Conductivity and voltammetry in liquid and supercritical halogenated solvents.
Conductivity and voltammetry in liquid and supercritical halogenated solvents.
复制标题
液体和超临界卤化溶剂中的电导率和伏安法。
DOI：
10.1021/ac9511152
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发表时间：
1996
影响因子：
7.4
通讯作者：
D. Tallman
中科院分区：
文献类型：
--
作者：
S. Olsen;D. Tallman
二茂铁在液体和超临界二氟氯甲烷中的伏安特性研究表明，二茂铁在超临界流体中具有电化学可逆行为。然而，在半波电位作为流体条件的函数的变化被观察到，这是暂时归因于欧姆失真由于流体阻力的变化。为了更全面地理解这种流体中的伏安法，已经对一系列流体条件进行了电导率测量。此外，第二个参考对，六氟磷酸二茂钴，已被引入，并在两个氧化还原对之间的半波电位的差异已被检查作为流体条件的函数。在液体中，在恒定压力（5.2 MPa）下，校正欧姆失真的两对半波电势的差异随着流体温度的增加（25-85 °C）而减小。在恒定温度（115 °C）的超临界流体中，在相当大的流体压力范围（10-30 MPa）内，校正欧姆失真的半波电位差恒定在1.276 ± 0.005 V。超临界流体中的离子聚集是由电导率测量和由伏安图计算的钴茂金属的相当大的流体动力学半径指示的。本文还介绍了在超临界三氟甲烷中的初步伏安法。
A previous study of the voltammetry of ferrocene in liquid and supercritical chlorodifluoromethane revealed electrochemically reversible behavior. However, shifts in the half-wave potential as a function of fluid conditions were observed which were tentatively attributed to ohmic distortion due to changes in fluid resistance. To more completely understand the voltammetry in this fluid, conductivity measurements have been made for a range of fluid conditions. Additionally, a second reference couple, cobaltocenium hexafluorophosphate, has been introduced, and the difference in half-wave potentials between the two redox couples has been examined as a function of fluid conditions. In the liquid, the difference in the half-wave potentials of the two couples corrected for ohmic distortion decreases as the fluid temperature increases (25-85 °C) at constant pressure (5.2 MPa). In the supercritical fluid at constant temperature (115 °C), the difference in the half-wave potentials corrected for ohmic distortion is constant at 1.276 ± 0.005 V over a considerable range of fluid pressure (10-30 MPa). Ion aggregation in the supercritical fluid is indicated both by the conductivity measurements and by the rather large hydrodynamic radius of cobaltocenium computed from the voltammograms. Preliminary voltammetry in supercritical trifluoromethane is also presented.