HFC refrigerants and polyolester lubricants are being used in many refrigerating systems today and are proposed for many more in the near future. There are reported cases of unusually high bearing wear and of copious solid deposit formations in these units under, as yet, unknown conditions. These deposits may be contributing to capillary tube blockage occasionally reported with polyolester lubricants. When there is strong evidence of direct interactions between the hermetic system working fluids and materials of construction, as revealed with RP-887, it is imperative that these interactions be fully understood so that equipment is designed and manufactured in a manner that avoids the conditions that lead to detrimental interactions.

The objective of this research project is to review literature for information on the interaction of iron with polyolesters, polyesters, esters, and carbohydrates in general, and to document the effect of other active metals such as magnesium and zinc; and the effect of certain catalysts and inhibitors such as rust inhibitors or metal passivators on the reaction of iron with esters. Using this information, the contractor will propose a reaction mechanism, or mechanisms, that is likely to produce the phenomena observed in RP-887.

Based on the literature findings, the researcher will conduct sealed glass tube or metal vessel tests to determine the thermal and chemical boundaries necessary for the reaction of iron with POE lubricants to occur.