Ionic Liquid Trihexyl Tetradecyl Phosphonium 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.

Use of ionic liquids for extraction separation and concentration of iodide ions in brine samples.

Iodine in natural salt waters such as iodine-rich underground brine generally exists as iodide ions, and to extract iodide ions, it is necessary to oxidize them to nonpolar iodine molecules. In this study, we report that iodide ions in natural brine containing high concentrations of chloride ions can be quantitatively extracted without oxidation by extraction using ionic liquids. Extraction with the ionic liquids trihexyltetradecylphosphonium chloride and trioctyl ammonium chloride was found to be able to enrich trace amounts of iodide in brine samples up to 40- and 100-fold, respectively. The selectivity coefficients for I- over Cl- determined in this study clearly show that the ionic liquids have much higher I-/Cl- selectivity than typical strongly basic anion exchangers. Extraction with trihexyltetradecylphosphonium chloride was applicable as a preconcentration method for iodine determination by XRF analysis. Iodide ions extracted with trioctyl ammonium chloride were quantitatively stripped with an aqueous alkaline solution. These results indicate that ionic liquid extraction is useful for the separation and concentration of iodide from brines.

Treatment of Pulp Black Liquor with an Ionic Liquid: Optimisation by Using Response Surface Methodology.

: In this study, selective extraction towards ionic liquid trihexyltetradecylphosphonium chloride ([P66614]Cl) of lignin residues, polysaccharides and organic acids present in black liquor (BL), the main principal wastewater of pulping industry was studied. With the objective of finding optimized conditions allowing to extract lignin resideus while polysaccharides and organic acids remain in aqueous solution, a design of experiments approach based on a response surface methodology was used. Three continuous factors, namely initial pH varying from 9 to 13.5, dilution of BL varying from 5 to 20 and volumetric ratio of black liquor vs. ionic liquid RV., varying from 1 to 19, were investigated. Concentration of ligni residues, polysaccharides and organic acids were measured using Folin-Ciocalteu method, the anthrone method and HPLC, respectively. Results showed that a multi-response optimization led to the extraction of 84.8 % of lignin residues, 66.0 % of polysaccharides, and no extraction of OA under optimised conditions.

Extraction of rare earth elements from aqueous solutions using the ionic liquid trihexyltetradecylphosphonium 3-hydroxy-2-naphthoate.

The task-specific ionic liquid trihexyltetradecylphosphonium 3-hydroxy-2-naphthoate has been described as a suitable extraction agent for numerous metals from aqueous phases, while additionally providing reduced leaching into the used matrices. Here, we investigate the extraction properties of this extractant towards rare earth elements. Of these, La, Ce, Nd, Ho und Lu were chosen as a representative mix of light and heavy elements. Single- as well as double-element extractions were carried out under varying conditions regarding pH, temperature and extraction time. The highest extraction efficacies and minimalized precipitation of the respective metals were recorded at a pH of 2.5. Satisfactory extraction efficacies (>80%) were achieved already after 6 hours for the elements Ce, Nd and Lu in single-element extraction experiments at room temperature. Increased temperatures improved the extraction efficacy for Nd from 36% at 20 °C to 80% at 30 °C after only 2 hours. Surprisingly, this effect was not observed for Ce in single-element experiments. In double-element feed solutions containing both Ce and Nd, however, the time-dependant extraction efficacy of Ce mirrored that of Nd. The pH in the aqueous extraction matrix changed during the extraction, showing a positive correlation with the extraction efficacy and revealing the extraction mechanism to be via anion exchange. The leaching was in good agreement with literature values, showed a positive correlation with extraction efficacies, and ranged for all extractions between 0.8 and 1.2%. Remarkably, increasing the temperature from 20 °C to 30 °C had no significant influence on leaching.

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.

Ultrasound-assisted extractive/oxidative desulfurization of oil using environmentally benign trihexyl tetradecyl phosphonium chloride

A phosphonium-based ionic liquid (PIL) trihexyl tetradecyl phosphonium chloride ([THTDP]Cl) was applied as an effective catalyst/extractant for the desulfurization of model oil (MO) as well as base oil. In the ultrasound-assisted extractive/oxidative desulfurization (UEODS) process, a liquid–liquid catalytic oxidative desulfurization system containing MO/base oil, hydrogen peroxide, and PIL was observed at 30 °C and maximum sulfur removal of 98.67% was obtained. After completion of the reaction, PIL was separated from MO. The PIL was then regenerated and recycled 5 times without a significant decrease in efficiency. The influence of UAODS of MO containing dibenzothiophene (DBT), benzothiophene (BT), thiophene (T), and 3-methyl thiophene (3-MT) was also observed, which shows fast oxidative desulfurization capability under ultrasound irradiation. The oxidation reactivity of sulfur compounds follows the order of DBT > BT > TH > 3-MT at the DBT optimized conditions. The quantity of PIL, H2O2/DBT mole ratio, oxidation temperature, and time all played significant roles in sulfur removal, which were also analyzed in detail to optimize the reaction conditions during UEODS. The density functional theory study was carried out to understand the exact mechanism responsible for the effective interaction between PIL and sulfur compounds. The desulfurization of base oil was also carried out to check the feasibility of the UEODS process and achieved 74.98% desulfurization efficiency. These results proved the efficacy of the UEODS process for industrial application.

Closed-loop process for recovery of metals from NdFeB magnets using a trichloride ionic liquid

A solvometallurgical process was developed to recover rare-earth elements and cobalt from end-of-life NdFeB magnets, using the ionic liquid (IL) trihexyltetradecylphosphonium trichloride ([P666,14][Cl3]), or a mixture of [P666,14][Cl3] and the corresponding chloride IL [P666,14]Cl. The process comprises dissolution, stripping and regeneration of the ionic liquid. Pure [P666,14][Cl3] or its mixture with [P666,14]Cl could quantitatively dissolve NdFeB magnets when the solid-to-liquid ratio was less than a certain threshold value that depended on the volume percentage of [P666,14][Cl3] in the lixiviant. Increasing the temperature from 25 to 50 °C enhanced the dissolution rate significantly, but the dissolution efficiency increased only marginally. The volume percentage of [P666,14][Cl3] in [P666,14]Cl had a positive effect on the dissolution efficiency. The rare-earth and transition metals could be removed selectively by two sequential stripping steps, using 3 mol∙L−1 of NaCl aqueous solution and >2 mol∙L−1 of aqueous ammonia solutions, respectively. The regenerated IL [P666,14][Cl3] showed a similar dissolution efficiency to the fresh ionic liquid.

Nanostructure, electrochemistry and potential-dependent lubricity of the catanionic surface-active ionic liquid [P6,6,6,14] [AOT

HypothesisA catanionic surface-active ionic liquid (SAIL) trihexyltetradecylphosphonium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate ([P6,6,6,14] [AOT]) is nanostructured in the bulk and at the interface. The interfacial nanostructure and lubricity may be changed by applying a potential. ExperimentsThe bulk structure and viscosity have been investigated using small angle X-ray scattering (SAXS) and rheometry. The interfacial structure and lubricity as a function of potential have been investigated using atomic force microscopy (AFM). The electrochemistry has been investigated using cyclic voltammetry. Findings[P6,6,6,14] [AOT] shows sponge-like bulk nanostructure with distinct interdigitation of cation–anion alkyl chains. Shear-thinning occurs at 293 K and below, but becomes less obvious on heating up to 313 K. Voltammetric analysis reveals that the electrochemical window of [P6,6,6,14] [AOT] on a gold micro disk electrode exceeds the potential range of the AFM experiments and that negligible redox activity occurs in this range. The interfacial layered structure of [P6,6,6,14] [AOT] is weaker than conventional ILs and SAILs, whereas lubricity is better, confirming the inverse correlation between the near-surface structure and lubricity. The adhesive forces of [P6,6,6,14] [AOT] are lower at −1.0 V than at open circuit potential and +1.0 V, likely due to reduced electrostatic interactions caused by shielding of charge centres via long alkyl chains.

Preparation of sustainable activated carbon-alginate beads impregnated with ionic liquid for phenol decontamination

Powder activated carbon (PAC), derived from calligonum pollygonides, was successfully modified with the ionic liquid (IL) trihexyltetradecylphosphonium bromide ([PC6C6C6C14][Br]) in the presence of sodium alginate and characterized using SEM, FTIR and TGA. PAC, granular AC (GAC), AC-alginate and AC-Alg-IL bead were assessed for the removal of phenol from aqueous media via batch adsorption. Both PAC and AC-Alg-IL beads displayed high adsorption capacities, 123 mg/g and 78 mg/g, respectively, under optimized conditions. In contrast, GAC gave a much lower adsorption capacity than AC-ALG-IL beads, indicating that AC-ALG-IL beads are superior as potential adsorbents for this industrial application. Theoretical studies showed that the pseudo-second-order kinetic and Freundlich isotherm models were suitable to describe the adsorption process. The interaction between phenol and AC-Alg-IL beads was analyzed using the conductor-like screening model for realistic solvents (COSMO-RS). It has been concluded that AC-Alg-IL beads can be used as an efficient adsorbent for phenol and other organic compounds.

A proof-of-concept of parallel single-drop microextraction for the rapid and sensitive biomonitoring of pesticides in urine.

In this study, a lab-made parallel single-drop microextraction methodology using the magnetic ionic liquid trihexyltetradecylphosphonium tetrachloromanganate (II) as extraction solvent was developed to determine the pesticides tebuconazole, pendimethalin, dichlorodiphenyltrichloroethane, and dichlorodiphenyldichloroethylene in human urine samples. The experimental setup consisted of a 96-well plate system containing a set of magnetic pins that allowed for the manipulation of up to 96 samples simultaneously, providing an enhanced drop stability compared to traditional single-drop microextraction approaches. The optimal conditions employed 5.38 ± 0.55mg of extraction solvent, 1.5mL of diluted urine samples (1:10), extraction time of 130min, and subsequent dilution in 20 μL of acetonitrile. The method exhibited satisfactory analytical performance, with limits of detection of 7.5μg/L for all analytes and coefficients of determination higher than 0.9955. Intraday and interday precisions ranged from 3 to 17% (n=3) and 15 to 18% (n=9), respectively, with relative recovery of analytes ranging from 70 to 122%. The method proposed was successfully applied in two human urine samples and no sign of the analytes was detected. The results demonstrated that the proposed method allowed for cost-effective and high-throughput methodology to be explored as a valuable tool in bioanalytical applications.

Biorefining of lignocellulosic feedstock and waste materials using ionic liquid

The ionic liquid trihexyltetradecylphosphonium hydrogen sulphate (THTDP HSO4) was used to extract cellulose from various lignocellulosic sources:- wheat straw, perennial ryegrass, willow, anaerobic digestate (AD) and spent mushroom compost (SMC). This was compared with a traditional dilute sulphuric acid extraction to evaluate the potential for this ionic liquid to be of use in the biorefining industry. The use of ultrasonication to facilitate the reaction was also tested. Results showed that this ionic liquid, which combines the features of a hydrophobic solvent with an acidic catalyst was effective in hydrolysing lignocelluloses. Compared to the use of dilute sulphuric acid, the ionic liquid produced purer, more thermally stable cellulosic fibres. It was also shown to be as effective as the dilute sulphuric acid in pretreating lignocelluloses for enzymatic hydrolysis. Finally, ultrasonication was shown to be compatible with the ionic liquid and suggests an energy efficient method for pretreatment of lignocellulose.

Solvent extraction fractionation of manganese, cobalt, nickel and lithium using ionic liquids and deep eutectic solvents

The recycling of spent lithium-ion batteries remains a challenging task due to the complexity of the leach liquors, which contains several metals in acidic solution. The recovery of valuable metals, viz. Co, Li, Mn, Ni, is also difficult due to the similar chemical behavior of the divalent metal ions. Solvent extraction is mainly used for the separation of these metals, but the conventional extractants used in combination with molecular diluents usually lack of selectivity. We report a new solvent extraction system based on N,N,N',N'-Tetra-n-octyldiglycolamide (TODGA) diluted in the room temperature hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Up to 99% of manganese can be extracted in one step with separation factors in the range 40–60 for Mn/Co separation and higher than 200 for the other metals. The mechanism of extraction was detailed. Cobalt separation was done using the ionic liquid tri-hexyltetradecylphosphonium chloride. More than 90% of cobalt can be extracted with very high separation factors. Nickel and lithium separation was carried out by deep eutectic solvents (DESs) based on lidocaine and carboxylic acids. The use of a DES made of decanoic acid and lidocaine shows a high extraction efficiency for nickel while lithium is left in solution.

A methodology to detect explosive residues using a gelled ionic liquid based field-deployable electrochemical device

A simple and robust, low-cost electrochemical device is proposed for the combined sampling and detection of the trace solid explosive 2,4,6-trinitrotoluene (TNT) from a non-porous surface. Four different substrates were investigated to collect explosive residue – a bare thin-film electrode, glass microfiber filter paper, a gel-polymer electrolyte (GPE), and a GPE-filter paper composite. The GPE contained the hydrophobic room temperature ionic liquid (RTIL) trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P14,6,6,6][NTf2]) and the polymer poly(methyl methacrylate) (PMMA). A simple “swabbing” technique was used to sample explosive residue on all substrates. Square wave voltammetry was performed to determine the effects of oxygen and moisture on the current response. The most robust method for use in the field – a GPE drop-casted on a TFE – was applied in real environments using a hand-held portable potentiostat. The prototype device was able to detect TNT with a 30 min development time in different ambient environmental conditions. The portability, ease of use and low-cost of the sensor device makes this a viable platform for the rapid onsite detection of explosives.

Synergistic Effect Between Phosphonium-Based Ionic Liquid and Three Oxide Nanoparticles as Hybrid Lubricant Additives

Abstract The tribological properties of ionic liquid (IL) trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate along with Al2O3, CuO, and SiO2 nanoparticles (NPs) have been investigated as a lubricant additive in a group 1 mineral base oil. About 0.5 wt% concentration of additives were added in base oil, and tribological tests were conducted at mild (stipulated) and severe (ASTM D 4172D) working conditions to assess the synergy between IL and NPs. This study shows the excellent synergy between IL, Al2O3, and CuO NPs in improving tribological and extreme pressure (EP) properties. Al2O3 and CuO hybrid nanolubricants decreased friction by 19% and 24%, whereas wear by 32% and 36%, respectively, at ASTM test conditions. IL displayed very good EP properties with a total improvement of 19%, and the highest load-bearing capacity was observed for Al2O3 and CuO hybrid nanolubricants with an improvement of 30% and 34%, respectively. No conclusive evidence of synergy has been observed between IL and SiO2 NPs. Surface characterization techniques, such as scanning electron microscope, energy dispersive X-ray spectrometer, and Raman spectra, demonstrated the formation of a tribofilm rich in phosphate and tribosintered NPs on the worn surface responsible for improved triboperformances.

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.

One-pot resource-efficient synthesis of SnSb powders for composite anodes in sodium-ion batteries.

SnSb alloy, which can be used as an anode in a sodium-ion cell, was synthesized following a resource-efficient route at low temperature. This one-pot approach greatly reduces the energy consumption and maximizes the efficient use of raw materials. The reaction of elemental tin and antimony in the ionic liquid (IL) trihexyltetradecylphosphonium chloride ([P66614]Cl) at 200 °C led to a microcrystalline powder of single-phase SnSb within 10 h with very high yield (95%). Liquid-state nuclear magnetic resonance spectroscopy revealed that the IL remains essentially stable during the reaction. It was recovered almost quantitatively by distilling off the organic solvent used for product separation. Composites of SnSb powder and carbon nanotubes (CNTs) were fabricated by a simple ball milling process. Electrochemical measurements demonstrate that the Na‖SnSb/CNTs cell retains close to 100% of its initial capacity after 50 cycles at a current of 50 mA g−1, which is much better than the Na‖SnSb cell. The greatly increased capacity retainability can be attributed to the conductive network formed by CNTs inside the SnSb/CNTs electrode, providing 3D effective and fast electronic pathways during sodium intercalation and de-intercalation.

Feature vector clustering molecular pairs in computer simulations.

A clustering framework is introduced to analyze the microscopic structural organization of molecular pairs in liquids and solutions. A molecular pair is represented by a representative vector (RV). To obtain RV, intermolecular atom distances in the pair are extracted from simulation trajectory as components of the key feature vector (KFV). A specific scheme is then suggested to transform KFV to RV by removing the influence of permutational molecular symmetry on the KFV as the predicted clusters should be independent of possible permutations of identical atoms in the pair. After RVs of pairs are obtained, a clustering analysis technique is finally used to classify all the RVs of molecular pairs into the clusters. The framework is applied to analyze trajectory from molecular dynamics simulations of an ionic liquid (trihexyltetradecylphosphonium bis(oxalato)borate ([P6,6,6,14 ][BOB])). The molecular pairs are successfully categorized into physically meaningful clusters, and their effectiveness is evaluated by computing the product moment correlation coefficient (PMCC). (Willett, Winterman, and Bawden, J. Chem. Inf. Comput. Sci. 1986, 26, 109-118; Downs, Willett, and Fisanick, J. Chem. Inf. Comput. Sci. 1994, 34, 1094-1102) It is observed that representative configurations of two clusters are related to two energy local minimum structures optimized by density functional theory (DFT) calculation, respectively. Several widely used clustering analysis techniques of both nonhierarchical (k-means) and hierarchical clustering algorithms are also evaluated and compared with each other. The proposed KFV technique efficiently reveals local molecular pair structures in the simulated complex liquid. It is a method, which is highly useful for liquids and solutions in particular with strong intermolecular interactions. © 2019 Wiley Periodicals, Inc.

Rh(III) Aqueous Speciation with Chloride as a Driver for Its Extraction by Phosphonium Based Ionic Liquids.

In this work, the aqueous speciation of Rh(III) in chloride medium was investigated by UV-vis spectroscopy for ligand to metal ratios R = (Cl−)/(Rh) ranging from 300 to 5000, at fixed Rh concentration (2.4 × 10−3 M). Under the chemical conditions of this work, no time evolution was observed, which allows for the fitting of the UV-vis data by Principal Component Analysis (PCA) and Multi-Curve Resolution (MCR). From this, and by comparison with literature data, the three independent species [RhCl4]−, [RhCl5]2− and [RhCl6]3− were identified, their individual absorption spectra derived and their respective contribution to the collected experimental UV-vis spectra calculated. Then, extraction of Rh(III) towards the ionic liquid trihexyltetradecylphosphonium chloride was performed. Comparison with the speciation data gives insight into the extraction mechanism and the extracted species.

Application of trihexyltetradecylphosphonium dicyanamide ionic liquid for various types of separations problems: Activity coefficients at infinite dilution measurements utilizing GLC method

In this work, the ionic liquid trihexyltetradecylphosphonium dicyanamide [P 6 6 6 14] [DCA] was evaluated as a potential extraction solvent for organic compounds. The assessment was done based on the solute retention data obtained by gas liquid chromatography (GLC) for 33 solutes: (alkanes, alkenes, ketones, alcohols, alkynes, aromatic hydrocarbons, tetrahydrofuran, thiophene, acetonitrile and water). The experiment was conducted at a series of four temperatures (313.15–343.15) K at 10 K intervals. Experimental activity coefficients at infinite dilution data acquired over the investigated temperature range was then utilized to compute the thermodynamic functions at infinite dilution including partial molar excess enthalpy, ΔH1E,∞, Gibbs free energy, ΔG1E,∞ and entropy term, TrefΔS1E,∞. The selectivity and capacity values for some of the separation challenges (heptane/thiophene, water/butanol and heptane/benzene) were computed from the γ13∞ data and in contrast to the other phosphonium based ionic liquids in the literature. The selectivity and capacity data shows that the investigated ionic liquid can be utilized in the separation of heptane/thiophene or water/butan-1-ol mixtures.