Properties of alkylbenzimidazoles for CO2 and SO2 capture and comparisons to ionic liquids

Shannon, Matthew S.; Hindman, Michelle S.; Danielsen, Scott P. O.; Tedstone, Jason M.; Gilmore, Ricky D.; Bara, Jason E.

doi:10.1007/s11426-012-4661-3

Cited by 29 publications

(26 citation statements)

References 65 publications

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“…23,39−44 While we observed CO 2 absorption in these imidazoles to occur strictly through physical mechanisms, 40,41,43 SO 2 absorption in 1-hexylimidazole occurred via both physical and chemical mechanisms while SO 2 absorption in 1-butylbenzimidzole was solely based on physical solubility. 23,41 Weaker interactions in an alkylbenzimidazole can be attributed to reduced nucleophilicity of the N(3) site toward SO 2 due to the electron withdrawing nature of the fused ring system. Huang et al also observed a strong binding of SO 2 using 1-methylimidazole, 1-dodecylimidazoe and an ether-bridged bis(imidazole) solvents.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Shannon

Irvin

Liu

et al. 2014

Ind. Eng. Chem. Res.

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Sulfur dioxide (SO 2 ) removal is a key component of many industrial processes, especially coal-fired power generation. Controlling SO 2 emissions is vital to maintaining environmental quality, as SO 2 is a contributor to acid rain, but has value as a chemical feedstock. Although a number of novel solvents/materials including ionic liquids (ILs) have recently been proposed for alternatives to limestone scrubbing for SO 2 capture/removal from point sources, the imidazole architecture presents a convenient, inexpensive and efficient class of low volatility and low viscosity solvents to accomplish this goal. On the basis of our prior work with imidazoles for CO 2 capture, we have extended our interests toward understanding the relationship between imidazole structure and SO 2 absorption. Using a series of imidazole compounds with various substituents at the 1, 2 and/or 4(5) positions of the five-membered ring, SO 2 absorption via both chemical and physical mechanisms was observed. The chemical absorption product is a relatively stable 1:1 SO 2 −imidazole complex, while physical absorption of SO 2 is dependent on pressure and temperature. Because imidazoles are relatively small molecules, they are an efficient absorption medium for SO 2 and can form adducts wherein the mass fraction of bound SO 2 is >40 wt %. The SO 2 −imidazole complexes were also observed to produce distinct color and/or phase changes that are associated with the nature of the substituents present. The chemically bound SO 2 can be released under vacuum at moderate temperature (∼100°C) and vacuum, yielding the original neat solvent, while the physically dissolved SO 2 can be readily removed at ambient temperature under vacuum. This behavior corresponds to a much smaller enthalpy of absorption for physical dissolution (−4 to −13 kJ/mol) as determined via thermodynamic relationships compared to the binding energies of chemical complexation (−35 to −42 kJ/mol) as determined via density functional theory calculations. Increasing chemical complexation energies are correlated with increased substitution on the imidazole ring. Simulations were also employed to gain insight into the structures of the SO 2 −imidazole complexes, illustrating changes in partial charge distribution before and after complexation as well as confirming a charge transfer complex is formed based on the N−S bond length.

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Section: Introductionmentioning

confidence: 99%

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Shannon

Irvin

Liu

et al. 2014

Ind. Eng. Chem. Res.

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“…[17] In prior work with solutions of amines in ILs, [13] it was observed that upon reaction of the amine with CO 2 , the overall viscosity of the solvent was markedly increased due to the formation of an extended ionic network that resembled non-covalent crosslinking. [23,31] We have observed that both physical and chemical mechanisms for SO 2 absorption exist in imidazoles. [23] Verevkin's group has also recently become interested in the relationships between imidazole structure and vapor pressure.…”

Section: Experimental and Computational Resultsmentioning

confidence: 99%

Imidazole-Based Solvents and Membranes for CO₂ Capture Applications

et al. 2014

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Imidazoles present a tunable, versatile and economical platform for the development of novel liquid solvents and polymer membranes for CO 2 capture. An overview of our studies in this area is presented, with emphasis on characterization of structure-property relationships in imidazole-based materials through both experimental and computational studies. To this end, a growing library of systematically varied imidazole compounds has been synthesized using only commercial available starting materials and straightforward reactions. Using this library of compounds, we have sought to understand and develop predictive models for thermophysical properties relating to process design, including: density, viscosity, vapor pressure, pK a and CO 2 absorption capacity. Furthermore, we have discovered that imidazoles are stable in the presence of SO 2 and can form reversible 1:1 adducts, which can be beneficial as SO 2 is typically present at ppm levels alongside CO 2 in flue gas from coal-fired power plants.

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“…According to reported methods [ 36 , 37 , 38 ], 1 mmol CPBI 0 , different molar n -C 5 H 11 Br ( Table 1 ), 10 mL MeCN, and moderate NaOH were added into the reaction flask. After refluxing for 24 h, the organic solvent was evaporated in vacuo.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Large Conjugated Polybenzimidazole Fluorescent Materials and Their Application in Metal Ion Detection

et al. 2021

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A new type of conjugated polybenzimidazole (CPBI) was synthesized through a simple polycondensation reaction without metal catalysis, and N-alkylation modification was carried out to solve the problems of solubility and fluorescence properties. A series of nano-microsphere polymers CPBIn with large conjugation, good solubility, and strong fluorescence has been successfully used as “turn-off” fluorescent probes for the first time. The results show that, under suitable N-alkylation conditions, the obtained CPBIn can be used as a highly sensitive and selective fluorescent probe for the detection of Cu2+ and Zn2+ at the same time, and their detection limits are both nM levels. In addition, CPBI2 can be designed as an ultra-sensitive IMPLICATION logic gate at the molecular level, cyclically detecting Cu2+. With the test paper containing CPBI2, easy and quick on-site detection can be achieved. This research provides a new idea for the brief synthesis of multifunctional materials.

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Properties of alkylbenzimidazoles for CO2 and SO2 capture and comparisons to ionic liquids

Cited by 29 publications

References 65 publications

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Imidazole-Based Solvents and Membranes for CO₂ Capture Applications

Preparation of Large Conjugated Polybenzimidazole Fluorescent Materials and Their Application in Metal Ion Detection

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Properties of alkylbenzimidazoles for CO2 and SO2 capture and comparisons to ionic liquids

Cited by 29 publications

References 65 publications

Chemical and Physical Absorption of SO2 by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Chemical and Physical Absorption of SO2 by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Imidazole-Based Solvents and Membranes for CO2 Capture Applications

Preparation of Large Conjugated Polybenzimidazole Fluorescent Materials and Their Application in Metal Ion Detection

Contact Info

Product

Resources

About

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Chemical and Physical Absorption of SO₂ by N-Functionalized Imidazoles: Experimental Results and Molecular-level Insight

Imidazole-Based Solvents and Membranes for CO₂ Capture Applications