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Ren, Daxing; Gellman, Andrew J.

doi:10.1023/a:1019184312290

Cited by 25 publications

(7 citation statements)

References 12 publications

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“…The reaction between TBT and iron was proposed to occur via an initial P=S bond scission to give tributyl phosphite. In accordance with [3,8,11,[17][18][19], this compound successively produced butoxy groups through P-O bond cleavage.…”

Section: Introductionmentioning

confidence: 67%

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Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

2009

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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 473 K) 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 423 K for 168 h and at 473 K for 72 h. The degradation of the TPPT molecule, which turned out to be a first-order reaction, started taking place after 6 h 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.

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Section: Introductionmentioning

confidence: 67%

“…metal-free) additives, such as organosulfur compounds [6], phosphates [6][7][8][9][10][11][12][13][14][15][16], amine phosphates [12], phosphites [11,[17][18][19], phosphorothionates [12][13][14][20][21][22][23][24][25][26], and dithiophosphates [12,21,22,24].…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

2009

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“…In addition, since the applied loads are higher under the EP conditions at which such high temperatures are attained, significant surface wear will also remove the oxide layer. Under these conditions, the chemistry found on the clean metal surface more appropriately models EP lubrication [22,23]. In this case, both 1-butene and CO formation are found for tributyl phosphate on clean iron.…”

Section: Discussionmentioning

confidence: 84%

“…The chemistry of tributyl phosphate has been investigated previously on clean iron surfaces in ultrahigh vacuum [22,23]. It was proposed that the surface reaction could be initiated either by cleavage of the PAO bond to yield a surface alkoxy species or alternatively by the cleavage of the CAO bond to yield a surface alkyl group.…”

Section: Introductionmentioning

confidence: 99%

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

et al. 2005

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The chemistry of tributyl phosphate on Fe 3 O 4 was studied in ultrahigh vacuum using temperature-programmed desorption (TPD) and Auger spectroscopy. A portion of the tributyl phosphate desorbs intact with an activation energy of $120 kJ/mol. The remainder decomposes either by PAO bond scission to deposit surface butoxy species or appears to dehydrogenate desorbing C 2 or C 3 compounds and depositing hydrogen and carbon on the surface. The resulting hydrogen reacts either with the oxide to desorb water or with butoxy species yielding 1-butanol. The remaining butoxy species are stable up to $600 K where they decompose to desorb butanal via hydride elimination where again the hydrogen reacts with butoxy species to form 1-butanol or with the oxide to form water. The carbon deposited onto the surface further reduces the oxide to desorb as CO above $750 K, although a small amount of carbon is detected on the surface using Auger spectroscopy. Substantially larger amounts of carbon are deposited onto the surface when Fe 3 O 4 is exposed to tributyl phosphate at 300 K, where an Auger depth profile reveals that the carbon is located at the surface while the PO x species formed by tributyl phosphate decomposition diffuse rapidly into the oxide layer, leading to a film structure in which graphitic carbon is deposited onto a phosphorus-containing oxide layer.

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“…Phosphite compounds are widely used in engine oils, especially for gearbox components as extreme pressure (EP), anti-wear (AW) and friction modier (FM) additives. Nevertheless, few studies have been dedicated to phosphites [1][2][3][4][5][6][7] and little is known of the mechanisms by which these compounds decompose and modify the chemical composition of the metal surface, and consequently reduce friction. Among all types of phosphite additives, trimethyl-phosphite, (CH 3 O) 3 P, is probably the simplest compound containing alkoxy groups, thus it has been chosen as a model to provide a basic understanding of how these molecules interact with the iron surface.…”

Section: Introductionmentioning

confidence: 99%

Trimethyl-phosphite dissociative adsorption on iron by combined first-principle calculations and XPS experiments

et al. 2015

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The reaction of trimethyl-phosphite, TMPi, with a clean Fe(110) surface has been investigated by ab initio calculations. The most stable configurations and energies are identified for both molecular and dissociative adsorption. The calculated reaction energies indicate that dissociation is energetically more favorable than molecular adsorption and we provide a description of the dissociation path and the associated energy barrier. In situ XPS analysis of adsorbed TMPi on metallic iron confirmed molecular chemisorption and dissociation at high temperature. These results shed light on the mechanism of phosphorus release from organophosphites at the iron surface, which is important for the functionality of these phosphorus-based additives, included in lubricants for automotive applications

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Cited by 25 publications

References 12 publications

Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Reactivity of Triphenyl Phosphorothionate in Lubricant Oil Solution

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

Trimethyl-phosphite dissociative adsorption on iron by combined first-principle calculations and XPS experiments

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