Tribochemical reactions of dibenzyl and diphenyl disulphides in boundary lubrication

Plaza, S.; Comellas, L.; Starczewski, L.

doi:10.1016/s0043-1648(96)07319-x

Cited by 13 publications

(14 citation statements)

References 16 publications

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“…The rate of formation of copper sulfide is 2 times of the rate of the formation of BiBZ from equation (5). Figure 11 shows the temperature dependence of the rate of generation of copper sulfide (dot line obtained from equation (3) and dot-dash line obtained from equation (5)) and DBDS-Cu complex (solid line obtained from equation (1)).…”

Section: The Rate Of Chemical Reactionmentioning

confidence: 97%

“…8Cu+3(C 6 H 5 CH 2 ) 2 S 2 → 4Cu 2 S+ C 6 H 5 CH 2 CH 2 C 6 H 5 +2(C 6 H 5 CH 2 ) 2 S …………… (3) Furthermore, DBS formed in equation (3) react with copper. 2Cu+(C 6 H 5 CH 2 ) 2 S →Cu 2 S+ C 6 H 5 CH 2 CH 2 C 6 H 5 ………… (4) Then, equations (3) and (4) can be combined to give equation (5). 4Cu+ (C 6 H 5 CH 2 ) 2 S 2 →2Cu 2 S+ C 6 H 5 CH 2 CH 2 C 6 H 5 …… (5) The principal chemical reaction will be determined by temperature and heating time.…”

Section: The Chemical Reaction Mechanism For the Formation Of Copper mentioning

confidence: 99%

“…It is thought that solid phase extraction (SPE) or other pretreatment is the suitable choice for the isolation of DBDS from insulating oil. DBDS improved the lubricant effectiveness of mineral oil, so several researchers reported the mechanism of tribochemical reaction and the thermal decomposition of DBDS [5,6]. Dibenzyl sulfide (DBS) and several compounds have been reported as the by-products generated from the chemical reaction of DBDS with iron.…”

Section: Introductionmentioning

confidence: 99%

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Highly sensitive detection method of dibenzyl disulfide and the elucidation of the mechanism

Toyama

Tanimura

Yamada

et al. 2009

IEEE Trans. Dielect. Electr. Insul.

110

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Highly sensitive detection method of dibenzyl disulfide (DBDS) in insulation oil was realized using solid phase extraction (SPE) with active alumina adsorbent followed by gas chromatography equipped with a mass spectrometry (GC-MS). The detection limit of DBDS is around 0.1 ppm. This method is also useful for detecting bibenzyl (BiBZ) and dibenzyl sulfide (DBS). The good relationship between the weight change of copper strip and BiBZ /DBS formation was obtained under heating with insulating oil containing DBDS and copper strip, so it was clarified that BiBZ and DBS are the byproducts of the copper sulfide generation with the chemical reaction between DBDS and copper. The chemical reaction formula between DBDS and copper was proposed based on the assumption that copper sulfide should be generated via Cu-DBDS complex. The temperature dependence of the weight change of copper strip before and after the heating in the insulating oil containing DBDS was quantitatively explained with the chemical reaction formula.

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Section: The Rate Of Chemical Reactionmentioning

confidence: 97%

Section: The Chemical Reaction Mechanism For the Formation Of Copper mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Highly sensitive detection method of dibenzyl disulfide and the elucidation of the mechanism

Toyama

Tanimura

Yamada

et al. 2009

IEEE Trans. Dielect. Electr. Insul.

110

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“…Other disulfides, thiols, and their oxygenated derivates, as well as elemental sulfur, can also lead to the formation of Cu 2 S . Thermal decomposition of disulfides (including DBDS) and thiols, under high oxygen concentrations, can result in the formation of their oxidized derivates and elemental sulfur. ,− Disulfides are readily oxidized to form sulfoxides, sulfones, and carbonyl compounds, whereas thiols, which can be formed by disulfide degradation, can oxidize to form disulfides again. − Elemental sulfur, as a possible degradation product of various disulfides, and oxygenated derivates of disulfides and thiols (thiolate radicals and thiolate anions) can react with CuO generated through decomposition of copper peroxides, resulting in the formation of copper sulfide under certain conditions …”

Section: Introductionmentioning

confidence: 99%

Removal of Sulfur Compounds from Mineral Insulating Oils by Extractive Refining with N-Methyl-2-pyrrolidone

Lukić

Nikolić

Mandić

et al. 2012

Ind. Eng. Chem. Res.

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Copper sulfide deposits in the insulation systems of power transformers decrease the dielectric properties of the insulation and therefore constitute a significant risk for the operation of power transformers. Disulfides, oxidized sulfur compounds, thiols, and elemental sulfur, which could be present in insulating oil, have been recognized as the sources of reactive sulfur responsible for copper sulfide formation. Selective liquid−liquid extraction using N-methyl-2-pyrrolidone solvent was investigated for the purification of mineral insulating oils through the removal of compounds and precursors responsible for copper sulfide formation. The efficiency of the extraction process was evaluated using corrosive sulfur test IEC 62535, SEM/EDX measurements of paper before and after the IEC 62535 test, and measurements of the dibenzyl disulfide concentration in the oil using GC-ECD method. The oxidation stability of refined oils was evaluated using the IEC 61125 method. Precursors of copper sulfide deposits were completely removed from different mineral oils as a result of purification by extraction with N-methyl-2pyrrolidone and 1.0 wt % water as a cosolvent.

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“…In the last decades, considerable studies have been made to investigate the tribological properties [1][2][3] and action mechanism [4,5] of this kind of compounds as additive in lubricating oil as well as the kinetics of film growth [6] . However, limited by surface analytical technique, the chemical nature of the tribochemical films generated from this kind of compound has been little reported.…”

mentioning

confidence: 99%

XANES analysis of tribo-chemical and thermal films generating from some organic polysulfides

Zeng

Cao

et al. 2006

CHINESE SCI BULL

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X-ray absorption near edge structure (XANES) spectroscopy has been firstly used to characterize the chemical nature of tribochemical and thermal films generated from alkyl, benzyl and acylcontaining organic polysulfides. It has been found that the thermal films generated from these polysulfides are mainly composed of FeSO 4 , and alkyl disulfides also exist in the subsurface and bulk of thermal films generated from acyl-containing polysulfides. Under tribochemical conditions, the composition of film is dependent on the molecular structure of the additives. Namely, the tribochemical film generated from alkyl polysulfide is composed of alkyl disulfide in the out surface, a mixture of FeSO 4 , FeS 2 and sulfoxide in the subsurface, and FeSO 4 in the bulk; the composition of the tribochemical film for benzyl polysulfide consists of FeSO 4 in the out surface, while the composition in subsurface and bulk is the same as the alkyl polysulfide. For acyl-containing polysulfides, the tribochemical films consist of alkyl disulfide in the out surface, and FeS 2 in the subsurface and bulk.

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Tribochemical reactions of dibenzyl and diphenyl disulphides in boundary lubrication

Cited by 13 publications

References 16 publications

Highly sensitive detection method of dibenzyl disulfide and the elucidation of the mechanism

Highly sensitive detection method of dibenzyl disulfide and the elucidation of the mechanism

Removal of Sulfur Compounds from Mineral Insulating Oils by Extractive Refining with N-Methyl-2-pyrrolidone

XANES analysis of tribo-chemical and thermal films generating from some organic polysulfides

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