Study On Extraction Of Nitrogen Heterocyclic Compounds By Imidazole Ionic Liquid

In this thesis,the extraction separation performance and extraction driving forces of?pseudo?ionic liquids for nitrogen heterocyclic compounds have been studied systematically.The main contents and results are as follows:?1?Synthesis of a series of functionalized ionic liquids containing ether groups,hydroxyl groups,benzyl groups and dialkyl groups.The effects of temperature,pH value of phase,phase to volume ratio,inorganic salts and ionic liquids on the extraction efficiency of vitamin B₃,niacin and niacinamide were investigated.The results show that the increase of the length of the side chain of the ionic liquid leads to the increase of steric hindrance,which leads to the decrease of extraction efficiency.Non-covalent weak interactions such as hydrophobic interaction,hydrogen bonding and?-?stacking are the driving forces of the extraction process.Thermodynamic studies have shown that during the extraction process,hydrogen bonding is the main driving force for the extraction of niacin,and the extraction of nicotinamide is mainly driven by hydrophobic interaction.The back extraction of vitamin B3 and the recycling of ionic liquids can be achieved by adjusting the pH of the aqueous solution.?2?Proton-type ionic liquids were synthesized by acid-base reaction,and their extraction ability for nitrogen heterocyclic compounds?quinoline,anthracene and carbazole?in model oil?n-dodecane?was investigated.The results show that compared with the ionic liquid based on 1-butyl-3-methylimidazole?[C₄mim]⁺?,due to the stronger?-?interaction between the p-toluenesulfonic acid anion and the nitrogen compound,Triethylammonium tosylate?TEA-TSA,containing a slight excess of p-toluenesulfonic acid?2%,mole percent??has a stronger ability to extract hydrazine and carbazole.Hydrophobic effect is the main driving force for the extraction of quinoline by[C_nmim]X?n=2,4;X=Cl,N?SO₂CF₃?₂,BF₄,MeSO₃?.Due to the acid-base reaction between quinoline and the acidic extractant,the acidic extractant has a higher extraction capacity for quinoline.Hydrogen bonding is the main driving force for the extraction of non-basic nitrogen compounds ruthenium and carbazole by[C₄mim]X?X=Cl,N?SO₂CF₃?₂,BF₄?.Ionic liquid recovery experiments show that TEA-TSA can be regenerated and reused by a back extraction process.?3?A natural fragrance-based ionic liquid was synthesized,and the effects of pH value,phase volume ratio,temperature and time on the extraction of Hal base were investigated.Haline was extracted from Peganum harmala L.using hydrochloric acid and compared with the methanol extraction method.The results showed that hydrochloric acid could be used instead of methanol for extraction of Halal from Peganum harmala seeds.The extraction ability of ionic liquids for Hal base is similar to that of dialkyl functionalized ionic liquids,and is stronger than traditional organic solvents.However,the synthesis of ionic liquids is simpler than ionic liquids.Reduced costs and environmental pollution,more in line with the"green chemistry"concept.