ABSTRACT
Estolides are a family of chemical compounds most simply defined as oligomers of fatty acids. Estolides have been evaluated for use in metalworking fluids, greases, gear oils, stern tube oils, compressor oils, drilling fluids, hydraulic fluids, dielectric fluids, heat transfer fluids, and even as rubber additives and plasticizers. Due to their environmental profiles, lubricant performance, and synthetic flexibility, estolides are rapidly gaining traction as an alternative to conventional, petroleum-derived, lubricant base oils. Depending on the chemistry of the fatty acid reagents, there are two primary mechanisms by which estolides can be produced. The first type of estolide reaction, referred to as the olefin addition reaction, occurs when oligomerization proceeds by the addition of the carboxylic acid to the site of unsaturation on another fatty acid. The second type of estolide reaction, referred to as the hydroxy addition reaction, occurs when hydroxy fatty acids are used as raw materials.
