SOLVATION EFFECTS ON REACTIONS OF TRIPLET BENZOPHENONE IN SUPERCRITICAL FLUIDS

被引：29

作者：

ROBERTS, CB ^{[1
]}

BRENNECKE, JF ^{[1
]}

CHATEAUNEUF, JE ^{[1
]}

机构：

[1] UNIV NOTRE DAME, RADIAT LAB, NOTRE DAME, IN 46556 USA

来源：

AICHE JOURNAL | 1995年 / 41卷 / 05期

关键词：

D O I：

10.1002/aic.690410525

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

Laser flash photolysis of the hydrogen abstraction reaction of triplet benzophenone ((BP)-B-3) from 2-propanol and 1,4-cyclohexadiene in supercritical ethane and fluoroform was investigated. Bimolecular rate constants based on bulk concentrations decrease with an increase in pressure along both isotherms studied. These results corroborate our previous studies in CO2 that show increased reaction rates due to enhanced local compositions of cosolvent around the (BP)-B-3 solute. Analysis of the results includes prediction of the thermodynamic pressure effect on the rate constant, which suggests an increase in the rate constant with pressure, as well as the effects of increased local cosolvent concentrations about (BP)-B-3. Spectroscopic measurements of the local composition of 2-propanol about a solute in supercritical CO2 are used to explain the apparent discrepancy between experiment and prediction, providing reasonable evidence that the local environment can influence kinetically controlled reactions in supercritical fluids.

引用

页码：1306 / 1318

页数：13

共 36 条

[1]

International Thermodynamic Tables of the Fluid State: Carbon Dioxide, (1976)

[2]

Brennecke J.F., Spectroscopic Investigation of Reactions in Supercritical Fluids: A Review, Supercritical Fluid Engineering Science: Fundamentals and Applications, 514, (1993)

[3]

Brennecke J.F., Tomasko D.L., Peshkin J., Eckert C.A., Fluorescence Spectroscopy Studies of Dilute Supercritical Solutions, Ind. Eng. Chem. Res., 29, 8, (1990)

[4]

Carlier C., Randolph T.W., Dense‐Gas Solvent‐Solute Clusters at Near‐Infinite Dilution: EPR Spectroscopic Evidence, AIChE Journal, 39, (1993)

[5]

Chateauneuf J.E., Roberts C.B., Brennecke J.F., Laser Flash Photolysis Studies of Benzophenone in Supercritical CO<sub>2</sub>, Supercritical Fluid Technology, 488, (1992)

[6]

Eckert C.A., Knutson B.L., Molecular Charisma in Supercritical Fluids, Fluid Phase Equil., 83, (1993)

[7]

Ellington J.B., Park K.M., Brennecke J.F., The Effect of Local Composition Enhancements on the Esterification of Phthalic Anhydride with Methanol in Supercritical Carbon Dioxide, Ind. Eng. Chem. Res., 33, 4, (1994)

[8]

Ellison T.K., (1986)

[9]

Evans M.G., Polanyi M., Some Applications of the Transition State Method to the Calculation of Reaction Velocities, Especially in Solution, Trans. Faraday Soc., 31, (1935)

[10]

Gehrke Ch., Schroeder J., Schwarzer D., Troe J., Vobeta F., Photoisomerization of Diphenylbutadiene in Low‐Viscosity Nonpolar Solvents: Experimental Manifestations of Multidimensional Kramers Behavior and Cluster Effects, J. Chem. Phys., 92, 8, (1990)

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