This project will investigate the following two approaches for development of ozone-safe solvents: tropodegradable chlorinated or brominated fluorocarbons, and fluorocarbon/hydrocarbon emulsifiers to enhance hydrocarbon solubility.

Tropodegradable (meaning an atmospheric lifetime of days or weeks) perfluorocarbons and bromofluorocarbons have been investigated and in some cases commercialized as ozone safe fire suppressants to replace CF313r. The presence of chlorine (which causes ozone depletion) is a key component in achieving the favorable solvency properties of CFC-113 and HCFC-141b. However, the use of similar chemical structures (e.g., a double bond or a carbonyl group) such as those identified in the search for Halon replacements would provide a means of achieving a low environmental impact for both ozone depletion and global warming, while retaining favorable solvation and flammability properties. The use of emulsifiers that promote the solvation of poorly soluble compounds (hydrocarbons in the case of a fluorocarbon solvent) is similar in principle to the use of a detergent to promote the solvation of hydrocarbons in water. The concept investigated here is distinct in that it involves no aqueous phase, and the emulsifiers are not surfactants in the traditional sense of containing hydrophilic and hydrophobic portions. Enhancement of solvation has been demonstrated in fluorocarbons in biomedical applications, but it has not been exploited for solvent cleaning applications.

DoD has a number of precision cleaning applications that are critical operational capabilities. These cleaning needs were previously fulfilled by ozone depleting solvents in which liquid oxygen compatibility is essential. The availability of a broader range of alternative technologies for cleaning needs will facilitate the replacement of ozone depleting solvents and reduce reliance on the DoD CFC stockpile.