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Title: Laser flash photolysis investigation of the triplet-triplet annihilation of anthracene in supercritical water

Abstract

A fundamental issue in understanding the influence of supercritical fluids (SCFs) on reactions has been the effect on reactions that would normally occur at the diffusion-controlled limit in liquids or gases. Numerous experimental, theoretical, and simulation studies have been conducted to address this issue. The effects of the supercritical water environment on the triplet-triplet annihilation of anthracene, a simple, well-characterized reaction that is known to be diffusion controlled in normal liquids, was investigated at temperatures from 375 to 450 C and pressures from 50 to 350 bar. The reaction was found to occur just slightly above the diffusion-control limit, which was estimated from the Stokes-Einstein based Debye equation, when spin statistical factors are taken into account. This is in qualitative agreement with previous studies of diffusion-controlled reactions in lower temperature supercritical fluids (SCFs). Thus, the supercritical water environment is similar to that of lower temperature SCFs for diffusion-controlled reactions of nonpolar hydrocarbon species. There is no evidence of solvent clustering and any influence of solute/solute interactions is small. Finally, the mechanism of the reaction appears to be the same as in nonpolar liquid solvents.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Univ. of Notre Dame, IN (US)
Sponsoring Org.:
US Army Research Office (ARO); National Science Foundation (NSF); Clare Boothe Luce Foundation; American Association of University Women; Department of Energy
OSTI Identifier:
20003184
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
Additional Journal Information:
Journal Volume: 103; Journal Issue: 33; Other Information: PBD: 19 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; LASER RADIATION; PHOTOLYSIS; ANTHRACENE; SUPERCRITICAL STATE; WATER; TRIPLETS; ANNIHILATION

Citation Formats

Kremer, M.J., Connery, K.A., DiPippo, M.M., Feng, J., Chateauneuf, J.E., and Brennecke, J.F. Laser flash photolysis investigation of the triplet-triplet annihilation of anthracene in supercritical water. United States: N. p., 1999. Web. doi:10.1021/jp991097i.
Kremer, M.J., Connery, K.A., DiPippo, M.M., Feng, J., Chateauneuf, J.E., & Brennecke, J.F. Laser flash photolysis investigation of the triplet-triplet annihilation of anthracene in supercritical water. United States. doi:10.1021/jp991097i.
Kremer, M.J., Connery, K.A., DiPippo, M.M., Feng, J., Chateauneuf, J.E., and Brennecke, J.F. Thu . "Laser flash photolysis investigation of the triplet-triplet annihilation of anthracene in supercritical water". United States. doi:10.1021/jp991097i.
@article{osti_20003184,
title = {Laser flash photolysis investigation of the triplet-triplet annihilation of anthracene in supercritical water},
author = {Kremer, M.J. and Connery, K.A. and DiPippo, M.M. and Feng, J. and Chateauneuf, J.E. and Brennecke, J.F.},
abstractNote = {A fundamental issue in understanding the influence of supercritical fluids (SCFs) on reactions has been the effect on reactions that would normally occur at the diffusion-controlled limit in liquids or gases. Numerous experimental, theoretical, and simulation studies have been conducted to address this issue. The effects of the supercritical water environment on the triplet-triplet annihilation of anthracene, a simple, well-characterized reaction that is known to be diffusion controlled in normal liquids, was investigated at temperatures from 375 to 450 C and pressures from 50 to 350 bar. The reaction was found to occur just slightly above the diffusion-control limit, which was estimated from the Stokes-Einstein based Debye equation, when spin statistical factors are taken into account. This is in qualitative agreement with previous studies of diffusion-controlled reactions in lower temperature supercritical fluids (SCFs). Thus, the supercritical water environment is similar to that of lower temperature SCFs for diffusion-controlled reactions of nonpolar hydrocarbon species. There is no evidence of solvent clustering and any influence of solute/solute interactions is small. Finally, the mechanism of the reaction appears to be the same as in nonpolar liquid solvents.},
doi = {10.1021/jp991097i},
journal = {Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory},
number = 33,
volume = 103,
place = {United States},
year = {1999},
month = {8}
}