Tribological study of OH- and N-containing imidazoline derivatives as additives in water–glycol

Abstract

Tribological properties of two hydroxyl- and only active nitrogen-containing water-soluble imidazoline derivatives, benzotriazole-containing imidazoline (BML) and caprylic acid-containing imidazoline (CML), as lubrication additive in water–glycol hydraulic fluid were evaluated with a four-ball tester. And the antirust and anticorrosion behaviors were also investigated. Results show that BML and CML were able to remarkably improve the antirust properties of water–glycol fluid when added at a low adding concentration, and also these performances of BML was better than CML. All additives exhibited good extreme pressure and antiwear properties, and BML showed better tribological properties than CML. Besides, the difference in the tribological and anticorrosion properties of these derivatives was closely related to their different molecular structures. There exists a synergistic tribological effect between benzotriazole and imidazoline group in the tribological and antiwear performances. Furthermore, significant improvement in the tribological performances of BML was detected and attributed to organic nitrogen compounds, iron oxide, and so on in tribofilm on the worn surfaces.

Tribochemistry of mercaptoimidazoline as an additive in emulsion between self-mated GCr15 ball interfaces and its friction-reduction mechanism

“…The nitrogen atoms with lone electron pairs in imidazoline molecules can form coordination bonds with iron atoms with their 3d orbitals, as well as form chemisorption films on metal surfaces during friction [19], and is therefore a common green lubricant additive, enhancing and improving the chemical and physical properties of lubricants. Xiong et al synthesized two water-soluble imidazoline derivatives in waterglycol hydraulic fluids, both of which exhibited good extreme pressure and anti-wear properties as well as good corrosion protection [25]. Pandey et al investigated a novel, silane-functionalized imidazoline-based ionic liquids (ILs), which reduced friction and wear by 39% and 53%, respectively, compared to base oils in blends containing 5 wt% TPEIPS BEHP [24].…”

Tribological performance of N‐containing heterocyclic triazine derivative as lubricant additive in ethylene glycol

“…1 Besides, due to their excellent tribological performance and weakly toxic, NCHCs such as triazine and imidazoline and so on were a common used green lubricant additive for improving and enhancing the lubricants' chemical and physical performances. [2][3][4][5][6][7] Especially, the ligands of 1,3 5-triazine (s-triazine) and its derivatives had three coordinating N-atoms with the bond angles of 120 , which could act as the threeconnected node and form coordination bonds, hydrogen bonds, π-π stacking and C H-π interactions. The addition of these compounds in water-glycol or rapeseed oil would effectively improve and enhance the tribological properties of the tribosystems.…”