Application Of Ionic Liquids And Deep Eutectic Solvents In Green Organic Synthesis

Green chemistry has become a research hotspot in oganic synthesis nowadays.One of the most effective ways to achieve this goal is to choose green solventsinstead of the traditional ones in organic reactions. Ionic liquids are one kind ofmolten salts at room temperature with excellent physical-chemical properties.Compared with traditional organic solvents, it has several advantages, such asnegligible vapour pressure, non-flammability, no pollution, easy to separate fromproduct and can be recycled. Deep eutectic solvents (DES) are green solventscombined of halide salts and hydrogen bond donor. Their synthesis method is easy,and the components are cheap and biodegradable. In recent years, ionic liquids anddeep eutectic solvents have been applied as green solvents in organic synthesiswidely.Herein, our aims are to use ionic liquids and deep eutectic solvents as greensolvents in organic reaction.1. A kind of double-core PEG ionic liquid was synthesized under microwaveirradiation. Then I2was found to be a valuable catalyst in the per-O-acetylation ofsaccharides in PEG ionic liquid. The results showed that the procedure is perfectlyeffective, the pure products were obtained easily and the system can be recycled morethan six times. Scale-up reaction is also discussed.2. Eutectic mixtures of urea and choline chloride were synthesized easily. Thetetrazoles were synthesized via an one-pot three-component reaction from aldehydeusing Cu(OAc)2as catalyst in DES. It is high efficient method to offer correspondingtetrazoles in good yields. And the scale-up reaction is also studied.3. The2-amino-4H-benzo[b]pyran and1,4-dihydrogen pyridine derivativeswere obtained in excellent yields through a one-pot multicomponent reaction by usingcyclodextrins as catalyst in urea-choline chloride DES. The effects of three kinds ofdifferent cyclodextrins on the reactions were studied, and γ-cyclodextrin is the best.Post-processing is easy by just adding water and reaction system could be recycled more than six times with high yields.