Esters from castor oil functionalized with aromatic amines as a potential lubricant

Abstract

Vegetable oils are very promising alternatives to fossil lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants. However, it showed poor thermal-oxidative stability and a higher pour point. This study used castor oil fatty acids prepared by transesterification (EHRO), epoxidation (TEPO), and oxirane ring opening with the aromatic amines aniline (ANIL) and p-anisidine (ANIS). The chemical structure of these oils was verified by 1 H and 13 C NMR analysis, and mass spectrometry. Measurements show that the presence of an aromatic amine increases the viscosity resulting in 172 (ANIL) and 199 (ANIS) cSt at 40 C, but reduces viscosity index to 16 and 1, respectively. In addition, the amine groups can scavenge radicals increasing their thermal and oxidative stability. These products do not oxidize copper, and tribological analysis reveals that ANIS has the lowest torque with wear equivalent to commercial mineral lubricant NH-140. K E Y W O R D S aromatic amines, bio-based lubricant, castor oil, epoxide opening, tribological properties

Polyols from castor oil (Ricinus communis) and epoxidized soybean oil (Glycine max) for application as a lubricant base

“…Vegetable oils are highly promising alternatives to fossil‐based lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants (De Andrade et al, 2023). Castor oil is a triglyceride present at levels of 40% to 50% in the seed of the plant Ricinus communis , obtained by pressing the seeds or by solvent extraction, it is a natural and renewable resource (Santan et al, 2018).…”