Relationship between hydrogen bond and viscosity for a series of pyridinium ionic liquids: Molecular dynamics and quantum chemistry

Abstract

The relationship between molecular structure and viscosity for four pyridinium ionic liquids is explored by combination of molecular dynamics and quantum chemistry. Our central aim is to study the relationship between hydrogen bond and viscosity. It is expected that a simple method would be built to judge the relative sequence of viscosity for a series of ionic liquids with similar structures. Although some items related with the viscosity are omitted, it is no doubt a direct method to estimate the range of viscosity. The methyl group substituted in ortho position would greatly increase the viscosity since more hydrogen bonds would be formed with stronger strength. While the pyridinium ionic liquids with the substitution in meta and para position has the similar viscosity, which is consistent with the similar features of hydrogen bonds in them.