热可逆离子液体-低共熔溶剂双水相体系的相行为及理化特性研究

doi:10.11949/0438-1157.20201412

摘要/Abstract

摘要：

与聚合物双水相体系相比，离子液体双水相体系具有相分离效率高和选择性强的特点，在萃取领域得到了广泛关注。然而，离子液体双水相体系中常见的kosmotropic组分为无机盐或有机盐，溶液环境通常呈现强碱性，不利于保持萃取分子的稳定性和生物活性。以低共熔溶剂替代盐类作为kosmotropic组分、以离子液体为chaotropic组分构建新型离子液体-低共熔溶剂双水相体系，考察了不同温度下的相行为规律，筛选出具有高临界共熔温度（UCST）和低临界共熔温度（LCST）两种截然相反的热可逆相转变行为的萃取体系，从宏观角度探索了离子液体-低共熔溶剂-水三元体系的黏度、密度、电导率以及pH等理化特性随温度变化的规律，利用量子化学计算从微观角度分析离子液体、低共熔溶剂与水分子之间的相互作用。研究旨在揭示热可逆离子液体-低共熔溶剂双水相体系的成相机理，为萃取温敏性生物分子设计新的理想萃取体系提供基础数据。

关键词: 热可逆, 离子液体, 低共熔溶剂, 双水相, 相行为, 理化特性

Abstract:

Compared with the polymer-based aqueous biphasic systems (ABSs), the ionic liquid (IL)-based ABSs exhibited higher phase separation efficiency and stronger selectivity, and have attracted increasing attention in separation and purification. However, the kosmotropic components in the IL-based ABSs were inorganic salts or organic salts, which were adverse to maintain the stability and biological activity of the biomolecules in a strong alkaline solution. In this study, deep eutectic solvents (DESs) were used as alternative kosmotropic components to form novel ABSs with ILs (chaotropic components). The law of phase behavior at different temperature was investigated to screen out thermoreversible systems showing upper critical solution temperature (UCST) and lower critical solution temperature (LCST). Moreover, the physicochemical properties, such as the viscosity, density, conductivity, and pH of the IL-DES-water ternary systems as function of temperature were explored. Furthermore, quantum chemical calculations were used to analyze the interaction between the IL and water or DES and water. The research aims to reveal the mechanism of the thermoreversible IL-DES ABS and provide essential data for the desigin of a new ideal extraction system for the extraction of thermo-sensitive biomolecules.

Key words: thermoreversible, ionic liquid, deep eutectic solvent, aqueous biphasic system, phase behavior, physicochemical properties

中图分类号:

TQ 013

张莉莉, 李艳, 高静. 热可逆离子液体-低共熔溶剂双水相体系的相行为及理化特性研究[J]. 化工学报, 2021, 72(5): 2493-2505.

ZHANG Lili, LI Yan, GAO Jing. Phase behavior and physicochemical properties of thermoreversible aqueous biphasic systems composed of ionic liquids and deep eutectic solvents[J]. CIESC Journal, 2021, 72(5): 2493-2505.

图/表 12

图1 离子液体及低共熔溶剂的化学结构

Fig.1 Chemical structure of ionic liquid sand deep eutectic solvents

表1 离子液体及低共熔溶剂的基本性质

Table 1 Properties of ionic liquids and deep eutectic solvents

ILs/DESs	W_c/%	η×10^-3/(mPa·s)(298.15 K)	α (298.15 K)	β (298.15 K)	π^* (298.15 K)	$E T N$ (298.15 K)	T_i/K	T_peak/K	T_f/K	W_lost/%	W_973.15/%
[C₄mim]BF₄	0.52±0.01	0.10±0.00	0.69±0.02	0.32±0.01	1.05±0.03	0.70±0.02	644.45	691.05	701.75	370.71	1.12
[C₄mim]Br	0.27±0.02	ND	ND	ND	ND	ND	556.75	587.15	595.25	362.91	3.61
[C₄mim]Cl	0.13±0.02	ND	ND	ND	ND	ND	538.95	560.75	569.85	360.51	4.33
[C₄mim]CF₃COO	1.49±0.02	0.08±0.00	0.61±0.03	0.71±0.03	0.96±0.02	0.64±0.01	454.05	471.45/551.45	519.25	353.05	7.16
[P₄₄₄₄]BF₄	0.29±0.01	ND	ND	ND	ND	ND	719.45	741.35	753.45	364.74	3.19
[P₄₄₄₄]Br	0.52±0.02	ND	ND	ND	ND	ND	645.55	675.45	691.05	369.57	1.88
[P₄₄₄₄]Cl	0.02±0.01	ND	ND	ND	ND	ND	640.25	669.95	685.65	364.47	3.72
[P₄₄₄₄]CF₃COO	0.15±0.01	ND	ND	ND	ND	ND	462.15	476.65/499.15/518.35	512.05	350.60	3.91
[P₄₄₄₈]BF₄	1.25±0.45	0.89±0.00	ND	0.68±0.01	0.87±0.02	ND	703.95	743.95	751.35	366.02	5.31
[P₄₄₄₈]Br	2.69±0.30	ND	ND	ND	ND	ND	639.85	665.45	685.05	364.95	6.31
[P₄₄₄₈]Cl	3.11±0.11	1.26±0.02	ND	1.30±0.01	0.04±0.01	ND	635.25	664.55	680.65	357.40	5.80
[P₄₄₄₈]CF₃COO	0.27±0.01	0.24±0.00	ND	1.07±0.04	0.87±0.02	ND	480.95	472.85/548.55	569.85	359.71	6.17
[N₄₄₄₄]BF₄	0.94±0.06	ND	ND	ND	ND	ND	469.75	492.25/664.75	676.65	367.82	3.65
[N₄₄₄₄]Br	0.94±0.00	ND	ND	ND	ND	ND	473.35	492.85/536.15	506.35	349.57	4.14
[N₄₄₄₄]Cl	8.51±0.08	ND	ND	ND	ND	ND	464.95	485.25	497.35	361.95	4.76
[N₄₄₄₄]CF₃COO	0.16±0.03	ND	ND	ND	ND	ND	480.25	504.25	513.75	365.62	6.35
[ChCl][Rib]	0.06±0.04	23.40±0.25	ND	ND	ND	ND	520.55	545.05	557.75	342.81	18.29
[ChCl][Glu]	0.01±0.00	654.05±39.65	ND	ND	ND	ND	494.35	520.85	563.25	341.91	19.06
[ChCl][Fru]	12.93±0.12	54.06±0.48	ND	ND	ND	ND	432.75	448.85/514.55/564.35	563.75	347.21	16.17
[ChCl][Sur]	7.87±0.08	>2201.00±83.00	ND	ND	ND	ND	509.05	543.85	559.65	338.53	20.83

表1 离子液体及低共熔溶剂的基本性质

Table 1 Properties of ionic liquids and deep eutectic solvents

ILs/DESs	W_c/%	η×10^-3/(mPa·s)(298.15 K)	α (298.15 K)	β (298.15 K)	π^* (298.15 K)	$E T N$ (298.15 K)	T_i/K	T_peak/K	T_f/K	W_lost/%	W_973.15/%
[C₄mim]BF₄	0.52±0.01	0.10±0.00	0.69±0.02	0.32±0.01	1.05±0.03	0.70±0.02	644.45	691.05	701.75	370.71	1.12
[C₄mim]Br	0.27±0.02	ND	ND	ND	ND	ND	556.75	587.15	595.25	362.91	3.61
[C₄mim]Cl	0.13±0.02	ND	ND	ND	ND	ND	538.95	560.75	569.85	360.51	4.33
[C₄mim]CF₃COO	1.49±0.02	0.08±0.00	0.61±0.03	0.71±0.03	0.96±0.02	0.64±0.01	454.05	471.45/551.45	519.25	353.05	7.16
[P₄₄₄₄]BF₄	0.29±0.01	ND	ND	ND	ND	ND	719.45	741.35	753.45	364.74	3.19
[P₄₄₄₄]Br	0.52±0.02	ND	ND	ND	ND	ND	645.55	675.45	691.05	369.57	1.88
[P₄₄₄₄]Cl	0.02±0.01	ND	ND	ND	ND	ND	640.25	669.95	685.65	364.47	3.72
[P₄₄₄₄]CF₃COO	0.15±0.01	ND	ND	ND	ND	ND	462.15	476.65/499.15/518.35	512.05	350.60	3.91
[P₄₄₄₈]BF₄	1.25±0.45	0.89±0.00	ND	0.68±0.01	0.87±0.02	ND	703.95	743.95	751.35	366.02	5.31
[P₄₄₄₈]Br	2.69±0.30	ND	ND	ND	ND	ND	639.85	665.45	685.05	364.95	6.31
[P₄₄₄₈]Cl	3.11±0.11	1.26±0.02	ND	1.30±0.01	0.04±0.01	ND	635.25	664.55	680.65	357.40	5.80
[P₄₄₄₈]CF₃COO	0.27±0.01	0.24±0.00	ND	1.07±0.04	0.87±0.02	ND	480.95	472.85/548.55	569.85	359.71	6.17
[N₄₄₄₄]BF₄	0.94±0.06	ND	ND	ND	ND	ND	469.75	492.25/664.75	676.65	367.82	3.65
[N₄₄₄₄]Br	0.94±0.00	ND	ND	ND	ND	ND	473.35	492.85/536.15	506.35	349.57	4.14
[N₄₄₄₄]Cl	8.51±0.08	ND	ND	ND	ND	ND	464.95	485.25	497.35	361.95	4.76
[N₄₄₄₄]CF₃COO	0.16±0.03	ND	ND	ND	ND	ND	480.25	504.25	513.75	365.62	6.35
[ChCl][Rib]	0.06±0.04	23.40±0.25	ND	ND	ND	ND	520.55	545.05	557.75	342.81	18.29
[ChCl][Glu]	0.01±0.00	654.05±39.65	ND	ND	ND	ND	494.35	520.85	563.25	341.91	19.06
[ChCl][Fru]	12.93±0.12	54.06±0.48	ND	ND	ND	ND	432.75	448.85/514.55/564.35	563.75	347.21	16.17
[ChCl][Sur]	7.87±0.08	>2201.00±83.00	ND	ND	ND	ND	509.05	543.85	559.65	338.53	20.83

表2 热可逆离子液体-低共熔溶剂-水体系的构建

Table 2 Construction of thermo reversible ILs-DESs-H2O system

ILs	[ChCl][Rib]	[ChCl][Glu]	[ChCl][Fru]	[ChCl][Sur]
[C₄mim]BF₄	?	UCST	UCST	UCST
[C₄mim]Br	?	?	?	?
[C₄mim]Cl	?	?	?	?
[C₄mim]CF₃COO	?	?	?	?
[P₄₄₄₄]BF₄	×	×	×	×
[P₄₄₄₄]Br	LCST	LCST	LCST	LCST
[P₄₄₄₄]Cl	LCST	?	LCST	LCST
[P₄₄₄₄]CF₃COO	?	?	?	?
[P₄₄₄₈]BF₄	×	×	×	×
[P₄₄₄₈]Br	LCST	LCST	LCST	LCST
[P₄₄₄₈]Cl	LCST	LCST	LCST	LCST
[P₄₄₄₈]CF₃COO	×	×	×	×
[N₄₄₄₄]BF₄	×	×	×	×
[N₄₄₄₄]Br	?	?	?	?
[N₄₄₄₄]Cl	?	?	?	?
[N₄₄₄₄]CF₃COO	LCST	LCST	LCST	LCST

图2 UCST型(a)与LCST型(b)离子液体-低共熔溶剂体系的双水相相图

Fig.2 Phase diagrams of UCST (a) and LCST (b) of IL-DES-H2O

图3 离子液体-[ChCl][Fru]和离子液体-[ChCl][Sur]在308.15 K下的双水相相图

Fig.3 Phase diagrams of ILs-[ChCl][Fru]-H2O and ILs-[ChCl][Sur]-H2O at 308.15 K

图4 [P4444]Br-低共熔溶剂(a)和[N4444]CF3COO-低共熔溶剂(b)在308.15 K下的双水相相图

Fig.4 Phase diagrams of DESs-[P4444]Br-H2O (a) and DESs-[N4444]CF3COO-H2O (b) at 308.15 K

表3 离子液体-低共熔溶剂体系双水相相图实验数据相关性拟合

Table 3 Phase diagram of ILs-DESs-H2O with the corresponding fitting of the experimental data

ILs	DESs	T/K	A	B	C	R²
[C₄mim]BF₄	[ChCl][Fru]	298.15	1.00	-1.02	9.75	0.9999
	[ChCl][Glu]	298.15	1.19	-2.05	8.86	0.9941
	[ChCl][Glu]	328.15	1.23	-1.67	0.31	0.9982
	[ChCl][Sur]	308.15	1.21	-1.99	1.08	0.9929
[P₄₄₄₄]Br	[ChCl][Rib]	308.15	1.48	-1.70	4.17	1.0000
	[ChCl][Glu]	308.15	2.10	-2.54	3.44	0.9994
	[ChCl][Fru]	308.15	1.58	-1.81	4.30	0.9998
	[ChCl][Sur]	308.15	1.04	-0.91	11.69	0.9983
[P₄₄₄₄]Cl	[ChCl][Fru]	308.15	0.07	3.83	8.64	0.9996
[P₄₄₄₄]Cl	[ChCl][Sur]	308.15	0.62×10^-17	59.49	65.87	0.9928
[P₄₄₄₈]Br	[ChCl][Fru]	308.15	0.58	-4.97	24.29	0.9976
[P₄₄₄₈]Br	[ChCl][Sur]	308.15	0.10	-2.04	133.00	0.9912
[P₄₄₄₈]Cl	[ChCl][Fru]	308.15	0.72	-0.61	63.26	0.9890
[P₄₄₄₈]Cl	[ChCl][Sur]	308.15	1.47	-2.31	51.95	0.9971
[N₄₄₄₄]CF₃COO	[ChCl][Rib]	308.15	8.05	-5.90	2.34	0.9916
	[ChCl][Glu]	308.15	2.66	-4.36	9.64	0.9978
	[ChCl][Fru]	298.15	3.65	-4.23	5.02	0.9961
	[ChCl][Fru]	308.15	28.17	-8.74	-3.85	0.9976
	[ChCl][Fru]	328.15	3.57	-5.40	-1.52	0.9976
	[ChCl][Sur]	308.15	3696.29	-19.26	-23.64	0.9782

图5 308.15 K下[P4444]Br-[ChCl][Fru]双水相相图实验数据相关性拟合

Fig.5 Phase diagram of [P4444]Br-[ChCl][Fru]-H2O with the corresponding fitting of the experimental data at 308.15 K

图6 不同温度下离子液体-低共熔溶剂-水三元体系黏度、密度、电导率和pH的变化趋势

Fig.6 Viscosities, densities, conductivities, pH for ILs-DESs-H2O as a function of temperature

图7 不同温度下离子液体-低共熔溶剂-水三元体系摩尔体积(Vm)、标准摩尔熵(S?)和晶格能(UPOT)的变化趋势

Fig.7 Molar volume (Vm), standard molar entropy (S?) and lattice energy (UPOT) for ILs-DESs-H2O as a function of temperature

图8 离子液体-低共熔溶剂-水三元体系几何平衡构型(青色、蓝色、红色、绿色、橙色和白色分别为C、N、O、Cl、P和H原子)

Fig.8 Geometric equilibrium configuration of ILs-DESs-H2O ternary system

表4 离子液体-低共熔溶剂-水三元体系的相互作用能

Table 4 Interaction energy of ILs-DESs-H2O ternary system

System	E_complex/(kJ·mol^-1)	E_[ChCl][Fru]/(kJ·mol^-1)	$E [P 4448] C l$ /(kJ·mol^-1)	$E H 2 O$ /(kJ·mol^-1)	E_BSSE/(kJ·mol^-1)	ΔG/(kJ·mol^-1)
[P₄₄₄₈]⁺-Cl^-	-998.19×10³	-709.25×10³	-288.84×10³	—	4.79	-91.01
[P₄₄₄₈]Cl-H₂O	-1046.19×10³	-998.19×10³	-47.98×10³	—	1.36	-16.39
[Ch]⁺-Cl^-	-495.19×10³	-206.35×10³	-288.84×10³	—	4.05	-110.71
[ChCl][Fru]	-926.74×10³	-495.29×10³	-431.41×10³	—	2.10	-43.25
[ChCl][Fru]-H₂O	-974.74×10³	-926.73×10³	-47.98×10³	—	1.68	-20.95
[P₄₄₄₈]Cl-[ChCl][Fru]-H₂O	-1972.96×10³	-926.73×10³	-998.18×10³	-47.98×10³	3.70	-60.43

表4 离子液体-低共熔溶剂-水三元体系的相互作用能

Table 4 Interaction energy of ILs-DESs-H2O ternary system

System	E_complex/(kJ·mol^-1)	E_[ChCl][Fru]/(kJ·mol^-1)	$E [P 4448] C l$ /(kJ·mol^-1)	$E H 2 O$ /(kJ·mol^-1)	E_BSSE/(kJ·mol^-1)	ΔG/(kJ·mol^-1)
[P₄₄₄₈]⁺-Cl^-	-998.19×10³	-709.25×10³	-288.84×10³	—	4.79	-91.01
[P₄₄₄₈]Cl-H₂O	-1046.19×10³	-998.19×10³	-47.98×10³	—	1.36	-16.39
[Ch]⁺-Cl^-	-495.19×10³	-206.35×10³	-288.84×10³	—	4.05	-110.71
[ChCl][Fru]	-926.74×10³	-495.29×10³	-431.41×10³	—	2.10	-43.25
[ChCl][Fru]-H₂O	-974.74×10³	-926.73×10³	-47.98×10³	—	1.68	-20.95
[P₄₄₄₈]Cl-[ChCl][Fru]-H₂O	-1972.96×10³	-926.73×10³	-998.18×10³	-47.98×10³	3.70	-60.43

参考文献 56

1	Wang B, Qin L, Mu T, et al. Are ionic liquids chemically stable?[J]. Chemical Reviews, 2017, 117(10): 7113-7131.
2	Xue Z M, Qin L, Jiang J Y, et al. Thermal, electrochemical and radiolytic stabilities of ionic liquids[J]. Physical Chemistry Chemical Physics, 2018, 20(13): 8382-8402.
3	Gutowski K E, Broker G A, Willauer H D, et al. Controlling the aqueous miscibility of ionic liquids: aqueous biphasic systems of water-miscible ionic liquids and water-structuring salts for recycle, metathesis, and separations[J]. Journal of the American Chemical Society, 2003, 125(22): 6632-6633.
4	Santana-Mayor Á, Socas-Rodríguez B, Rodríguez-Ramos R, et al. A green and simple procedure based on deep eutectic solvents for the extraction of phthalates from beverages[J]. Food Chemistry, 2020, 312: 125798.
5	Yu D K, Mou H Y, Fu H, et al. “Inverted” deep eutectic solvents based on host-guest interactions[J]. Chemistry — An Asian Journal, 2019, 14(23): 4183-4188.
6	Yu D K, Mu T C. Strategy to form eutectic molecular liquids based on noncovalent interactions[J]. The Journal of Physical Chemistry B, 2019, 123(23): 4958-4966.
7	Yu D K, Mou H Y, Zhao X H, et al. Eutectic molecular liquids based on hydrogen bonding and π-π interaction for exfoliating two-dimensional materials and recycling polymers[J]. Chemistry — An Asian Journal, 2019, 14(19): 3350-3356.
8	Zeng Q, Wang Y, Huang Y, et al. Deep eutectic solvents as novel extraction media for protein partitioning[J]. The Analyst, 2014, 139(10): 2565-2573.
9	Xu K J, Wang Y Z, Huang Y H, et al. A green deep eutectic solvent-based aqueous two-phase system for protein extracting[J]. Analytica Chimica Acta, 2015, 864: 9-20.
10	Xu P L, Wang Y Z, Chen J, et al. Development of deep eutectic solvent-based aqueous biphasic system for the extraction of lysozyme[J]. Talanta, 2019, 202: 1-10.
11	Zhang H M, Wang Y Z, Zhou Y G, et al. Aqueous biphasic systems containing PEG-based deep eutectic solvents for high-performance partitioning of RNA[J]. Talanta, 2017, 170: 266-274.
12	Li N, Wang Y Z, Xu K J, et al. High-performance of deep eutectic solvent based aqueous bi-phasic systems for the extraction of DNA[J]. RSC Advances, 2016, 6(87): 84406-84414.
13	Reichardt C. Solvatochromic dyes as solvent polarity indicators[J]. Chemical Reviews, 1994, 94(8): 2319-2358.
14	Li Y, Lu X, He W, et al. Influence of the salting-out ability and temperature on the liquid-liquid equilibria of aqueous two-phase systems based on ionic liquid-organic salts-water[J]. Journal of Chemical and Engineering Data, 2016, 61: 475–486.
15	Freire M G, Cláudio A F, Araújo J M, et al. Aqueous biphasic systems: a boost brought about by using ionic liquids[J]. Chemical Society Reviews, 2012, 41(14): 4966-4995.
16	Dilip M, Bridges N J, Rodríguez H, et al. Effect of temperature on salt-salt aqueous biphasic systems: manifestations of upper critical solution temperature[J]. Journal of Solution Chemistry, 2015, 44(3/4): 454-468.
17	Zafarani-Moattar M T, Hamzehzadeh S. Phase diagrams for the aqueous two-phase ternary system containing the ionic liquid 1-butyl-3-methylimidazolium bromide and tri-potassium citrate at T= (278.15, 298.15, and 318.15) K[J]. Journal of Chemical & Engineering Data, 2009, 54(3): 833-841.
18	Pang J Y, Han C R, Chao Y H, et al. Partitioning behavior of tetracycline in hydrophilic ionic liquids two-phase systems[J]. Separation Science and Technology, 2015, 50(13): 1993-1998.
19	Freire M G, Teles A R R, Canongia Lopes J N, et al. Partition coefficients of alkaloids in biphasic ionic-liquid-aqueous systems and their dependence on the hofmeister series[J]. Separation Science and Technology, 2012, 47(2): 284-291.
20	Sadeghi R, Golabiazar R, Shekaari H. The salting-out effect and phase separation in aqueous solutions of tri-sodium citrate and 1-butyl-3-methylimidazolium bromide[J]. The Journal of Chemical Thermodynamics, 2010, 42(4): 441-453.
21	Gao J, Chen L, Yan Z C. Extraction of dimethyl sulfoxide using ionic-liquid-based aqueous biphasic systems[J]. Separation and Purification Technology, 2014, 124: 107-116.
22	Taha M, Quental M V, Correia I, et al. Extraction and stability of bovine serum albumin (BSA) using cholinium-based Good's buffers ionic liquids[J]. Process Biochemistry, 2015, 50(7): 1158-1166.
23	Pereira M M, Pedro S N, Quental M V, et al. Enhanced extraction of bovine serum albumin with aqueous biphasic systems of phosphonium- and ammonium-based ionic liquids[J]. Journal of Biotechnology, 2015, 206: 17-25.
24	Deive F J, Rodríguez A, Pereiro A B, et al. Ionic liquid-based aqueous biphasic system for lipase extraction[J]. Green Chemistry, 2011, 13(2): 390-396.
25	Gao J, Guo J Y, Nie F H, et al. LCST-type phase behavior of aqueous biphasic systems composed of phosphonium-based ionic liquids and potassium phosphate[J]. Journal of Chemical & Engineering Data, 2017, 62(4): 1335-1340.
26	Pandey A, Pandey S. Solvatochromic probe behavior within choline chloride-based deep eutectic solvents: effect of temperature and water[J]. The Journal of Physical Chemistry B, 2014, 118(50): 14652-14661.
27	Guan W, Chang N, Yang L L, et al. Determination and prediction for the polarity of ionic liquids[J]. Journal of Chemical & Engineering Data, 2017, 62(9): 2610-2616.
28	Gao J, Chen L, Xin Y, et al. Ionic liquid-based aqueous biphasic systems with controlled hydrophobicity: the polar solvent effect[J]. Journal of Chemical & Engineering Data, 2014, 59(7): 2150-2158.
29	Sánchez P B, González B, Salgado J, et al. Physical properties of seven deep eutectic solvents based on l-proline or betaine[J]. The Journal of Chemical Thermodynamics, 2019, 131: 517-523.
30	Shafie M H, Yusof R, Gan C Y. Synthesis of citric acid monohydrate-choline chloride based deep eutectic solvents (DES) and characterization of their physicochemical properties[J]. Journal of Molecular Liquids, 2019, 288: 111081.
31	Zhao Y, Truhlar D G. The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals[J]. Theoretical Chemistry Accounts, 2008, 120(1/2/3): 215-241.
32	Stewart J J P. MOPAC: a semiempirical molecular orbital program[J]. Journal of Computer-Aided Molecular Design, 1990, 4(1): 1-103.
33	Grimme S, Antony J, Ehrlich S, et al. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu[J]. The Journal of Chemical Physics, 2010, 132(15): 154104.
34	Rappoport D, Furche F. Property-optimized Gaussian basis sets for molecular response calculations[J]. The Journal of Chemical Physics, 2010, 133(13): 134105.
35	Boys S F, Bernardi F. The calculation of small molecular interactions by the differences of separate total energies. Some procedures with reduced errors[J]. Molecular Physics, 1970, 19(4): 553-566.
36	Simon S, Duran M, Dannenberg J J. How does basis set superposition error change the potential surfaces for hydrogen-bonded dimers?[J]. The Journal of Chemical Physics, 1996, 105(24): 11024-11031.
37	Zafarani-Moattar M T, Shekaari H, Ghaffari F. Evaluation of solute-solvent interaction and phase separation for aqueous polymers solutions containing choline chloride/D-sucrose natural deep eutectic solvent through vapor-liquid equilibria, volumetric and acoustic studies[J]. The Journal of Chemical Thermodynamics, 2020, 142: 105963.
38	金文彬, 李雪楠, 张依, 等. 离子液体在结构相似物分离中的进展[J]. 中国科学: 化学, 2016, 46(12): 1251-1263.
	Jin W B, Li X N, Zhang Y, et al. Separation of structurally-related compounds with ionic liquids[J]. Scientia Sinica (Chimica), 2016, 46(12): 1251-1263.
39	胡丽华, 陈砺, 方泳华, 等. 低共熔溶剂的分子结构及物性估算的研究进展[J]. 化学试剂, 2017, 39(9): 937-941.
	Hu L H, Chen L, Fang Y H, et al. Molecular structure and physical property estimation of deep eutectic solvents(DESs)[J]. Chemical Reagents, 2017, 39(9): 937-941.
40	Passos H, Luís A, Coutinho J A P, et al. Thermoreversible (ionic-liquid-based) aqueous biphasic systems[J]. Scientific Reports, 2016, 6: 20276.
41	Silva F A E, Pereira J F B, Kurnia K A, et al. Temperature dependency of aqueous biphasic systems: an alternative approach for exploring the differences between coulombic-dominated salts and ionic liquids[J]. Chemical Communications, 2017, 53(53): 7298-7301.
42	Griffin S T, Dilip M, Spear S K, et al. The opposite effect of temperature on polyethylene glycol-based aqueous biphasic systems versus aqueous biphasic extraction chromatographic resins[J]. Journal of Chromatography B, 2006, 844(1): 23-31.
43	Schaeffer N, Pérez-Sánchez G, Passos H, et al. Mechanisms of phase separation in temperature-responsive acidic aqueous biphasic systems[J]. Physical Chemistry Chemical Physics, 2019, 21(14): 7462-7473.
44	Gao J, Chen L, Yan Z C. Phase behavior of aqueous biphasic systems composed of ionic liquids and organic salts[J]. Journal of Chemical & Engineering Data, 2015, 60(3): 464-470.
45	Qin M Y, Zhong F, Sun Y, et al. Experimental and DFT studies on surface properties of sulfonate-based surface active ionic liquids[J]. Journal of Molecular Structure, 2020, 1215: 128258.
46	Gao J, Fang C L, Lin Y Z, et al. Enhanced extraction of astaxanthin using aqueous biphasic systems composed of ionic liquids and potassium phosphate[J]. Food Chemistry, 2020, 309: 125672.
47	张莉莉, 高静, 魏媛仪, 等. LCST型离子液体-盐双水相体系提取虾青素[J]. 中国食品学报, 2020, 20(4): 170-178.
	Zhang L L, Gao J, Wei Y Y, et al. Extraction of astaxanthin by LCST-type ionic liquid-salt aqueous biphasic systems[J]. Journal of Chinese Institute of Food Science and Technology, 2020, 20(4): 170-178.
48	Cai G M, Yang S Q, Wang X X, et al. Densities and viscosities of binary mixtures containing the polyhydric protic ionic liquid(2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium methanesulfonate) and water or alcohols[J]. Journal of Solution Chemistry, 2020, 49(4): 423-457.
49	Boli E, Katsavrias T, Voutsas E. Viscosities of pure protic ionic liquids and their binary and ternary mixtures with water and ethanol[J]. Fluid Phase Equilibria, 2020, 520: 112663.
50	Guo S, Chen F, Liu L, et al. Effects of the water content on the transport properties of ionic liquids[J]. Industrial & Engineering Chemistry Research, 2019, 58(42): 19661-19669.
51	Bounsiar R, Gascón I, Amireche F, et al. Volumetric properties of three pyridinium-based ionic liquids with a common cation or anion[J]. Fluid Phase Equilibria, 2020, 521: 112732.
52	Sardar S, Wilfred C D, Mumtaz A, et al. Physicochemical properties, Brönsted acidity and ecotoxicity of imidazolium-based organic salts: non-toxic variants of protic ionic liquids[J]. Journal of Molecular Liquids, 2018, 269: 178-186.
53	Bessa A M M, Venerando M S C, Feitosa F X, et al. Low viscosity lactam-based ionic liquids with carboxylate anions: synthesis, characterization, thermophysical properties and mutual miscibility of ionic liquid with alcohol, water, and hydrocarbons[J]. Journal of Molecular Liquids, 2020, 313: 113586.
54	Xue Z M, Yan C Y, Zhao X H, et al. How Hofmeister ions change the local environment around thermoresponsive polymers in aqueous solutions: an NMR study[J]. Acta Physico-Chimica Sinica, 2019, 35(1): 49-57.
55	Yan C, Xue Z M, Zhao W C, et al. Surprising Hofmeister effects on the bending vibration of water[J]. ChemPhysChem, 2016, 17(20): 3309-3314.
56	郭晶涛. 离子液体结构性质与相互作用的计算[D]. 兰州: 西北师范大学, 2009.
	Guo J T. The calculations of structural properties and the interaction between the anions and cations in ionic liquids[D]. Lanzhou: Northwest Normal University, 2009.

[1]	王琪, 张斌, 张晓昕, 武虎建, 战海涛, 王涛. 氯铝酸-三乙胺离子液体/P₂O₅催化合成伊索克酸和2-乙基蒽醌[J]. 化工学报, 2023, 74(S1): 245-249.
[2]	车睿敏, 郑文秋, 王小宇, 李鑫, 许凤. 基于离子液体的纤维素均相加工研究进展[J]. 化工学报, 2023, 74(9): 3615-3627.
[3]	米泽豪, 花儿. 基于DFT和COSMO-RS理论研究多元胺型离子液体吸收SO₂气体[J]. 化工学报, 2023, 74(9): 3681-3696.
[4]	宋明昊, 赵霏, 刘淑晴, 李国选, 杨声, 雷志刚. 离子液体脱除模拟油中挥发酚的多尺度模拟与研究[J]. 化工学报, 2023, 74(9): 3654-3664.
[5]	杨绍旗, 赵淑蘅, 陈伦刚, 王晨光, 胡建军, 周清, 马隆龙. Raney镍-质子型离子液体体系催化木质素平台分子加氢脱氧制备烷烃[J]. 化工学报, 2023, 74(9): 3697-3707.
[6]	陈美思, 陈威达, 李鑫垚, 李尚予, 吴有庭, 张锋, 张志炳. 硅基离子液体微颗粒强化气体捕集与转化的研究进展[J]. 化工学报, 2023, 74(9): 3628-3639.
[7]	程业品, 胡达清, 徐奕莎, 刘华彦, 卢晗锋, 崔国凯. 离子液体基低共熔溶剂在转化CO₂中的应用[J]. 化工学报, 2023, 74(9): 3640-3653.
[8]	王俐智, 杭钱程, 郑叶玲, 丁延, 陈家继, 叶青, 李进龙. 离子液体萃取剂萃取精馏分离丙酸甲酯+甲醇共沸物[J]. 化工学报, 2023, 74(9): 3731-3741.
[9]	陈杰, 林永胜, 肖恺, 杨臣, 邱挺. 胆碱基碱性离子液体催化合成仲丁醇性能研究[J]. 化工学报, 2023, 74(9): 3716-3730.
[10]	陆俊凤, 孙怀宇, 王艳磊, 何宏艳. 离子液体界面极化及其调控氢键性质的分子机理[J]. 化工学报, 2023, 74(9): 3665-3680.
[11]	郑佳丽, 李志会, 赵新强, 王延吉. 离子液体催化合成2-氰基呋喃反应动力学研究[J]. 化工学报, 2023, 74(9): 3708-3715.
[12]	张缘良, 栾昕奇, 苏伟格, 李畅浩, 赵钟兴, 周利琴, 陈健民, 黄艳, 赵祯霞. 离子液体复合萃取剂选择性萃取尼古丁的研究及DFT计算[J]. 化工学报, 2023, 74(7): 2947-2956.
[13]	毛磊, 刘冠章, 袁航, 张光亚. 可捕集CO₂的纳米碳酸酐酶粒子的高效制备及性能研究[J]. 化工学报, 2023, 74(6): 2589-2598.
[14]	龙臻, 王谨航, 任俊杰, 何勇, 周雪冰, 梁德青. 离子液体协同PVCap抑制天然气水合物生成实验研究[J]. 化工学报, 2023, 74(6): 2639-2646.
[15]	杨灿, 孙雪琦, 尚明华, 张建, 张香平, 曾少娟. 相变离子液体体系吸收分离CO₂的研究现状及展望[J]. 化工学报, 2023, 74(4): 1419-1432.