Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Mangolini, Filippo; Rossi, Antonella; Spencer, Nicholas D.

doi:10.1007/s11249-009-9429-3

Cited by 32 publications

(75 citation statements)

References 46 publications

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“…As already demonstrated in our previous works [59,60] and as extensively reported in the literature [61], hydrocarbons, such as PAO, are susceptible to thermo-oxidative aging, which leads to the production of oxygenated compounds, such as carboxylic acids. The detection of an absorption band, which could be assigned to the carbonyl stretching vibration, in the ATR/ FT-IR spectra acquired upon sliding for more than 3 h and in the transmission FT-IR spectrum of the oil solution used for running the tribotests (analysis performed at the end of the tribological experiment.…”

Section: Correlation Of the Friction Results With The Atr/ft-ir Spectsupporting

confidence: 68%

In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry: A Powerful Tool for Investigating Tribochemistry at the Lubricant–Substrate Interface

2011

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To investigate the chemical changes occurring at metal/lubricant interfaces under tribological conditions in the boundary-lubrication regime, an in situ system for conducting quantitative tribological measurements has been constructed by combining an attenuated total reflection Fourier-transform infrared (ATR/FT-IR) spectrometer with a reciprocating tribometer. By periodically acquiring ATR/FT-IR spectra during sliding, spectroscopic changes due to thermal and/or tribochemical reactions occurring at the metal/oil interface can be monitored and correlated with friction measurements. The usefulness of this tribological test system has been demonstrated by performing ATR tribological experiments in the presence of a poly-α-olefin base oil at high temperature (423 K) on iron-coated germanium ATR crystals

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Section: Correlation Of the Friction Results With The Atr/ft-ir Spectsupporting

confidence: 68%

In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry: A Powerful Tool for Investigating Tribochemistry at the Lubricant–Substrate Interface

2011

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“…A comparison with the results presented in our previous work and obtained using the unsubstituted molecule (i.e. TPPT) [21,24] has also been performed.…”

Section: Introductionmentioning

confidence: 87%

“…Both the 1-H and 13-C NMR spectra of b-TPPT showed the characteristic signals of benzene in TPPT (not substituted with any alkyl chain) [21,43,44]: in the 1-H spectrum two doublets were found at 7.40 and 7.28 ppm, whereas in the 13-C spectrum four signals were detected at 150.9 (A), 129.9 (C), 125.7 (D) and 121.3 (B) ppm. The partial substitution of the phenyl rings in TPPT with a t-butyl group resulted in the presence, in the 1-H spectrum, of a doublet at 7.19 ppm, assigned to protons in substituted benzene [43], and of a singlet at 1.35 ppm, which is characteristic of methyl protons in t-butyl [45].…”

Section: Nuclear Magnetic Resonance (Nmr) Spectroscopymentioning

confidence: 99%

“…For this reason, the reactivity of triphenyl phosphorothionate (TPPT) in synthetic oil (poly-a-olefin, PAO) at 423 and 473 K has been recently investigated in our group by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy [21]. The FT-IR and NMR results showed that this molecule possesses high thermal stability in lubricant oil solution.…”

Section: Introductionmentioning

confidence: 99%

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Substituent Effect on the Reactivity of Alkylated Triphenyl Phosphorothionates in Oil Solution in the Presence of Iron Particles

2010

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The effect of the substituent attached to the phenyl rings on the reactivity of alkylated triphenyl phosphorothionates (t-butyl TPPT (b-TPPT) and p-nonyl TPPT (n-TPPT)) in oil solution at high temperature (423 and 473 K) was investigated by means of Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The FT-IR and NMR results show that the alkylated TPPTs were highly thermally stable and did not completely decompose in oil, even upon heating at 423 K for 168 h and at 473 K for 72 h, with and without steel filings and iron particles (both metallic iron and iron oxide particles). The reaction of alkylated TPPTs was found to start with the scission of the P=S bond to yield alkylated triphenyl phosphate. The kinetics of the thermooxidative reaction was slower when steel filings and iron particles were added to the oil solutions during the heating experiments. The reactivity of the unsubstituted molecule (TPPT) was higher than that of alkylated TPPTs at 423 K, while at 473 K TPPT and n-TPPT were more reactive than b-TPPT. In the case of the experiments performed at 473 K in the presence of steel filings or metallic iron or iron oxide particles, the reactivity of the alkylated TPPT molecules decreased with the length of the alkyl chain bound to the phenyl rings. The XPS results show that a reaction layer consisting of carbon, oxygen, phosphorus and iron was formed on the 100Cr6 steel filings immersed for 72 h in oil solutions containing alkylated TPPTs and heated at 473 K. Sulphur was neither detected on the surface nor in the composition vs depth profile. During the heating experiments, the base oil (PAO) was oxidized. At 423 K, the alkylated TPPTs had a strong antioxidant effect, which was found to be more pronounced upon increasing the length of the alkyl chain bound to the phenyl rings. At 473 K, the TPPTs did not inhibit the oxidation of the base oil as effectively as at 423 K.Keywords Thermo-oxidative degradation Á t-butyl triphenyl phosphorothionate (b-TPPT) Á Irgalube Ò 232 Á p-nonyl triphenyl phosphorothionate (n-TPPT) Á Irgalube Ò 211 Á Ashless anti-wear additives Á Low-SAPS additives Á FT-IR Á NMR Á XPS Á Iron particles 1 Introduction

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“…According to Giinther et al (1997), organic sulphur compounds can act as secondary antioxidants, decomposing peroxides radicals formed during the oxidation process. Recently, Mangolini et al (2009) proposed that, under elevated temperatures, a scission of the P=S bond occurs to give triphenyl phosphite, followed by a thermo-oxidative reaction that leads to oxidation to triphenyl phosphate (Scheme 2). Scheme 2: Proposed reactions of compound 5 under elevated temperatures.…”

Section: Oxidative Stability Analysesmentioning

confidence: 99%

Antiwear and antioxidant studies of cardanol phosphate ester additives

Mazzetto

Oliveira

Lomonaco

et al. 2012

Braz. J. Chem. Eng.

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-In the search for new applications and products derived from Cashew Nut Shell Liquid (CNSL), we report herein the synthesis and characterization (GC/MS and 1 H, 13 C, and 31 P NMR) of four phosphate esters derived from hydrogenated cardanol, including their applications as antiwear additives for diesel (S500) and as antioxidant additives for mineral oils, evaluated through the HFRR test and oxidative stability analyses, respectively. The results obtained showed very good to excellent performances promoted by the bioadditives evaluated, especially for the thiophosphorylated derivative, which notably reduced the sludge residue and the acidity index of the oxidized oil (0.52 mg NaOH/g sample) and also improved the diesel lubricity, reducing the wear of metal parts by more than 50% (330 μm).

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Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Cited by 32 publications

References 46 publications

In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry: A Powerful Tool for Investigating Tribochemistry at the Lubricant–Substrate Interface

In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry: A Powerful Tool for Investigating Tribochemistry at the Lubricant–Substrate Interface

Substituent Effect on the Reactivity of Alkylated Triphenyl Phosphorothionates in Oil Solution in the Presence of Iron Particles

Antiwear and antioxidant studies of cardanol phosphate ester additives

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