Although any liquid may be used as a solvent; relatively few are in general use. However, as the introduction of cleaner technologies has become a major concern throughout both industry and academia, the search for alternatives to the most damaging solvents has become a high priority. Solvents are high on the list of damaging chemicals for two simple reasons: 1.
They are used in huge amounts.
They are usually volatile liquids (VOCs) that are difficult to contain. Solvent properties of ILs
They are good solvents for a wide range of both inorganic and organic materials, and unusual combinations of reagents can be brought into the same phase; •
They are often composed of poorly coordinating ions, so they have the potential to be highly polar yet non-coordinating solvents; •
They are immiscible with a number of organic solvents and provide a non-aqueous, polar alternative for two-phase systems. Hydrophobic ionic liquids can also be used as immiscible polar phases with water; •
Ionic liquids are non-volatile, hence they may be used in high-vacuum systems and eliminate many containment problems. They do not evaporate. •
One of the most distinct advantages of RTILs that has been the rationale for their characterization as “Green Solvents” is their negligible volatility. This characteristic renters them promising replacements to volatile organic compounds (VOCs), which are used in large quantities in chemical and engineering industries and are a source of major environmental problems.5 Moreover, many ILs can be recycled and reused repeatedly. Although the ionic liquids do not comply fully with green chemistry principles, they are very promising as alternatives to organic solvents.
It must be emphasized that reactions in ionic solvents are not difficult to perform and usually require no special apparatus or methodologies. The reactions are often quicker and easier to carry out than in conventional organic solvents. Applications of ionic solvents
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