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化学学报
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化学学报 ›› 1997, Vol. 55 ›› Issue (8): 755-760. 上一篇    下一篇

研究论文

对、间位卤代苯甲酸在水-乙醇混合溶剂中电离过程的焓、熵贡献

南延青;林瑞森;俞庆森   

  1. 浙江大学化学系
  • 发布日期:1997-08-15

Enthalpic and entropic contributions to the ionization process of m- and p-halobenzoic acids in water-ethanol mixtures

NAN YANQING;LIN RUISEN;YU QINGSEN   

  • Published:1997-08-15

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433

被引次数

7

用LKB-2277Bioactivity Monitor测定了25℃时间氯、对氯和对氟苯甲酸在水-乙醇混合溶剂中的标准电离焓, 计算了相应体系的标准电离熵。利用Hammett方程对溶剂中酸的取代基常数σ进行了计算, 求取了对应的焓、熵取代基常数σH和σS值及熵反应常数ρS, 利用内部-环境模型和上述常数对溶剂效应和取代基效应进行了解释。

关键词: 乙醇, 水, 苯甲酸 P, 电离, 溶剂效应, 熵, 焓, 取代基效应, 国家教委高等学校博士学科点专项科研基金

The ionization enthalpies of m-Cl, p-Cl and p-F benzoic acids were measured by LKB-2277 Bioactivity Monitor at 25℃ in water-ethanol mixtures. In the same solution, the corresponding ionization entropies were calculated. The substituted constants α were calculated according to Hammett equation, the corresponding enthalpic constants, entropic constants and entropic reaction constants were also calculated. The effects caused by solvent and substituent were explained by the interaction between solute and solvent, and by the above constants.

Key words: ETHANOL, WATER, BENZENECARBOXYLIC ACID P, IONIZATION, SOLVENT EFFECT, ENTROPY, ENTHALPY, SUBSTITUENT EFFECT

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