Synthesis and Characterization of New Derivatives of Trithiocarbonic Acids as Additives for Lubricating Oils

The development of effective lubricant additives is essential for reducing friction and wear under demanding operating conditions. In this study, a series of sulphur-rich trithiocarbonate derivatives containing hydroxyl, ether, and chlorine functionalities was synthesized using epichlorohydrin-derived intermediates. The structures of the synthesized compounds were characterized by IR, 1H NMR and 13C NMR spectroscopy. Their tribological performance was evaluated in MC-20 transmission oil using a four-ball friction tester. The results revealed differences in lubrication performance depending on the functional groups present in the molecular structure. The hydroxyl- derivative exhibited the highest effectiveness, followed by the allyloxymethoxy- and butoxymethoxy derivatives. The improved performance of the hydroxyl containing compound may be attributed to stronger interactions with the metal surface, which can promote additive adsorption and protective boundary-film formation. The findings suggest that functional group composition plays an important role in governing the tribological behaviour of trithiocarbonate-based additives.