ABSTRACT
This chapter focuses on synthetic organic ester basefluids, that is, viscous, water-immiscible liquids, containing only carbon, hydrogen, and oxygen, manufactured by esterification processes, and used as major components of formulations intended to reduce friction and wear in machinery. The raw materials used for ester lubricants generally carry relatively large hydrocarbon substituent groups and the properties of ester lubricant basefluids are largely influenced by the number and structure of these hydrocarbon groups. Monoesters result from reaction of monofunctional acid with monofunctional alcohol. There are typically four distinct stages to manufacture of ester lubricant basefluids: esterification, stripping of excess reactants, neutralization and filtration. Esters are good solvents for polar additives and for the polar initial products of thermal decomposition of lubricant components that lead to deposit and varnish formation. Ester basefluids show similar shear stability to hydrocarbons of similar viscosity profiles. Esters used as lubricant basefluids generally have low acute toxicity by ingestion, skin absorption, or inhalation of airborne mist.
