Study on Structure Properties of Pyridine Ionic Liquids of Different Acid-Based Chain Lengths

By density functional theory (DFT) at B3LYP/6-311+G** levels, the pyridine ionic liquid with different substituent length has been studied. The calculated results show that the ionic liquid formed by pyridine and a chlorine ion has two main configurations (CCOOH-PyCl and CCOOHPyPCl). There are three combinative locations in each configuration of anion and cation. When the anion is located in the same location, as the acid length becomes longer, the hydrogen bond length between chlorine ion and hydrogen atom in pyridine ring becomes longer, the binding energy between chlorine ion and pyridine with different acid length becomes stronger.