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SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES: QSAR DEVELOPMENT
Citation:
Weber, E J., D Colon, AND G L. Baughman. SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES: QSAR DEVELOPMENT. Presented at 220th American Chemical Society National Meeting, Washington, DC, August 20-24, 2000.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
Despite the common occurrence of the aromatic amine functional group in environmental contaminants, few quantitative structure-activity relationships (QSARs) have been developed to predict sorption kinetics for aromatic amines in natural soils and sediments. Towards the goal of developing successful QSARs, the sorption kinetics for a series of anilines with substituents in the 3- or 4-positions were measured in sediment slurries. Generally, the sorption kinetics of the substituted anilines were characterized by a rapid, initial loss of substrate from the aqueous
phase followed by a much slower rate of disappearance. The initial rates of sorption varied with the type and position of the substituent group. Sorption rate constants were correlated with molecular descriptors including ionization constants (pKa's), HOMO energies, E1 and E2 oxidation potentials, and Hammett s-constants. Based on the strength of linear correlations and the availability of data, ionization constants appear to be the most useful molecular descriptor for predicting initial rates of sorption of substituted anilines in natural soils and sediments.