Multifunctional lubricant additives derived from natural amino acids and methyl oleate

Abstract

Novel multifunctional additives were synthesized from methyl oleate via thioglycolic acid addition followed by condensation with different amino acid methyl esters. Seven additives were synthesized and the structures of all the additives were fully characterized by mass, IR and NMR spectral studies. The tribological properties were evaluated using laboratory tribotests in biolubricant base oil, which suggest that all the prepared compounds act as antiwear and extreme pressure additives. Among the synthesized additives, heterocyclic containing compounds exhibited superior performance compared to others. Antioxidant properties evaluated using differential scanning calorimetry reveal that all the additives improved the oxidation stability of base oil with heterocyclic based additives exhibiting better performance compared to commercial antioxidant BHT. The synthesized amino acid-based derivatives have potential as biodegradable multifunctional additives in biolubricant formulations.