Determination of Acetic Acid Dissociation Constants to 400 °C and 32 MPa by Potentiometric pH Measurements
Determination of Acetic Acid Dissociation Constants to 400 °C and 32 MPa by Potentiometric pH Measurements
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通过电位 pH 测量确定 400 °C 和 32 MPa 下的乙酸解离常数
DOI：
10.1021/je030142j
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发表时间：
2003
影响因子：
--
通讯作者：
K. Arai
中科院分区：
文献类型：
--
作者：
K. Sue;A. Usami;K. Arai
用流通式电化学池测定了0.01 mol·kg-1乙酸水溶液在亚临界和超临界条件下的pH值，在21.8 ~ 400.4 °C和23.0 ~ 32.3 MPa下，pH值由21.8 °C和23.0 MPa下的3.38变为400.4 °C和28.1 MPa下的6.90。根据测定的pH值确定了CH_3COOH解离反应的摩尔平衡常数，其值在400.4 ℃和28.1 MPa下为4.29 × 10 ~（-10），在21.8 ℃和23.0 MPa下为1.79 × 10 ~（-5）。在亚临界条件下，该值显示出良好的协议与文献值确定的电位与静态电池，量热法，和电导率。的经验密度模型的平衡常数的温度和压力的依赖性的描述被用来关联的数据。
pH of 0.01 mol·kg-1 CH3COOH aqueous solutions at subcritical and supercritical conditions was measured at temperatures from (21.8 to 400.4) °C and pressures from (23.0 to 32.3) MPa by a flow-through electrochemical cell, and it changed from 3.38 at 21.8 °C and 23.0 MPa to 6.90 at 400.4 °C and 28.1 MPa. The molal equilibrium constant for the dissociation reaction of CH3COOH was determined on the basis of the measured pH, and the value varied from 4.29 × 10-10 at 400.4 °C and 28.1 MPa to 1.79 × 10-5 at 21.8 °C and 23.0 MPa. At subcritical conditions, the values showed good agreement with the literature values determined from potentiometry with a static cell, from calorimetry, and from electrical conductivity. An empirical density model for the description of the temperature and pressure dependence of the equilibrium constants was used to correlate the data.