Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy
作者： Jie Lu , Buxing Han , Haike Yan
DOI: 10.1016/S0896-8446(98)00132-6
关键词: Standard molar entropy 、 Tautomer 、 Enol 、 Physical chemistry 、 Chemical equilibrium 、 Supercritical carbon dioxide 、 Ultraviolet visible spectroscopy 、 Internal energy 、 Chemistry 、 Organic chemistry 、 Acetonitrile
摘要: Abstract The keto-enol tautomeric equilibrium of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) was investigated using UV-Vis spectroscopy in various solvents, including liquid acetonitrile (CH3CN), supercritical carbon dioxide (SC CO2) and SC CO2–CH3CN. content the enol tautomer CH3CN is much higher than that CO2. With addition a small amount cosolvent into CO2, increases with respect to pure comparison thermodynamic functions for tautomerism made these solvents. It found change standard internal energy (ΔU0) CO2–CH3CN close remarkably different from On other hand, maximum decrease entropy (ΔS0) observed indicates preferentially aggregates about two tautomers. ΔS0 becomes dominant driving force tautomerization cosolvent-modified
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