Efficient SO2 Absorptions by Four Kinds of Deep Eutectic Solvents

Article pubs.acs.org/IECR

Efficient SO2 Absorptions by Four Kinds of Deep Eutectic Solvents Based on Choline Chloride Shaoyang Sun,† Yanxia Niu,†,‡ Qiang Xu,† Zuchen Sun,† and Xionghui Wei*,† †

Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China

‡

Downloaded by FLORIDA ATLANTIC UNIV on August 28, 2015 | http://pubs.acs.org Publication Date (Web): August 12, 2015 | doi: 10.1021/acs.iecr.5b01789

S Supporting Information *

ABSTRACT: Four kinds of deep eutectic solvents (DESs) based on choline chloride (ChCl) with ethylene glycol (EG), malonic acid (MA), urea, and thiourea as hydrogen bond donors were prepared and characterized. All these DESs show good thermal stability and can be stable at 363 K, which is beneficial for the application in flue gas desulfurization. Then, SO2 absorption capacities of these DESs were determined at different temperatures and SO2 partial pressures. The absorption results demonstrate that ChCl−EG (1:2) and ChCl−thiourea (1:1) DESs exhibit excellent absorption performances, and the absorption capacities are 2.88 and 2.96 mol SO2 per mol DES at 293 K and 1 atm, respectively. In addition, the SO2 absorption and regeneration experiments were conducted. All solvents can be regenerated at 343 K with N2 bubbling, and the absorption capacities of DESs remain without a significant loss after six absorption and desorption cycles. What’s more, the absorption mechanism of SO2 in these DESs were investigated by IR and 1H NMR.

■

INTRODUCTION Sulfur dioxide (SO2), which is one of the most important air pollutions, causes serious damage to the environment and human health.1 Because SO2 is mainly emitted from the combustion of fossil fuels, the removal of SO2 from flue gas has become a global concern. The most commonly used technology over the past decades is limestone scrubbing.2 However, it still has some drawbacks, including irreversible process, low efficiency and production of useless byproducts like wastewater and CaSO4. Thus, new sorbents that can absorb SO2 efficiently, reversibly, and selectively are of great importance. In recent years, different organic solvents like ethylene glycol,3 N,N-dimethylformamide,4,5 1,4-dioxane,6 and sulfolane,7 have been studied in the removal of SO2. The SO2 absorption capacities of these solvents have been determined, and the mechanisms were also discussed. However, the boiling points of these solvents are relatively low, and the solvents may volatilize at high temperatures in regeneration processes. So new sorbents with high boiling points and thermal stabilities are still needed. Because of their excellent properties, such as negligible vapor pressure, wide liquid temperature range, high thermal stability, tunable structure, and excellent SO2 absorption capacity, ionic liquids (ILs) have been broadly studied in the absorption of SO2.8,9 In 2004, 1,1,3,3-tetramethylguandinium lactate [TMG][L] was first noted for SO2 removal, and the result showed that the ionic liquid can absorb about 1 mol SO2 per mole IL at 1 bar with 8% SO2 in gas phase.10 Later, numerous ILs based on guanidinium,11,12 alkanolaminium,13,14 imidazolium,15−18 pyridinium,19,20 and phosphonium21 were synthesized and applied in the SO2 removal. Recently, ether-functionalized22−27 and anion-functionalized task-specific ionic liquids28−30 have been discovered to improve the SO2 absorption capacity, which is attributed to the multiple binding sites for SO2 in the © 2015 American Chemical Society

functionalized molecules. Nevertheless, the preparation of ILs usually needs several complex steps, and the application of ILs in SO2 removal is also limited by the high expenses. Deep eutectic solvents (DESs) are known as a kind of ionic liquid analogues because of the similar characteristics and properties.31 DESs are usually obtained by the complexation of a quaternary ammonium salt and hydrogen bond donors (HBDs), and the hydrogen bond formed between halide ions and hydrogen bond donors can efficiently lower the melting points. Choline chloride (ChCl) is the common quaternary ammonium used, while a range of HBDs such as amides,32 diols,33 and dicarboxylic acids,34 are employed. These DESs can be simply prepared by mixing two compounds and stirring at about 343 K without further purification. The physical properties of these DESs have been broadly investigated.35 Because of their advantages of low volatility, non−toxic, low price, and easy preparation, DESs have been widely used in metal extractions,36 metal electrodepositions,37,38 organic synthesis,39,40 and CO2 absorptions.41−43 In addition, Yang et al. determined the SO2 absorption capacities of ChCl−glycerol DESs with different mole ratios at different temperatures and SO2 partial pressures, and the absorption capacity of ChCl− glycerol (1:1 mol ratio) DES can be as high as 0.678 g SO2 per g DES at 293 K and 1 atm. Liu et al. determined the SO2 absorption capacities in amide-thiocyanates DESs, and the capacity of acetamide-KSCN (3:1) can be as high as 0.588 g SO2/g DES at 293 K and 1 atm.44 In the work, we determined the absorption capacities of SO2 in four kinds of DESs, including ChCl−EG (1:2), ChCl−MA (1:1), ChCl−urea (1:2), and ChCl−thiourea (1:1) at different Received: Revised: Accepted: Published: 8019

May 14, 2015 August 4, 2015 August 7, 2015 August 7, 2015 DOI: 10.1021/acs.iecr.5b01789 Ind. Eng. Chem. Res. 2015, 54, 8019−8024

Article

Industrial & Engineering Chemistry Research temperatures and SO2 partial pressures. Then, thermal stabilities and regeneration properties were also investigated. Furthermore, mechanisms of the interactions between SO2 and DESs were studied by IR and 1H NMR, and the differences of absorption capacities between the HBDs were discussed.


■

EXPERIMENTAL SECTION

Materials. Choline Chloride (ChCl), ethylene glycol (EG), malonic acid (MA), urea, and thiourea were purchased from Sinopharm Chemical Reagent Co. Ltd. All reagents were obtained in the highest purity grade possible (>99.9%), and directly used as received without further purification. Chromatographic grade Ethanol and distilled water were also used in this work. A certified standard pure SO2 gas (>99.9%), supplied by Beijing Gas Centre, Peking University (China), was employed to determine the SO2 absorption capacity of DESs. Preparation of DESs. All DESs were prepared by simply mixing choline chloride and HBDs (including EG, MA, urea, and thiourea) with stirring and heating. For example, the ChCl−thiourea was prepared by mixing the equimolar ChCl and thiourea, and then stirring at 343 K for half an hour. The formed liquids were purified by heating at 333 K in vacuum for 2 h. No impurities were found in 1H NMR and IR spectra. We determined the water contents of the DESs with the Carl Fischer method, and the result showed that the water content of each DES is below 0.5%. Absorption and Regeneration of SO2 in DESs. The SO2 absorption and desorption experiments were performed in an absorption tube with an inner diameter of 15 mm, which is consistent with the method in the literature.45 SO2 gas of atmospheric pressure was bubbled through the samples (about 3 mL) in the absorption tube with a flow of 250 mL/min. The absorption tube was immersed in a circulating water bath to keep a certain temperature in absorption experiments, whereas an oil bath was used in desorption experiments. The absorption capacity of SO2 was determined by an analytical balance (Sartorius BS 224S, with an uncertainty of 0.1 mg) at regular intervals. We measured the SO2 absorption capacities for each DES at 303 K for 5 times, and the relative derivations are all below 1.0%. During the absorption experiments with different pressures, SO2 was diluted by N2 to obtain a mixed gas with a certain SO2 partial pressure by controlling the flow rates of SO2 and N2. The regeneration experiments were conducted at 353 K with a N2 flow of 250 mL/min, with the similar method mentioned above. Spectral Measurements. IR and 1H NMR were employed to confirm the structure of DESs and investigate the interaction between DESs and SO2. The IR spectra were recorded on a Bruker Vector 22 FT-IR spectrophotometer, in which a typical thin film method was performed at ambient conditions, with the wavenumber ranging from 400 to 4000 cm−1 and a resolution of 1 cm−1. A 500 MHz Bruker Avance III spectrometer was used to conduct the 1H NMR experiments. The NMR experiments were performed with external references. For external references, the samples and deuterated reagents were injected into capillary tubes (25 cm × 0.9 mm) and NMR tubes (17.8 cm × 5 mm), respectively. Then the capillary tube was inserted into the NMR tube to separate the samples from the solvents (deuterated regents).

Figure 1. SO2 absorption capacities of four DESs as a function of time at 293 K and 1 atm.

■

RESULTS AND DISCUSSION Four kinds of DESs, ChCl−EG (1:2), ChCl−MA (1:1), ChCl− urea (1:2), and ChCl−thiourea (1:1), were prepared and their SO2 absorption capacities were determined. As shown in Figure 1, SO2 absorptions of all DESs with the change of absorption time at 293 K and 1 atm are presented. The results demonstrate that the absorption processes can be completed within 15 min, which is very efficient. Compared the absorption capacities of these DESs, ChCl−EG (1:2) and ChCl−thiourea (1:1) exhibited the best performances with the capacities of 2.88 mol SO2/mol DES (0.70 g SO2/g DES) and 2.96 mol SO2/mol DES (0.88 g SO2/g DES), respectively, which are better than the value of ChCl−glycerol.46 The absorption capacities of SO2 in some cheap ionic liquids are listed in Table 1. For these nonfunctionalized ionic liquids, the SO2 capacities are usually below 2 mol SO2/mol IL. Compared with these ionic liquids, the DESs exhbit a better absorption performance. When SO2 was bubbled into the ChCl−urea (1:2) and ChCl−thiourea (1:1), the solutions turned yellow, and a crystal precipitation happened as the SO2 in ChCl−urea (1:2) was close to saturation at 293 K. The crystal was detected to be urea according to the results of element analysis, IR, and 1H NMR. However, when applied in a higher temperature, no precipitation was observed. We also studied the different mole ratio of ChCl and HBDs, and found that the mixtures of ChCl−urea (1:1) and ChCl−thiourea (1:2) were solids at 293 K, whereas the mixtures of ChCl−MA (1:2) volatilized when applied in the regeneration process at 343 K. As a result, the four DESs mentioned above were finally selected in the research of SO2 absorption. Then, we determined the SO2 absorption capacities in the DESs at different temperatures with the pressure of SO2 equal to 1 atm, and the data are presented in Table 2. The effect of temperatures on SO2 absorption of the DESs is shown in Figure 2, which indicates that the capacities of SO2 in DESs decrease continuously with the increasing of temperature. For ChCl−thiourea (1:1), the capacity decreased from 2.96 to 1.32 mol SO2/mol DES, which means heating can be used as an efficient method for the regeneration of DESs. Particularly, the capacity of ChCl−urea (1:2) at 293 K are lower than that at 303 K, which is because of the precipitation of urea at 293 K as mentioned above. Hence, ChCl−urea (1:2) is not benefit for the application of SO2 removal at low temperatures. The influence of SO2 partial pressure on absorption capacity of DESs were also taken into consideration, and the 8020

DOI: 10.1021/acs.iecr.5b01789 Ind. Eng. Chem. Res. 2015, 54, 8019−8024

Article

Industrial & Engineering Chemistry Research Table 1. Absorption Capacities of SO2 in Some Ionic Liquids ILs

T (°C)

P (bar)

absorption capacity (mol SO2/mol IL) pure SO2

ref

[TMG][L] [BMIM][BTA] [BMIM][BF4] [TMG][BF4] [TMG][BTA] [TMGB2][BTA] [BMIM][OAc] [BMIM][MeSO4] [N2224][dimalonate] [N2224][dimaleate] [N2224][disuccinate]

40 20 20 20 20 20 25 25 40 40 40

1.2 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

1.7 1.33 1.50 1.27 1.18 1.60 1.91 2.11 1.88 1.72 1.58

Wu10 Huang15 Huang15 Huang15 Huang15 Huang15 Shiflett16 Shiflett16 Huang14 Huang14 Huang14

Table 2. Absorption Capacities of SO2 in Four DESs at Different Temperatures Downloaded by FLORIDA ATLANTIC UNIV on August 28, 2015 | http://pubs.acs.org Publication Date (Web): August 12, 2015 | doi: 10.1021/acs.iecr.5b01789

SO2 absorption capacity (mol SO2/mol DES) T (K)

ChCl + 2 EG

ChCl + MA

ChCl + 2 urea

ChCl + thiourea

293 303 313 323 333

2.88 2.25 1.64 1.29 0.98

1.88 1.40 1.05 0.80 0.64

1.41 1.57 1.17 0.90 0.69

2.96 2.37 1.89 1.53 1.32

a

The pressure of SO2 is 1 atm.

Figure 3. SO2 absorption capacity curves of four DESs at 303 K with different SO2 volume fractions.

Figure 2. SO2 absorption capacity curves of four DESs at different temperatures under a SO2 pressure of 1 atm.

Table 3. Absorption Capacities of SO2 in Four DESs at Different SO2 Partial Pressures SO2 absorption capacity (mol SO2/mol DES) p (atm)

ChCl + 2 EG

ChCl + MA

ChCl + 2 urea

ChCl + thiourea

0.20 0.40 0.60 0.80 1.00

0.65 1.00 1.34 1.75 2.25

0.28 0.54 0.84 1.09 1.40

0.56 0.98 1.27 1.54 1.57

0.30 0.73 1.45 1.88 2.37

a

Figure 4. Thermal gravity analysis of the DESs.

As shown in Figure 3, the absorption capacities of DESs increase with the increasing of SO2 partial pressure from 0.2 to 1.0 atm. For ChCl−thiourea (1:1), the capacity at 0.2 atm is 0.30 mol SO2/mol DES, whereas the value is 2.37 at 1.0 atm. It means that SO2 partial pressure has a significant influence on the absorption capacity, and the absorbed SO2 can be regenerated by reducing the SO2 partial pressure. We use the thermodynamic model to calculate the Henry’s law constants of SO2 in each DES. The Henry’s law is defined as below:

The system temperature is 303 K.

temperature was chosen to be 303 K in order to avoid the precipitation problem for ChCl−urea (1:2). All results are listed in Table 3. The SO2 partial pressure was controlled by the volume fractions of SO2 in mixed gas with different flow rates of pure SO2 gas and N2 gas.

H = Cg /C l 8021


Article

Industrial & Engineering Chemistry Research

the temperatures in regeneration process, so these DESs meet the demands in the application of FGD. Then, the absorption and regeneration experiments were conducted, and the desorption results are shown in Figure 5. It indicates that the absorption equilibrium of DESs and SO2 can be reached in 15 min, whereas 100% SO2 molecules can be regenerated in 15 min under the given condition, which means that the SO2 absorbed can be recycled, and the solvent can be reused. What is more, the DESs exhibits stable absorption capacities without a significant solvent loss after 6 cycles. Above all, the cheap and easy prepared DESs with excellent SO2 absorption capacity and favorable recyclability are promising alternatives in SO2 removal. IR and 1H NMR spectra of the DESs before and after SO2 absorption were recorded to investigate the absorption mechanisms. The IR spectra are presented in Figure 6. Compared the spectra before and after SO2 absorption, three typical vibrational frequencies of SO2 appear around 1320, 1145 and 530 cm−1, which are attribute to asymmetrical stretching vibration (vs̅ a), symmetrical stretching vibration (vs̅ ) and bending vibration (γ), respectively.47 No other new peaks or a significant shift of peaks can be observed except the −OH stretching vibration, which means that the absorption processes are physical absorptions. In addition, the shifts of − OH stretching vibration indicated that the −OH of ChCl cations may interact with SO2 by the formation of hydrogen bonds, which is in accordance with the SO2 absorption in diols.48 As we discussed above, the absorption processes are physical absorption, so a 1H NMR with D2O as an external reference was employed here to avoid the solvation of SO2 in deuterated reagents. The 1H NMR spectra of the four DESs before and after SO2 absorption are shown in Figure 7. The results demonstrate that the chemical shifts of all hydrogen atoms in


Figure 5. SO2 absorption and regeneration experiments of the four DESs. ■, ChCl + 2 EG; ●, ChCl + MA; ▲, ChCl + 2 urea; ▼, ChCl + thiourea.

where H is the Henry’s law constant (kPa), and Cg is the SO2 partial pressure in gas phase (kPa), whereas Cl is the SO2 capacity in DES (mol SO2/mol DES). As calculated, the Henry’s law constant of SO2 at 303 K in ChCl−EG (1:2), ChCl−MA (1:1), ChCl−urea (1:2), and ChCl−thiourea (1:1) are 47.6, 53.6, 73.4, and 41.0 kPa, respectively. The result also indicates that ChCl−thiourea (1:1) has the best absorption performance. When applied in SO2 removal, thermal stability of the sorbent is very important. Here, thermal gravity analysis (TGA) of the DESs was conducted as shown in Figure 4. It demonstrated that the regeneration temperatures of ChCl− EG (1:2), ChCl−MA (1:1), ChCl−urea (1:2), and ChCl− thiourea (1:1) are 369, 389, 409, and 476 K, which is all above

Figure 6. IR spectra of the four DESs before and after SO2 absorption. 8022


Article


Industrial & Engineering Chemistry Research

Figure 7. 1H NMR spectra of the four DESs before and after SO2 absorption with D2O as an external reference. and the implications on health effects research. Environ. Sci. Technol. 1979, 13, 1276−1280. (2) Kaplan, V.; Wachtel, E.; Lubomirsky, I. Carbonate melt regeneration for efficient capture of SO2 from coal combustion. RSC Adv. 2013, 3, 15842−15849. (3) Zhang, J. B.; Zhang, P. Y.; Chen, G. H.; Han, F.; Wei, X. H. Gasliquid equilibrium data for the mixture gas of sulfur dioxide/nitrogen with ethylene glycol at temperatures from (298.15 to 313.15) K under low pressures. J. Chem. Eng. Data 2008, 53, 1479−1485. (4) Niu, Y. X.; Gao, F.; Zhu, R. M.; Sun, S. Y.; Wei, X. H. Solubility of dilute SO2 in mixtures of N,N-dimethylformamide plus polyethylene glycol 400 and the density and viscosity of the mixtures. J. Chem. Eng. Data 2013, 58, 639−647. (5) Gao, F.; Zhang, J. B.; Niu, Y. X.; Wei, X. H. Desorption property and spectral investigation of dilute sulfur dioxide in ethylene glycol plus N,N-dimethylformamide system. Ind. Eng. Chem. Res. 2014, 53, 7871−7876. (6) Niu, Y. X.; Gao, F.; Sun, S. Y.; Xiao, J. B.; Wei, X. H. Solubility of dilute SO2 in 1,4-dioxane, 15-crown-5 ether, polyethylene glycol 200, polyethylene glycol 300, and their binary mixtures at 308.15 K and 122.66 kPa. Fluid Phase Equilib. 2013, 344, 65−70. (7) Huang, K.; Xia, S.; Zhang, X. M.; Chen, Y. L.; Wu, Y. T.; Hu, X. B. Comparative study of the solubilities of SO2 in five low volatile organic solvents (sulfolane, ethylene glycol, propylene carbonate, Nmethylimidazole, and N-methylpyrrolidone). J. Chem. Eng. Data 2014, 59, 1202−1212. (8) Huang, K.; Wang, G. N.; Dai, Y.; Wu, Y. T.; Hu, X. B.; Zhang, Z. B. Dicarboxylic acid salts as task-specific ionic liquids for reversible absorption of SO2 with a low enthalpy change. RSC Adv. 2013, 3, 16264−16269. (9) Tian, S. D.; Hou, Y. C.; Wu, W. Z.; Ren, S. H.; Zhang, C. Absorption of SO2 by thermal-stable functional ionic liquids with lactate anion. RSC Adv. 2013, 3, 3572−3577.

methyl or methylene of DESs move downfield significantly, which is attribute to the aromatic solvent-induced shift (ASIS) of SO2 based on the charge-transfer interactions between sulfur atoms in SO2 and oxygen or nitrogen atoms in DESs.48 In addition, the chemical shifts of active hydrogen atoms in −OH and −NH2 turned to be the same after the SO2 absorption, which means the addition of SO2 activates the active hydrogen atoms, and accelerates the exchanges of active hydrogen atoms.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.iecr.5b01789. SO2 capacities in DESs of absorption and regeneration experiments (PDF).

■

AUTHOR INFORMATION

Corresponding Author

*Xionghui Wei. Tel/Fax: +86-010-62670662. E-mail: xhwei@ pku.edu.cn. Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS This work is supported by Boyuan Hengsheng HighTechnology Co., Ltd., Beijing, China. REFERENCES

(1) Spengler, J. D.; Ferris, B. G., Jr; Dockery, D. W.; Speizer, F. E. Sulfur dioxide and nitrogen dioxide levels inside and outside homes 8023


Article


Industrial & Engineering Chemistry Research (10) Wu, W.; Han, B.; Gao, H.; Liu, Z.; Jiang, T.; Huang, J. Desulfurization of flue gas: SO2 absorption by an ionic liquid. Angew. Chem., Int. Ed. 2004, 43, 2415−2417. (11) Wang, Y.; Wang, C.; Zhang, L.; Li, H. Difference for SO2 and CO2 in TGML ionic liquids: a theoretical investigation. Phys. Chem. Chem. Phys. 2008, 10, 5976. (12) Yu, G.; Chen, X. SO2 Capture by guanidinium-based ionic liquids: A theoretical study. J. Phys. Chem. B 2011, 115, 3466−3477. (13) Zhai, L. Z.; Zhong, Q.; He, C.; Wang, J. Hydroxyl ammonium ionic liquids synthesized by water-bath microwave: Synthesis and desulfurization. J. Hazard. Mater. 2010, 177, 807−813. (14) Huang, K.; Lu, J. F.; Wu, Y. T.; Hu, X. B.; Zhang, Z. B. Absorption of SO2 in aqueous solutions of mixed hydroxylammonium dicarboxylate ionic liquids. Chem. Eng. J. 2013, 215, 36−44. (15) Huang, J.; Riisager, A.; Wasserscheid, P.; Fehrmann, R. Reversible physical absorption of SO2 by ionic liquids. Chem. Commun. 2006, 38, 4027. (16) Shiflett, M. B.; Yokozeki, A. Separation of carbon dioxide and sulfur dioxide using room-temperature ionic liquid [bmim][MeSO4]. Energy Fuels 2010, 24, 1001−1008. (17) Yokozeki, A.; Shiflett, M. B. Separation of carbon dioxide and sulfur dioxide gases using room-temperature ionic liquid [hmim][Tf2N]. Energy Fuels 2009, 23, 4701−4708. (18) Shiflett, M. B.; Yokozeki, A. Chemical absorption of sulfur dioxide in room-temperature ionic liquids. Ind. Eng. Chem. Res. 2010, 49, 1370−1377. (19) Zeng, S. J.; Gao, H. S.; Zhang, X. C.; Dong, H. F.; Zhang, X. P.; Zhang, S. J. Efficient and reversible capture of SO2 by pyridiniumbased ionic liquids. Chem. Eng. J. 2014, 251, 248−256. (20) Wang, J.; Zeng, S. J.; Bai, L.; Gao, H. S.; Zhang, X. P.; Zhang, S. J. Novel ether-functionalized pyridinium chloride ionic liquids for efficient SO2 capture. Ind. Eng. Chem. Res. 2014, 53, 16832−16839. (21) Qu, G. F.; Zhang, J.; Li, J. Y.; Ning, P. SO2 Absorption/ desorption characteristics of two novel phosphate ionic liquids. Sep. Sci. Technol. 2013, 48, 2876−2879. (22) Hong, S. Y.; Im, J.; Palgunadi, J.; Lee, S. D.; Lee, J. S.; Kim, H. S.; Cheong, M.; Jung, K.-D. Ether-functionalized ionic liquids as highly efficient SO2 absorbents. Energy Environ. Sci. 2011, 4, 1802. (23) Yang, Z. Z.; He, L. N.; Song, Q. W.; Chen, K. H.; Liu, A. H.; Liu, X. M. Highly efficient SO2 absorption/activation and subsequent utilization by polyethylene glycol-functionalized Lewis basic ionic liquids. Phys. Chem. Chem. Phys. 2012, 14, 15832−15839. (24) Cui, G.; Wang, C.; Zheng, J.; Guo, Y.; Luo, X.; Li, H. Highly efficient SO2 capture by dual functionalized ionic liquids through a combination of chemical and physical absorption. Chem. Commun. 2012, 48, 2633−2635. (25) Tang, S. K.; Baker, G. A.; Zhao, H. Ether- and alcoholfunctionalized task-specific ionic liquids: attractive properties and applications. Chem. Soc. Rev. 2012, 41, 4030−4066. (26) Ding, F.; Zheng, J. J.; Chen, Y. Q.; Chen, K. H.; Cui, G. K.; Li, H. R.; Wang, C. M. Highly efficient and reversible SO2 capture by surfactant-derived dual functionalized ionic liquids with metal chelate cations. Ind. Eng. Chem. Res. 2014, 53, 18568−18574. (27) Zhang, L. H.; Zhang, Z. J.; Sun, Y. L.; Jiang, B.; Li, X. G.; Ge, X. H.; Wang, J. T. Ether-functionalized ionic liquids with low viscosity for efficient SO2 capture. Ind. Eng. Chem. Res. 2013, 52, 16335−16340. (28) Wang, C.; Cui, G.; Luo, X.; Xu, Y.; Li, H.; Dai, S. Highly efficient and reversible SO2 capture by tunable azole-based ionic liquids through multiple-site chemical absorption. J. Am. Chem. Soc. 2011, 133, 11916−11919. (29) Cui, G. K.; Zheng, J. J.; Luo, X. Y.; Lin, W. J.; Ding, F.; Li, H. R.; Wang, C. M. Tuning anion-functionalized ionic liquids for improved SO2 capture. Angew. Chem., Int. Ed. 2013, 52, 10620−10624. (30) Wang, C. M.; Zheng, J. J.; Cui, G. K.; Luo, X. Y.; Guo, Y.; Li, H. R. Highly Efficient SO2 capture through tuning the interaction between anion-functionalized ionic liquids and SO2. Chem. Commun. 2013, 49, 1166−1168. (31) Smith, E. L.; Abbott, A. P.; Ryder, K. S. Deep eutectic solvents (DESs) and their applications. Chem. Rev. 2014, 114, 11060−11082.

(32) Abbott, A. P.; Capper, G.; Davies, D. L.; Rasheed, R. K.; Tambyrajah, V. Novel solvent properties of choline chloride/urea mixtures. Chem. Commun. 2003, 1, 70−71. (33) Lin, C. M.; Leron, R. B.; Caparanga, A. R.; Li, M. H. Henry’s Constant of carbon dioxide-aqueous deep eutectic solvent (choline chloride/ethylene glycol, choline chloride/glycerol, choline chloride/ malonic acid) systems. J. Chem. Thermodyn. 2014, 68, 216−220. (34) Abbott, A. P.; Boothby, D.; Capper, G.; Davies, D. L.; Rasheed, R. K. Deep eutectic solvents formed between choline chloride and carboxylic acids: versatile alternatives to ionic liquids. J. Am. Chem. Soc. 2004, 126, 9142−9147. (35) Zhang, Q. H.; De Oliveira Vigier, K.; Royer, S.; Jerome, F. Deep eutectic solvents: syntheses, properties and applications. Chem. Soc. Rev. 2012, 41, 7108−7146. (36) Abbott, A. P.; Capper, G.; Davies, D. L.; Rasheed, R. K.; Shikotra, P. Selective extraction of metals from mixed oxide matrixes using choline-based ionic liquids. Inorg. Chem. 2005, 44, 6497−6499. (37) Abbott, A. P.; El Ttaib, K.; Frisch, G.; McKenzie, K. J.; Ryder, K. S. Electrodeposition of copper composites from deep eutectic solvents based on choline chloride. Phys. Chem. Chem. Phys. 2009, 11, 4269− 4277. (38) Abbott, A. P.; El Ttaib, K.; Frisch, G.; Ryder, K. S.; Weston, D. The electrodeposition of silver composites using deep eutectic solvents. Phys. Chem. Chem. Phys. 2012, 14, 2443−2449. (39) Abbott, A. P.; Capper, G.; Davies, D. L.; Rasheed, R. H.; Tambyrajah, V. Quaternary ammonium Zinc- or Tin-containing ionic liquids: water insensitive, recyclable catalysts for Diels-Alder reactions. Green Chem. 2002, 4, 24−26. (40) Morales, R. C.; Tambyrajah, V.; Jenkins, P. R.; Davies, D. L.; Abbott, A. P. The regiospecific Fischer indole reaction in choline chloride ·2ZnCl2 with product isolation by direct sublimation from the ionic liquid. Chem. Commun. 2004, 2, 158−159. (41) Zhu, A. L.; Jiang, T.; Han, B. X.; Zhang, J. C.; Xie, Y.; Ma, X. M. Supported choline chloride/urea as a heterogeneous catalyst for chemical fixation of carbon dioxide to cyclic carbonates. Green Chem. 2007, 9, 169−172. (42) Li, G. H.; Deng, D. S.; Chen, Y. F.; Shan, H. F.; Ai, N. Solubilities and thermodynamic properties of CO2 in choline-chloride based deep eutectic solvents. J. Chem. Thermodyn. 2014, 75, 58−62. (43) Sze, L. L.; Pandey, S.; Ravula, S.; Pandey, S.; Zhao, H.; Baker, G. A.; Baker, S. N. Ternary deep eutectic solvents tasked for carbon dioxide capture. ACS Sustainable Chem. Eng. 2014, 2, 2117−2123. (44) Liu, B. Y.; Wei, F. X.; Zhao, J. J.; Wang, Y. Y. Characterization of amide-thiocyanates eutectic ionic liquids and their application in SO2 absorption. RSC Adv. 2013, 3, 2470−2476. (45) Wang, C.; Guo, Y.; Zhu, X.; Cui, G.; Li, H.; Dai, S. Highly efficient CO2 capture by tunable alkanolamine-based ionic liquids with multidentate cation coordination. Chem. Commun. 2012, 48, 6526− 6528. (46) Yang, D. Z.; Hou, M. Q.; Ning, H.; Zhang, J. L.; Ma, J.; Yang, G. Y.; Han, B. X. Efficient SO2 absorption by renewable choline chlorideglycerol deep eutectic solvents. Green Chem. 2013, 15, 2261−2265. (47) Maybury, R. H.; Gordon, S.; Katz, J. J. Infrared spectra of liquid anhydrous hydrogen fluoride, liquid sulfur dioxide, and hydrogen fluoride-sulfur dioxide solutions. J. Chem. Phys. 1955, 23, 1277−1281. (48) Sun, S.; Niu, Y.; Sun, Z.; Xu, Q.; Wei, X. Solubility properties and spectral characterization of sulfur dioxide in ethylene glycol derivatives. RSC Adv. 2015, 5, 8706−8712.

8024


Efficient SO2 Absorptions by Four Kinds of Deep Eutectic Solvents

Recommend Documents