ALTHOUGH THE DEVELOPMENT OF SYNTHETIC ESTER LUBRICANTS is relatively recent, the use of esters as lubricating fluids is as old as human technology. Before suitable mineral oils became widely available as a byproduct of the petroleum based fuels industry, lubricants were based on natural fats or oils, which are either triesters of glycerine with natural fatty acids, e.g., tallow and olive oil, or long chain monoesters of fatty acids with fatty alcohols, e.g., sperm whale oil.