Phosphorus-containing moieties can be added to the ninth and/or tenth positions of a fatty chain of a methyl ester utilising an epoxide route. In this route, methyl oleate is epoxidised, and then ring opened using dibutyl phosphate to yield - among others - a dioxaphospholane-containing derivative of methyl octadecanoate. Progress of the reaction was determined by gas chromatography-mass spectrometry and compounds were identified by nuclear magnetic resonance spectroscopy. Addition of a titanium and zirconium oxide catalyst increased the yield of dioxaphospholane from 27%, observed without catalyst, to 37%. A similar reaction using bis-2-ethylhexyl phosphate gave 22% and 29% yield. However, an aryl phosphate, diphenyl phosphate, was not active in these reactions. The aliphatic compounds obtained are likely to be useful sulphur and metal-free extreme pressure lubricant additives which are highly compatible with vegetable oil-based lubricants.
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