关于离子液体？ an ionic liquid is a salt in which the ions are poorly coordinated, which results in these solvents being liquid below 100癈, or even at room temperature (room temperature ionic liquids, rtil's). at least one ion has a delocalized charge and one component is organic, which prevents the formation of a stable crystal lattice. the methylimidazolium and pyridinium ions have proven to be good starting points for the development of ionic liquids: roperties, such as melting point, viscosity, and solubility of starting materials and other solvents, are determined by the substituents on the organic component and by the counterion. many ionic liquids have even been developed for specific synthetic problems. for this reason, ionic liquids have been termed "designer solvents". one of the first rtils was a mixture of [emim]cl with alcl 3 forming a series of equilibria between [emim][alcl 4 ], [emim][al 2 cl 7 ], and [emim][al 3 cl 10 ]. this rtil is not water stable. the discovery of water-insoluble rtils such as [bmim][pf 6 ] allowed the development of new work-up methods, including the separation of water-soluble byproducts by simple extraction. some transition metal catalysts that are soluble in ionic liquids may be recycled together with the ionic liquid, after extraction with water and the non-polar organic solvent used for product separation. the catalyst and ionic liquid may be recycled several times. in addition, the following rtil, derived from fructose (a renewable feedstock), is a promising solvent for implementing fully "green" chemistry methods: s. t. handy, m. okello, g. dickenson, org. lett. , 2003 , 5 , 2513-2515. this ionic liquid was proven to be suitable for heck reactions: s. t. handy, m. okello, g. dickenson, org. lett. , 2003 , 5 , 2513-2515. the absence of volatility is one of the most important benefits of ionic liquids, offering a much lower toxicity as compared to low-boiling-point solvents. ionic liquids can also make for safer microwave synthesis methods, because sudden pressure surges are not possible. the dipole characteristics of ionic liquids translate into rapid excitation by microwaves, and consequently faster reactions. 查看更多
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