Solvent Properties of CXLs

As has already been described in Table 9.1, transport properties are enhanced in CXLs compared with conventional solvents. For example, diffusivities of solutes are enhanced up to 7-fold in carbon dioxide expanded methanol, with little effect being seen on the nature of the solute (benzene pyrazine). Therefore, it is thought that physical rather than chemical interactions are causing this phenomenon, including reduced viscosity and surface tension upon carbon dioxide addition. The solubility of solids, liquids and gases in CXLs will 

Densities of gas expanded acetonitrile ( ) and acetone ( ), with varying CO2 mol fraction. [Reprinted with permission from J. Phys. Chem. B, 2006, 110, 13195-13202. Copyright 2006 American Chemical Society.] 

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