The future generation solvent systems include ionic liquids, water, fluorous solvents, supercritical fluids, etc. One popular example is as follows-
Ionic liquides are liquid comprizing of ions. They are usually formed by reacting quaternary ammonium salt with acids like AlCl3, HBF4, HPF6, etc. The melting point is governed by the cationic part while anionic part influences the chemical behavior. There are some liquids which are extremely water sensitive while others are water stable. The acidity, basicity can be adjusted as per the need by varying the proportions of acid and the cataonic part.
Instead of AlCl3, if HPF6 is used water stable ionic liquid is formed.
The research in the field has been increasing rapidly.