Critical Behavior of the Electrical Conductivity of Concentrated Electrolytes: Ethylammonium Nitrate in n-Octanol Binary Mixture
Critical Behavior of the Electrical Conductivity of Concentrated Electrolytes: Ethylammonium Nitrate in n-Octanol Binary Mixture
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浓电解质电导率的临界行为：正辛醇二元混合物中的硝酸乙铵
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
M. Bonetti
中科院分区：
文献类型：
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作者：
A. Oleinikova;M. Bonetti
在临界盐摩尔分数x = 0.766和非临界盐摩尔分数x = 0.908时，在临界溶质点以上的扩展温度范围内测量了硝酸乙胺在正辛醇中的高浓度二元离子混合物的电导率κ。在远离临界温度Tc的情况下，电导率可以用VFT定律精确地描述。然而，在ΔT = (T−Tc)≤3k的温度范围内，电导率与VFT表现出单调的偏差。这种异常在Tc处是有限的，对于临界混合物，其振幅为κ (Tc)的0.23%。电导率异常的渐近行为用幂律τ(1−α)来描述，其中τ = (T−Tc)/Tc为还原温度，α为恒压比热异常的临界指数。这种临界异常与在其他高浓度临界电解质中观察到的异常相似。临界混合物中盐的解离度αdiss = 0.78±0.04，由在Tc处计算的瓦尔登积值估计，并解释了体系临界坐标下的有效自由离子浓度。
The electrical conductivity κ of highly concentrated binary ionic mixtures of ethylammonium nitrate in n-octanol at a critical salt mole fraction x = 0.766 and at an off-critical one x = 0.908 was measured over an extended temperature range above the critical consolute point. Far from the critical temperature Tc, the conductivity is accurately described by the Vogel–Fulcher–Tammann (VFT) law. However, in a temperature range ΔT = (T − Tc) ≤ 3 K, the conductivity exhibits a monotonous deviation from the VFT behavior. This anomaly is finite at Tc and, for the critical mixture, its amplitude is ≅ 0.23% of κ (Tc). The asymptotic behavior of the conductivity anomaly is described by a power law τ(1 − α), with τ = (T − Tc)/Tc, the reduced temperature, and α, the critical exponent of the specific heat anomaly at constant pressure. This critical anomaly is similar to the one observed in other highly concentrated critical electrolytes. The degree of dissociation of the salt for the critical mixture, αdiss ≅ 0.78 ± 0.04, is estimated from the value of the Walden product computed at Tc, and accounts for the effective free ion concentration in the reduced critical coordinates of the system.