Preparation of meadowfoam dimer acids and dimer esters, and their use as lubricants

Abstract Meadowfoam dimer acids have been prepared in a thermal clay‐catalyzed reaction. Reaction conditions have been optimized, and yields of 44% were obtained with 2% water and 6–8% of an acid‐washed montmorillonite clay, based on the meadowfoam fatty acids. Purity of the distilled dimer acids was 79–89% with most of the remaining 11–22% being residual mono‐ and tribasic acids. Dimethyl, di‐(2‐ethylhexyl), and di‐n‐butyl meadowfoam dimer ester derivatives were also prepared. Color, viscosity, and wear‐preventive characteristics of the meadowfoam dimer acids and dimer ester derivatives were compared to those of commercial dimer acids and dimer esters. The viscosity of the meadowfoam dimer acids is similar to that of Empol® 1010, which is also derived from a highly monounsaturated fatty acid source. Viscosities of the meadowfoam dimer esters were also comparable to those of commercial dimer esters. Wear prevention characteristics, as determined by the four‐ball test method, of the meadowfoam dimer acids and dimer esters were similar to those of the commercial products. In one case, the di‐n‐butyl esters, the meadowfoam derivative showed a significantly smaller wear scar than that shown by the di‐n‐butyl derivative of Unidyme® 14.