Ionic liquids

Ionic liquids or low-temperature molten salts represent a new class of solvents for a cleaner chemistry. Their low melting point, often below room temperature, offers significant energy savings. And unlike other solvents, they are infinitely recyclable.

Ionic liquids (also called room temperature molten salts or ionic solvents) are a new class of solvents offering interesting opportunities as a reaction medium for cleaner chemistry. Ionic liquids are salts comprising organic cations (for example imidazolium or pyridinium salts), complexed with inorganic or organic anions (such as, for example Cl-, Br-, AlCl4-, PF6- et BF4-, NO3-, (CF3SO2)2N-, etc.) which are liquid around room temperature.

General properties, based on an innovative technology, ionic liquids are:

• Non volatile
• non-flammable
• Stable at high temperature (up to 200°C / 392°F or 400°C / 752°F depending on the product) and Chemical (water and oxygen)
• Hydrophobic or Hydrophilic
• Good conductors (electrolytes)
• Broad electrochemical range

The physico chemical properties of ionic liquids depend on the type and the size of the two ions forming them. For example, ionic liquids containing chloride, bromide or trifluoroacetate anions are highly water soluble (hydrophilic). Conversely, when they are associated with an anion such as hexafluorophosphate or bis(trifluoromethanesulfonyl)imide, water solubility is very limited (hydrophobic), forming two liquid phases.

Advantages

• Safer for the environment and for users (non flammable and non volatile)
• Process optimization: better selectivity and higher yield
• Immobilization of the catalyst or biocatalyst in ionic liquids
• Tunable physico-chemical properties, thanks to facile cation or anion exchange and/or chemical functionalization
• Very good solvent for a wide range of compounds: organic and inorganic materials, transition metals, enzymes, cellulose, polymers, … etc.
• Recyclable without performance loss.