Acidic Ionic Liquid Research Articles

Improvement of tetracycline removal using amino acid ionic liquid modified magnetic biochar based on theoretical design

In current research, biochar is widely used to remove antibiotic contamination from the environment. However, original biochar produced through direct pyrolysis has significant limitations in removing antibiotics. In this paper, response surface methodology provided the laudable choice for magnetic poplar biochar (MPBC) considering the synergistic effect of multi-factors as well as the restrictions abundance experiments during the preparation of MPBC. Amino acid ionic liquids (AAILs) are a class of ionic liquids in which amino acids act as the anionic component, combining the tunable properties of ionic liquids with the biocompatibility and functionality of amino acids. To ameliorate adsorption capacity of MPBC, tetra-ethylammonium glycinate ([TEA][Gly]) with the best affinity for tetracycline (TC) were screened from 600 AAILs based on theoretical predictions using the conductor-like screening model for real solvents (COSMO-RS) without extensive experimental. Furthermore, AAILs-modified magnetic biochar (MPBC-AAIL) was synthesized chemically for the first time. Adsorption kinetics, isotherms, and thermodynamic analyses revealed that TC adsorption by both MPBC and MPBC-AAIL is a monolayer, spontaneous, and exothermic chemical process. Moreover, MPBC-AAIL exhibited a maximum adsorption capacity of 305.9 mg·g−1. Meanwhile, MPBC-AAIL maintains superior adsorption performance for TC in different impurity solutions as well as in real water samples. The excellent reusability and selective adsorption capacity of the material demonstrate the superiority of the theoretical based design. The characterization reveals that the adsorption mechanisms include pore filling, π-π interactions, surface complexation, hydrogen bonding, and electrostatic interactions. In addition, theoretical calculations showed that ionic liquid modification altered the adsorption sites between TC and MPBC-AAIL, leading to enhanced adsorption. This comprehensive study introduces an innovative modification of biochar, providing a novel approach to designing biochar composites and promoting their application in the remediation of complex environmental pollution.

Efficient selective CO2 composite sorbent from amino acid ionic liquids and silica gel: Insight on the CO2-binding mechanism and in-pore microscopic viscosity by means of 2H NMR.

A promising CO2 sorbent based on the [Emim][Gly]/silica gel composite has been studied. Absorption experiments have shown that the optimum loading of [Emim][Gly] ionic liquid in silica gel is 40 wt%. The 2-step process CO2 binding mechanism in [Emim][Gly] has been proposed based on the results of absorption experiments, 2H NMR spectroscopy and ab-initio calculations. The impact of CO2 on the microscopic viscosity and the dynamical melting of ionic liquid has been thoroughly investigated. 2H NMR spectroscopy has revealed that CO2 strongly binds cation and anion in [Emim][Gly], forcing them to move in a correlated fashion.

Hierarchically fibrillated spunlaced nonwovens from waste wool supported ionic liquid as solid amine adsorbents for CO2 capture

The environmental crisis caused by excessive emissions of carbon dioxide-based greenhouse gases has garnered widespread public concern. Solid amine is considered to be one of the most effective carbon dioxide (CO2) adsorbents. However, traditional solid amine carriers have problems such as structural collapse, low efficiency and poor regeneration. In this study, waste wool having hierarchical fibrous structure was spunlaced, fibrillated and later compounded with amino acid ionic liquids (AAIL) leading to the formation of the AAIL@feather-like wool nonwoven absorbents. A synergistic co-amine effect was observed after primary and secondary fibrillation without any sacrifice in the mechanical property of wool nonwovens. Also, the fibrillated nonwovens had high specific area which provided high loading rate (13.53 %) on AAIL. Compared with untreated wool nonwovens, the CO2 adsorption capacity of feather-like wool nonwovens was higher by 65 % (11.75 mmol/g) after loading AAIL. Furthermore, the CO2 adsorption capacity was retained (95.2 %) even after 12 cycles at 80 ℃, indicating that the AAIL@ feather-like wool nonwovens possess good long-term stability. This work paves the way for large scale manufacturing of biobased solid adsorbents with a hierarchical nonwoven structure for efficient CO2 capture.

Reusable magnetic room-temperature Brönsted acidic ionic liquid: synthesis, characterization and evolution of catalytic and biological properties

Reusable magnetic room-temperature Brönsted acidic ionic liquid: synthesis, characterization and evolution of catalytic and biological properties

Diosgenin production from Dioscorea zingiberensis tubers by novel pressurized hydrolysis in acidic ionic liquids

Diosgenin production from Dioscorea zingiberensis tubers by novel pressurized hydrolysis in acidic ionic liquids

Acidic phosphonium-based ionic liquid encapsulated on titania particles with enhanced electrorheological response

Research on electrorheological (ER) fluids has led to significant advancements in the development of smart materials that adjust their viscosity in response to applied electric fields. This study focused on synthesizing titania ionogel-based particles (TiO2-IL) using an environmentally friendly sol-gel process involving tetrabutoxy-titanium (TBT) combined with an ionic liquid (IL), specifically 11-carboxyundecyl-triphenyl-phosphonium bromide. The successful incorporation of the IL into the TiO2 particles was confirmed through thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and zeta potential analysis. The electrorheologial properties of TiO2-IL ionogel suspension in silicone oil were compared with those of pure TiO2 suspension. The addition of the ionic liquid (IL) significantly enhanced the electrorheological (ER) properties of the fluid, achieving a shear stress of approximately 1340Pa at an electric field strength of 5kV/mm. The fluid also exhibited excellent reversibility and a rapid response to changes in the electric field, which is attributed to the higher polarizability by the IL. Furthermore, the study observed low current density during operation, which helps maintain the fluid’s integrity and longevity under high electric fields. The fluids demonstrated stable ER effect across a temperature range of 40 to 70 ℃ and a reasonable sedimentation stability of around 80%. These characteristics, combined with the moderate conditions for particle preparation, make the TiO2-IL fluid a promising candidate for ER applications.

Lipid bilayer permeabilities and antibiotic effects of tetramethylguanidinium and choline fatty acid ionic liquids

Ionic liquids (ILs) have been studied as potential components in antibiotic formulations based on their abilities to permeabilize and penetrate lipid bilayer, which correlate with their antibacterial effects. Fatty acid-based ILs (FAILs), in which the anion is a long-chain fatty acid, can permeabilize lipid membranes and have been used in biomedical applications since they have low human cell cytotoxicity. In this work we investigated the abilities of several different FAILs to permeabilize lipid bilayers and how that permeabilization correlates with antibacterial activity, cell membrane permeability, and cytotoxicity. The FAILs consisted of the cations tetramethylguanidinium (TMG) or choline combined with octanoate or decanoate. These FAILs were tested on model bilayer vesicles with three different lipid compositions for membrane permeabilization using a leakage assay. They were then tested for antibiotic and membrane permeabilization on bacterial and mammalian cells. The results show that while the octanoate-based FAILs do not form micelles and have low activities on vesicles and biological cells, the decanoate-based FAILs can permeabilize bilayers and have biological activities that correlate with the model vesicle results. The ILs with both cation and fatty-acid anion have strong activities while the decanoate alone has only minimal permeabilization and antibiotic activity. Membrane permeabilization occurs at FAIL concentrations below their CMC values which suggests that their mechanism of action may not involve micelle formation.

Synthesis and application of merrifield resin based supported ionic liquids as organocatalyst for the greener synthesis of bio-active triazoles

A green and highly efficient catalysts based on merrifield resin supported acidic ionic liquids (MRBT-SILs) were synthesized using merrifield resin (non-toxic and chemically inert) and benzothiazole. The application of MRBT-SILs for the greener synthesis of 1,2,4-triazole-3-thiones or 1,2,4-triazole-3-oxones from condensation of ketones and thiosemicarbazide or semicarbazide respectively in 60% ethanol under ultra-sonication was studied. The protocol so developed has many additional benefits compared to those reported in previous articles such as smooth reaction, use of alcohol as solvent, good yield, ambient temperature, an easy workup procedure, catalyst recyclability, and high atom economy, making it highly efficient for synthesis as it obeys green chemistry principles. Further, catalyst could be reused up to eight cycles without any loss of its catalytic activity.

Ionic liquid supported chitosan-g-SPA as a biopolymer-based single ion conducting solid polymer electrolyte for energy storage devices

This article discusses the preparation of different grades of single-ion conducting quasi-solid polymer electrolytes (q-SPE) material (Chit-g-SPA-IL) based on biopolymer (chitosan), polyacrylic acid and DBU-acetate (DBUH+ AcO−) ionic liquid. Chit-SPA-60 %-IL exhibited the highest conductivity within the range of 10−4 S/cm. TGA analysis demonstrated the stability of electrolytes up to a temperature of 120 °C. SEM-EDS analysis unveiled the porous nature of the electrolyte and even distribution of ions throughout the matrix. It exhibited an electrochemical stability window (EWS) of 2.53 V with significant current density and an ionic transference number (ITN) of ~99.9 %. The temperature-dependent conductivity established an Arrhenius-type conduction mechanism with an activation energy of 0.149 eV for ion movement within the electrolyte matrix. The AC conductivity analysis emphasized the time-temperature independence of the ionic conduction mechanism. Dielectric analysis highlighted the capacitive nature of the electrolyte, underlining its substantial capacitance, while modulus studies indicated minimal influence from the electrode-electrolyte interface. Chit-SPA-60 %-IL at 30 °C included a self-diffusion coefficient of 4.57 × 10−5 m2/s, ionic mobility of 1.75 × 10−3 m2/Vs, and drift ionic velocity of 0.44 m/s. These findings makes SPE as a promising candidate for sodium-ion-based energy storage devices.

Ionic Liquid-Mediated Transdermal Delivery of Organogel Containing Cyclosporine A for the Effective Treatment of Psoriasis.

The dermal delivery of peptide therapeutics that are of high molecular weight is a challenge. Cyclosporine A (CsA) is a cyclic undecapeptide with poor aqueous solubility and high molecular weight (1202 Da) indicated for psoriasis. The objective of the study was to evaluate the effect of ionic liquids mixed with the Pluronic F127 matrix in skin permeation of CsA and its efficacy in psoriasis treatment. Choline and geranic acid (CAGE) ionic liquids in a 1:2 molar ratio were mixed with Pluronic F127 (22.7%) and PEG 400 (45%) to prepare an organogel formulation. The CsA-loaded CAGE (CsA-CAGE) and CAGE-Pluronic F127 gels (CsA-CAGE-P gel) were characterized for physical and rheological characteristics. The skin transport studies showed that free CsA did not permeate across the excised porcine skin after 48 h. The amount of CsA permeated across the oleic acid (0.25% v/v) and palmitic acid (0.25% w/v) cotreated skin was found to be 244 ± 4 and 1236 ± 17 μg/cm2, respectively. The application of CsA-CAGE and CsA-CAGE-P gel enhanced CsA flux by 110- and 135-fold, respectively, compared with the control. The thermal analysis and biophysical studies changed the barrier property of the skin significantly (p < 0.05) after incubation with CAGE and CAGE-P gel. The pharmacokinetic studies in the rat model showed that topical application of CsA-CAGE-P gel provided 2.6- and 1.9-fold greater C max and AUC0-t, respectively, compared to the control group. In vitro-in vivo level A correlations were established with R 2 values of 0.991 and 0.992 for both linear and polynomial equations for the CsA-CAGE-P gel formulation using the Wagner-Nelson method. The topical application of CsA-CAGE-P gel (10 mg/kg) on an imiquimod-induced plaque psoriatic model reduced the area of the psoriasis and severity index (PASI) score significantly for erythema and scaling, reversing the changes to skin thickness, blood flow rate, and transepidermal water loss. Together, CAGE-Pluronic F127 organogel was developed as an effective topical formulation for the local and systemic delivery of CsA for the treatment of psoriasis.

BPBSBDM as an influential Brønsted acidic ionic liquid catalyst in preparing bis(pyrazolyl)methanes under mild conditions

BPBSBDM as an influential Brønsted acidic ionic liquid catalyst in preparing bis(pyrazolyl)methanes under mild conditions

Enhancing CO2 adsorption performance of cold oxygen plasma-treated almond shell-derived activated carbons through ionic liquid incorporation

To enhance the CO2 adsorption of almond shell-derived activated carbon (AC) samples treated with cold oxygen plasma, the samples were impregnated with cholinium-amino acid ionic liquids ([Cho][AA] ILs) using the vacuum-assisted impregnation method. The physicochemical and textural properties of the resulting composites (ILs@AC) were characterized using various techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy, and Brunauer-Emmett-Teller (BET) surface area measurement. The CO2 adsorption performance of the samples was evaluated using a quartz crystal microbalance (QCM) over a temperature range of 288.15–308.15 K and gas pressures up to 1 bar. The IL@AC composite materials exhibited notably improved CO2 adsorption capacities compared to pristine AC. The CO2 adsorption isotherms onto the IL@AC composite samples closely conformed to the Langmuir isotherm model, indicating the dominant involvement of strong intermolecular interactions, particularly driven by amine functionalities. Meanwhile, the results revealed that [Cho][His]@AC showed lowered CO2 adsorption capacity compared to [Cho][Pro]@AC and [Cho][Gln]@AC. Among the studied ionic liquids, [Cho][Pro]@AC showed the highest absorption capacity (2.332 mmol·g−1 at 288 K and 1 bar). This was due to the obstruction of internal pores within the AC structure caused by excessive amine incorporation into its porous framework. In the meantime, for a deeper insight into the impregnation process of ILs onto the AC surfaces and their potential interactions with CO2 molecules, we conducted density-functional theory (DFT) calculations using the ωB97XD/6-31 + G(d,p) method. The calculated interaction energies, ranging from − 1.19 to − 1.44 eV, along with calculated quantum chemical descriptors, indicated a notable stabilization of IL species on the AC surfaces, with high affinity toward CO2 molecules.

Brønsted Acidic Ionic Liquid: An Efficient Organocatalyst for the Synthesis of Pyrrolo[1,2‐a]indoles under Neat Conditions

A new synthetic approach has emerged for constructing the 9H-pyrrolo[1,2-a]indole scaffolds by the reactions between indoles and chalcones under metal and solvent-free conditions at 80 °C. The reaction occurs smoothly in presence of Brønsted acidic ionic liquid named 1-butane sulfonic acid-3-methylimidazolium tosylate, [BSMIM]OTs (BAIL) as a catalyst, enabling the synthesis of the desired products with satisfactory yields. The developed protocol is applicable for the construction of biologically important pyrrolo[1,2-a]indole derivatives from easily accessible chalcones having various substituents. The process commenced with Michael addition to chalcones, followed by annulations induced by the elimination of a water molecule yielded the 9H-pyrrolo[1,2-a]indole scaffolds. Few control experiments were carried out for better understanding the reaction pathway. The feasibility of catalyst recycling was also demonstrated. This method produces only water as the byproduct and represents a green synthetic protocol. Clean reaction, easily accessible reactants, and metal and solvent-free and environmentally friendly reaction conditions are the notable advantages of this procedure.

Brønsted Acid Ionic Liquid Catalyzed Depolymerization of Poly-(3-hydroxybutyrate) to 3-Hydroxybutyric Acid: Highly Selective and Sustainable Transformation in Methyl Isobutyl Ketone and Water-Containing Phase-Separable Reaction Media

Brønsted Acid Ionic Liquid Catalyzed Depolymerization of Poly-(3-hydroxybutyrate) to 3-Hydroxybutyric Acid: Highly Selective and Sustainable Transformation in Methyl Isobutyl Ketone and Water-Containing Phase-Separable Reaction Media

Sustainable and versatile Aza-Michael additions promoted by acidic ionic liquids

Acidic ionic liquids are a subset of ionic liquids where the cation or anion possess acidic properties with huge applications in various fields. Here we describe environmentally safe and highly efficient conjugate addition of aromatic and aliphatic amines to α, β-unsaturated compounds in the presence of novel acidic ionic liquids. The acidic ionic liquid catalyst was prepared by combining benzyl chloride with 2-(dimethylamino) ethanol and SnCl2 in a simpler manner. The resulting acidic ionic liquid was characterized using SEM, EDS and FTIR spectroscopy. In the presence of ionic liquids, a wide variety of amines undergo facile conjugate addition to α, β-unsaturated compounds affording the corresponding β-amino compounds in good to excellent yields (72–97 %), shorter reaction times (1–4 h) and mild reaction conditions (60 °C). Furthermore, the study demonstrated the sustainability of the process by showcasing that the acidic ionic liquids could be reclaimed and reused for up to five cycles without compromising their catalytic effectiveness.

Selective adsorption of trace CO2 by immobilized amino acid ionic liquids with ultra-micropores based on amino MOFs

Great attention has been paid to effectively capture trace CO2 in air or a confined space for ensuring human safety, but it remains challenging to enhance CO2 capacity and selectivity concurrently. In this study, metal–organic frameworks (MOFs) were combined with amino groups (NH2-MIL-125(Ti) and NH2-UIO-66(Zr)) and amino acid anion-functionalized ionic liquids (ILs), namely 1-Butyl-3-methylimidazolium glycinate ([BMIm]Gly) and 1-Butyl-3-methylimidazolium arginine ([BMIm]Arg) to prepare various ionic liquid (IL) composites containing various IL contents. Relative to pristine supports, incorporating ILs significantly enhanced CO2 capacity together with CO2/N2 selectivity, in particular in the confined spaces (<5000 ppm) or in air (415 ppm). At a 50 wt% IL loading, new ultra-micropores (<0.65 nm) could be obtained in IL-NH2-UIO-66(Zr) composite, but they did not occur within pristine supports or the rest IL-NH2-UIO-66(Zr) (10 wt%, 30 wt% and 70 wt%). Among them, CO2 uptake of 50 wt% [BMIm]Arg-NH2-UIO-66(Zr) peak at 0.0005 and 0.005 bar (2.93 and 3.87 mmolCO2/g-adsorbent, respectively) at 313 K; besides, recyclability significantly increased compared with the latest values reported. Additionally, the excellent optimal CO2/N2 selectivity was determined to be 8916 at 0.005 bar and 288 K, which increased by 254.7 folds relative to NH2-UIO-66(Zr). In the meantime, as revealed by mixed gas breakthrough experimental results, 50 wt% [BMIm]Arg-NH2-UIO-66(Zr) showed superb CO2 separation effect in air and simulated confined spaces. Such ultra-high CO2 separation efficacy is associated with the synergistic effect of chemical interaction of IL anion with amino groups in MOFs and CO2 and the novel ultra-micropore effect. Findings in the present work shed more lights on designing hierarchically porous IL composites that possess ultra-micropores to efficiently remove trace CO2.

Introduction of amino acid ionic liquid into the gelatin matrix enhances the performance of immobilized laccase in degrading 2,4-dichlorophenol

The utilization of immobilized laccase to degrade and remove phenolic pollutants in water has promising application prospects. However, maintaining the activity and stability of the immobilized laccase remains a significant challenge. In this work, an amino acid-based ionic liquid (IL) modified magnetic composite material (IL-Magnetic gelatin) was prepared as a support for laccase immobilization. We conducted a detailed characterization of the nanocomposite and it exhibited excellent magnetic responses and dispersion. The catalytic performance of the immobilized enzyme was also investigated. Compared to free laccase, the immobilized laccase (Lac-IL-Magnetic gelatin) exhibited higher catalytic activity and better thermal stability. The various interactions (hydrogen bonds, ionic interaction) between enzyme molecule and ionic liquid can cause conformational rearrangement of laccase. Lac-IL-Magnetic could degrade 98.6 % of 2,4-dichlorophenol (2,4-DCP) within 20 h and maintained 55.2 % activity after 10 cycles. Moreover, the biocatalyst is easy to recycle using magnet. The results indicated that Lac-IL-Magnetic gelatin holds significant potential for the degradation of phenolic substances in environmental wastewater.

A novel MOF-808 derived material for oxidative desulfurization: the synergistic effect of hydrophobicity and electron transfer.

A functionalized modified metal-organic framework material, T-MOF-808, was synthesized through hydrophobic modification with tetraethyl orthosilicate (TEOS) and chlorotrimethylsilane (TMCS). Then a supported oxidative desulfurization catalyst, [C12Py]3(NH4)3Mo7O24/T-MOF-808(s), was prepared by using a heteropoly acid ionic liquid as the active component. The prepared samples were characterized using FT-IR, XRD, SEM, TEM, XPS, etc. [C12Py]3(NH4)3Mo7O24/T-MOF-808(s) was used in the oxidative desulfurization of dibenzothiophene (DBT). At the same time, the effects of different loadings of the active component, oxygen sulfur ratios, reaction temperatures, and reaction time were also investigated. [C12Py]3(NH4)3Mo7O24/T-MOF-808-15%(s) could oxidize 100% of DBT in 40 min at 60 °C. Significantly, the catalyst exhibited no discernible decline in catalytic activity after 14 runs. In addition, the efficiency of sulfur removal was 85.76% in actual diesel oil. It was found that the cooperative impact of hydrophobic modification and electron transfer makes an important contribution to the high activity. The hydrophobic modification provides a novel approach for using MOF materials in the oxidative desulfurization process.

Graph transformer based transfer learning for aqueous pKa prediction of organic small molecules

The acid-base dissociation constant (pKa) is an essential physicochemical parameter that indicates the extent of proton dissociation. However, accurately predicting pKa values is still challenging due to limited data availability for organic small molecules in aqueous solutions. In this work, we propose an open-source pKa prediction tool based on Graph Transformer, which combines the graph neural network and transformer to take both local and global information into account. To address the limitation of data scarcity, the experimental dataset is expanded, while transfer learning is employed by pre-training on the ChEMBL (computational) dataset and fine-tuning on the experimental dataset. The performance and generalization of the obtained models are comprehensively evaluated on both internal and external test sets. Additionally, two exemplary applications, namely the screening of tertiary amines for CO2 absorption and acidic ionic liquids for reactive extraction, are investigated to validate the reliability of our tool. The results show that our model can effectively guide the identification of promising candidates for the target applications by achieving accurate pKa predictions.

Acid-base neutralization strategy for immobilization amino acid ionic liquid within sulfonic acid-based COF as a switch for selective conversion of epoxides

Covalent organic frameworks (COFs) and ionic liquids (ILs) as raw materials exhibit effective catalytic performance and adsorption capabilities in the reaction of epoxides and atmospheric CO2, respectively. Nonetheless, bonding modes between ILs and COFs have restricted their utility, thereby constraining the in-depth study of synergistic catalytic mechanisms over these composite catalysts. Herein, a heterogeneous composite ([DBUH]2Cys@COF-X) were successfully prepared by the facile acid-base neutralization method, incorporating varying amounts of amino acid ILs ([DBUH]2Cys) into the pore channels of sulfonic acid-based COF (TpPa-SO3H). [DBUH]2Cys@COF-3 efficiently catalyzed epichlorohydrin with a yield of 96.38 % without any solvent or co-catalyst under atmospheric CO2. Notably, larger sterically hindered epoxides were selectively blocked on the surface of [DBUH]2Cys@COF-3, enabling [DBUH]2Cys@COF-3 to act as a gatekeeper for selectively catalyzing small sterically hindered epoxides due to [DBUH]2Cys was distributed within the pore channels of [DBUH]2Cys@COF-3. Through DFT calculations, comprehensive understanding of the synergistic activation conferred of -COO- and [DBUH]+ towards CO2 and epoxides in [DBUH]2Cys@COF-3 and the ring-opening mechanism was clarified. This work presents a fresh outlook on the catalyst design by the facile acid-base neutralization method for efficiently catalyzing small-hindered epoxides under atmospheric CO2.