Water effects on physicochemical properties of protic ionic liquid with N-hexylamine as cation and bis(trifluoromethylsulfonyl) imide as anion

doi:10.16085/j.issn.1000-6613.2020-0940

Abstract

Abstract:

The effect of water content (w₀=0.12, 0.23, 0.47, 0.74, 1.0, 1.28) on physicochemical properties such as density, dynamic viscosity and electric conductivity of HHexam(Tf₂N) composed of hexylamine(Hexam) cation and bis(trifluoromethylsulfonyl) imide (Tf₂N) anion was studied in the temperature range of T = 303.15~353.15K. In this study, Hexam was Br?nsted base and HTf₂N was Br?nsted acid. HHexam(Tf₂N) dissolved a small amount of water 6.33% (corresponding to w₀=[H₂O]/[PIL]=1.44) as it was hydrophobic. The density, dynamic viscosity decreased and the electric conductivity increased with increasing water content at the same temperature range. Meanwhile, the density linearly decreased, dynamic viscosity exponentially decreased, and the electric conductivity exponentially increased with increasing temperature at the same water content. The Walden lines for HHexam(Tf₂N) with w₀=0.12—1.28 water content were in ΔW=0.5—1.0 range, implying that they could offer a better ionicity. The maximum transconductance (2.79mS) of PEDOT OECT fabricated in HHexam (Tf₂N) was 3.4 times as that (0.832mS) of PEDOT:PSS OECT fabricated in aqueous solution at -0.6V of the drain potential.

Key words: protic ionic liquid, water effect, dynamic viscosity, electric conductivity, ionicity

摘要：

通过Br?nsted酸碱中和反应，合成了由碱正己胺（hexylamine, Hexam）与酸双三氟甲基磺酰亚胺[bis(trifluoromethylsulfonyl) imide，HTf₂N]形成的质子化离子液体（protic ionic liquids, PILs），简称为HHexam(Tf₂N)型PILs，其疏水性较强，但仍溶解少量水，其中饱和水含量可达6.33% (w₀=[H₂O]/[PIL]=1.44 )。PILs中水分含量的多少对其物理化学性质影响较大，因此本研究在温度T=303.15~353.15K的范围内、不同含水量（w₀=0.12、0.23、0.47、0.74、1.0、1.28）条件下，测定了HHexam(Tf₂N)的密度、黏度及电导率。结果显示，在相同温度条件下，随着水分含量的增加，其密度和黏度值均降低，电导率升高。在相同含水量条件下，随着温度的升高，其密度值呈直线下降，黏度均呈指数下降趋势，电导率均呈指数上升趋势，并且lnη、lnσ与1000/T之间基本呈线性关系，基本符合Arrhenius方程。在w₀=0.12~1.28 范围内，HHexam(Tf₂N)的Walden线均在ΔW=0.5~1.0内，离子性较好，并且随着水分含量的增加，其Walden线靠近KCl理想线，即离子化程度增大。另外，当漏极电压为-0.6V时，由HHexam(Tf₂N)制备的聚(3,4-亚乙二氧基噻吩)有机电化学晶体管（PEDOT OECT）的最大跨导（2.79mS）为水溶液获得的PEDOT:PSS OECT最大跨导（0.832mS）的3.4倍。

关键词: 质子化离子液体, 水分影响, 黏度, 电导率, 离子性

CLC Number:

O645.16

LIU Zheng, LIU Ran, HUA Er, JI Jianlong. Water effects on physicochemical properties of protic ionic liquid with N-hexylamine as cation and bis(trifluoromethylsulfonyl) imide as anion[J]. Chemical Industry and Engineering Progress, 2021, 40(4): 2270-2277.

刘铮, 刘燃, 花儿, 冀健龙. 水分含量对正己胺-Tf₂N型质子化离子液体物理化学性质的影响[J]. 化工进展, 2021, 40(4): 2270-2277.

Figures/Tables 11

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w₀	密度ρ/g·cm^-3
w₀	303.15K	308.15K	313.15K	318.15K	323.15K	328.15K	333.15K	338.15K	343.15K	348.15K	353.15K
0.12	1.4243	1.4202	1.4193	1.4130	1.4087	1.4055	1.4005	1.3968	1.3905	1.3860	1.3819
0.23	1.4236	1.4201	1.4174	1.4137	1.4085	1.4037	1.3996	1.3954	1.3894	1.3854	1.3797
0.47	1.4194	1.4146	1.4091	1.4059	1.4019	1.3969	1.3915	1.3882	1.3828	1.3785	1.3755
0.74	1.4060	1.4038	1.3990	1.3960	1.3890	1.3845	1.3808	1.3770	1.3722	1.3674	1.3639
0.99	1.3968	1.3908	1.3876	1.3855	1.3807	1.3773	1.3729	1.3692	1.3664	1.3622	1.3567
1.28	1.3894	1.3855	1.3798	1.3724	1.3700	1.3659	1.3621	1.3598	1.3535	1.3524	1.3467

w₀	密度ρ/g·cm^-3
w₀	303.15K	308.15K	313.15K	318.15K	323.15K	328.15K	333.15K	338.15K	343.15K	348.15K	353.15K
0.12	1.4243	1.4202	1.4193	1.4130	1.4087	1.4055	1.4005	1.3968	1.3905	1.3860	1.3819
0.23	1.4236	1.4201	1.4174	1.4137	1.4085	1.4037	1.3996	1.3954	1.3894	1.3854	1.3797
0.47	1.4194	1.4146	1.4091	1.4059	1.4019	1.3969	1.3915	1.3882	1.3828	1.3785	1.3755
0.74	1.4060	1.4038	1.3990	1.3960	1.3890	1.3845	1.3808	1.3770	1.3722	1.3674	1.3639
0.99	1.3968	1.3908	1.3876	1.3855	1.3807	1.3773	1.3729	1.3692	1.3664	1.3622	1.3567
1.28	1.3894	1.3855	1.3798	1.3724	1.3700	1.3659	1.3621	1.3598	1.3535	1.3524	1.3467

w₀	黏度η/mPa·s
w₀	303.15K	308.15K	313.15K	318.15K	323.15K	328.15K	333.15K	338.15K	343.15K	348.15K	353.15K
0.12	3.02×10²	2.26×10²	1.66×10²	1.29×10	1.02×10²	8.12×10	6.62×10	5.45×10	4.55×10	3.85×10	3.29×10
0.23	2.16×10²	1.64×10²	1.26×10²	9.96×10	7.99×10	6.50×10	5.37×10	4.49×10	3.80×10	3.25×10	2.82×10
0.47	9.69×10	7.62×10	6.06×10	4.90×10	4.02×10	3.32×10	2.80×10	2.38×10	2.04×10	1.77×10	1.54×10
0.74	5.65×10	4.54×10	3.71×10	3.09×10	2.59×10	2.20×10	1.89×10	1.64×10	1.44×10	1.27×10	1.13×10
0.99	3.41×10	2.81×10	2.34×10	1.98×10	1.69×10	1.46×10	1.27×10	1.11×10	0.98×10	0.88×10	0.79×10
1.28	2.79×10	2.31×10	1.95×10	1.66×10	1.43×10	1.24×10	1.09×10	0.96×10	0.85×10	0.76×10	0.68×10

w₀	黏度η/mPa·s
w₀	303.15K	308.15K	313.15K	318.15K	323.15K	328.15K	333.15K	338.15K	343.15K	348.15K	353.15K
0.12	3.02×10²	2.26×10²	1.66×10²	1.29×10	1.02×10²	8.12×10	6.62×10	5.45×10	4.55×10	3.85×10	3.29×10
0.23	2.16×10²	1.64×10²	1.26×10²	9.96×10	7.99×10	6.50×10	5.37×10	4.49×10	3.80×10	3.25×10	2.82×10
0.47	9.69×10	7.62×10	6.06×10	4.90×10	4.02×10	3.32×10	2.80×10	2.38×10	2.04×10	1.77×10	1.54×10
0.74	5.65×10	4.54×10	3.71×10	3.09×10	2.59×10	2.20×10	1.89×10	1.64×10	1.44×10	1.27×10	1.13×10
0.99	3.41×10	2.81×10	2.34×10	1.98×10	1.69×10	1.46×10	1.27×10	1.11×10	0.98×10	0.88×10	0.79×10
1.28	2.79×10	2.31×10	1.95×10	1.66×10	1.43×10	1.24×10	1.09×10	0.96×10	0.85×10	0.76×10	0.68×10

w₀	电导率σ/μS·cm^-1
w₀	303.15K	308.15K	313.15K	318.15K	323.15K	328.15K	333.15K	338.15K	343.15K	348.15K	353.15K
0.12	4.28×10²	4.43×10²	5.76×10²	7.41×10²	9.23×10²	1.15×10³	1.47×10³	1.67×10³	2.04×10³	2.46×10³	2.94×10³
0.23	5.03×10²	6.03×10²	7.27×10²	8.93×10²	1.11×10³	1.36×10³	1.66×10³	1.97×10³	2.33×10³	2.77×10³	3.26×10³
0.47	9.59×10²	1.13×10³	1.38×10³	1.65×10³	2.01×10³	2.42×10³	2.88×10³	3.34×10³	3.92×10³	4.43×10³	5.04×10³
0.74	1.97×10³	2.48×10³	2.94×10³	3.44×10³	4.02×10³	4.71×10³	5.50×10³	6.33×10³	7.08×10³	8.03×10³	8.99×10³
0.99	3.39×10³	3.81×10³	4.47×10³	5.17×10³	6.02×10³	6.85×10³	7.75×10³	8.67×10³	9.8×10³	1.10×10⁴	1.23×10⁴
1.28	4.29×10³	4.51×10³	5.39×10³	6.26×10³	7.04×10³	8.15×10³	8.95×10³	1.00×10⁴	1.13×10⁴	1.25×10⁴	1.37×10⁴