Two fatty acid anion-based ionic liquids - part I: Physicochemical properties and tribological behavior as neat lubricants

Abstract

Two new ionic liquids ([N 6,6,6,6 ][C 8:0 ] and [N 6,6,6,6 ][C 16:0 ]) synthetized from fatty acids through a salt metathesis reaction were both characterized from a physicochemical and tribological point of view. Density, viscosity, corrosion activity and thermal stability tests were performed before making tribological tests under ball-on-disc both unidirectional (with fixed and variable slide-to-roll ratio) and reciprocating configuration. The main results of this work were the following: the longer the length of the alkyl chain of the anion the lower both viscosity and density and higher both viscosity index and thermal stability; these ionic liquids (ILs) are not corrosive; the [N 6,6,6,6 ][C 16:0 ] behaved better changing from elastohydrodynamic to mixed lubrication regime at lower speeds; their antiwear behavior at high load seems depend on their viscosity (for tests made at room temperature) and thermal stability and IL-surface interaction (for tests made at high temperature).

Two fatty acid anion-based ionic liquids - part II: Effectiveness as an additive to a polyol ester

“…These properties were measured in the first part of this research [83], exhibiting the same behavior that other FAILs employed in previous research [84][85][86][87]. In addition, Table 1 shows density and viscosity values at reference temperatures (additional data can be found as Supplementary Information) of the blends resulting of mixing the FAILs at 0.5 and 2% in POE.…”

“…Besides, 1 H and 13 C nuclear magnetic resonance (NMR) and FTIR spectroscopy were executed to ascertain the chemical structure. The synthesis/identification procedure of these FAILs were described extensively in the first part of this research, as well as their density and viscosity data [83].…”

“…Two novel FAILs (tetrahexylammonium octanoate, [N 6,6,6,6 ][C 8:0 ], and tetrahexylammonium palmitate, [N 6,6,6,6 ][C 16:0 ]) were studied as neat lubricant in the first part of this work [83]. Now, this paper addresses the use of them as an additive to a polyol ester with the goal of assessing their tribological performance.…”

pH-Responsive Nanostructures Based on Surface Active Fatty Acid-Protic Ionic Liquids for Imiquimod Delivery in Skin Cancer Topical Therapy

“…Ionic liquids (ILs) are organic salts with melting points below 100 °C which are endowed with unique physico-chemical properties such as low flammability, negligible vapor pressure, high thermal and chemical stability, and wide electrochemical window [ 24 , 25 , 26 , 27 , 28 ]. By careful selection of the constituting ions, the features of interest of an IL can be tailored to a given application.…”

Application of Ionic Liquids for Chemical Demulsification: A Review

“…They are made of natural-derived compounds, and their physical properties can be changed by manipulating their anion alkyl chain length. Longer anion alkyl chain length of fatty acid ionic liquids results in lower viscosity, density, water solubility (C 18 -stearate ionic liquid are not soluble in water), and corrosiveness as well as higher thermal stability [ 132 , 133 , 134 ]. Investigations indicated that the presence of hydroxyl group in the imidazolium cation part of fatty acid ionic liquids increased their thermal stability [ 132 ].…”