High performance lubricants prepared from Naphthalene-1,4,5,8-Tetracarboxylic acid: Synthesis, physicochemical and Tribological properties.

Ester oils (1,4,5,8-4C n) were synthesized through esterification of naphthalene-1,4,5,8-tetracarboxylic acid with aliphatic alcohols. The molecular structures were confirmed with 1H NMR, 13C NMR, FT-IR and elemental analysis. Their KV, VI, FP, PP, oxidation and thermal stabilities, friction reducing and anti-wear performances were measured. The results demonstrate that the 1,4,5,8-4C n have obviously higher thermal and oxidation stabilities than the existing esters DOS, PIS and Phe-3C i8. They also have predominant tribological behavior at both 50 °C and 120 °C. Analyzing from the results of ECR, QCM and XPS, it could be concluded that strongly and orderly physicochemical adsorption of the 1,4,5,8-4C n molecules on the sliding surfaces is the critical factor for these oils to demonstrate excellent tribological performance for steel contacts. • Naphthoate oils were prepared and evaluated as lubricants for steel/steel contact. • The oils have high thermal and oxidation stabilities. • The oils exhibited predominant tribological property. • The predominant property owns to physiochemically adsorbed film formation. [ABSTRACT FROM AUTHOR]