Amino-functionalized Ionic Liquids Research Articles

Inductive effect in amino functionalized ionic liquids modified TS-1 nanosheets for efficiently sunlight-driven CO2 reduction

Photocatalytic technology for converting CO2 into useful chemicals or clean energy is an effective strategy to solve today's energy and environmental problems. In this study, we present a direct photocatalytic pathway for the conversion of CO2-to-CO involving the formation and activation of carboxyl intermediates over amino-functionalized ionic liquid (3-aminopiperidine hydrochloride, [3APip]Cl)-modified titanium silicalite-1 (TS-1) molecular sieve nanosheets. Various in-situ characterizations reveal that the key to activating this pathway lies in the CO2 adsorption capacity and the efficiency of photoexcited charge migration induced by [3APip]Cl in the hybrid catalyst. In the above catalytic pathway, CO2 molecules are first adsorbed on the surface of the [3APip]Cl/TS-1 hybrid catalyst under the induction of amino groups in the ionic liquid. Then, these adsorbed CO2 are activated and transformed into carboxyl intermediate, which can be further converted into CO and CH4 through photoexcited electrons captured by [3APip]Cl. Based on the results of CO2 reduction performance, the optimized [3APip]Cl/TS-1 hybrid catalyst achieves a 6-fold increase, and the CO selectivity is 83.0%. This research provides new insights into the CO2 reduction pathway in mild conditions and emphasizes the importance of the adsorption–activation tandem process for enhancing photoactivity and selectivity.

Supercapacitive properties of MnNiSx@Ti3C2Tx MXene positive electrode assisted by functionalized ionic liquid

MnNiSx@Ti3C2Tx as the positive electrode of supercapacitor was successfully prepared by hydrothermal method with the assistance of amino-functionalized ionic liquids. The micromorphological structures of MnNiSx@Ti3C2Tx were analyzed using X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscope, and energy dispersive spectrometer to reveal the synergistic effect between MnNiSx and Ti3C2Tx MXene. MnNiSx grew into a three-dimensional coral-like structure on the surface and between layers of Ti3C2Tx nanosheets. This structure alleviated the collapse and stacking of Ti3C2Tx, increased the specific surface area of Ti3C2Tx, and promoted the charges transfer on the surface of Ti3C2Tx. The electrochemical performances of MnNiSx@Ti3C2Tx positive electrode, such as cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy, were investigated. The synergistic effect between MnNiSx and Ti3C2Tx MXene improved the specific capacitance and the capacitance retention of the MnNiSx@Ti3C2Tx electrode. An asymmetric solid-state supercapacitor (ASC) assembled using MnNiSx@Ti3C2Tx as cathode material had the power density of 816.34 W·kg−1, and the energy density of 35.11 Wh·kg−1. The capacitance retention of ASC reached 98% after 5000 cycles at a current density of 5 A·g−1.

Effect of water content on transport properties and interactions of amino-functionalized ionic liquids

Dual amino-functionalized ionic liquids (AFILs) have attracted great interest in recent years because of their application in catalysis and carbon capture industries. Density data for [aP4443][Gly] – water mixtures were supplementary measured with different water mass fractions at 296.15 K. Molecular dynamics (MD) simulation of [aP4443][Gly] – water and [aP4443][Ala] – water was carried out to research the effect of water content on the density, viscosity and the interactions of ILs - water. It was found that with the increase of water content, the density of ILs - water mixtures increased slightly and the viscosity decreased significantly. It was found that strong hydrogen bonding exits between anions and water, in which the interaction of [Gly]− - water was stronger than [Ala]− - water. Water molecules would form water clusters at lower water content. Furthermore, it could be found that with the increase of water content, all interactions were weakened.

Synthesis, measurement, and correlation study of physico-chemical properties of diethanolamine glycinate ionic liquid as a solvent for CO2 capture units

Amino acid-functionalized ionic liquids (ILs), known as environmentally green non-molecular solvents, have been particular interested in the CO2 capture processes due to their unique physico-chemical properties. Proper development of CO2 capture processes utilizing amino-functionalized ILs, requires the exact determination of the ILs’ physico-chemical properties. In this paper, a novel amino acid-functionalized IL, namely diethanolamine glycinate ([DEA][GLY]), was synthesized and then characterized via Nuclear Magnetic Resonance (H NMR) and Fourier Transform Infrared (FT-IR) spectroscopy analysis. The density, dynamic viscosity, and surface tension were experimentally measured over the temperature range of 303.15–323.15 K and a wide verity of IL concentrations from 5 to 25 wt% of IL aqueous solution under atmospheric pressure. Furthermore, simple but reliable correlations with minimum input variables were implemented to model the density, dynamic viscosity, and surface tension data of the binary mixtures of [DEA][GLY] + H2O in terms of temperature and composition. Regarding the statistical criteria, it was indicated that the two-descriptor-based models could well describe the effect of temperature in different concentrations of the glycine amino acid-functionalized IL compared with those single temperature-dependent correlations.

One-step supramolecular fabrication of ionic liquid/ZIF-8 nanocomposites for low-energy CO2 capture from flue gas and conversion

High-efficient capture of CO2 from flue gas at discharged temperatures (100–120 °C) and convert CO2 under mild condition is of vital importance for low energy consumption and emission reduction, which yet remains a great challenge. A one-step supramolecular strategy for incorporating amino-functionalized ionic liquids (AFILs) into ZIF-8 is proposed for capture and conversion of CO2 from flue gas at discharged temperatures. AFILs are attached through metal-coordination interaction between Zn (II) and the NH2 group on AFIL, by which the large BET surface area and high thermal stability inherited from ZIF-8 are maintained well. The nanocomposites with low IL consumptions can rapidly capture CO2 from the flue gas with a high capacity of 2.68 mmol·g−1 within 4 min and efficiently catalyze CO2 into cyclic carbonates with excellent yield (95.6%) and selectivity (97.0%) at 40 °C and 0.1 MPa. In-situ DRIFTS and DFT calculation elucidated the effective synergistic mechanism of multiple active sites (C2-proton on imidazolium ring, imidazolium cation, protons of methyl group, protons of methylene group, Cl anion and Zn (II)) for CO2 adsorption and conversion. The activities in both the CO2 capture and conversion can be easily recycled, endowing the nanocomposites with outstanding practical potentials.

Hollow MOF capsule encapsulated amino-functionalized ionic liquid for excellent CO2 catalytic conversion

• Ionic liquids promote the CO 2 cycloaddition reaction. • The core-shell structure can effectively avoid the leaching of active ILs. • Catalyst shows an excellent catalytic performance under solvent and co-catalyst free conditions. The engineering of highly efficient and stable heterogeneous catalysts for catalytic conversion of CO 2 to high value-added products is highly desirable but presents a great challenge. Herein, we reported the synthesis of a series of multifunctional IL@H-Zn/Co-ZIF composite catalysts with a unique porous hollow capsule structure and encapsulated amino-functionalized ionic liquids (ILs). The unique hollow capsule structure of IL@H-Zn/Co-ZIF provides sufficient space for loading active ILs ([C 2 NH 2 Mim + ][Br − ]) and fast mass transfer of substrate molecules during catalysis. Furthermore, the microporous Zn-ZIF shell can effectively avoid the leaching of active ILs. Benefiting from the unique hollow structure, the resultant IL@H-Zn/Co-ZIF demonstrated excellent catalytic performance (>95% yield), and good recyclability (still remained about 90% activities after 5 cycles) when applied in the CO 2 cycloaddition reaction under solvent and co-catalyst free conditions.

Interface modulation of twinned PtFe nanoplates branched 3D architecture for oxygen reduction catalysis

Highly-branched dendritic Pt-based nanocrystals possess great potential in catalyzing the oxygen reduction reaction (ORR), but encounter performance ceiling due to their poor thermal and electrochemical stability. Here, we present a novel PtFe nanodendrites (NDs) branched with two-dimensional (2D) twinned nanoplates rather than conventional 1D nanowires, which breaks the ORR performance ceiling of dendritic catalysts by inducing the unique Pt-skin configuration via rationally thermal treatment. By further hybridizing the Pt-skin PtFe NDs/C with amino-functionalized ionic liquids (ILs), we achieve an unprecedented mass activity of 3.15 A/mgPt at 0.9 V versus reversible hydrogen electrode (RHE) in the PtFe-based ORR electrocatalytic system. They also show excellent electrocatalytic durability for ORR with negligible activity decay and no apparent structural change after 20,000 cycles, in sharp contrast to the nanowires branched PtFe NDs counterpart. The remarkable catalytic performance is attributed to a combination of several structural features, including 2D morphology, twin boundary, partially ordered phase and strong coordination with amino group. This work highlights the significance of stabilizing electrocatalytic structures via morphology tuning, which thus enables further surface and interface modification for performance breakthrough in ORR electrocatalysis.

How did the corrosion inhibitor work in amino-functionalized ionic liquids for CO2 capture: Quantum chemical calculation and experimental

Quantum chemical calculations was used for efficiently screening of the corrosion inhibitors from a series of organic and inorganic inhibitors for 20# carbon steel in CO2-saturated [TETAH][Lys] solution in the this work, which was different from the traditional usage by employed for confirming the experimental results. The inhibitors of MBI and Na2MoO4 were emerged as the best alternatives, inhibiting the corrosion by provided a layer of protection between the carbon steel and the solution. It was found that the greatest contribution to the adsorption of MBI and Na2MoO4 was S15 and Mo1, and these two inhibitors were of the mixed and anodic type inhibitor, respectively. The adsorption of them on carbon steel obeyed the Langmuir isotherm and involved competitive physisorption and chemisorption. The kinetic of the adsorptions were investigated, and the thermodynamic parameters had been calculated. The experimental results demonstrated a reasonably good agreement between theory and experiment, and a reference was provide for the optimum additive agent in the technical design.

Is it Always Chemical When Amino Groups Come Across CO2? Anion-Anion-Interaction-Induced Inhibition of Chemical Adsorption.

Amino-functionalized ionic liquids (IL) are often applied to fix CO2. However, as far as we know, none of them have ever been reported to exhibit considerable physical CO2 capture. Herein, we describe an amino-functionalized room-temperature ionic liquid, 1-butyl-3-methylimidazolium 3-amino-1H-1,2,4-triazolate ([Bmim][ATZ]), with an unusual ultrafast physical CO2 capture at room temperature and atmospheric pressure. Within the time needed for a chemisorbent to reach an equilibrium, 15 adsorption and desorption cycles are finished for [Bmim][ATZ], with an accumulative molar ratio of up to 2.04. The CO2/IL ratio for one adsorption process reaches 0.14, which is 4 times the highest recorded physical CO2 solubility by [thtdp][Cl] (trihexyltetradecylphosphonium chloride). The first theoretical study on anion-anion interactions of ionic liquids is reported, which rationalizes the inhibition of chemical adsorption. These results provide a new perspective on the aspect of CO2 capture, as well as designing of ionic liquids.

Development of Amino-Functionalized New Task Specific Ionic Liquids (Tsils) for Efficient Co2 Capture

Development of Amino-Functionalized New Task Specific Ionic Liquids (Tsils) for Efficient Co2 Capture

Understanding the corrosion behavior of carbon steel in amino-functionalized ionic liquids for CO2 capture assisted by weight loss and electrochemical techniques

One of the main challenges in post-combustion CO2 capture with chemical absorbents is equipment corrosion, which contradicted the requirements of green economy and sustainable development. As novel solvents for CO2 capture, amino-functionalized ionic liquids (AFILs) have attracted wide attentions in recent years. Nevertheless, equipment corrosion of CO2 capture into AFILs solution is still rarely studied. In the present work, corrosion behavior of 20# carbon steel in five AFILs solutions ([N1111][Gly], [AEMIm][Gly], [AEMIm][Lys], [DETAH][Lys], [TETAH][Lys]) were evaluated by weight loss methods, Tafel curve and electrochemical impedance spectroscopy (EIS). The experimental results indicated that all of the fresh AFILs solutions showed a negligible corrosivity, while the CO2-loaded solutions presented high corrosivity on carbon steel. The corrosion was accelerated as the amount of amino-functionalized group in AFILs increased. Moreover, the carbon steel before and after corrosion were analyzed by SEM, EDS, XRD. The characterization analysis showed that there was only Fe, but no protective layer of FeCO3 presented on the surface of 20# carbon steel, which was different with that of amine solutions in the reported works. On the basis of the experimental data and characterization analysis, the corrosion mechanism of carbon steel in AFILs system was proposed. The corrosion process was controlled by charge transfer. In the fresh AFILs solutions, there were no cathodic substances (HCO3−, H+) to promote the dissolution of iron. In CO2-saturated AFILs solutions, CO2 was absorbed to form HCO3−/CO32− and carbamates, which fasted the rapid dissolution of iron on carbon steel surface and promoted the corrosion.

Efficient Absorption of CO2 by Introduction of Intramolecular Hydrogen Bonding in Chiral Amino Acid Ionic Liquids

Developing advanced materials, such as ionic liquids (ILs), is highly desired for post-combustion capture of carbon dioxide (CO2). In this paper, we first develop a series of chiral amino acid ILs for efficient, fast, and reversible capture of CO2. Our data reveal that the dianionic form of IL is beneficial to the formation of intramolecular hydrogen bonding, which can remarkably mitigate the viscosity increase during CO2 absorption. The enhanced absorption capacity of CO2 in the IL is mainly due to the multi-site absorption from both the amino group and the negative oxygen group. The dominating absorption pathway is that the amino group reacts with CO2 via an intramolecular proton transfer from the amino group to the negative oxygen group, leading to the formation of the intramolecular hydrogen bonding between carbamate and the protonated oxygen group. As a result, the enhanced absorption performance of amino-functionalized ionic liquids (AFILs) is achieved, especially a controllable viscosity change dur...

A novel biphasic solvent of amino-functionalized ionic liquid for CO2 capture: High efficiency and regenerability

Due to its great potential of energy consumption saving, the biphasic solvent has attracted more and more attention. In the present work, an efficient absorbent of amino-functionalized ionic liquids (AFILs) was dissolved in ethanol-water solvent to form a novel biphasic solvent for CO2 capture. When the concentration of triethylenetetramine l-lysine ([TETAH][Lys]) was 0.5 mol/L and the volume ratio of ethanol-water solvent was 4:6, the [TETAH][Lys] solution separated into two phases after CO2 absorption. Under the optimal conditions, the volume of the CO2-rich phase was about one third of the total volume of the mixture, which meant that only one third of the solution needed to be regenerated and the energy consumption could be greatly reduced. Meanwhile, the loading of the CO2-rich phase contributed about 93% of the total loading of the solution, and its viscosity was only 27.95 mPa s. The regeneration efficiency of the solvent after the 5th absorption-desorption cycle still kept at 91.3%. Based on the experimental and 13C NMR analysis results, the reaction and phase change mechanisms of CO2 capture into the [TETAH][Lys]-ethanol-water solution were clarified. CO2 absorption into [TETAH][Lys] firstly formed carbamate, which would further hydrolyze to HCO3−/CO32− and react with ethanol to form the ethyl carbonate. Due to the limited solubility of these absorption products in ethanol, as well as the good solubility in H2O, the products transferred to the lower phase while the ethanol stayed in the upper phase in the biphasic system.

Designing and Screening of Multi-Amino-Functionalized Ionic Liquid Solution for CO2 Capture by Quantum Chemical Simulation

The structure and group combination of amino-functionalized ionic liquids (AFILs), such as chain length, number of amino groups, interaction energy, and activation barrier, were the important facto...

Dual amino-functionalized ionic liquids as efficient catalysts for carbonate synthesis from carbon dioxide and epoxide under solvent and cocatalyst-free conditions

In the present study, the dual amino-functionalised imidazolium ionic liquids of 1-(3-aminopropyl)-3-butylimidazolium glutamic acid [APbim][Glu], 1-(3-aminopropyl)-3-butylimidazolium aspartic acid [APbim][Asp], 1-(3-aminopropyl)-3- butylimidazolium glycine [APbim][Gly], have been synthesized and characterized by 1H NMR, 13C NMR spectroscopy and IR spectroscopy. The synthesis of cyclic carbonate by cycloaddition reaction of CO2 and various epoxides catalyzed by dual amino-functionalized imidazolium ionic liquids, was carried out under no additional organic solvent required and halogen free condition. Simultaneously, the influence of anion type, catalyst dose, reaction temperature, reaction time and CO2 pressure on the yields of cyclic carbonates was examined. The dual amino-functionalized imidazolium ionic liquids possess good yields and selectivity and provide a reasonably environmentally benign and recycled chemical process.

Ionic Polyimides: Hybrid Polymer Architectures and Composites with Ionic Liquids for Advanced Gas Separation Membranes

Polyimides and ionic liquids (ILs) are two classes of materials that have been widely studied as gas separation membranes, each demonstrating respective advantages and limitations. Both polyimides and ILs are amenable to modification/functionalization based on selection of the requisite precursors. However, there have been but a handful of reports considering how polyimides and ILs could be integrated to obtain fundamentally new materials with synergistic properties. In this manuscript, we demonstrate a new and versatile way to synthesize polyimides with imidazolium cations directly located within the polymer backbone to form polyimide–ionene hybrids, or “ionic polyimides”. Our strategy for synthesizing ionic polyimides does not require the use of amino-functionalized ILs. Instead, the imidization reaction occurs prior to polymerization in the formation of an imidazole-functionalized diimide monomer. This monomer is then reacted via step-growth (condensation) polymerization with p-dichloroxylene via Mensh...

CO2/N2 separation using alumina supported membranes based on new functionalized ionic liquids

Abstract In the present work, supported liquid membranes based on three ionic liquids (ILs) (1-(2-aminoethyl)-3-methylimidazolium trifluoromethanesulfonate ([AEMIm]Tf), 1-(2-aminoethyl)-3-methylimidazolium tetrafluoroborate ([AEMIm]BF4) and trioctylmethylammonium anthranilate ([TOMA])), used as mobile phases, were studied in the separation of carbon dioxide from nitrogen. The IL chemical structures and thermal properties were confirmed by spectroscopic techniques and thermogravimetric analysis (TGA), respectively. The IL homogeneous distribution of the impregnation on alumina tubular supports was determined by scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX). Permeation tests were carried out using pure gases at 30 °C and 1 bar. The amino-functionalized ILs, two of them in the cation, [AEMIm]BF4 and [AEMIm]Tf, and the other one in the anion, [TOMA]An, reacted with CO2, leading to the formation of carbamates. [TOMA]An, which has the amine group at the anionic part, showed the best permselectivity, reaching a selectivity of 70.

CO<sub>2</sub> Absorption Performance of “Dry Matter” Prepared with Amino Acid-Based Ionic Liquids

Dry Matter (DM) is a powdery substance which is composed of micro droplets and surrounding hydrophobic silica nanoparticles. Because of the much larger surface area than that of the corresponding bulk liquid, DM, which contains amino-functionalized ionic liquids (ILs), is a promising CO2 absorption material provided with quick absorption speed. In the present study, we successfully prepared powdery DMs by utilizing aqueous solutions of amino acid-based ILs (tetraethylammonium glycine [N2222][Gly], and tetraethylammonium alanine [N2222][Ala]). Although a DM with lysine-based IL (N2222) [Lys]) was also prepared, only a souffle-like material was obtained. We measured CO2 absorption performance for the DMs to find that the mass-base absorption ability (mass-base A.A.) (CO2 mol/DM kg) and the mol-base one (CO2 mol/IL mol) of [N2222][Lys] were ca. two times of [N2222][Gly] and [N2222][Ala], while the absorption speed of the former was inferior to the latter two, i.e., ca.15 min vs. 5 min for 90% absorption. In order to improve the mass-base A.A. of [N2222][Gly], we used 10% of aqueous poly(allylamine) (PAlAm) solution instead of water. The resultant mass-base A.A. proved to be significantly larger (1.9) than either of those of the respective single component systems (1.1 and 0.75 for the bulk IL and aq. PAlAm, respectively), and comparable to the A.A. (1.6 - 2.5) of 20% - 30% monoethanolamine solution which is commonly used in industrial application.

Amino-functionalized ionic liquids as carbon dioxide scavengers. Ab initio thermodynamics for chemisorption

Carbon dioxide (CO2) capture by aqueous amine solutions is an industry grade technology nowadays. Some drawbacks of this technology motivate development of new CO2 scavengers. Due to low volatility, thermal stability, non-flammability, and tunability, room-temperature ionic liquids (RTILs) are viewed as prospective universal solvents. The amino groups can be grafted to the organic cations yielding species with the increased CO2 capture performance. Many favorable physical properties of the original RTILs can be retained in this way. We report systematic computational analysis (enthalpy, entropy, Gibbs free energy, geometric parameters, partial charges, vibrational frequencies) of six organic cations, each representing a different family of RTILs. We found that the longer side hydrocarbon chain of the cations offer the most prospective sites in view of the CO2 capture. In turn, chemisorption in the rings is less thermodynamically favorable. It was possible to corroborate the thermodynamic regularities in terms of electrophile+nucleophile organic reactions involving partial charges and structure perturbations due to carbamate formation. The reported results foster development of alternative CO2 scavengers by eliminating their volatility and increasing reaction yields.

Decreasing the Viscosity in CO2 Capture by Amino-Functionalized Ionic Liquids through the Formation of Intramolecular Hydrogen Bond.

A strategy for decreasing the viscosity variation in the process of CO2 capture by amino-functionalized ionic liquids (ILs) through the formation of intramolecular hydrogen bond was reported. Different with the dramatic increase in viscosity during CO2 uptake by traditional amino-functionalized ILs, slight increase or even decrease in viscosity was achieved through introducing a N or O atom as hydrogen acceptor into amino-functionalized anion, which could stabilize the active hydrogen of produced carbamic acid. Quantum chemical calculations and spectroscopic investigations demonstrated that the formation of intramolecular hydrogen bond between introduced hydrogen acceptor and carbamic acid was the key to avoid the dramatic increase in viscosity during the capture of CO2 by these amino-functionalized ILs.