Grantee Research Project Results
Oxidative Coupling as a Cause of Substituent Release from Aromatic Pollutants
EPA Grant Number: R823847Title: Oxidative Coupling as a Cause of Substituent Release from Aromatic Pollutants
Investigators: Bollag, Jean-Marc , Dec, Jerzy
Institution: Pennsylvania State University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1995 through October 1, 1998 (Extended to September 30, 1999)
Project Amount: $425,000
RFA: Exploratory Research - Chemistry and Physics of Water (1995) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Safer Chemicals
Description:
The objective of this project is to establish that the release of substituents through dehalogenation, decarboxylation, demethoxylation, demethylation, dehydroxylation, and dehydrogenation of phenolic and anilinic compounds is caused by oxidative coupling reactions. Recent studies indicated that the stoichiometric patterns of the release were in agreement with the free radical mechanism of oxidative coupling. According to this mechanism, release of a substituent may occur only if the unpaired electron of a free radical involved in coupling is located at the substituted aromatic carbon. Under certain conditions, substituents can also be released from the formed o-quinones during nucleophilic attack by phenoxide ions. Since the release patterns will reveal the sites on substrate molecules at which the coupling takes place, the research may be of great importance for elucidating reaction pathways involving oxidative coupling.
The investigation will be completed in three stages: (1) the determination of the rates and stoichiometry of substituent release under different reaction conditions; (2) the development of methods to distinguish between degradative and non-degradative substituent release and to assess their effect on the overall transformation of substrates in the environment; (3) the determination of the pathways of the studied processes and the identification of the formed products.
The non-degradative release of substituents from aromatic compounds constitutes a new and as yet unexplored aspect of oxidative coupling reactions. It is expected that research in this area will advance the understanding of such significant environmental and industrial processes as humification, delignification, binding of aromatic chemicals to soil, and polymerization of pollutants in aqueous environments.
Publications and Presentations:
Publications have been submitted on this project: View all 20 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 15 journal articles for this projectSupplemental Keywords:
soil, humus, PAHs, bioremediation, environmental chemistry, immunoassays., Scientific Discipline, Water, Physics, Environmental Chemistry, Chemistry, Engineering, Chemistry, & Physics, immunoassay, aromatic pollutants, oxidative coupling, anilinic compounds, dehalogenation, stochiometry, humification, phenolic compoundsRelevant Websites:
http://www.cos.comProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.