文摘
New functionalized 1-butyl-3-Xpyridinium dicyanamide ionic liquids (ILs) were synthesized by adding groups (X = cyano, amino, chlorine, alkyl) with different substituent effects. Experimental and computational analyses were performed to evaluate the role of the pyridinium substituent on IL solvent properties, particularly as an extracting agent of pyridine from fuels. Quantum chemical calculations and NMR measurements indicated that the hydrogen bond (HB) donor character of the cation was successfully tuned by an adequate substitution. The COSMO-RS study showed that pyridine produces exothermic mixtures with these ILs, mainly due to favorable HB interactions. However, the mixture behavior was found to be controlled by entropy. Experimental and calculated Liquid–Liquid Equilibrium (LLE) data of pyridine-heptane-IL mixtures revealed that the new functionalized ILs present favorable partition coefficients and selectivity for extracting N-compounds from aliphatic mixtures. It was possible to enhance the solvent performance by using tetraalkyl substituents, which increases the entropy of the system.