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

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

doi:10.1007/s11249-010-9659-4

Cited by 10 publications

(9 citation statements)

References 42 publications

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“…Various types of extreme-pressure anti-wear molecules have been developed. Well-known examples include an organic-inorganic compound of zinc dialkyldithiophosphate (ZDDP), [6][7][8][9] organic sulfur compound of triphenyl phosphorothionate (TPPT), [10][11][12] and organic phosphorus compound of tricresyl phosphate (TCP). [13][14][15][16][17] Among various kinds of ZDDP, the one containing a branched structure of a secondary alkyl group has superior anti-wear capability owing to its steric hindrance.…”

Section: Introductionmentioning

confidence: 99%

Pressure‐assisted decomposition of tricresyl phosphate on amorphous FeO using hybrid quantum‐classical simulations

et al. 2022

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The moving components of combustion engines are operated under harsh conditions of high pressures and temperatures. Extreme‐pressure anti‐wear additives, such as tricresyl phosphate (TCP), are mixed with base oil to prevent wear through the formation of a lubricant film on the substrate. We studied the effect of liquid pressure on the decomposition pathway of TCP in base oil molecules (2,5‐dimethylhexane) using hybrid quantum‐classical simulations with density functional theory for electrons. At a temperature of 300 K, we found that: (i) bond‐breaking barrier energies of both the OC and PO bonds of TCP decrease monotonically as the liquid pressure increases; (ii) the bond‐breaking barrier energy of PO is lower than that of OC at pressures of 0 and 2.0 GPa, but is higher at a pressure of 5.0 GPa; and (iii) the applied pressure significantly lowers the bond‐breaking barrier energies of both OC and PO when the PO bond of TCP is directed upward from the substrate. These findings are explained by the inhomogeneous distribution of base oil molecules around TCP and the steric repulsion of the PO bond of TCP. These results indicate that the internal structures of the lubricant films are pressure‐dependent.

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Section: Introductionmentioning

confidence: 99%

Pressure‐assisted decomposition of tricresyl phosphate on amorphous FeO using hybrid quantum‐classical simulations

et al. 2022

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“…The chemical reactivity of alkylated phosphorothionates (triphenyl phosphorothionates (TPPTs) substituted with alkyl chains of different lengths) in synthetic oil at high temperature (423 and 473 K) was recently investigated in our group by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. − The unsubstituted molecule (TPPT) exhibited a high thermal stability in lubricant oil solution . Upon heating at 423 and 473 K for more than 6 h, the thermo-oxidative degradation of TPPT resulted in the scission of the PS to give triphenyl phosphate (TPP).…”

Section: Introductionmentioning

confidence: 99%

Tribochemistry of Triphenyl Phosphorothionate (TPPT) by In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry

2012

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The surface reactivity of triphenyl phosphorothionate (TPPT) on air-oxidized iron surfaces under tribological conditions in the boundary-lubrication regime has been investigated by in situ attenuated total reflection (ATR) FT-IR tribometry and ex situ X-ray photoelectron spectroscopy (XPS). In situ ATR/FT-IR tribometry allowed the measurement of the friction force during the tribological tests and its correlation with ATR/FT-IR results, providing an insight into the chemical reactions taking place at the buried interface. The TPPT molecule, which did not behave as a friction-modifier additive, reacted at the air-oxidized iron surface upon tribotesting at 423 K to give pyrophosphate, organo-phosphate, and sulfate species. The oxygenated compounds produced by the oxidation of the base oil (poly-α-olefin, PAO) during the tribological tests, adsorbed onto the iron surface and reacted with it to form carbonates and carboxylates. During the tribotests, the iron coating was worn away and corroded by the aggressive species formed during the thermo-oxidative aging of PAO. This resulted in the availability of iron cations necessary for the production of orthophosphate compounds. The ATR/FT-IR results also suggested that the rate of tribofilm formation was lower than that of tribofilm removal. The ex situ XPS analysis corroborated the formation of short-chain iron polyphosphates, organo-phosphates, and iron sulfates, together with carbonates and carboxylates. Long-chain polyphosphates and sulfoxides were also generated in the boundary lubricant layers formed by TPPT at 423 K. The composition of the tribofilms formed by TPPT was found to differ significantly from that of the boundary layers generated by ZnDTP

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“…Oil oxidation is defined as “the chemical reaction of an oil molecule with oxygen, which is present from either the ambient or entrained air” (Machinery Lubrication, n.d.c). The chemical reaction with oxygen leads to the creation of alcohols, hydroperoxides, ketones, aldehydes, carboxylic acids, esters and lactones (Mangolini et al , 2010). Among these chemical reactions, carboxylic acids represent the compound with the potential for the greatest damage.…”

Section: Literature Review On Construction Equipment Oil Degradationmentioning

confidence: 99%

Engine oil degradation analysis of construction equipment in Latin America

Azevedo¹,

Olsen

2019

JQME

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Purpose The purpose of this paper is to determine and describe the effect of oil degradation on the engine of a 20-ton class excavator operating in Latin America. Design/methodology/approach The research parameters include: a specific engine class and equipment, the John Deere PowerTech Plus 6068 Tier 3 diesel engine that powers the 20-ton class excavator; identical OSA3 oil analysis laboratory equipment in 11 target countries in Latin America was employed to analyze oil samples; and the same sampling scope and method were followed for each oil sample. Findings The research results indicated that at 500 h of use, 73.4 percent of the oil sample results indicated that soot accumulation was a significant problem. When associating the engine oil contamination with the environment risk drivers: altitude and diesel quality have the greatest impact on iron readings; bio-diesel impacts copper; and precipitation and poor diesel quality are associated with silicon levels. Practical implications Due to diverse machine operating conditions, research offers an accurate global representation. Because there is an exponential count of particles as oil use approaches 250 h, the interval of engine maintenance (oil change) for machinery operating under similar conditions should not exceed 250 h of use. Originality/value The main contribution of this paper will help machinery final users and manufacturers to implement mitigation strategies to improve engine durability in countries with similar operating conditions.

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

Cited by 10 publications

References 42 publications

Pressure‐assisted decomposition of tricresyl phosphate on amorphous FeO using hybrid quantum‐classical simulations

Pressure‐assisted decomposition of tricresyl phosphate on amorphous FeO using hybrid quantum‐classical simulations

Tribochemistry of Triphenyl Phosphorothionate (TPPT) by In Situ Attenuated Total Reflection (ATR/FT-IR) Tribometry

Engine oil degradation analysis of construction equipment in Latin America

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