(300g) A Theoretical Study of SO2 Capture by Hydroxyl Ammonium Ionic Liquids

  Room-temperature ionic liquids, simply known as ionic liquids (ILs), are defined as a class of organic salts with melting points below 100°C. Owing to some unique physical and chemical properties, ILs have been initially proposed as replacements for conventional organic solvents in a variety of fields such as separation, organic synthesis, catalysis, electrochemistry, fuel and solar cells, lubricants, and functional materials, etc.

  Recently, it was found that hydroxyl ammonium ionic liquids show good performances in SO2 separation science. In this study, the interaction between sulfur dioxide (SO₂) and room temperature ionic liquid tri-(2-hydroxy ethyl)-ammonium (THEA) lactate (LAC) (THEAL) have been investigated theoretically by using quantum chemical calculation (QM) at B3LYP/6-31++G* level. The relevant geometrical characteristics, energy properties as well as the characters of the intermolecular hydrogen bonds (HB) have been systematically discussed. The calculation results give us a deeper understanding of the factors which determine the high solubility of SO₂ in THEAL. The most stable geometries and binding energies indicate a strong association of the SO₂ and the THEAL molecule, especially the LAC anion. The results demonstrate that the LAC anion is the main factor for the absorption of SO₂.