Lanzhou Greenchem ILs (Center for Greenchemistry and catalysis), LICP, CAS. Ionic Liquids

 

Undoubtedly the talk which aroused the most interest at the first International Congress on ionic liquids (COIL-1) in Salzburg, was a presentation by Dan Tempel of Air Products. He revealed a new Air Products technology, which is based around entrainment by the complexing of reactive gases in ionic liquids. It produces at least twice the performance of the main rival process, which relies on the physical adsorption of gases on solids, and provides a method to deliver these reactive and hazardous gases in a safe, effective, more easily handled way, reducing both the risks and hazards in the work place – a true green chemistry success. The gases can be stored and transported at sub-atmospheric pressure , instead of the normal pressurised cylinders, adding dramatically to safety. It is marketed as Gasguard Sub-Atmospheric System, Complexed Gas Technology (CGT); the gas is removed from the cylinder by the application of vacuum.

The system is based on the inherent Lewis acidity or basicity of the gases; Lewis acidic gases (such as boron(III) fluoride) are stored in Lewis basic ionic liquids (such as [Cnmim][BF4]), whereas Lewis basic gases (such phosphine, PH3, or arsine, AsH3) are stored in Lewis acid ionic liquids (such as [Cnmim][Cu2Cl3] or [Cnmim][Cu2Br3]). It can thus be used to deliver high purity gases to the electronics market.