Synthesis Of Ionic Liquids And Application In Condensation Reaction

Ionic liquids is another kind of green solvent after water and supercritical carbon dioxide, it has been found wide application in organic synthesis, catalysis chemistry, electrochemistry and material science due to their excellent properties, such as non-volatility, non-combustible, high stability and wide electrochemical potential window and so on. In this work, some simple synthesis of ionic liquids and their use in condensation reactions were discussed.[Bmim]BF₄ and [Bpy]BF₄ ionic liquids were synthesized and characterized by FT-IR, ’H NMR. The ionic liquid were used in benzaldehyde and acrylonitrile condensation reaction as an alternative to acetonitrile and other traditional solvents to overcome the traditional solubles environmental pollution as well as disadvantage of low yield. In the reaction, the effect of [Bpy]BF₄ is better than [Bmim]BF₄, the yield is 59.2%.A series of long chain of ionic liquid [Cndabco]BF₄ （n=2,3,4,6,8,10,12） were synthesized with triethylene diamine as material, and characterized by FT-IR、1H NMR and DSC-TGA. The result showed that the ionic liquids have good thermodynamic stability and the melting point exist a minimum point. The lowest melting point is 39.94℃when the substituent chain length was 8. [C8dabco]BF₄ was used in condensation reaction of acrylonitrile and benzaldehyde, the yield is up to 68.7%.Br（?）nsted acidic ionic liquids [BPy]CH₃C₆H₄SO₃、[Bmim]HSO₄、[BPy]HSO₄ and HnmpHSO₄ were synthesized and characterized by FT-IR and 1H NMR, The acidity was determined using Hammett function, the acidity（Ho） of HnmpHSO₄ was-0.9. Allantoin was synthesized by urea and glyoxylate with the catalyst of Br（?）nsted ionic liquids. The results showed that the catalystic activity of HnmpHSO₄ was best, the yield is up to 62.8%. The optimal condition were as follows:molar ratio of urea and glyoxylate is 3.5:1, the reaction temperature is 70℃, reaction time is 5h.The condensation reaction of cyclohexanone and ethylene glycol with Br（?）nsted ionic liquids of [BPy]CH₃C₆H₄SO₃、[Bmim]HS04、[BPy]HSO₄ and HnmpHSO₄ as catalyst was investigated. The result showed that the reaction yield is highest and upto 93.7% by the catalyst HnmpHSO₄. The optimal conditions were as follows:molar ratio of cyclohexanone and ethylene glycol is 1:3.0, reaction temperature is 120℃, reaction time is 90 min.