Tribological Characteristics of Three Novel Imidazoline-Type Thiadiazole Derivatives in Colza Oil and Synthetic Diester

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Lin Shui ◽  
Yi Zhou ◽  
Guoru Zhang ◽  
Huan Chen ◽  
Yidong Zhao
Keyword(s):  
Ferrous Sulfate ◽  
Lubricant Additives ◽  
Metallic Surface ◽  
Organic Sulfide ◽  
Tribological Behaviors ◽  
Ferrous Sulfide ◽  
Thiadiazole Derivative ◽  
Thiadiazole Derivatives ◽  
Main Component ◽  
Thermal Films

Owing to the requests of exploring environment-friendly and multifunctional lubricant additives, three novel imidazoline-type thiadiazole derivatives are prepared and used as lubricant additives in two biodegradable base stocks, colza oil and synthetic diester, respectively, and their tribological performance is tested using the four-ball tester. For further understanding of their tribological behaviors, x-ray absorption near edge structure (XANES) spectroscopy is adopted to analyze the thermal films and tribofilms generated from these additives in two base stocks. Tribological tests show that all these thiadiazole derivatives are effective in reducing wear in synthetic diester, and derivative SIB (stearic acid-imidazoline-type thiadiazole derivative) is better than derivative OIB (oleic acid-imidazoline-type thiadiazole derivative) and derivative DIB (lauric acid-imidazoline-type thiadiazole derivative) in reducing friction at high additive concentrations. But these derivatives almost fail in improving the tribological characteristic of colza oil. According to XANES spectra, thermal films formed in two base stocks are mainly composed of ferrous sulfate and adsorbed organic sulfide. These derivatives are also easily oxidized into high-valent sulfate in colza oil during the rubbing process, and ferrous sulfate is the main component of these tribofilms. But in synthetic diester, tribofilms are mainly composed of ferrous sulfide, and it is notable that the tribofilm generated by derivative SIB at 1.0 wt. % is composed of ferrous sulfide and ferrous disulfide. Under extreme-pressure conditions, these derivatives easily react with the metallic surface to generate ferrous sulfide in colza oil. But in synthetic diester, adsorbed organic sulfide is the main component of those films. The base stock has a great impact on the compositions of these reaction films, so the tribological behaviors of these derivatives are different in two base stocks.

Tribological behaviors of three novel imidazoline-type thiadiazole derivatives as multifunctional lubricant additives in biodegradable lithium grease

2012 ◽  
Vol 226 (8) ◽  
pp. 668-677 ◽  
Author(s):  
Huan Chen ◽  
Jing Li ◽  
Tianhui Ren ◽  
Lei Zheng ◽  
Yidong Zhao
Keyword(s):  
Oleic Acid ◽  
Ferrous Sulfate ◽  
Extreme Pressure ◽  
Lithium Grease ◽  
Extreme Pressure Additives ◽  
Organic Sulfide ◽  
Ferrous Sulfide ◽  
Thiadiazole Derivative ◽  
Thiadiazole Derivatives ◽  
Thermal Films

Three novel imidazoline-type thiadiazole derivatives are prepared and used as antiwear and extreme-pressure additives in biodegradable lithium grease, and their tribological performances are evaluated using a four-ball tester. Tribological tests show that all derivatives are effective in reducing wear, especially at lower additive concentrations. Oleic acid-imidazoline-type thiadiazole derivative is a preferred additive to reduce wear. For the friction-reducing property of base grease, improvements after using these derivatives are not remarkable. On the other hand, these derivatives are also effective extreme-pressure additives. In order to understand the friction process further, chemical composition of tribofilms under antiwear/extreme-pressure regime is analyzed by X-ray absorption near edge structure spectroscopy, and thermal films are also considered for comparison. Thermal films formed by these imidazoline-type thiadiazole derivatives consist of adsorbed organic sulfide and ferrous sulfide. Sulfur presents several chemical valences in the antiwear regime, and tribofilms generated by stearic acid and lauric acid-imidazoline-type thiadiazole derivatives at 1.0 wt% are composed of ferrous disulfide, ferrous sulfide and ferrous sulfate. The appearance of disulfide suggests that the interfacial temperature between the upper ball and three lower balls under antiwear conditions is considerably low. Composition of extreme-pressure films generated by oleic acid and lauric acid-imidazoline-type thiadiazole derivatives is only ferrous sulfide, and the extreme-pressure film for stearic acid imidazoline-type thiadiazole derivative is a mixture of ferrous sulfide, ferrous sulfate, and adsorbed organic sulfide.

Tribological behaviors of some novel dimercaptothiadiazole derivatives containing hydroxyl as multifunctional lubricant additives in biodegradable lithium grease

2014 ◽  
Vol 66 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Huan Chen ◽  
Junhui Jiang ◽  
Tianhui Ren ◽  
Lei Zheng ◽  
Yidong Zhao
Keyword(s):  
Lubricant Additives ◽  
Short Chain ◽  
Lithium Grease ◽  
Edge Structure ◽  
Content Type ◽  
Organic Sulfide ◽  
Ferrous Sulfide ◽  
Heterocyclic Derivatives ◽  
Main Component ◽  
Thermal Films

Purpose – In order to meet the requests of exploring environmental-friendly and multifunctional lubricant additives, some novel dimercaptothiadiazole derivatives containing hydroxyl are prepared and used as antiwear (AW) and extreme-pressure (EP) additives in biodegradable lithium grease. The paper aims to discuss these issues. Design/methodology/approach – The tribological performances of the grease samples containing these derivatives are evaluated by using a four-ball tester. X-ray absorption near edge structure (XANES) spectroscopy is used to analyze the chemistry of tribofilms under AW/EP regime, and thermal films are also considered for comparison. Findings – The tribological tests show that these derivatives are all effective in reducing wear, especially at lower additive concentrations, but they are basically failed in reducing friction. They are also helpful in improving the EP characteristic of the base grease. The thermal films generated by these derivatives are composed of adsorbed organic sulfide and ferrous sulfate, though for short-chain derivatives, organic sulfide is the only component at 5.0 wt.%. Ferrous sulfide is the main component of the tribofilms formed by these derivatives at various additive concentrations. But for short-chain derivatives, these tribofilms consist of ferrous sulfide and ferrous disulfide at 5.0 wt.%, and the appearance of disulfide suggests that the interfacial temperature between the upper ball and three lower balls under these conditions is considerably low. The EP films generated by short-chain derivatives are all composed of organic sulfide and ferrous sulfide, while for long-chain derivatives, ferrous sulfide is the main component. Originality/value – These low-toxic and oil-soluble dimercaptothiadiazole derivatives are effective in improving the tribological characteristic of the biodegradable lithium grease, and these heterocyclic derivatives may be good substitutes for some harmful traditional additives.

scholarly journals Structural Features of 1,3,4-Thiadiazole-Derived Ligands and Their Zn(II) and Cu(II) Complexes Which Demonstrate Synergistic Antibacterial Effects with Kanamycin

2020 ◽  
Vol 21 (16) ◽  
pp. 5735 ◽  
Author(s):  
Dariusz Karcz ◽  
Arkadiusz Matwijczuk ◽  
Daniel Kamiński ◽  
Bernadette Creaven ◽  
Ewa Ciszkowicz ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Metal Ion ◽  
Hydroxyl Group ◽  
Moderate Activity ◽  
Spectroscopic Techniques ◽  
Concomitant Treatment ◽  
Bacterial Strains ◽  
Thiadiazole Derivative ◽  
Metal Ratio ◽  
Thiadiazole Derivatives

Classical synthetic protocols were applied for the isolation of three novel 1,3,4-thiadiazole derivatives which were then complexed with the biologically important Cu(II) and Zn(II) ions. All free ligands and their corresponding complexes were characterized using a number of spectroscopic techniques including Ultraviolet-visible (UV–vis), Fluorescence, Infrared (FT-IR), tandem liquid chromatography-mass (LC-MS), X-ray diffraction (XRD), and Nuclear Magnetic Resonance (NMR) spectroscopy (1H, 13C, HSQC, HMBC). The results obtained are consistent with the formation of dihydrate complexes, in which the chelation of the metal ion occurs via one of the thiadiazole nitrogen atoms and the deprotonated hydroxyl group of the neighboring resorcynyl moiety. The Zn(II) complexes utilize a 1:1 ligand–metal ratio, while in the Cu(II) complexes the ligand–metal ratio is 2:1. Although the antibacterial testing identified moderate activity of the compounds against the tested bacterial strains and additionally modest antioxidant activity, a strong synergistic antibacterial effect against Staphylococcus aureus, using concomitant treatment of thiadiazole derivatives with the commercial antibiotic kanamycin, was observed. The most active thiadiazole derivative demonstrated a minimal inhibitory concentration (MIC) of 500 μg/mL while it was 125 μg/mL in the presence of kanamycin. Moreover, in the presence of few thiadiazole derivatives the MIC value of kanamycin decreased from 0.39 μg/mL to 0.5 μg/mL. The antioxidant activity (IC50) of the most active thiadiazole derivative was determined as 0.13 mM which was nearly three-fold lower compared to that of TROLOX (0.5 mM).

Synthesis and Mesomorphic Property of 2,5-Aryl-1,3,4-Oxadiazole/Thiadiazole Derivatives Bearing a Terminal Thiophene Unit

2010 ◽  
Vol 428-429 ◽  
pp. 52-56 ◽  
Author(s):  
Jie Han ◽  
Feng Yan Zhang ◽  
Juan Yu Wang
Keyword(s):  
Heterocyclic Compounds ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
Rigid Core ◽  
Good Thermal Stability ◽  
Smectic C ◽  
Thiadiazole Derivative ◽  
Thiadiazole Derivatives ◽  
Mesomorphic Property

The synthesis and characterization of a series of heterocyclic compounds 2a-2d based on 1,3,4-oxadiazole/ thiadiazole, furan and thiophene units are reported. The thermal behaviors of these compounds were investigated by means of differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analysis (TGA). The 1,3,4-thiadiazole derivative 2b exhibited enantiotropic smectic C and A mesophases with wide temperature range and good thermal stability, while all of the other compounds did not show liquid crystalline behaviors. The results indicate that 1,3,4-thiadiazole-based compounds are more beneficial to form stable mesophases than the corresponding 1,3,4-oxadiazole analogues, and the compounds with a central furan unit as the rigid core may result in the loss of the meosgenic behaviors due to the non-linear molecular structure.

A study of 2,5-dimercapto-1,3,4-thiadiazole derivatives as multifunctional additives in water-based hydraulic fluid

2014 ◽  
Vol 66 (3) ◽  
pp. 402-410 ◽  
Author(s):  
Junming Wang ◽  
Jianhua Wang ◽  
Chunsheng Li ◽  
Gaiqing Zhao ◽  
Xiaobo Wang
Keyword(s):  
Water Soluble ◽  
Lubricant Additives ◽  
Test Machine ◽  
Hydraulic Fluid ◽  
Copper Strip ◽  
Content Type ◽  
Multifunctional Additives ◽  
Thiadiazole Derivatives ◽  
Friction Reducing ◽  
Base Liquid

Purpose – The purpose of this paper is to present the tribological, anticorrosion and antirust properties of three 2,5-dimercapto-1,3,4-thiadiazole (DMTD) derivatives as water-soluble additives in water–glycol hydraulic fluid. Design/methodology/approach – DMTD derivatives possessing excellent corrosion inhibiting and extreme-pressure (EP) properties have long been used as metal passivators and load-carrying additives in lubricating oils and grease. However, there are seldom literatures about DMTD derivatives as water-soluble lubricant additives as yet. In this work, three DMTD derivatives were synthesized and investigated as water-soluble additives in the water–glycol hydraulic fluid. Their tribological properties were evaluated in detail by four-ball wear test machine and Optimol SRV-IV oscillating friction and wear tester. Meanwhile, their anticorrosion and antirust properties were also investigated by copper strip corrosive tests and antirust tests, respectively. The worn surfaces were analyzed by scanning electron microscope and X-ray photonelectron spectroscope, and the EP, antiwear and friction-reducing mechanisms were primarily proposed. Findings – The synthesized three DMTD derivatives (coded as A, B and C) have excellent solubility in the base liquid of the water–glycol hydraulic fluid. The experimental results demonstrated that all these compounds, especially A, could remarkably improve the EP, antiwear and friction-reducing properties of the base liquid. Furthermore, they all have perfect copper corrosion inhibiting and antirust properties with low adding concentration (< 3 weight per cent) in the base liquid and hence could be used as multifunctional additives in the water–glycol hydraulic fluid. Research limitations/implications – This research only focused on the synthesized DMTD derivatives. If possible, some other thiadiazole derivatives also should be investigated. Practical implications – The synthesized DMTD derivatives, especially compound A, can be used as multifunctional water-soluble additives in the water–glycol hydraulic fluid. Originality/value – In this paper, three DMTD derivatives were synthesized and their tribological behaviors as water-soluble lubricant additives were investigated for the first time. In addition, the EP, antiwear and friction-reducing mechanisms were also put forward.

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