Partitioning of acidic solutes between water and supercritical carbon dioxide. Effect of pH and ionic strength

被引：13

作者：

Curren, MSS

Burk, RC

机构：

[1] Carleton Univ, Dept Chem, Ctr Analyt & Environm Chem, Ottawa, ON K1S 5B6, Canada

[2] USDA ARS, Natl Ctr Agr Utilizat Res, Peoria, IL 61604 USA

来源：

JOURNAL OF CHEMICAL AND ENGINEERING DATA | 2000年 / 45卷 / 05期

关键词：

D O I：

10.1021/je000008o

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

Partitioning of pentachlorophenol (PCP) between water and CO2 was investigated to determine the effects of pH and ionic strength on the value of the distribution coefficient, K. Decreasing the pH or increasing the ionic strength increased the value of K. The distribution coefficient was larger than that; predicted by considering the extent of hydrolysis of the solute in the aqueous phase. However, impedance measurements suggest that negligible concentrations of ions exist in the CO2 phase. Together, these two facts suggest that the aqueous phase hydrolysis equilibrium is shifted toward unhydrolyzed solute as PCP partitions to CO2. The value of K was smaller than the ratio of solubilities of the solute in the two phases, likely due to the effect of solute composition on the solute activity coefficients in each phase. Partitioning isotherms are also reported for the solutes pentachlorophenol, 2,3,4,5-tetrachlorophenol and 2,4-dichlorophenoxyacetic acid at about 40 degrees C, between about 100 to 270 bar.

引用

页码：746 / 750

页数：5

共 13 条

[1] EQUILIBRIUM PARTITIONING OF 2,4-DICHLOROPHENOL BETWEEN WATER AND NEAR-CRITICAL AND SUPERCRITICAL CARBON-DIOXIDE [J].

AKGERMAN, A ;

CARTER, BD .

JOURNAL OF CHEMICAL AND ENGINEERING DATA, 1994, 39 (03) :510-512

[2] Supercritical fluid extraction of sulfonylureas from aqueous matrices [J].

Betz, LR ;

Anderson, GA ;

McNally, ME .

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES, 1999, 34 (02) :171-192

[3] DIRECT SUPERCRITICAL-FLUID EXTRACTION FROM WATER [J].

BREWER, SE ;

KRUUS, P .

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES, 1993, 28 (06) :671-685

[4] Solubilities of acidic pesticides in water and liquid and supercritical carbon dioxide [J].

Curren, MS ;

Burk, RC .

JOURNAL OF CHEMICAL AND ENGINEERING DATA, 1997, 42 (04) :727-730

[5] Supercritical fluid extraction of acidic, polar solutes from aqueous matrices: Partitioning data for pentachlorophenol between carbon dioxide and water [J].

Curren, MS ;

Burk, RC .

JOURNAL OF CHEMICAL AND ENGINEERING DATA, 1998, 43 (06) :978-982

[6]

Gupta S., 1991, J. Supercrit. Fluids, V4, P181, DOI [10.1016/0896-8446, DOI 10.1016/0896-8446, 10.1016/0896-8446(91)90006-R, DOI 10.1016/0896-8446(91)90006-R]

[7]

HEDRICK JL, 1992, ACS SYM SER, V488, P206

[8] THE MUTUAL SOLUBILITIES OF WATER WITH SUPERCRITICAL AND LIQUID CARBON-DIOXIDE [J].