化学学报 ›› 1991, Vol. 49 ›› Issue (12): 1445-1449.    下一篇

研究论文

乙酸、卤代乙酸在水溶液中电离焓的测量和热力学过程的研究

胡瑞定;林瑞森;俞庆森   

  1. 浙江大学化学系.杭州(310027)
  • 发布日期:1991-12-15

The measurement of ionization enthalpies of acetic acid, halogenoacetic acids and study on their thermodynamic process

Hu Ruiding;Lin Ruisen;Yu Qingsen   

  1. Zhejiang Univ, Dept Chem.Hangzhou(310027)
  • Published:1991-12-15

本文用LKB-2277BioActivityMonitor以5℃的间隔测量了20-45℃温度区间乙酸、氯乙酸、溴乙酸和碘乙酸在水溶液中的电离焓。通过每一温度下测量五个不同浓度酸的热效应并外推至酸浓度无限稀,得到了电离焓ΔH~i^ⅲ。实验结果表明,在实验温度范围内,ΔH~i^ⅲ为:乙酸>氯乙酸>溴乙酸>碘乙酸;上述各个酸的ΔH~i^ⅲ跟温度呈线性变化的关系。本文用溶液中溶质与溶剂的相互作用及"内部-环境"模型较圆满地解释了取代基和温度对乙酸、氯乙酸、溴乙酸和碘乙酸的电离焓和电离熵的影响。

关键词: 乙酸, 热力学过程, 测量, 电离焓, 卤代乙酸, 水溶液

The ionization enthalpies of acetic acid, chloro-, bromo- and iodo- acetic acids were measured at 5℃ intervals between 20℃ and 45℃ in aqueous solution by LKB-2277 Bioactivity Monitor. The experimental results indicated that the order of ionization enthalpies is: acetic acid>chloroacetic acid>bromoacetic acid>iodoacetic acid. There is linear relationship between the ionization enthalpies and temperature at the range of the experimental temperature. The effects caused by substituent group and temperature were explained by interaction between solute and solvent and by "Internal-environmental" model.

Key words: ACETIC ACID, THERMODYNAMIC PROCESS, MEASUREMENTS, AQUEOUS SOLUTION

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