Theoretical Study On The Properties Of Acetate Ionic Liquid And Its Application

Chitosan is one of the most abundant bio-renewable and biocompatible material,and has been widely used in industry as drug carriers, water treatment additives,wound-healing agents and so on. However, owing to their intramolecular and intermolecular hydrogen bonds, they have very low solubility in water and conventional organic solvents, which limits their application in practical processes.Ionic liquids have unique properties, such as high chemical and thermal stability,non-flammability, low melting point and non-detectable vapor pressure. The properties of ILs can be changed by altering the cation or anion, which dramatically increases their potential fields of application.First we select five acetate ionic liquid to determine the solubility of chitosan in ionic liquids. Because chitosan is a very large system for DFT calculation, we selected chitobiose as a model compound for the assessment of the hydrogen bond and its chemical environment of chitosan. The complexes formed between five ILs and chitobiose are optimized at B3LYP/6-31G(d,p) level. From the results we can see that [Bmim]OAc is the best suitable IL for the dissolution of chitsan. To further understand the interaction mechanism on dissolution of chitobiose in [Bmim]OAc, the hydrogen bonds between [Bmim]OAc and chitobiose are studied by discussing the geometric parameter variations and the vibration mode analyses. Atom in molecules(AIM) theory and natural orbital(NBO) theory are used to further study the nature of the hydrogen bond to explain the solution mechanism of chitosan in [Bmim]OAc.At present, it has reported the recovery of chitosan and cellulose from[Bmim]OAc by compressed CO2 and found that using compressed CO2 is a more efficient method than using conventional high boiling-point solvents. So We focus on the changes of ionic liquids in the dissolution process of CO2 in ionic liquids, which provide theoretical data to regeneration of chitosan. CO2 and [Bmim]OAc are optimized at B3LYP/6-311++G(d,p) level. We analyze the interaction between CO2 and [Bmim]OAc. At the same time the hydrogen bond are analyzed in detail by vibration mode analysis, AIM theory and NBO methods.Vinyl chloride is a highly reactive and toxic substance, which is is basic raw material of poly(vinyl chloride)(PVC) production. At present, the domestic process methods of vinyl chloride all have drawbacks. We calculate the absorption of vinyl chloride in [Bmim][BF4], [Bmim][PF6], TMGL and [TMGHPO2][BF4]. Four ionicliquids and vinyl chloride are optimized at B3LYP/6-311++G(d,p) level. Through vibration mode analysis and the analysis of the interaction energy, it prove that[TMGHPO2][BF4] is best for the absorption of vinyl chloride. AIM theory and NBO theory are used to further study the nature of the hydrogen bond to explain the absorption mechanism of vinyl chloride in [TMGHPO2][BF4].