Esters

Prior to the early Nineteenth century, one of the main classes of lubricants in use were natural esters contained in animal fats such as sperm, oil lard oil or in vegetable oils such as rapeseed or castor oil. The earliest recorded use of animal fats is 1400 b.c. when they were used to lubricate chariot axles. Around 1937, Dr Zorn of I.G. Faben in Germany began intensive work on synthetic lubricants. During World War II a range of synthetic oils were developed for commercial production. The great difficulty encountered in Russia in starting trucks and tanks in the winter of 1941 to 42 due to the cold provided an impetus to the development of synthetic ester lubricant. Among these, esters of long chain alcohols and acids proved to be excellent as low temperature lubricants. The production of 200 bbl/day of adipic and methyl adipic acid esters was planned in Germany, but the rate attained did not exceed 100 bbl/day [1]. Another ester research development in Germany meriting notice was one by the Deutsche Fettsaure Werke in Whitten (Ruhr). This company, which worked with fatty acids and produced synthetic butter and other esters, studied the use of esters as lubricants. They concluded that an ester of pentaerythritol and C6 to C10 fatty acids was well suited for such an application [1]. Following World War II, the further development of esters was closely linked to that of the aviation gas turbine. The U.S. military began the use of synthetic gas turbine lubricants in the 1950s following the publication of MIL-L-7808 specification for dibasic acid esters. In the early 1960s, neopentyl polyol esters were used in this application because of their low volatilities, high flashpoints, and good thermal stabilities.