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标题：Determination of Dissociation Constants of Propionic Acid and Lactic Acid (2-hydroxypropionic acid) by Potentiometry and Conductometry
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作者：SAEEDUDDIN ; A.W.K. KHANZADA
期刊名称：Pakistan Journal of Analytical & Environmental Chemistry
印刷版ISSN：1996-918X
电子版ISSN：2221-5255
出版年度：2004
卷号：5
期号：1
页码：24-29
语种：English
出版社：National Centre of Excellence in Analytical Chemsitry
摘要：Dissociation constants of propionic acid and 2-hydroxypropionic acid (lactic acid) have been studied at different temperatures between 25 to 50 °C at 5°C interval. Propionic acid is analyzed by conductometry while 2-hydroxypropionic acid is analyzed by potentiometry. Both investigated compounds are symmetrical carboxylic acids having same length of carbon chain but are markedly different in ionic behaviour. We were interested to see how the hydroxyl group (-OH) induction in propionic acid affects on pKa values of 2-hydroxypropionic acid. We observed that as temperature increases pKa values increases. The increase is observed for both the investigated compounds. pKa values of 2-hydroxypropionic acid are lower as compared to propionic acid because of electron withdrawing group (-OH)..