Phase diagram of pyridyl ionic liquid + organic salt aqueous two-phase system and study of salting-out ability

doi:10.11949/0438-1157.20200243

Abstract

Abstract:

The binodal curve and tie-line data of N-ethylpyridinium tetrafluoroborate ([EPy]BF₄) + organic salts [sodium succinate((CH₂COONa)₂)/ammonium citrate (C₆H₅O₇(NH₄)₃)/sodium citrate(C₆H₅O₇Na₃)] ionic liquid-based aqueous two-phase systems have been studied. The tie-line data were determined using gravimetric method based on the lever rule. Then, the Othmer-Tobias, Bancroft equations and NRTL model were used to fit the data. The effective excluded volume of salt and Setschenow-type equation were used to investigate the salting-out ability of the three salts. As a result, all the three empirical equations fit the binodal curves well, but some redundant parameters may be meaningless. The tie-lines data were satisfactory correlated to the equations, and show that the data is reliable. The root-mean-square deviation (RMSD) indicates tie-lines data fit NRTL model very well. The two-phase systems are easier to form at lower temperatures. All the three salts can form aqueous two-phase system with [EPy]BF₄, and C₆H₅O₇Na₃ possesses stronger salting-out ability. The data provided in this article provides a theoretical reference for the recycling of ionic liquids.

Key words: ionic liquids, phase equilibrium, salting-out ability, separation, aqueous two-phase system

摘要：

测定了离子液体N-乙基吡啶四氟硼酸盐([EPy]BF₄)+有机盐[丁二酸钠（CH₂COONa)₂/柠檬酸铵C₆H₅O₇(NH₄)₃/柠檬酸钠C₆H₅O₇Na₃] +水双水相体系在303.15、308.15和313.15 K下的双节线及系线数据。基于相图中的杠杆定律通过质量法研究双水相体系的系线，并用Othmer-Tobias方程、Bancroft方程等经验方程以及NRTL活度系数模型对数据进行关联。采用有效排除体积和Setschenow-type的拟合参数深入研究三种有机盐的盐析能力。结果表明，双节线的三个经验式拟合效果良好，但较多参数的经验式会导致部分参数失去意义；双水相体系的系线满足经验方程，数据可靠性较好，且均方根偏差表明系线数据很好地符合NRTL模型；低温更有利于该双水相体系的形成；三种盐都能和[EPy]BF₄离子液体形成双水相体系，且C₆H₅O₇Na₃的盐析能力更优。本文提供的数据为离子液体的回收循环利用提供了理论参考依据。

关键词: 离子液体, 相平衡, 盐析, 分离, 双水相

CLC Number:

TQ 028.8

Xuliang LIN,Shuai XU,Shaojie XU,Manjing YUAN,Jinzhu CHEN,Yuliang LI,Yanlin QIN. Phase diagram of pyridyl ionic liquid + organic salt aqueous two-phase system and study of salting-out ability[J]. CIESC Journal, 2020, 71(11): 5067-5079.

林绪亮,徐帅,徐少杰,袁慢景,陈金珠,李宇亮,秦延林. 吡啶基离子液体+有机盐双水相体系相图的测定及盐析性能研究[J]. 化工学报, 2020, 71(11): 5067-5079.

Figures/Tables 13

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w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=303.15 K
77.05	0.43	59.01	3.00	47.80	5.83	37.70	9.21	26.58	13.37	15.39	19.23
74.70	0.65	58.01	3.30	46.98	6.10	36.34	9.61	25.70	13.70	14.03	19.94
71.64	1.06	56.92	3.52	46.10	6.32	35.16	9.99	24.88	14.14	13.24	20.51
70.19	1.25	55.83	3.71	45.28	6.59	33.98	10.30	24.25	14.57	12.06	21.16
68.29	1.53	54.93	3.97	44.47	6.86	33.01	10.62	23.25	14.95	11.43	21.82
66.84	1.77	53.93	4.14	43.56	7.19	32.38	10.98	21.98	15.61	11.07	22.33
65.41	1.94	52.76	4.47	42.75	7.49	31.56	11.41	21.26	16.10
63.78	2.20	51.69	4.74	41.84	7.79	30.56	11.85	19.74	16.88
62.24	2.45	50.79	5.01	40.94	8.12	29.57	12.15	18.38	17.46
61.16	2.59	49.97	5.26	39.94	8.47	28.48	12.67	17.57	18.01
60.43	2.78	48.79	5.53	38.87	8.80	27.67	13.02	16.66	18.57
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=308.15 K
76.24	0.70	57.85	3.45	46.69	6.50	38.44	9.47	30.54	12.75	20.51	17.21
72.75	1.04	56.38	3.73	45.10	6.97	37.43	9.91	29.55	13.15	19.38	17.87
70.03	1.35	54.93	4.10	44.31	7.29	36.41	10.28	28.41	13.81	18.13	18.55
68.02	1.70	53.68	4.41	43.29	7.60	35.52	10.63	27.17	14.40	16.68	19.15
66.32	1.92	52.10	4.85	42.52	7.97	34.50	11.07	25.70	14.90	15.55	19.74
64.39	2.17	50.85	5.13	41.50	8.35	33.94	11.37	24.45	15.49	14.31	20.30
62.04	2.60	49.52	5.63	40.60	8.69	32.58	11.94	23.11	16.06	13.29	21.08
59.66	2.94	47.71	6.19	39.58	9.13	31.33	12.34	21.76	16.65	12.04	21.92
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=313.15 K
78.05	1.06	57.28	4.47	41.93	9.24	30.93	13.62	24.16	17.10	16.75	21.25
75.69	1.23	55.38	4.98	40.41	9.83	30.02	13.95	23.07	17.51	15.57	21.90
72.91	1.53	53.32	5.45	38.97	10.51	29.02	14.36	22.53	18.01	15.05	22.52
68.92	2.18	51.51	6.02	37.24	11.14	28.14	14.79	21.46	18.36	13.79	23.13
66.50	2.53	49.43	6.59	36.07	11.57	27.60	15.25	20.38	18.90	12.79	23.89
63.78	3.02	46.73	7.41	34.73	12.18	26.96	15.72	19.56	19.45	11.88	24.81
61.52	3.46	44.83	8.12	33.19	12.64	26.06	16.15	18.74	19.97
59.19	3.97	43.29	8.66	31.92	13.18	24.97	16.59	17.75	20.53
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=303.15 K
77.26	1.23	56.75	41.21	9.18	47.80	28.60	14.69	17.93	21.77	9.27	31.12
75.19	1.47	55.27	40.34	9.57	46.98	27.89	15.15	16.88	22.71	8.25	32.22
72.85	1.86	53.95	39.45	9.97	46.10	26.56	15.78	16.02	23.57	7.81	33.25
70.38	2.10	52.34	38.00	10.52	45.28	25.54	16.34	15.12	24.43	6.79	34.43
68.16	2.41	50.43	36.68	11.23	44.47	24.22	17.20	14.26	25.14	6.21	35.77
66.25	2.81	49.13	35.20	11.94	43.56	23.20	17.99	13.24	26.09	5.90	36.94
64.06	3.20	47.07	34.03	12.57	42.75	21.88	18.77	12.78	26.88	5.16	38.28
62.30	3.60	45.62	32.42	12.95	41.84	20.70	19.48	11.61	27.89	4.43	39.77
60.54	3.98	44.45	31.10	13.43	40.94	19.81	20.11	10.90	28.68	3.99	41.43
58.94	4.30	42.69	30.08	14.14	39.94	18.95	21.14	10.16	29.86	3.56	43.39
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=308.15 K
75.24	1.63	53.34	6.25	36.78	11.49	23.38	18.46	13.42	26.09	6.41	36.54
72.52	2.00	51.30	6.63	35.35	12.09	22.77	19.06	13.01	27.18	6.21	37.69
70.17	2.38	49.67	7.13	34.13	12.64	21.85	19.50	12.20	28.04	5.39	38.72
67.93	2.82	48.24	7.40	32.60	13.39	20.83	20.26	11.58	29.03	4.88	40.25
65.89	3.15	46.84	7.84	31.40	14.21	20.02	21.07	10.77	29.85	4.27	42.16
64.39	3.53	45.31	8.49	29.77	15.14	19.10	21.62	10.28	30.72	3.56	44.01
62.25	3.86	43.99	9.15	28.04	16.07	17.88	22.38	9.37	31.64	3.05	45.92
60.62	4.24	42.25	9.41	26.61	16.39	17.19	23.15	8.35	32.57	2.36	48.10
58.38	4.84	40.62	9.85	25.70	16.82	16.47	23.97	8.04	33.28	1.95	49.72
56.77	5.12	39.91	10.28	24.80	17.26	15.35	24.61	7.53	34.43
54.74	5.81	38.41	11.05	24.40	17.91	14.54	25.43	6.92	35.67
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=313.15 K
77.41	1.47	52.93	6.20	35.78	11.77	23.48	18.14	13.37	26.80	7.38	35.60
74.76	1.86	51.17	6.58	34.77	12.17	22.61	18.77	12.93	27.58	6.64	36.54
71.24	2.26	49.57	7.14	33.75	12.64	21.88	19.40	12.20	28.21	5.90	37.65
69.05	2.66	47.96	7.37	32.57	13.35	20.86	20.11	11.91	28.83	5.62	38.99
66.99	2.97	46.79	7.77	31.53	13.89	20.27	20.66	11.61	29.71	5.01	40.09
65.23	3.28	45.31	7.92	30.23	14.52	19.38	21.37	10.90	30.42	4.43	41.58
63.32	3.60	43.99	8.63	28.91	15.23	18.36	22.31	10.44	31.20	4.30	43.23
61.44	4.06	42.38	9.18	27.89	15.78	17.77	23.02	9.72	31.91	3.99	44.49
59.68	4.38	40.78	9.65	27.15	16.41	16.88	23.80	9.27	32.62	3.84	45.91
58.20	4.94	39.45	10.28	25.98	16.72	15.71	24.68	8.83	33.32
56.60	5.09	38.13	10.75	24.80	17.37	15.00	25.46	8.40	34.11
54.41	5.72	36.80	11.23	24.07	17.75	14.11	26.17	7.97	34.82
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=303.15 K
59.83	1.59	45.16	5.19	34.79	8.54	26.08	11.85	18.33	16.10	12.51	21.35
57.07	2.11	44.20	5.60	33.83	8.90	25.09	12.26	17.78	16.74	11.55	21.99
54.71	2.65	42.82	5.90	32.84	9.20	24.42	12.74	16.79	17.39	10.71	22.82
52.79	3.06	41.57	6.18	31.73	9.55	23.43	13.08	16.12	17.92	9.89	23.71
51.25	3.48	40.47	6.66	31.06	9.97	22.62	13.62	15.57	18.40	9.19	24.59
49.73	3.95	39.07	7.13	30.07	10.20	21.36	14.09	15.01	19.05
48.48	4.36	38.11	7.49	29.11	10.61	20.67	14.62	14.03	19.57
46.96	4.72	37.15	7.83	27.74	11.09	19.99	15.03	13.62	20.11
46.14	5.01	35.90	8.26	27.04	11.43	19.15	15.50	13.35	20.70
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=308.15 K
60.65	1.83	46.55	5.13	35.90	8.49	26.20	12.14	17.64	17.10	11.26	23.17
58.17	2.30	45.59	5.43	34.64	8.96	25.38	12.50	17.23	17.69	10.71	23.77
55.55	2.82	44.61	5.71	33.68	9.25	24.42	12.91	16.12	18.40	9.89	24.48
53.89	3.12	43.38	6.01	32.72	9.61	23.58	13.50	15.42	18.99	9.60	25.01
52.79	3.42	42.39	6.31	31.73	10.02	22.88	13.91	14.87	19.57	9.19	25.72
51.53	3.76	41.29	6.60	30.92	10.44	21.92	14.45	14.17	20.11
50.57	4.06	40.32	6.95	30.07	10.67	20.96	15.03	13.76	20.75
49.47	4.42	39.22	7.25	28.97	10.96	19.70	15.50	12.92	21.29
48.48	4.72	38.11	7.66	28.00	11.38	19.01	16.04	12.37	21.88
47.52	4.95	36.86	8.19	27.19	11.73	18.45	16.57	11.96	22.53
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=313.15 K
62.60	1.88	47.93	5.07	37.96	8.07	28.70	11.32	20.81	15.45	13.35	21.58
60.39	2.24	46.82	5.36	37.00	8.54	27.74	11.73	19.85	15.86	12.10	23.00
58.17	2.65	45.86	5.71	35.90	8.84	27.04	12.20	19.15	16.57	10.85	24.41
56.11	3.01	44.48	6.13	34.79	9.20	25.94	12.61	18.33	17.10	9.74	26.00
54.71	3.35	43.23	6.42	33.95	9.61	25.09	13.08	17.35	17.75	8.64	27.37
53.34	3.71	41.84	6.78	32.84	9.97	23.99	13.56	16.53	18.33
52.23	3.95	40.73	7.13	31.47	10.25	22.88	13.98	16.12	18.93
50.98	4.30	40.06	7.49	30.63	10.67	22.06	14.45	15.28	19.76
49.59	4.60	39.22	7.78	29.66	11.02	21.36	15.03	14.32	20.58

w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)	w₁/%(mass)	w₂/%(mass)
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=303.15 K
77.05	0.43	59.01	3.00	47.80	5.83	37.70	9.21	26.58	13.37	15.39	19.23
74.70	0.65	58.01	3.30	46.98	6.10	36.34	9.61	25.70	13.70	14.03	19.94
71.64	1.06	56.92	3.52	46.10	6.32	35.16	9.99	24.88	14.14	13.24	20.51
70.19	1.25	55.83	3.71	45.28	6.59	33.98	10.30	24.25	14.57	12.06	21.16
68.29	1.53	54.93	3.97	44.47	6.86	33.01	10.62	23.25	14.95	11.43	21.82
66.84	1.77	53.93	4.14	43.56	7.19	32.38	10.98	21.98	15.61	11.07	22.33
65.41	1.94	52.76	4.47	42.75	7.49	31.56	11.41	21.26	16.10
63.78	2.20	51.69	4.74	41.84	7.79	30.56	11.85	19.74	16.88
62.24	2.45	50.79	5.01	40.94	8.12	29.57	12.15	18.38	17.46
61.16	2.59	49.97	5.26	39.94	8.47	28.48	12.67	17.57	18.01
60.43	2.78	48.79	5.53	38.87	8.80	27.67	13.02	16.66	18.57
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=308.15 K
76.24	0.70	57.85	3.45	46.69	6.50	38.44	9.47	30.54	12.75	20.51	17.21
72.75	1.04	56.38	3.73	45.10	6.97	37.43	9.91	29.55	13.15	19.38	17.87
70.03	1.35	54.93	4.10	44.31	7.29	36.41	10.28	28.41	13.81	18.13	18.55
68.02	1.70	53.68	4.41	43.29	7.60	35.52	10.63	27.17	14.40	16.68	19.15
66.32	1.92	52.10	4.85	42.52	7.97	34.50	11.07	25.70	14.90	15.55	19.74
64.39	2.17	50.85	5.13	41.50	8.35	33.94	11.37	24.45	15.49	14.31	20.30
62.04	2.60	49.52	5.63	40.60	8.69	32.58	11.94	23.11	16.06	13.29	21.08
59.66	2.94	47.71	6.19	39.58	9.13	31.33	12.34	21.76	16.65	12.04	21.92
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS T=313.15 K
78.05	1.06	57.28	4.47	41.93	9.24	30.93	13.62	24.16	17.10	16.75	21.25
75.69	1.23	55.38	4.98	40.41	9.83	30.02	13.95	23.07	17.51	15.57	21.90
72.91	1.53	53.32	5.45	38.97	10.51	29.02	14.36	22.53	18.01	15.05	22.52
68.92	2.18	51.51	6.02	37.24	11.14	28.14	14.79	21.46	18.36	13.79	23.13
66.50	2.53	49.43	6.59	36.07	11.57	27.60	15.25	20.38	18.90	12.79	23.89
63.78	3.02	46.73	7.41	34.73	12.18	26.96	15.72	19.56	19.45	11.88	24.81
61.52	3.46	44.83	8.12	33.19	12.64	26.06	16.15	18.74	19.97
59.19	3.97	43.29	8.66	31.92	13.18	24.97	16.59	17.75	20.53
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=303.15 K
77.26	1.23	56.75	41.21	9.18	47.80	28.60	14.69	17.93	21.77	9.27	31.12
75.19	1.47	55.27	40.34	9.57	46.98	27.89	15.15	16.88	22.71	8.25	32.22
72.85	1.86	53.95	39.45	9.97	46.10	26.56	15.78	16.02	23.57	7.81	33.25
70.38	2.10	52.34	38.00	10.52	45.28	25.54	16.34	15.12	24.43	6.79	34.43
68.16	2.41	50.43	36.68	11.23	44.47	24.22	17.20	14.26	25.14	6.21	35.77
66.25	2.81	49.13	35.20	11.94	43.56	23.20	17.99	13.24	26.09	5.90	36.94
64.06	3.20	47.07	34.03	12.57	42.75	21.88	18.77	12.78	26.88	5.16	38.28
62.30	3.60	45.62	32.42	12.95	41.84	20.70	19.48	11.61	27.89	4.43	39.77
60.54	3.98	44.45	31.10	13.43	40.94	19.81	20.11	10.90	28.68	3.99	41.43
58.94	4.30	42.69	30.08	14.14	39.94	18.95	21.14	10.16	29.86	3.56	43.39
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=308.15 K
75.24	1.63	53.34	6.25	36.78	11.49	23.38	18.46	13.42	26.09	6.41	36.54
72.52	2.00	51.30	6.63	35.35	12.09	22.77	19.06	13.01	27.18	6.21	37.69
70.17	2.38	49.67	7.13	34.13	12.64	21.85	19.50	12.20	28.04	5.39	38.72
67.93	2.82	48.24	7.40	32.60	13.39	20.83	20.26	11.58	29.03	4.88	40.25
65.89	3.15	46.84	7.84	31.40	14.21	20.02	21.07	10.77	29.85	4.27	42.16
64.39	3.53	45.31	8.49	29.77	15.14	19.10	21.62	10.28	30.72	3.56	44.01
62.25	3.86	43.99	9.15	28.04	16.07	17.88	22.38	9.37	31.64	3.05	45.92
60.62	4.24	42.25	9.41	26.61	16.39	17.19	23.15	8.35	32.57	2.36	48.10
58.38	4.84	40.62	9.85	25.70	16.82	16.47	23.97	8.04	33.28	1.95	49.72
56.77	5.12	39.91	10.28	24.80	17.26	15.35	24.61	7.53	34.43
54.74	5.81	38.41	11.05	24.40	17.91	14.54	25.43	6.92	35.67
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS T=313.15 K
77.41	1.47	52.93	6.20	35.78	11.77	23.48	18.14	13.37	26.80	7.38	35.60
74.76	1.86	51.17	6.58	34.77	12.17	22.61	18.77	12.93	27.58	6.64	36.54
71.24	2.26	49.57	7.14	33.75	12.64	21.88	19.40	12.20	28.21	5.90	37.65
69.05	2.66	47.96	7.37	32.57	13.35	20.86	20.11	11.91	28.83	5.62	38.99
66.99	2.97	46.79	7.77	31.53	13.89	20.27	20.66	11.61	29.71	5.01	40.09
65.23	3.28	45.31	7.92	30.23	14.52	19.38	21.37	10.90	30.42	4.43	41.58
63.32	3.60	43.99	8.63	28.91	15.23	18.36	22.31	10.44	31.20	4.30	43.23
61.44	4.06	42.38	9.18	27.89	15.78	17.77	23.02	9.72	31.91	3.99	44.49
59.68	4.38	40.78	9.65	27.15	16.41	16.88	23.80	9.27	32.62	3.84	45.91
58.20	4.94	39.45	10.28	25.98	16.72	15.71	24.68	8.83	33.32
56.60	5.09	38.13	10.75	24.80	17.37	15.00	25.46	8.40	34.11
54.41	5.72	36.80	11.23	24.07	17.75	14.11	26.17	7.97	34.82
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=303.15 K
59.83	1.59	45.16	5.19	34.79	8.54	26.08	11.85	18.33	16.10	12.51	21.35
57.07	2.11	44.20	5.60	33.83	8.90	25.09	12.26	17.78	16.74	11.55	21.99
54.71	2.65	42.82	5.90	32.84	9.20	24.42	12.74	16.79	17.39	10.71	22.82
52.79	3.06	41.57	6.18	31.73	9.55	23.43	13.08	16.12	17.92	9.89	23.71
51.25	3.48	40.47	6.66	31.06	9.97	22.62	13.62	15.57	18.40	9.19	24.59
49.73	3.95	39.07	7.13	30.07	10.20	21.36	14.09	15.01	19.05
48.48	4.36	38.11	7.49	29.11	10.61	20.67	14.62	14.03	19.57
46.96	4.72	37.15	7.83	27.74	11.09	19.99	15.03	13.62	20.11
46.14	5.01	35.90	8.26	27.04	11.43	19.15	15.50	13.35	20.70
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=308.15 K
60.65	1.83	46.55	5.13	35.90	8.49	26.20	12.14	17.64	17.10	11.26	23.17
58.17	2.30	45.59	5.43	34.64	8.96	25.38	12.50	17.23	17.69	10.71	23.77
55.55	2.82	44.61	5.71	33.68	9.25	24.42	12.91	16.12	18.40	9.89	24.48
53.89	3.12	43.38	6.01	32.72	9.61	23.58	13.50	15.42	18.99	9.60	25.01
52.79	3.42	42.39	6.31	31.73	10.02	22.88	13.91	14.87	19.57	9.19	25.72
51.53	3.76	41.29	6.60	30.92	10.44	21.92	14.45	14.17	20.11
50.57	4.06	40.32	6.95	30.07	10.67	20.96	15.03	13.76	20.75
49.47	4.42	39.22	7.25	28.97	10.96	19.70	15.50	12.92	21.29
48.48	4.72	38.11	7.66	28.00	11.38	19.01	16.04	12.37	21.88
47.52	4.95	36.86	8.19	27.19	11.73	18.45	16.57	11.96	22.53
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS T=313.15 K
62.60	1.88	47.93	5.07	37.96	8.07	28.70	11.32	20.81	15.45	13.35	21.58
60.39	2.24	46.82	5.36	37.00	8.54	27.74	11.73	19.85	15.86	12.10	23.00
58.17	2.65	45.86	5.71	35.90	8.84	27.04	12.20	19.15	16.57	10.85	24.41
56.11	3.01	44.48	6.13	34.79	9.20	25.94	12.61	18.33	17.10	9.74	26.00
54.71	3.35	43.23	6.42	33.95	9.61	25.09	13.08	17.35	17.75	8.64	27.37
53.34	3.71	41.84	6.78	32.84	9.97	23.99	13.56	16.53	18.33
52.23	3.95	40.73	7.13	31.47	10.25	22.88	13.98	16.12	18.93
50.98	4.30	40.06	7.49	30.63	10.67	22.06	14.45	15.28	19.76
49.59	4.60	39.22	7.78	29.66	11.02	21.36	15.03	14.32	20.58

System	T/K	a	b	c	R²	SD^①
[EPy]BF₄ + (CH₂COONa)₂ + H₂O	303.15	96.41	-0.2858	8.6916×10^-5	0.9982	0.27
	308.15	97.27	-0.2807	7.4187×10^-5	0.9997	0.20
	313.15	105.8	-0.2923	5.3099×10^-5	0.9995	0.34
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O	303.15	116.1	-0.3373	5.3415×10^-5	0.9979	0.94
	308.15	120.8	-0.3408	2.107×10^-5	0.9974	0.95
	313.15	123.3	-0.3525	1.7644×10^-5	0.9979	0.85
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O	303.15	96.19	-0.3395	5.736×10^-5	0.9942	0.98
	308.15	102.7	-0.3571	4.624×10^-5	0.9955	0.97
	313.15	104.0	-0.3527	4.636×10^-5	0.9937	0.99

System	T/K	a	b	c	R²	SD^①
[EPy]BF₄ + (CH₂COONa)₂ + H₂O	303.15	96.41	-0.2858	8.6916×10^-5	0.9982	0.27
	308.15	97.27	-0.2807	7.4187×10^-5	0.9997	0.20
	313.15	105.8	-0.2923	5.3099×10^-5	0.9995	0.34
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O	303.15	116.1	-0.3373	5.3415×10^-5	0.9979	0.94
	308.15	120.8	-0.3408	2.107×10^-5	0.9974	0.95
	313.15	123.3	-0.3525	1.7644×10^-5	0.9979	0.85
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O	303.15	96.19	-0.3395	5.736×10^-5	0.9942	0.98
	308.15	102.7	-0.3571	4.624×10^-5	0.9955	0.97
	313.15	104.0	-0.3527	4.636×10^-5	0.9937	0.99

T/K	a	b	c	d	R²	SD^①
[EPy]BF₄ + (CH₂COONa)₂ + H₂O ATPS
303.15	4.501	-0.2218	-0.00534	-0.00187	0.9997	0.35
308.15	4.615	-0.3567	0.03889	-0.00262	0.9997	0.32
313.15	4.666	-0.3261	0.02409	-0.0019	0.9983	0.42
[EPy]BF₄ + C₆H₅O₇(NH₄)₃+ H₂O ATPS
303.15	4.602	-0.2015	-0.02387	-5.398×10^-4	0.9998	0.26
308.15	4.570	-0.1526	-0.03351	-4.163×10^-4	0.9998	0.29
313.15	4.627	-0.1929	-0.02857	-3.551×10^-4	0.9998	0.33
[EPy]BF₄ + C₆H₅O₇Na₃+ H₂O ATPS
303.15	4.119	0.1004	-0.1046	3.217×10^-4	0.9995	0.45
308.15	4.180	0.06926	-0.09801	3.119×10^-4	0.9997	0.34
313.15	4.181	0.09774	-0.1067	5.177×10^-4	0.9995	0.36