Computer‐Assisted Design of Imidazolate‐Based Ionic Liquids for Improving Sulfur Dioxide Capture, Carbon Dioxide Capture, and Sulfur Dioxide/Carbon Dioxide Selectivity

A series of novel dual-functionalized ionic liquids (FILs) with the combinations of diethylenetriamine cation ([DETAH]+) and aprotic heterocyclic anion (AHA) are explored for efficient and reversible CO2 capture, which was distinguished from the traditional strategy by increasing the amino group number of ionic liquids. The structural features and the interactions between ions and CO2 were performed under the DFT method, at the B3LYP/6-311++G** level. The CO2 absorption loadings of [DETAH][Im], [DETAH][Py], and [DETAH][Tz] were 11.91, 11.36, and 10.10 mol CO2/ kg IL, respectively. After the fifth cycle, their regeneration efficiencies still kept above 90%. Based on the calculation and 13C NMR results, the reaction mechanisms of CO2 capture into [DETAH][AHA] solutions were clarified. The amino groups of [DETAH]+ reacted with CO2 to produce [DETAH]+-carbamates, which guaranteed the high absorption rate. Meanwhile, [AHA]− could also equimolecularly react with CO2 to form carbamate, which subsequently hydrolyzes into HCO3 –/CO3 2–. Notably, the [AHA]− was protonated during the CO2 absorption process, and [AHA]-H could react with [DETAH]+-carbamates to produce [DETAH]+, which helped to recycle the active components of the absorbent and further increased the CO2 capacity and regenerability of the absorbent. The novel dual FILs present as an efficient candidate for CO2 capture.

Section: Resultsmentioning

confidence: 99%

Aprotic Heterocyclic Anion-Based Dual-Functionalized Ionic Liquid Solutions for Efficient CO₂ Uptake: Quantum Chemistry Calculation and Experimental Research

et al. 2019

“…Due to the unique chemical and physical properties, functionalized ionic liquids (ILs) with active sites on their cations or anions as a kind of alternative absorbent result in efficient gas capture. , For example, functionalized ILs with amine-containing cations, − ether-containing cations, − aprotic heterocyclic anions, − cyano-containing anions, , carbonyl-containing anion, − carboxylate anions, − and phenolate anions − have been designed and synthesized for improving SO 2 or CO 2 capture. These functionalized ILs are usually prepared through complicated processes, including cationization, anion-exchange, and acid–base neutralization, with kinds of organic solvents used and large quantities of wastewater produced which may enhance their cost and limit their large-scale applications. , …”

Section: Introductionmentioning

confidence: 99%

Tuning Environmentally Friendly Chelate-Based Ionic Liquids for Highly Efficient and Reversible SO₂ Chemisorption

Cui

Liu

et al. 2018

Self Cite

Because of lots of outstanding properties of ionic liquids (ILs), three kinds of environmentally friendly chelatebased ILs such as [Li(TDA-1)][SCN], [Li(TDA-1)][TFSI], and [Li(G3)][TFSI] were designed and synthesized in this work with easy procedure and no byproduct generation. Ligands of the ILs are cheap, nontoxic, thermally stable, and highly active. Density and viscosity of the ILs were determined, and they decreased linearly with increasing temperature. With the lowest flow activation energy, the [Li(TDA-1)][SCN], containing tertiary amine in the cation and thiocyanate as the anion, exhibited the highest absorption rate and remarkable SO 2 chemisorption capacity. The effect of SO 2 partial pressure and absorption temperature on the uptake performance of SO 2 were also investigated, where a high absorption capacity up to 2.36 and 2.01 mol SO 2 per mol IL can be achieved by [Li(TDA-1)][SCN] under low partial pressure of SO 2 (10 vol % SO 2 ) or high absorption temperature (70 °C), respectively. Spectroscopic investigations and quantum mechanical calculations show that the chemical interactions between SO 2 and two active sites (N and S) in ILs resulted in the high SO 2 absorption capacities. Furthermore, the chelate-based ionic liquids can be regenerated and recycled several times without losing capacity.

“…It was found that SO 2 absorption capacities in EmimCl-Im (2:1) decrease with the increasing content of water, affording a SO 2 absorption capacity of 1.178 g SO 2 per g DES when EmimCl-Im (2:1) contains 10 wt % water (Figure b). By comparing the SO 2 gravimetric absorption capacities with previously reported ILs − or DESs, − these bisazole-based DESs exhibit higher SO 2 absorption (Table S4). As a result, the bisazole-based DESs are highly efficient SO 2 absorbers.…”

Section: Resultsmentioning

confidence: 80%

Bisazole-Based Deep Eutectic Solvents for Efficient SO₂ Absorption and Conversion without Any Additives

Long

Yang

et al. 2020

Four bisazole-based deep eutectic solvents (DESs) consisting of 1ethyl-3-methylimidazolium chloride and azoles are prepared for the efficient absorption and conversion of SO 2 . These DESs can not only absorb SO 2 up to 1.402 g/g at 20 °C and 1 bar but can also serve as catalysts for the cycloaddition of SO 2 with epoxides. Moderate to good yields of cyclic sulfites are acquired for varied epoxides under mild conditions (60 °C and 1 bar of SO 2 ) without any additives.