Hydro fluoroethers

Solvents, like contaminants, may be polar or nonpolar. As a general rule, polar solvents dissolve polar residues while nonpolar solvents dissolve nonpolar residues. Thus, ionic residues such as chlorides, salts, acids, acid fluxes, and alkalis are best dissolved and removed with polar solvents such as water, isopropyl alcohol, ethanol, or methylethyl ketone. Greases, oils, silicones, rosin flux, and low-molecular-weight monomers are best dissolved and removed with solvents such as hydrocarbons, Freons , hydrochloro-fluorocarbons, xylene, terpenes, and naphtha. To remove both polar and nonpolar residues, a two-step process using both types of solvents may be used or, more conveniently, an azeotrope mixture of the two solvents can be used in a one-step process. Most of the chlorofluorocarbon solvents (Freons ) and their azeotropes with alcohols, methylene chloride, or ketones are being phased out due to their high ozone-depletion potentials. Solvent blends and azeotropes of hydro-fluoroethers and hydrochlorofluorocarbons (HCFC) are now replacing these solvents. 

Naoi, K. Iwama, E. Ogihara, N. Nakamura, Y. Segawa, H. Ino, Y., Nonflammable hydro-fluoroether for lithium-ion batteries enhanced rate capability, cyclabiUty, and low-temperature performance, J. Electrochem. Soc. 2009, 156, A272-A276. 

Cosolvents and Surfactants Many nonvolatile polar substances cannot be dissolved at moderate temperatures in nonpolar fluids such as CO2. Cosolvents (also called entrainers, modifiers, moderators) such as alcohols and acetone have been added to fluids to raise the solvent strength. The addition of only 2 mol % of the complexing agent tri-w-butyl phosphate (TBP) to CO2 increases the solubility of hydro-quinone by a factor of 250 due to Lewis acid-base interactions. Very recently surfactants have been used to form reverse micelles, microemulsions, and polymeric latexes in SCFs including CO2. These organized molecular assemblies can dissolve hydrophilic solutes and ionic species such as amino acids and even proteins. Examples of surfactant tails which interact favorably with CO2 include fluoroethers, fluoroaciylates, fluoroalkanes, propylene oxides, and siloxanes. 

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