Synthesis And Tribological Properties Of Xanthogenate And N-containing Compounds Derivatives Lubricant Additive

The anti-wear and extreme pressure lubricating oil additives have a increasingly important role in the modern industry, for the friction and wear of machine will effect on its reliability, durability and energy utilization. With the increasingly notice on environment protection, there are new requests on the development of lubricating oil additives such as studying ash-less, multifunctional and reducing environmental pollution lubricating oil additives and ensuring no phosphor, no metal or no chlorine contained in additives. Large amounts of former research papers have proved that the N containing heterocyclic compounds and their additives are noticed due to their excellent antioxidant, corrosion-resistant, antifriction, anti-wear, good thermal stability, and less harmful to environment,and they are a well-known multifunctional lubricating oil additives to substitute ZDDP.In this paper, 30 compounds as N-S lubricating oil additives were synthesized and 26 of them were novel additives. Their preparative conditions were investigated. Moreover molecular structures of the compounds were confirmed by 1H NMR,13C NMR, IR,UV,MS and elementary analysis.Their dissolution in various solvent were studied. 21 of the derivatives start to thermally decompose above 290℃,and all the additives completely decompose above 200℃,which indicating that they may be used for formulation of conventional lubricating oils. The tribological behavior of the synthetic compounds as additives in liquid paraffin were evaluated with a four-ball machine. The results show that the compounds as additives in liquid paraffin can enormously increase the load-carrying capacity, and the maximum PB value of most of them can achieve, even exceed to ZDDP. They also can improve the anti-wear ability in liquid paraffin,among which the thiadiazole derivatives possess the best properties of the additives. We found that the length and shape of the alkyl can impact the PB value and the anti-wear performance. If the length of the aklyl between 4 to 10, they will poessess good PB value. With the longer of the alkyl, the anti-wear of the additive is better and the properties of the branched chain is better than that of the linear chain. According to the analysis of their molecular structures, it can be considered that during the sliding process, the N, S containing heterocyclic compounds decomposed or part of them decomposed, and they react with the metal surface to generate a protective film containing C and S, so it can improve the tribological performance of liquid paraffin. But the process of tribology is a complex physical and chemical programm, so we will do further research on its mechanism.