Choline Amino Acid Ionic Liquids Research Articles

Theoretical study on the energy storage performance of Electrical double layer supercapacitors with choline amino acid ionic liquids electrolyte

Choline amino acid ionic liquids have attracted much attention in recent years due to their simple extraction process, rich sources, and easy degradation. Due to the high viscosity of such ionic liquids, the addition of organic solvents can adjust the transport performance of ionic liquids. Here, we explore the effects of different solvents (methanol, ethanol) and different temperatures on the diffusion properties and conductivity of ionic liquids through molecular dynamics simulations. The results showed that with the increase of temperature, the conductivity linearly increased. The addition of organic solvents can improve the conductivity of ionic liquids, and the addition of methanol solvent has a higher compatibility with choline amino acid ionic liquids. The conductivity after mixing methanol and choline glycine in a certain proportion is 5 times higher than before. In addition, this article investigated the performance of choline glycine ionic liquid electrolytes in Electrical Double Layers (EDLs) near planar graphene electrodes. The results indicate that similar double layer structures and double layer capacitors can be observed regardless of whether solvents are added.

Evaluation of rheological properties and tribological properties of choline/acetylamino acid ionic liquids at different frequencies

With the increasing average lifespan of human beings, the wear and tear caused by daily activities on joints will also escalate. Consequently, there is a growing focus on the development of green, environmentally friendly, and biocompatible non-toxic lubricating materials. The presence of dual chemical active centers in natural amino acids results in anions and cations that lead to precipitation and poor lubrication effects in traditional choline amino acid ionic liquids. In this study, nine types of choline acetyl-amino acid ionic liquids ([Ch][Ac-AA]ILs) were synthesized using acetylated amino acids (Ac-AA) as anions and choline (Ch) as cations. The physicochemical properties and tribological behavior of [Ch][Ac-AA]ILs at different frequencies were evaluated. The results demonstrated that [Ch][Ac-AA]ILs exhibited excellent tribological properties and maintained effective lubrication even under high-frequency friction conditions compared to sodium hyaluronate (HA-T). This performance was attributed to the carbon chain length and functional group composition of [Ch][Ac-AA]ILs' anions. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy analysis revealed that the superior lubrication performance of [Ch][Ac-AA]ILs was associated with the formation of chemical reaction films and physical adsorption films on the surface of friction pairs. This research enriches our understanding of [Ch][AA]ILs-based lubrication systems while providing valuable insights for selecting joint lubricants suitable for different activity frequencies.

Effect of Amino Acid Types on the Mechanical and Antimicrobial Properties of Amino Acid-Based Polyionic Liquid Hydrogels.

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.

Effect of choline amino acid ionic liquids on maize seed germination and endogenous plant hormone levels.

Prior research has established choline-based ionic liquids (ILs) as safe for various organisms. However, their impact on plants has been underexplored. To identify effective eco-friendly ILs, we synthesized seven choline amino acid ([Chl][AA]) ILs and analyzed their physiological influence on maize seed germination. In contrast to the traditionally used N-octyl pyridinium bromide IL, these seven [Chl][AA] ILs exhibited substantially lower toxicity. Moreover, within a broad treatment concentration range (10-100 mg L-1), these ILs notably enhanced maize germination indices and root and shoot growth. Specifically, treatment with 100 mg L-1 choline tryptophan resulted in a 21.2% increase in germination index compared to those of control maize. Compared to the control, the application of choline serine, choline aspartic acid, choline phenylalanine, and choline tryptophan at 100 mg L-1 led to respective increases of 23.9%, 21.5%, 22.5%, and 24.5% in maize shoot length. Analysis of endogenous hormones and free amino acid contents revealed elevated levels of growth-promoting plant hormones (gibberellic acid and zeatin) in maize shoot tips, as well as increased contents of major amino acids (glutamate, glycine, and arginine) following treatment with different [Chl][AA] ILs at 100 mg L-1. These findings indicate that [Chl][AA] holds promise for the development and application of novel low-toxicity ILs.

Removal of Acetaminophen (Paracetamol) from Water Using Aqueous Two-Phase Systems (ATPSs) Composed of Choline-Amino Acid Ionic Liquids

Removal of Acetaminophen (Paracetamol) from Water Using Aqueous Two-Phase Systems (ATPSs) Composed of Choline-Amino Acid Ionic Liquids

Thermodynamic and spectroscopic studies of biotin supplement in aqueous solution of biocompatible choline amino acid ionic liquids

Thermodynamic and spectroscopic studies of biotin supplement in aqueous solution of biocompatible choline amino acid ionic liquids

Choline amino acid ionic liquids as green corrosion inhibitors of mild steel in acidic medium

The corrosion inhibition performance of three choline amino acid ionic liquids ([Ch][AA]ILs) for mild steel in 1 M HCl solution was evaluated by electrochemical analysis, gravimetric measurement, and surface morphological characterization in the temperature range of 298–328 K in this paper. The results of the polarization experiments show that [Ch][AA]ILs affect the cathode and anode reaction processes, proving that [Ch][AA]ILs are mixed corrosion inhibitors. Choline phenylalanine ionic liquids ([Ch][Phe]) exhibit the highest corrosion prevention efficiency among the three chosen corrosion inhibitors, as proven by SEM/EDS scanning, XPS analysis, and molecular dynamics simulation. The values of standard free energy of adsorption ΔGads range between − 20 kJ·mol-1 and − 40 kJ·mol-1, showing that inhibitor molecule adsorption on the metal surface involves both physical and chemical adsorption. According to the results of XPS research and quantum chemical calculations, the adsorption of corrosion inhibitor molecules on the metal surface is strongly related to the anions. The corrosion inhibitor molecules form a thick monolayer adsorption layer on the metal surface, preventing metal-corrosive media interaction. The molecular dynamics simulation findings reveal that the corrosion inhibitor molecules replace the solvent water or any other ions pre-adsorbed on the metal surface during the adsorption process, protecting the metal from corrosion.

Reaction Mechanism of CO2 with Choline-Amino Acid Ionic Liquids: A Computational Study.

Carbon capture and sequestration are the major applied techniques for mitigating CO2 emission. The marked affinity of carbon dioxide to react with amino groups is well known, and the amine scrubbing process is the most widespread technology. Among various compounds and solutions containing amine groups, in biodegradability and biocompatibility perspectives, amino acid ionic liquids (AAILs) are a very promising class of materials having good CO2 absorption capacity. The reaction of amines with CO2 follows a multi-step mechanism where the initial pathway is the formation of the C-N bond between the NH2 group and CO2. The added product has a zwitterionic character and can rearrange to give a carbamic derivative. These steps of the mechanism have been investigated in the present study by quantum mechanical methods by considering three ILs where amino acid anions are coupled with choline cations. Glycinate, L-phenylalanilate and L-prolinate anions have been compared with the aim of examining if different local structural properties of the amine group can affect some fundamental steps of the CO2 absorption mechanism. All reaction pathways have been studied by DFT methods considering, first, isolated anions in a vacuum as well as in a liquid continuum environment. Subsequently, the role of specific interactions of the anion with a choline cation has been investigated, analyzing the mechanism of the amine-CO2 reaction, including different coupling anion-cation structures. The overall reaction is exothermic for the three anions in all models adopted; however, the presence of the solvent, described by a continuum medium as well as by models, including specific cation- -anion interactions, modifies the values of the reaction energies of each step. In particular, both reaction steps, the addition of CO2 to form the zwitterionic complex and its subsequent rearrangement, are affected by the presence of the solvent. The reaction enthalpies for the three systems are indeed found comparable in the models, including solvent effects.

Choline amino acid ionic Liquids: A novel green potential lubricant

Given the depletion of global energy and crisis of environmental pollution, the social demand for lubricants concerning green and socioeconomic benefits is becoming stronger. Herein, a series of eco-friendly, non-corrosive and cost-effective choline amino acid ionic liquids ([Ch][AA]) ILs were synthesized. Among the five [Ch][AA] ILs, long-alkyl-chain and guanidyl group-containing ILs display superior wettability, kinematic viscosity and load-carrying property. Regulation of tribological behavior is achieved through the assembly of anionic structure. Additionally, various friction conditions govern the lubrication regime of [Ch][AA] ILs. Concurrently, the friction-heat is predicted according to the thermal-physical properties. Furthermore, lubrication performance of [Ch][AA] ILs is comparable to polyalphaolefin oil (PAO 40) in various lubrication regime, which are attributed to the resulting thermal-physical properties and physical adsorption tribofilms. This work not only perfects the lubricating system of the [Ch][AA] ILs, but also is of great significance to elucidating the applicable conditions of desired [Ch][AA] ILs lubricants.

Nanostructure in amino acid ionic molecular hybrid solvents

Choline amino acid ionic liquids ([Ch][AA]ILs) have shown outstanding capacity for extraction and biomass pre-treatment but their very high viscosity renders them difficult to handle and inhibits their large-scale application. As a result, [Ch][AA]ILs are commonly mixed with a low-viscosity molecular solvent such as water to form hybrid solvents, which preserves the favourable characteristics of ILs while enhancing physical properties. Here we investigate the structure of binary mixtures of choline lysinate and phenylalaninate with water and primary alcohols. Contrast-variation neutron diffraction and computational modelling shows the nanostructure of both [Ch][AA]ILs can be engineered by mixing with alcohols up to high concentrations, and that the abundance of hydrogen-bond donors is a critical determinant of the overall liquid structure. This provides a new strategy to engineer and fine tune solvent nanostructure for the design of application-specific, biofriendly hybrid solvent systems.

Design and applications of biocompatible choline amino acid ionic liquids

ChAAILs are often used in mixtures to lower cost and improve handling, but the effects of water and other molecular additives are poorly understood. This review describes structure at different dilution stages and design strategies for task-specific ChAAIL-based mixtures.

Aqueous choline amino acid deep eutectic solvents.

We have investigated the structure and phase behavior of biocompatible, aqueous deep eutectic solvents by combining choline acetate, hydrogen aspartate, and aspartate amino acid salts with water as the sole molecular hydrogen bond donor. Using contrast-variation neutron diffraction, interpreted via computational modeling, we show how the interplay between anion structure and water content affects the hydrogen bond network structure in the liquid, which, in turn, influences the eutectic composition and temperature. These mixtures expand the current range choline amino acid ionic liquids under investigation for biomass processing applications to include higher melting point salts and also explain how the ionic liquids retain their desirable properties in aqueous solution.

Upgrading the Topical Delivery of Poorly Soluble Drugs Using Ionic Liquids as a Versatile Tool.

Numerous studies are continuously being carried out in pursuit of formulations with higher performance. Problems such as poor drug solubility, which hinders drug incorporation into delivery systems and bioavailability, or limitations concerning the stability and performance of the formulations may cause difficulties, since solving all these drawbacks at once is a huge challenge. Ionic liquids (ILs), due to their tunable nature, may hypothetically be synthesized for a particular application. Therefore, predicting the impact of a particular combination of ions within an IL in drug delivery could be a useful strategy. Eight ILs, two choline amino acid ILs, two imidazole halogenated ILs, and four imidazole amino acid ILs, were prepared. Their applicability at non-toxic concentrations, for improving solubility and the incorporation of the poorly soluble, ferulic, caffeic, and p-coumaric acids, as well as rutin, into topical emulsions, was assessed. Next, the impact of the ILs on the performance of the formulations was investigated. Our study showed that choosing the appropriate IL leads to a clear upgrade of a topical emulsion, by optimizing multiple features of its performance, such as improving the delivery of poorly soluble drugs, altering the viscosity, which may lead to better sensorial features, and increasing the stability over time.

Unusual origin of choline phenylalaninate ionic liquid nanostructure

Choline amino acid ionic liquids have received much attention recently due to their environmental friendliness and low toxicity. Some of these ionic liquids have shown outstanding capacity for biomass and coal pretreatment, yet it remains unclear what structural features underpin performance. Despite sharing many structural features with other choline amino acid ionic liquids proven to be effective at lignin extraction, choline phenylalaninate (ChPhe) is surprisingly among the poorest solvents at such application. Using multi-contrast neutron diffraction we show that the liquid nanostructure of ChPhe – consisting of apolar domains in a continuous polar network – primarily consists of small clusters stabilised by inter-anion hydrogen bonds between amine and carboxylate groups. Within the apolar regions, phenyl side-chain rings adopt no preferred arrangements, signaling the absence of π-π stacking, but instead show evidence of competing cation-π interactions. This is the first example of self-assembled ionic liquid nanostructure not of solvophobic origin. The unusual suite of interactions also explains its water miscibility but inability to retain nanostructure upon water dilution, as well as its poor performance for biomass pretreatment, and provides a new strategy by which to engineer and tune ionic liquid nanostructure for the design of application-specific, renewable solvent systems.

Green choline amino acid ionic liquids aqueous two-phase extraction coupled with synchronous fluorescence spectroscopy for analysis naphthalene and pyrene in water samples

A novel aqueous two-phase extraction method has been established for the determination of polycyclic aromatic hydrocarbons in water sample. This method was based on the extraction of naphthalene and pyrene from water by means of choline amino acid ionic liquids aqueous two-phase system and their determination by synchronous fluorescence spectroscopy. In synchronous fluorescence spectroscopy, the fluorescence peaks of naphthalene and pyrene were completely separated to meet the requirement of simultaneous determination. For this method, good linear calibration curves of naphthalene and pyrene were obtained in the range of 0.50–10.0, 0.05–5.0 μg mL−1, respectively, and limits of detection were 0.211, 0.012 μg mL−1, respectively. The proposed method was successfully applied for the simultaneous determination of naphthalene and pyrene in water samples, which was considered as an excellent green analysis according Analytical Eco-Scale.

Anticancer Activity of Rutin and Its Combination with Ionic Liquids on Renal Cells.

The renal cell carcinoma (RCC) is the most common type of kidney cancer. Identifying novel and more effective therapies, while minimizing toxicity, continues to be fundamental in curtailing RCC. Rutin, a bioflavonoid widely found in nature, has shown promising anticancer properties, but with limited applicability due to its poor water solubility and pharmacokinetics. Thus, the potential anticancer effects of rutin toward a human renal cancer cell line (786-O), while considering its safety in Vero kidney cells, was assessed, as well as the applicability of ionic liquids (ILs) to improve drug delivery. Rutin (up to 50 µM) did not show relevant cytotoxic effects in Vero cells. However, in 786-O cells, a significant decrease in cell viability was already observed at 50 µM. Moreover, exposure to rutin caused a significant increase in the sub-G1 population of 786-O cells, reinforcing the possible anticancer activity of this biomolecule. Two choline-amino acid ILs, at non-toxic concentrations, enhanced rutin’s solubility/loading while allowing the maintenance of rutin’s anticancer effects. Globally, our findings suggest that rutin may have a beneficial impact against RCC and that its combination with ILs ensures that this poorly soluble drug is successfully incorporated into ILs–nanoparticles hybrid systems, allowing controlled drug delivery.

Structural effects of choline amino acid ionic liquids on the extraction of bovine serum albumin by green and biocompatible aqueous biphasic systems composed of polypropylene glycol400 and choline amino acid ionic liquids

Ionic liquid-based aqueous biphasic systems (IL-based ABSs) are considered as promising extraction and purification routes. For designing an efficient process of protein extraction, it is necessary to complete information about phase diagrams including binodal and tie-lines for new ABSs. In this respect, here, binodal curves and tie-lines for ternary aqueous solutions composed of polypropylene glycol 400 and some of choline amino acid ionic liquids, [Ch][AA]-ILs, including choline L-histidine, choline L-arginine, choline L-proline, and choline L-valine as a green and biocompatible entrainers have been determined at T = 298.15 under atmospheric pressure (≈85 kPa). The results indicated that the binodals of these ABSs affected strongly by the ILs structures; so that, biphasic region is increased by decreasing of hydrophobicity of IL anion from valine to arginine. The effective exclude volume theory (EEV) and Setschenow equation have been utilized for addressing phase formation capability in these systems. Phase formation ability in these ABSs followed in the order: choline L-arginine > choline L-histidine > choline L-proline > choline L-valine which is parallel with an increasing hydrophilicity of amino acid exists in each of IL structures. Moreover, osmotic virial equation was used for modeling of tie-lines in the studied ABSs. Finally, the performance of these ABSs for separation of biomolecules was evaluated by studying the partition behavior of bovine serum albumin, BSA, via measuring of partition coefficient and extraction efficiency. The obtained results from BSA partitioning in these ABSs indicated that BSA is migrated preferentially to the [Ch][AA]-ILs-rich bottom phase and this migration is increased by increasing hydrophilicity of amino acid exists in IL structure, i.e. choline L-arginine > choline L-histidine > choline L-proline > choline L-valine. Also, it was found that the salting-out effect and π-π interactions between BSA and [Ch][AA]-ILs have important role in BSA partitioning as well as hydrophilicity/hydrophobicity interactions.

Thermodynamic and transport investigation of aqueous solutions containing choline L-histidinate and some water soluble polymers such as polyethylene glycol di methyl ether, polyethylene glycol and polypropylene glycol: Evaluation of solute-solvent interactions and phase forming ability

Considering to the importance of choline amino acid ionic liquids, [Ch][AA]-ILs, as green biocompatible and biodegradable solvents utilized for separation of proteins through inducing aqueous biphasic systems in the presence of some water soluble polymers, it is vital to elucidate the solute-solute and solute-solvents interactions in water media which may be responsible for phase separation. In this respect, density, sound speed and viscosity of choline L-histidine, [Ch][L-His], in water and aqueous solutions of three polymers containing polyethylene glycol dimethyl ether 250, PEGDME250, polypropylene glycol 400, PPG400, and polyethylene glycol 400, PEG400, have been measured experimentally at T = (288.15 to 318.15) K and 298.15 K under atmospheric pressure, respectively. The obtained data from these measurements were employed for computing the limiting values for apparent molar volume (Vφ0), molar isentropic compressibility (κφ0), transfer molar volume (ΔtransVφ0) and isentropic compressibility (Δtransκφ0) for transferring [Ch][L-His] from water to aqueous polymer solutions, viscosity B-coefficient, transfer viscosity B-coefficient (ΔtransB), free energies of activation per mole of solvent (Δμ10≠) and solute (Δμ20≠). These quantities provide some useful information about [Ch][L-His]-polymer and [Ch][L-His]-water interactions, soluting-out ability of IL and capability of above ternary solutions for separation into two-phases. The results showed that the ΔtransVφ0 values for PPG and PEGDME are negative which indicates that IL-water interactions become stronger in the presence of these polymers. But, in the case of PEG, a positive value of ΔtransVφ0 shows that the IL-water interactions are weaker in the presence of this polymer.

Volumetric, acoustic and viscometric investigation of some choline amino acid ionic liquids in aqueous solutions of polypropylene glycol 400 and polyethylene glycol 400

Present study reports density (ρ), ultrasonic velocity (u), and viscosity (η) for some choline amino acid ionic liquids, [Ch][AA]-ILs, including choline glycine, choline L-valine and choline L-proline in aqueous solutions of two water soluble polymers, i.e. polypropylene glycol 400 (PPG400) and polyethylene glycol 400 (PEG400) with different mass fractions of polymer, w/w = (0.025, 0.050 and 0.075), at 298.15 K under atmospheric pressure (≈85 kPa). The experimental densities and sound speeds were used for calculation the apparent molar volume (Vφ), limiting apparent molar volume (Vφ0), apparent molar isentropic compressibility (κφ), limiting apparent molar isentropic compressibility (κφ0), and also the transfer molar volume (ΔtranVφ0) and isentropic compressibility (Δtranκφ0) of [Ch][AA] from water to aqueous polymer solutions. Moreover, the viscosity B-coefficient, hydration number (nH), transfer viscosity B-coefficient (ΔtranB), free energies of activation per mole of solvent (Δμ10≠) and solute (Δμ20≠) have been computed by the help of experimental viscosities measured for the studied solutions. These quantities are useful for evaluation the ILs solvation behaviour, their structure-making or breaking abilities in the presence of polymer in water medium and also the solute-solute or solute-solvent interactions exists in aqueous ([Ch][AA] + polymer) solutions. The results indicated that the IL-water interactions are more favourable in the presence of PPG400 and follow the order: [Ch][Gly] > [Ch][L-Pro] > [Ch][L-Val]. Inversely, the IL-water interactions become weaker by ILs transferring from water to aqueous PEG400 solutions.

The role of ionic association of choline amino acid ionic liquids on the two-phase formation and extraction of bovine serum albumin in ATPSs containing PEGDME250 and choline histidine or choline arginine at different temperatures

The choline amino acid ionic liquids, [Ch][AA]-ILs, as atoxic task-specific solvents are used for inducing an aqueous two-phase systems, ATPSs, in the presence of polymers such as polyethylene glycol di-methyl ether 250, PEGDME250. In these ILs, depending on anions structure the varied and strong interactions are existed between choline cation, [Ch]+, and amino acid anions, [AA], leading to an increase of ion association. These interactions affect ILs hydration behavior and therefore the studying of these ionic associations in some detail are useful in regard to phase formation ability. In this respect, binodal curve locations and tie-lines for ATPSs composed of PEGDME250 and choline histidine or choline arginine have been determined at three temperatures (298.15–318.15) K under atmospheric pressure (≈85 kPa) and followed by searching the effects of structure and ionic association of ILs together with temperatures on the phase diagram. The ionic association constants of the above ILs together with the previously studied ILs were calculated from ionic conductivity measurements made on the these binary aqueous IL solutions at T = (288.15–318.15) K using low concentration Chemical Model method. For correlation of equilibrium data the Othmar-Tobias, Bancraft and Setschenow equations along with osmotic virial and NRTL (e-or m-NRTL) models were utilized. Finally, influences of ionic association of ILs and temperature were investigated on the separation of bovine serum albumin. The results show that phase forming ability of different [Ch][AA]-ILs is increased by decreasing of Ka values which is parallel with decreasing of amino acid hydrophobicity.