Phosphonates from Lipids—Synthesis and Tribological Evaluation
There is a push toward using biobased lubricants due to their lower ecological impact. Unfortunately, despite some favorable properties, lipids have drawbacks, most notably oxidative stability and cold-flow properties, that hamper their use as high-quality lubricants. To overcome the drawbacks, researchers seek appropriate chemical modifications. In this chapter, we discuss hydrophosphonylation of lipids for obtaining better biobased lubricant – reaction chemistry, analysis, and tribological properties of the product. The synthesized lipid phosphonates, especially from di-n-butyl phosphite, have better oxidative stability, good cold flow properties, low compressibility (high bulk modulus), and low traction. While the viscosity index is worsened (lowered), it is still acceptable. The phosphonates also showed good wear reduction in a four-ball tester, when used as additive. These properties indicate that phosphonates from lipids have potential as biobased lubricants, and especially as hydraulic fluids.