Ammonium-based Ionic Liquids Research Articles

A Comprehensive Comparison Analysis between Ammonium-Based and Phosphonium-Based Bifunctional Ionic Liquids for Metal Extraction and Separation Processes

A Comprehensive Comparison Analysis between Ammonium-Based and Phosphonium-Based Bifunctional Ionic Liquids for Metal Extraction and Separation Processes

Mechanism of selectivity of tri-n-octylmethylammonium chloride for vanadium

Ionic liquid (IL)-based extraction is a promising and environmentally benign separation technology. Processes for quaternary ammonium-based IL extraction of vanadium have been extensively studied, but the vanadium extraction mechanism has not been accurately confirmed. This study investigated vanadium extraction from sulphuric acid leachate of shale by solvent extraction with tri-n-octylmethylammonium chloride (TOMAC/CH3NClR3). The results indicated that 90.50 % of the vanadium extraction percentage comprised one stage under the optimal condition experiments. These experiments were carried out at pH 1.8; the IL phase consisted of 25 vol% TOMAC, 15 vol% TBP, and 60 vol% sulfonated kerosene; O/A phase ratio of 1:7.5; extraction time of 120 s. The forms of vanadium and impurities present were revealed by the solution chemistry, Medusa software simulation. The extraction mechanism of vanadium was investigated using ultraviolet spec-trophotometer (UV–Vis), fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), and hotometer matrix-assisted laser-resolved ionization time-of-flight mass spectra (MALDI-TOF-MS). Under extraction conditions at pH 1.8, vanadium was present as an anion in the form H2V10O4- 28 and HV10O5- 28. Since the extraction mechanism of TOMAC was anion exchange, the extracted vanadium was mainly present as the anionic complex [(CH3NR3)4·H2V10O4- 28]/[(CH3NR3)5·HV10O5- 28]. The ESP map of TOMAC and V (V) was calculated to confirm the reaction sites and was used to verify the anion exchange mechanism.

Ethyl-dimethyl-(ferrocenylmethyl)ammonium-based ionic liquid: Structure, transport, and electrochemical properties of binary solutions in acetonitrile

Ethyl-dimethyl-(ferrocenylmethyl)ammonium-based ionic liquid: Structure, transport, and electrochemical properties of binary solutions in acetonitrile

Electrochemical stability of low viscosity ion-pair electrolytes: Structure and interaction in quaternary ammonium-based Ionic liquid containing bis(trifluoromethylsulfonyl)imide anion and analogue

Quaternary ammonium-based ionic liquids (QAIL) consist of an aliphatic cation and possess characteristic properties different from those of aromatic (like imidazolium) with extensive cited applications. The redox stability of QA cations has attractively nominated them to achieve static and dynamic electrochemical phenomena. Herein, we investigated the influence of various anions (bis(fluorosulfonyl)imide [FSI]− and bis(trifluoromethylsulfonyl)imide [NTf2]−) on the structure, electronic, and electrochemical properties of low-viscosity ILs comprising QA cation (triethylpentyl ammonium [N2225]+) by employing highly versatile empirical exchange-correlation functional M06–2X in the context of density functional theory (DFT). The electronic structure, cation-anion interaction energy, dipole moment, cation-anion charge transfer, cathodic and anodic potential boundaries, electrochemical window (ECW), and density of state (DOS) were calculated and discussed. Liquid state studied by polarizable continuum model (PCM). The thermodynamics cycle method, an alternative to HOMO/LUMO method, was used to predict ECW's more realistic. ECWs for [N2225][FSI] ≥ [N2225][NTf2] were found to be wider than the experimental imidazolium counterpart by about two volts. [FSI]− anion is overwhelmingly involved in charge transfer with the cation compared to [NTf2]−. The more redox-stable [N2225][FSI] IL is expected to have less corrosive effects with metal electrodes because the anion (1) cis conformer takes a particular orientation relative to the cation, (2) has a higher charge transfer, and (3) F's atoms have a higher occupation number than [N2225][NTf2] IL. Therefore, these results provide insight for further investigation to expand the electrochemical application of redox-stable aliphatic QAILs involving the two targeted anions.

A step closer to sustainable CO2 conversion: Limonene carbonate production driven by ionic liquids

This work aims to advance the biocarbonate concept by developing the first process to produce limonene carbonate based on ionic liquids (ILs). Conventional petroleum-derived cyclic carbonates are recognized products partially composed of CO2 with the main drawback of the high energy consumption that imposes epoxide production. In contrast, natural epoxidable compounds, such as terpenes, stand out in the literature as a more sustainable open research line to enable CO2 conversion processes with better sustainable indicators. Limonene, an abundant natural compound, is identified as a key terpene in the aforementioned discussion. Ammonium-based ILs are experimentally selected and optimized, after covering massive anion and cation substituent tuning, achieving high selectivity and competitive yields to limonene carbonate. The reaction-extraction platform concept, which recovers the catalyst by liquid-liquid extraction, is envisioned and developed using a rational experimental-computational approach. The work concludes with a novel process to effectively produce limonene carbonate by using an IL catalyst and water as an extracting solvent. Ultimately, taking advance of the process simulation, a CO2 emissions assessment was conducted. Using renewable raw materials enhances the sustainability of CO2 conversion to cyclic carbonate, reducing global warming impact compared to fossil-based epoxides. However, limonene extraction and epoxidation have a tangible impact on the overall result of CO2 balance, turning efforts outside battery limits of the CO2 conversion process in the search of a limonene carbonate production line with negative neat CO2 emissions that may change the paradigm in the fixation of CO2 through cycloaddition reactions.

Interaction between ammonium based ionic liquids and CRABP I Protein: A microenvironmental spectroscopic analysis

In this article, we have used circular dichroism (CD) and fluorescence to study the physicochemical behaviour of a β-sheet protein, CRABP I, in the presence of ammonium-based ionic liquids (ILs) as a co-solvent. From fluorescence spectroscopy, a rise in intensity was observed in the presence of ionic liquids in the micromolar range, but a reversal in fluorescence intensity at higher concentrations (millimolar range). The microenvironment of aromatic amino acids, tyrosine (Tyr) and tryptophan (Trp), have been compared using synchronous fluorescence data, and the results demonstrate a similar trend in both cases as it has been seen in steady-state spectra. By using CD spectroscopy to examine conformational behaviour, we found that the protein's secondary structure hardly changes at all. Functionality test showed marginal changes in secondary structure of the protein in the presence of ionic liquids. Binding study revealed the contribution of van der waal’s interaction in the case of N2, N4 and N6 and hydrophobic force in the case of N8. The computational study demonstrated that these biophysical behaviours can be accounted for by the hydrophobic interactions between proteins and ionic liquids.

Metal-Free Activation of Molecular Oxygen by Quaternary Ammonium-Based Ionic Liquid: A Detail Mechanistic Study.

Most oxidation processes in common organic synthesis and chemical biology require transition metal catalysts or metalloenzymes. Herein, we report a detailed mechanistic study of a metal-free oxygen (O2) activation protocol on benzylamine/alcohols using simple quaternary alkylammonium-based ionic liquids to produce products such as amide, aldehyde, imine, and in some cases, even aromatized products. NMR and various control experiments established the product formation and reaction mechanism, which involved the conversion of molecular oxygen into a hydroperoxyl radical via a proton-coupled electron transfer process. Detection of hydrogen peroxide in the reaction medium using colorimetric analysis supported the proposed mechanism of oxygen activation. Furthermore, first-principles calculations using density functional theory (DFT) revealed that reaction coordinates and transition state spin densities have a unique spin conversion of triplet oxygen leading to formation of singlet products via a minimum energy crossing point. In addition to DFT, domain-based local pair natural orbital coupled cluster, (DLPNO-CCSD(T)), and complete active space self-consistent field, CASSCF(20,14) methods complemented the above findings. Partial density of states analysis showed stabilization of π* orbital of oxygen in the presence of ionic liquid, making it susceptible to hydrogen abstraction in a mild, metal-free condition. Inductively coupled plasma atomic emission spectroscopic (ICP-AES) analysis of reactant and ionic liquids clearly showed the absence of any significant transition metal contamination. The current results described the origin of O2 activation within the context of molecular orbital (MO) theory and opened up a new avenue for the use of ionic liquids as inexpensive, multifunctional and high-performance alternative to metal-based catalysts for O2 activation.

Impedance Analysis of the Side Reactions of Li Electrodeposition in a Quaternary Ammonium-Based Ionic Liquid Electrolyte

Impedance Analysis of the Side Reactions of Li Electrodeposition in a Quaternary Ammonium-Based Ionic Liquid Electrolyte

Investigating the Wettability, Rheological, and Tribological Properties of Ammonium-Based Protic Ionic Liquids as Neat Lubricants for Steel–Steel and Steel–Aluminium Contacts

This study aims to evaluate the tribological properties of two protic ionic liquids (PILs) under different tribological conditions as a sustainable alternative for mineral oil-based neat lubricants. The synthesis of PILs in this study uses a relatively simple and less expensive method. The Fourier transform infrared (FTIR) spectroscopy results help validate the synthesised PILs’ formation. Further, their physicochemical and tribological properties were investigated. The PILs as neat lubricants were tested on a ball-on-plate reciprocating tribometer using bearing steel–bearing steel and bearing steel–aluminium alloy friction pairs at 30 °C and 80 °C. The results show that the investigated PILs significantly reduced the coefficient of friction and wear. The dodecylamine-based PILs performed better in friction and wear reduction than the other investigated lubricants. The formation of the adsorption layer on the friction pairs was assumed to be the dominant friction and wear reduction mechanism.

Study of the surfactant behaviour and physical properties of ammonium-based ionic liquids

The demand for oil and gas resources has increased dramatically recently; therefore, residual oil recovery from previously under-exploited reservoirs has attracted significant attention. In this context, chemical methods are considered promising owing to their efficiency. Therefore, it is essential to identify new compounds that can enable residual oil recovery. Among the studied chemical compounds, ionic liquids (ILs) have been considered alternatives to commercial surfactants because of their notable properties, such as low vapor pressure, flammability, and chemical stability. Recently, several studies have reported new ILs as alternatives to commercial surfactants. However, only a few studies have been conducted on protic ionic liquids for this purpose. This paper presents the characteristics of three ionic liquids (ILs) based on ammonium cations and hexanoate anions, namely 2-hydroxyethyl ammonium hexanoate [2HEA][Hx], bis(ethyl)tri(ammonium) [BHEA][Hx] hexanoate, and bis(ethyl)tri(ammonium) hexanoate [DETA][Hx]. The physicochemical properties of pure ILs, including viscosity, density, and sound velocity, were measured over a temperature range of 298.15–343.15 K. Our results showed that adding a hydroxyl group to the cation increased the density of the IL. Moreover, the IL with the highest number of amine groups in the cation exhibited a lower density and higher viscosity. Among the three ILs studied, [DETA][Hx] exhibited the lowest critical micellar concentration of 235 ppm. All the studied ILs reduced the interfacial tension between substances with different polarities. The analyzed properties show that hexanoate-based ionic liquids are competitive for chemical applications concerning commercial surfactants.

Molecular simulations of understanding the Na+ ion structure, dynamic and thermodynamic behavior in ionic liquids: Butyl ammonium hydrogen bisulfate and tri-butyl ammonium hydrogen bisulfate

This manuscript presents the all-atom molecular dynamics simulations to investigate intermolecular structure and solvation thermodynamics of Na+ ion in two different ammonium-based protic ionic liquids (1) Butyl Ammonium hydrogen bisulfate [BA+][HSO4−], (2) Tri-butyl ammonium hydrogen bisulfate [TBA+][HSO4−]. The ionic liquid [BA+][HSO4−] show a more coordinated behavior when compared to [TBA+][HSO4−], which is observed over the temperature range from 278 K to 348 K. Hydrogens of the cations show a hydrogen bonding interaction with oxygens of anions. The cationic [TBA+] molecules show more solvation behavior with anions when compared to the [BA+]. The Na+ ion show a strong coordination structure with [HSO4−] in [TBA+][HSO4−] when compared to the [BA+][HSO4−]. We further calculate the detailed solvation free energy (ΔG) calculations using thermodynamic integration. We found that the ΔG of Na+ is more favorable in [TBA+][HSO4−] when compared to [BA+][HSO4−] in the temperature range varying from 278 K to 348 K. With the temperature rise, we observe the more favorable solvation of Na+ in both ionic liquids. On the other hand, the solvation of Cl− becomes less favorable. Overall, this manuscript provides detailed molecular level structural and thermodynamic origins of Na+ in protic ionic liquids useful for designing and developing sustainable electrolytes for Na+ battery applications.

Counteraction Effects of Ammonium-Based Ionic Liquids on Urea-Induced Denaturation of α-Lactalbumin: A Comprehensive Molecular Simulation Study.

Ionic liquids (ILs) are known to stabilize protein conformations in aqueous medium. Importantly, ILs can also act as refolding additives in urea-driven denaturation of proteins. However, despite the importance of the problem, detailed microscopic understanding of the counteraction effects of ILs on urea-induced protein denaturation remains elusive. In this work, atomistic molecular dynamics (MD) simulations of the protein α-lactalbumin have been carried out in pure aqueous medium, in 8 M binary urea-water solution and in ternary urea-IL-water solutions containing ammonium-based ethyl ammonium acetate (EAA) as the IL at different concentrations (1-4 M). Attempts have been made to quantify detailed molecular-level understanding of the origin behind the counteraction effects of the IL on urea-induced partial unfolding of the protein. The calculations revealed significant conformational changes of the protein with multiple free energy minima due to its partial unfolding in binary urea-water solution. The counteraction effect of the IL was evident from the enhanced structural rigidity of the protein with propensity to transform into a single native free energy minimum state in ternary urea-IL-water solutions. Such an effect has been found to be associated with preferential direct binding of the IL components with the protein and simultaneous expulsion of urea from the interface, thereby providing additional stabilization of the protein in ternary solutions. Most importantly, modified rearrangement of the hydrogen bond network at the interface due to the formation of stronger protein-cation (PC) and protein-anion (PA) hydrogen bonds by breaking relatively weaker protein-urea (PU) and protein-water (PW) hydrogen bonds has been recognized as the microscopic origin behind the counteraction effects of EAA on urea-induced partial unfolding of the protein.

Effect of surface wetting on tribological behavior for laser textured steel using ionic liquid-based lubricants

In this study, the effect of surface wettability on the tribological performance is evaluated through a ball-on-flat reciprocating wear test. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The poly-alpha-olefin (PAO) base oil is used as the baseline lubricant, and ammonium- and phosphonium-based oil-miscible ionic liquids (ILs) are used as additives. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to identify the wear and frictional mechanisms of the tribosystem consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based IL provide an improved wear protection. Click here and insert your abstract text.© 2023 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights reserved.This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under responsibility of the Scientific Committee of the NAMRI/SME.

Ammonium-Based Ionic Liquids: Cross-Validation of Energetics Using Solution Calorimetry, Quartz Crystal Microbalance, Quantum Chemistry, and Structure–Property Relationships

Ammonium-Based Ionic Liquids: Cross-Validation of Energetics Using Solution Calorimetry, Quartz Crystal Microbalance, Quantum Chemistry, and Structure–Property Relationships

Application of New Ammonium-Based Ionic Liquids for Dehydration of Crude Oil Emulsions

Crude oil emulsions are prevalent in the petroleum industries due to different natural emulsifiers in crude oil. In addition, adding amphiphilic compounds for enhanced oil recovery at high temperatures and pressure under extreme shear stress conditions improved the stability of these emulsions. However, these emulsions are not desirable because they cause different operational problems. Herein, this work aims to synthesize and characterize two novel ionic liquids (ILs) and apply them to the dehydration of water-in-crude oil (W/O) emulsions. For that, tetraethylene glycol (TEG) was reacted with thionyl chloride (TC), yielding dialkyl halide (TEC). After that, TEC was reacted with 4-hexylaniline (HA) or 4-tetradecylaniline (TA) in the presence of sodium carbonate, obtaining the amines TC-HA and TC-TA, respectively. Finally, TC-HA and TC-TA were reacted with acetic acid, yielding the corresponding ionic liquids, THA-IL and TTA-IL. Chemical structure, surface tension (ST), interfacial tension (IFT), thermal stability, and micelle size were investigated using various techniques. The conventional bottle test was used to evaluate the performance of these ILs for dehydration W/O emulsion at different crude oil/brine ratios (ranging from 90/10 to 50/50). The results indicated that the dehydration performance (DP) increased with an increase in IL concentration. In addition, DP improved with increased water contents, reaching 100% for THA-IL and 80% for TTA-IL, respectively, at a crude oil/brine ratio of 50/50. Furthermore, TTA-IL showed higher DP and separated more clear water than THA-IL, which could be linked to its higher ability to reduce IFT due to a longer alkyl chain than THA-IL. The results showed that the synthesized ILs could serve as demulsifiers in the petroleum industry.

Solubility and Stability of Carotenoids in Ammonium- and Phosphonium-Based Ionic Liquids: Effect of Solvent Nature, Temperature and Water.

Ionic liquids (ILs) have arisen as alternatives to organic solvents and been used in natural pigment extraction in recent decades. However, the solubility and stability of carotenoids in phosphonium- and ammonium-based ILs are insufficiently explored. In this work, the physicochemical properties of the ILs, and the dissolution behavior and storage stability of three carotenoids (astaxanthin, β-carotene, and lutein) in the IL aqueous solution were investigated. The results showed that the solubility of the carotenoids in the acidic IL solution is higher than that in the alkaline IL solution, and the optimal pH is about 6. The solubility of astaxanthin (40 mg/100 g), β-carotene (105 mg/100 g), and lutein (5250 mg/100 g) was the highest in tributyloctylphosphonium chloride ([P4448]Cl) due to the van der Waals forces with [P4448]+ and hydrogen bonding with Cl-. A high temperature was beneficial to improve the solubility, but it can reduce the storage stability. Water has no significant effect on the carotenoid stability, but a high water content decreases the carotenoid solubility. A IL water content of 10-20%, an extraction temperature of 338.15 K, and a storage temperature of less than 298.15 K are beneficial for reducing the IL viscosity, improving carotenoid solubility, and maintaining good stability. Moreover, a linear correlation was found between the color parameters and carotenoid contents. This study provides some guidance for screening suitable solvents for carotenoid extraction and storage.

Synthesis of Ammonium-Based ILs with Different Lengths of Aliphatic Chains and Organic Halogen-Free Anions as Corrosion Inhibitors of API X52 Steel.

In the present work, synthesis and characterization of 15 ionic liquids (ILs) derived from quaternary ammonium and carboxylates were carried out in order to proceed to their evaluation as corrosion inhibitors (CIs) of API X52 steel in 0.5 M HCl. Potentiodynamic tests confirmed the inhibition efficiency (IE) as a function of the chemical configuration of the anion and cation. It was observed that the presence of two carboxylic groups in long linear aliphatic chains reduced the IE, whereas in shorter chains it was increased. Tafel-polarization results revealed the ILs as mixed-type CIs and that the IE was directly proportional to the CI concentration. The compounds with the best IE were 2-amine-benzoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AA]), 3-carboxybut-3-enoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AI]), and dodecanoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AD]) within the 56-84% interval. Furthermore, it was found that the ILs obeyed the Langmuir adsorption isotherm model and inhibited the corrosion of steel through a physicochemical process. Finally, the surface analysis by scanning electron microscopy (SEM) confirmed less steel damage in the presence of CI due to the inhibitor-metal interaction.

Role of surface wetting on tribological behavior for laser nanotextured steel using ionic liquid lubricants

This research evaluates the effect of surface wettability on the tribological performance through ball-on-flat tribology testing. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The baseline lubricant is poly-alpha-olefin (PAO) oil, and ionic liquids (ILs) are used as additives for this study. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to investigate the tribological behavior of the tribo-system consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based ILs provide an improved wear protection.

Biocompatible cellulose acetate supported ammonium based ionic liquid membranes; way forward to remediate water pollution

Dyes contaminated water has caused various environmental and health impacts in developing countries especially Pakistan due to different industrial activities. This issue has been addressed in present study by fabricating biocompatible ionic liquid (IL) membranes for the remediation of Crystal violet (CV) dye from contaminated water. Novel ammonium-based IL such as Triethyl dimethyl ammonium sulfate ([C3A][C2H6]SO4); (A2) was synthesized and further functionalized with hydroxyapatite (HAp; extracted from refused fish scales) resulting in the formation of HA2. Furthermore, A2 and HA2 were then used to fabricate the cellulose acetate (CA) based membranes with different volume ratios. The physicochemical properties of membranes-based composite materials were investigated using FTIR, XRD, and TGA and used for the adsorption of CV in the closed batch study. In results, CA-HA2 (1:2) showed higher efficiency of 98% for CV reduction, after the contact time of 90 min. Kinetic studies showed that the adsorption of CV followed the pseudo-second-order kinetic model for all adsorbents. The antibacterial properties of the synthesized membrane were investigated against gram-positive strain, S. aureus and CA-A2 (1:1) showed better antibacterial properties against S. aureus. The developed membrane is sustainable to be used for the adsorption of CV and against bacteria.

Synthesis and characterization of ammonium-based protic ionic liquids for carbon dioxide absorption.

A series of ammonium-based protic ionic liquids (APILs) namely ethanolammonium pentanoate [ETOHA][C5], ethanolammonium heptanoate [ETOHA][C7], triethanolammonium pentanoate [TRIETOHA][C5], triethanolammonium heptanoate [TRIETOHA][C7], tributylammonium pentanoate [TBA][C5] and tributylammonium heptanoate [TBA][C7] was synthesized via proton transfer. Their structural confirmation and physiochemical properties namely thermal stability, phase transition, density, heat capacity (Cp) and refractive index (RI) have been determined. Specifically, [TRIETOHA] APILs have crystallization peaks ranging from -31.67 to -1.00 °C, owing to their large density values. A comparison study revealed the low Cp values of APILs in comparison to monoethanolamine (MEA) which could be advantageous for APILs to be used in CO2 separation during recyclability processes. Additionally, the performance of APILs toward CO2 absorption was investigated by using a pressure drop technique under a pressure range of 1-20 bar at 298.15 K. It was observed that [TBA][C7] recorded the highest CO2 absorption capacity with the value of 0.74 mole fraction at 20 bar. Additionally, the regeneration of [TBA][C7] for CO2 absorption was studied. Analysis of the measured CO2 absorption data showed marginal reduction in the mole fraction of CO2 absorbed between fresh and recycled [TBA][C7] thus proving the promising potential of APILs as good liquid absorbents for CO2 removal.