The peaks at 1641 and 1555 cm À1 were characteristic bands of imidazole ring in the chemical structure, and the peaks at 3067 and 2421 cm À1 could be assigned to formation of hydrogen bonds [40][41][42]. While in the spectrum of imidazolium chloride salt [Cb-Me-Im]Cl, the peak intensity of 3067 and 2421 cm À1 was much weaker than those of imidazolium tetrachloroaluminate.…”