Thermal Behavior of Prospective Hydroxy Acid Grease Thickeners

Melting points and heats of fusion were determined for 13 hydroxy acids and their lithium salts with chain lengths ranging from 14 to 24 carbons. Included were hydroxy acids prepared from two unusual plant sources, Lesquerella sp. and Crambe abyssinica. Upper melting point temperatures, transition entropies, and heat capacity changes of the lithium salts on heating and cooling suggest that many of the salts, particularly those of 14-hydroxyeicosanoic and 9(10)-hydroxystearic acids, would perform satisfactorily as gelling agents in the production of lubricating greases.