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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 27, Number 5
JKCSEZ 27(5)
October 20, 1983 

 
Title
Pressure Effect on the Dissociation Reactions of Some Weak Acids

약산의 해리반응에 미치는 압력의 영향
Author
J. U. Hwang, J. J. Chung, Y. T. Park, J. G. Jee, E. S. Park

황정의, 정종재, 박용태, 지종기, 박은숙
Keywords
Abstract
Anilinium ion, o-toluidinium ion, phenol 및 o-chlorophenol의 해리상수를 10∼40℃온도범위와 1~2000 bar의 압력범위에서 분광광도법으로 측정하였다. phenols에서는 일반적인 약산에서처럼 온도와 압력이 증가할수록 해리상수가 증가하였으나 anilinium ions의 해리상수는 온도가 증가할수록 증가하였고, 압력이 증가할수록 감소하였다. 해리상수의 압력이 증가할수록 해리상수가 증가하나 anilinium ion와 같이 하전의 증감이 없으면 해리상수는 감소한다. 이들 해리상수값에서 열역학적 파라미터, ΔH°, ΔG°, ΔS°, ΔV 및 β를 계산하고 해리반응의 성질을 고찰하였다.

The dissociation constants of anilinium ion, o-toluidinium ion, phenol and o-chlorophenol were measured spectroscopically in aqueous solution over the temperature range of 10∼40℃ and at the pressures up to 2,000 bars. The effects of temperature and pressure on the dissociation of the phenols are the same as those of the ordinary weak acids. Meanwhile the dissociation constants of anilinium ions are increased with temperature raising and decreased with pressure elevation. The effects of pressure on the constants can be explained by taking account of change of charge during dissociation reaction; there are increase in charge in the dissociation of phenols but anilinium ions are not. Several thermodynamic properties, ΔH°, ΔG°, ΔS°, ΔV and β are calculated from those constants, and the dissociation reactions are discussed by them.

Page
311 - 319
Full Text
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