Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy

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	Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy
	Lu, J; Han, BX; Yan, HK
刊名	JOURNAL OF SUPERCRITICAL FLUIDS
	1999-06-15
卷号	15 期号:2 页码:135-143
关键词	Cosolvent Preferential Clustering Supercritical Co2 Tautomerism Thermodynamics
ISSN号	0896-8446
英文摘要	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. The content of the enol tautomer in liquid CH3CN is much higher than that in SC CO2. With the addition of a small amount of cosolvent CH3CN into SC CO2, the enol content increases with respect to that in pure SC CO2. The comparison of thermodynamic functions for the tautomerism was made in these solvents. It was found that the change of standard internal energy (Delta U-0) in SC CO2-CH3CN is close to that in liquid CH3CN and remarkably different from that in pure CO2. On the other hand, the maximum decrease in the change of the standard entropy (Delta S-0) was observed in SC CO2-CH3CN. It indicates that the cosolvent preferentially aggregates about the two tautomers. The Delta S-0 becomes the dominant thermodynamic driving force of the tautomerization in the cosolvent-modified SC CO2. (C) 1999 Elsevier Science B.V. All rights reserved.
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000080566200005
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/75391]
专题	中国科学院化学研究所
通讯作者	Han, BX
作者单位	Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Lu, J,Han, BX,Yan, HK. Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy[J]. JOURNAL OF SUPERCRITICAL FLUIDS,1999,15(2):135-143.
APA	Lu, J,Han, BX,&Yan, HK.(1999).Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy.JOURNAL OF SUPERCRITICAL FLUIDS,15(2),135-143.
MLA	Lu, J,et al."Thermodynamic studies of chemical equilibrium in supercritical carbon dioxide-cosolvent solutions using UV-Vis spectroscopy".JOURNAL OF SUPERCRITICAL FLUIDS 15.2(1999):135-143.