Abstract

Perfluoroaliphatic ethers and tertiary amines are members of a class of unreactive compounds known in the industry as inert fluids. These compounds are prepared by electrochemical fluorination, direct fluorination using elemental fluorine or cobalt trifluoride fluorination. They are nontoxic, nonflammable, have densities of 1.7–1.9 g/cm³, surface tensions of 9–19 dyn/cm and lower kinematic viscosities than hydrocarbons. Their thermal stabilities are comparable to the perfluoroalkanes. Their chemical properties are characterized by their extreme unreactivity. The lower molecular weight compounds are used in the electronics industry as heat-transfer fluids and electronic testing fluids. The higher molecular weight polymers are used as hazardous duty vacuum pump oils, specialty greases, and lubricants.

Hydrofluoroethers and hydrofluoropolyethers are new classes of highly fluorinated ethers having properties intermediate between the perfluoroethers and hydrocarbon ethers. They are low in toxicity, nonflammable, with densities of 1.4–1.7 g/cm³, surface tensions of 13–16 dyn/cm and low kinematic viscosity. The hydrofluoropolyethers are used as heat-transfer fluids. The hydrofluoroethers are used as heat-transfer fluids as well as precision cleaning solvents and solvents for specialty applications such as coating deposition.