The solvents which are not harmful to the environment are called green solvents.

The green solvent is newer concept involves technology which has been popularly preferred over conventional solvent extraction process because of environmental concerns.

Supercritical fluids, aqueous solvents, polymerized solvents, ionic liquids are the examples of green solvents.

Super critical fluid possesses properties of gases and liquids in an intriguing manner, which could offer range of applications/possibilities in both synthetic and analytical chemistry.

Supercritical ionic liquid carbon dioxide has found to be an energy conserving, selective and waste reducing alternatives to organic solvents and therefore is viewed as promising environmentally benign solvents. In addition supercritical fluids can lead to reaction, which are difficult or even impossible to achieve conventional solvents.

Application:

• Supercritical $CO_2$ is used in polymerization
• Ionic liquids are used in production of alkoxyphenylphosphine.