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Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Mangolini, Filippo ; Rossi, Antonella ; Spencer, Nicholas

In: Tribology Letters, 2009, vol. 35, no. 1, p. 31-43

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    Title
    • Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution
    Author
    • Mangolini, Filippo. Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, HCI H 523, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland
    • Rossi, Antonella. Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, HCI H 523, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland
    • Spencer, Nicholas. Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, HCI H 523, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Tribology Letters, 2009, vol. 35, no. 1, p. 31-43. Springer US; http://www.springer-ny.com
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:319049
    Summary
    Investigating the thermo-oxidative reactivity of anti-wear additives in lubricant oil solution at high temperature can significantly contribute to an understanding of the mechanism of thermal film and tribofilm formation on metal surfaces. In this study, the reactivity of triphenyl phosphorothionate (TPPT) in lubricant oil solution at high temperature (423 and 473K) has been studied by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The results show that the TPPT molecule was highly thermally stable and did not completely decompose in oil solution even upon heating at 423K for 168h and at 473K for 72h. The degradation of the TPPT molecule, which turned out to be a first-order reaction, started taking place after 6h at both temperatures, leading to the breakage of the P=S bond with the formation of triphenyl phosphate. During these heating experiments, no oil-insoluble compounds were detected. The oxidation of the base oil as a result of the prolonged heating demonstrated that the TPPT molecule did not effectively act as oxidation inhibitor