skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Consequences of Surface Confinement on Free Radical Chemistry

Abstract

Mass transport limitations impact the thermochemical processing of fossil and renewable energy resources, which involves the breakdown of cross-linked, macromolecular networks. To Investigate the molecular level details of the consequences of molecular confinement on high temperature (275-500°C) free-radical reaction pathways, we have been examining the pyrolysis of model compounds attached to the surface of non-porous silica nanoparticles through a thermally robust Si-O-C aryl, tetha. Pyrolysis of silica-immobilized diphenylalkanes and related ethers have been studied in detail and compared with the corresponding behavior in fluid phases. The diffusional constraints can lead to reduced rates of radical termination on the surface, and enhancement of neophyl-like rearrangements, cyclization-dehydrogenation pathways, and ipso- aromatic substitutions. Furthermore, studies of two-component surfaces have revealed the importance of a radical relay mechanism involving rapid serial hydrogen transfer steps resulting from the molecular pre-organization on the low fractal dimension silica surface. Key findings are reviewed in this paper, and the implications of these results for fuel processing are described.

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
7921
Report Number(s):
ORNL/CP-103215
KC 03 02 01 0; ON: DE00007921
DOE Contract Number:  
AC05-96OR22464
Resource Type:
Conference
Resource Relation:
Conference: American chemical Society National Meeting, New Orleans, LA, August 22-26, 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; Free Radicals; Pyrolysis; Surfaces; Diffusion

Citation Formats

Birtt, P.F., and Buchanan, A.C., III. The Consequences of Surface Confinement on Free Radical Chemistry. United States: N. p., 1999. Web.
Birtt, P.F., & Buchanan, A.C., III. The Consequences of Surface Confinement on Free Radical Chemistry. United States.
Birtt, P.F., and Buchanan, A.C., III. Sun . "The Consequences of Surface Confinement on Free Radical Chemistry". United States. https://www.osti.gov/servlets/purl/7921.
@article{osti_7921,
title = {The Consequences of Surface Confinement on Free Radical Chemistry},
author = {Birtt, P.F. and Buchanan, A.C., III},
abstractNote = {Mass transport limitations impact the thermochemical processing of fossil and renewable energy resources, which involves the breakdown of cross-linked, macromolecular networks. To Investigate the molecular level details of the consequences of molecular confinement on high temperature (275-500°C) free-radical reaction pathways, we have been examining the pyrolysis of model compounds attached to the surface of non-porous silica nanoparticles through a thermally robust Si-O-Caryl, tetha. Pyrolysis of silica-immobilized diphenylalkanes and related ethers have been studied in detail and compared with the corresponding behavior in fluid phases. The diffusional constraints can lead to reduced rates of radical termination on the surface, and enhancement of neophyl-like rearrangements, cyclization-dehydrogenation pathways, and ipso- aromatic substitutions. Furthermore, studies of two-component surfaces have revealed the importance of a radical relay mechanism involving rapid serial hydrogen transfer steps resulting from the molecular pre-organization on the low fractal dimension silica surface. Key findings are reviewed in this paper, and the implications of these results for fuel processing are described.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {8}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: