Ionic Liquid Trihexyltetradecylphosphonium Bis Research Articles

Tribological evaluation of rice bran oil based ionanolubricants containing ionic liquids and nanoparticles

ABSTRACT Environmental concerns and depleting mineral oil resources have forced us to develop environmentally acceptable lubricants. In this study, tribological properties of rice bran oil containing imidazolium-based ionic liquid 1- ethyl 3methylimidazolium dicyanamide ([EMIM][DCN]) (ILa), phosphonium based ionic liquid Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ([P66614][BTMPP]) (ILb) and titanium oxide (TiO2) nanoparticles (NPs) as hybrid additives have been investigated using four ball tester. Rice bran oil based ionanolubricants (INLs) were formulated with different concentrations of ILa, ILb and TiO2 NPs. Among all investigated ionanolubricant samples, rice bran oil containing 0.03 of TiO2 NPs and 0.5 vol.% of ILa showed the lowest AWSD. The improved characteristics of rice bran oil based INLs can be attributed to the ball bearing effect and tribofilm formation.

Evaluation of tribological properties of vegetable oil–based ionanolubricants: An experimental study

Growing environment concern has forced us for the development of environmentally acceptable lubricants. In this study, tribological properties of sesame oil and castor oil containing imidazolium-based ionic liquid 1-ethyl 3methylimidazolium dicyanamide ([EMIM][DCN]) (IL1), phosphonium-based ionic liquid Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ([P66614][BTMPP]) (IL2) and titanium oxide (TiO2) nanoparticles (NPs) as hybrid additives have been investigated using four-ball tester with ASTM D4172B. Three different concentrations of IL1, IL2 and TiO2 NPs were selected for the formulation of vegetable oil–based ionanolubricants. It was found that castor oil with the addition of 0.03[Formula: see text] of TiO2 NPs and 1.3 vol.% of IL1 shows the lowest specific wear rate amongst all investigated lubricant samples. It is evident from field emission scanning electron microscopy analysis of worn-out surfaces of steel balls that a combination of ball bearing effect and tribofilm formation is responsible for the improved tribological characteristics.

Desulfurization of diesel via joint adsorption and extraction using a porous liquid derived from ZIF-8 and a phosphonium-type ionic liquid.

A type-III porous liquid based on zeolitic imidazolate framework-8 (ZIF-8) and an ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([THTDP][BTI]) was synthesized and used for the desulfurization of model diesel. The desulfurization effect by ZIF-8/[THTDP][BTI] combined both the adsorptive desulfurization by ZIF-8 and the extraction desulfurization by [THTDP][BTI]. The removal of the three chosen aromatic organic sulfides by the ZIF-8/[THTDP][BTI] porous liquid followed the order of dibenzothiophene (73.1%) > benzothiophene (70.0%) > thiophene (61.5%). It was further found that deep desulfurization could be realized by ZIF-8/[THTDP][BTI] through triple desulfurization cycles and ZIF-8/[THTDP][BTI] can be regenerated readily. The desulfurization mechanism was explored further in detail by conformation search and density functional theory calculations. Calculations supported that the large molecular volume of [THTDP][BTI] excluded itself from the cavities of ZIF-8, making the pores of ZIF-8 in the porous liquid unoccupied and accessible by other guest species, here the studied organic sulfides. These calculations indicate that the van der Waals interactions were the main interactions between ZIF-8/[THTDP][BTI] and specifically benzothiophene. This work supports that the porous liquid ZIF-8/[THTDP][BTI] could potentially be used for desulfurization of diesel in industry.

Mixtures of octanol and an ionic liquid: Structure and transport

Ionic liquids (ILs) with long alkyl substituents are amphiphilic, which leads to a bicontinuous liquid structure. The strongly interacting anionic and cationic head groups form a long range charge network, with the hydrocarbon tails forming a nonpolar domain. Such nonpolar domains have been shown to dissolve a variety of neutral organic solvents. In mixtures of ILs with solvents the neutral organic molecules residing in the nonpolar domains experience different environments and friction from the charged cations and anions. Thus, the neutral molecules diffuse much faster than predicted by hydrodynamic scaling using the average viscosity of the mixture. In this work, we report studies on the structure and transport properties of mixtures of 1-octanol with the IL trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide (P6,6,6,14 +/NTf2 -). The majority of the atom fraction in the P6,6,6,14 + cation comprises four hydrocarbon substituents. The unique amphiphilic nature of ILs with the P6,6,6,14 + cation makes 1-octanol fully miscible with the IL at ambient temperatures. X-ray scattering experiments show that the IL structure persists in the mixtures for 1-octanol mole fractions as large as xoct = 0.90. The self-diffusion coefficients of the three molecular species in the mixtures were measured by NMR experiments. The self-diffusion of the P6,6,6,14 + cation is well described by the Stokes-Einstein equation, while the diffusivity of the NTf2 - anion is slightly lower than the hydrodynamic prediction. The measured diffusivities of octanol in these mixtures are 1.3-4 times higher than the hydrodynamic predictions.

Electrochemical Characterization of Bromine Reduction to Tribromide in Individual Nitrobenzene-in-Water Emulsion Droplets

We report an electrochemical study of bromine reduction to tribromide in a single nitrobenzene (NB) droplet during a single collision event. The feasibility of this study is based on the favorable distribution of Br2 in NB rather than in water, which was demonstrated by voltammetry at the NB/water interface. The NB-in-water emulsions containing the ionic liquids trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide (ILPA) as the supporting electrolyte and sodium dodecyl sulfate (SDS) as the surfactant were prepared by a high-power ultrasonication. Its single droplet as an attoliter reactor, colliding on a 25 μm Pt UME, was monitored by chronoamperometry. The spike-type current transients of Br2 reduction can elucidate the size and size distribution of NB, and measure the diffusion in the droplet as analyzed by a bulk electrolysis model. The frequency of collisions can provide diffusion coefficient of the droplets to the UME. Moreover, the i-t decay behavior can be simulated, which fits well with the experimental one.

Polyol Synthesis of Magnetite Nanocrystals in a Thermostable Ionic Liquid

We report on the development of a facile, one-pot synthesis of single-crystalline magnetite (Fe3O4) nanoparticles (NPs) based on the thermal decomposition of the nontoxic iron precursor iron(III)acetylacetonate within the ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14][Tf2N]) using 1,2-hexadecanediol as a polyol reducing agent in an “iono-polyol” process. In this expedient approach, the [P6,6,6,14][Tf2N] acts both as a low-volatility, thermostable solvent and as the colloid-stabilizing agent, eliminating the requirement for additional surface-capping agents. Performing the synthesis at 300 or 350 °C yielded quasi-spherical, monodispersed Fe3O4 NPs with a mean size of 14 nm. Evidence from thermogravimetry, X-ray fluorescence, and infrared analysis is consistent with nanocrystal coverage by a partial bilayer of [P6,6,6,14][Tf2N], accounting for the excellent dispersibility of the Fe3O4 NPs in solvents such as hexane, toluene, and methylene chloride. Time-dependent t...

Phase behavior of the surfactant ionic liquid trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate with water and dodecane

Abstract Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate is a surface-active room temperature ionic liquid: it is an ionic component, liquid at room temperature, and also a surfactant due to the presence of large (hydrophobic) alkyl chains attached to an ionic moiety. Moreover, since both the anion and the cation have large alkyl chains, both ions have surface active character, what has been called a catanionic or biamphiphillic surfactant. In this work, the surfactant has been characterized through the measurement of the critical micelle concentration in aqueous solutions and related parameters. The phase diagram for ternary mixtures with water and n-dodecane has been determined, showing a Winsor type III behavior. The effect of temperature and amphiphile concentration on the ternary system has been studied with fish diagrams. A large effect of temperature on the phase diagram has been found, with the existence of a triphasic region from 278 up to 305 K. Interfacial tension between equilibrium phases has been measured experimentally for the ternary system, using either pure water or 4 wt% NaCl brine. Density and viscosity of the involved phases have also been measured as valuable information in oil recovery. Results obtained are discussed in terms of the validity of this surfactant for this application.

Ion-Tagged Phosphines as Ligands for Suzuki Coupling of Aryl Halides in a Phosphonium Ionic Liquid

Gramine-based N-substituted phosphines were synthesized and utilized as ligands in Suzuki–Miyaura coupling of aryl bromides and chlorides in the room temperature ionic liquid trihexyltetradecylphosphonium bis(trifluoromethanesulfonyl)imide. Increased yields were achieved with ion-tagged ligands compared to ligands bearing pendant amines, likely due to higher solubility of the former. Cyclohexyl groups on the phosphine moiety generally resulted in higher yields than tert-butyl groups. In addition, a biphasic ionic liquid/water system outperformed catalysis in neat ionic liquid and provided higher yields at lower temperatures.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide using gas–liquid chromatography at T = (313.15, 333.15, 353.15 and 373.15) K

Activity coefficients at infinite dilution for organic solutes, which include n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols and ketones, in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide were measured by gas–liquid chromatography using the latter as the stationary phase. This ionic liquid had previously been studied and reported in literature; however due to significant discrepancies in the reported infinite activity coefficient values, there was justification for further study and reporting. The temperature range investigated in this study is significantly wider and at higher temperatures than presented previously in the literature. From the experimental infinite dilution activity coefficient data at the four different temperatures T=(313.15, 333.15, 353.15 and 373.15)K, partial molar excess enthalpies at infinite dilution were calculated. Values of the selectivity for hexane/benzene and methanol/benzene separations were determined from experimental values of the activity coefficients at infinite dilution and these results were compared to literature values for other ionic liquids, as well as for industrial solvents. The capacities were also determined as it gives an indication of the solvent extraction behavior of the ionic liquid.

Analysis by desorption of volatile impurities from an ionic liquid solution in an unmodified gas chromatograph inlet

A procedure for using ionic liquids to determine volatile impurities in compounds or matrices that are soluble in an ionic liquid is described. Using a conventional autosampler a droplet of ionic liquid solution is suspended in the inlet of the gas chromatograph and analytes are desorbed onto a GC column using splitless injection conditions. Results are presented for 1,2-propanediol, nonane, N,N-dimethylacetamide, and mesitylene in two different compounds in the ionic liquids trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide and trihexyltetradecylphosphonium dicyanamide.

Determination of Activity Coefficients at Infinite Dilution of Solutes in the Ionic Liquid, Trihexyltetradecylphosphonium Bis(trifluoromethylsulfonyl) Imide, Using Gas−Liquid Chromatography at T = (303.15, 308.15, 313.15, and 318.15) K

The activity coefficients at infinite dilution, γ13∞, for hydrocarbon solutes and some alcohols in the ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide [3C6C14P][Tf2N] have been determined by gas−liquid chromatography at temperatures T = (303.15, 308.15, 313.15, and 318.15) K. The selectivity values have been calculated at T = 308.15 K, and the results indicate that the ionic liquid [3C6C14P][Tf2N] should not be considered as a solvent for separation of alkanes and aromatics. The partial molar excess enthalpy values at infinite dilution ΔH1E∞, determined in this work, together with the values γ13∞ have been discussed in terms of intermolecular interactions and compared to results of related systems obtained from the literature.

Activity coefficients at infinite dilution measurements for organic solutes in the ionic liquid trihexyltetradecylphosphonium-bis-(2,4,4-trimethylpentyl)-phosphinate using g.l.c. at T = (303.15, 308.15, 313.15, and 318.15) K

A new phosphonium ionic liquid was investigated as a possible solvent for use in the separation of aromatic hydrocarbons from aliphatic hydrocarbons. The activity coefficients at infinite dilution, γ 13 ∞ , for 14 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, and aromatic hydrocarbons in the ionic liquid trihexyltetradecylphosphonium-bis-(2,4,4-trimethylpentyl)-phosphinate [3C 6C 14P][(C 8H 17) 2PO 2] were consequently determined by gas–liquid chromatography at four temperatures T = (303.15, 308.15, 313.15, and 318.18) K. The partial molar excess enthalpies at infinite dilution values, Δ H 1 E, ∞ , were calculated from experimental γ 13 ∞ values obtained over the temperature range studied. The selectivities for the n-hexane/benzene, hex-1-yne/benzene, and cyclohexane/benzene separations scenarios were calculated from the γ 13 ∞ and were compared to studies from the recent literature for results of other ionic liquids, as well as NMP and sulfolane, taken from the recent literature. The results indicate that [3C 6C 14P][(C 8H 17) 2PO 2] would make a poor solvent for the separation of an alkane or alk-1-ene or cycloalkene from benzene. The results do, however, expand our knowledge and point to some interesting facets of (solute + ionic liquid) interactions.