Synthesis and physical properties of potential biolubricants based on ricinoleic acid

The desire to replace petroleum-based materials with environmentally friendly and sustainable alternatives has stimulated the development of vegetable oil-based materials as biolubricants. Our studies have focused on molecules that might be produced by biosynthesis of genetically altered oilseed plants with limited post-harvest modification. Various ricinoleate and 12-hydroxystearate esters and estolides were synthesized and their melting points and viscosities were documented. The antifriction and antiwear properties of some esters were evaluated with a microtribometer. The purities of all the products were >98-99% by gas chromatography. Some of these compounds showed melting points, viscosities, and lubricity suitable for uses as biolubricants. Various ricinoleate esters acylated at the 12 positions with short-chain acids were particularly promising.