Research On The Extraction And Separation Of Ferulic Acid And Caffeic Acid From Chinese Herbs By Hydrophobic Ionic Liquids

There are four parts in this paper.Chapter 1 In this section, the application of ionic liquids (ILs in short) in the separation of organics were reviewed. And the significance and direction of the research were also elucidated.Chapter 2 1-butyl-3-methylidazolium tetrafluorophosphate ([C₄mim][PF₆], C₄ in short),1-hexyl-3-methylidazolium hexafluorophosphate ([C₆mim][PF₆], C₆ in short) were synthesized, and were identified and approved by UV, IR, ¹HNMR. And the basic properties were also included.Chapter 3 Using the two ionic liquids synthesized above as extracting agents, the effects of pH value, temperature, phase ratio, type and concentration of inorganic salts added, the structures of ILs, Ferulic acid (FA in short) and Caffeic acid (CA in short) on the extraction efficiency of by means of ultraviolet-visible spectrophotometry were investigated in this paper. And also, the mechanism of the extraction of organic acids by imidazolium ILs was also discussed. Furthermore, the retrieve of the compounds extracted, the reuse of ILs were also discussed. The results indicated that the changes of temperature, concentration and type of inorganic salts added had no obvious influence on the extraction efficiencies, whereas pH values of aqueous phase affected the extraction efficiencies significantly. The hydrogen interaction was important for the extraction process. The extraction efficiencies of FA and CA using C₄ as extract agent were higher than that of using C₆ as extract agent. Interestingly, the extraction efficiency of FA was much higher than that of CA whether using C₄ or using C₆ as extract agent, whereas, the residue of C₆ in aqueous phase was less than that of C₄. The FA and CA in the extraction phase could be retrieved quantitatively, and the ionic liquids could be reused.Chapter 4 The extraction abilities of FA and CA from angelica, rhizoma ligustici wallichii and dandelion by C₄, C₆ were researched, and the effect of pH value, the retrieve of the compounds extracted and the reuse of ILs were mainly discussed. And the results indicated that these two ILs could highly selectively extract FA and/or CA from the traditional Chinese Herbs investigated. And the extracts in the extraction phase could be retrieved quantitatively, and the ILs could be reused.