PREDICTION OF CHEMICAL REACTIVITY PARAMETERS AND PHYSICAL PROPERTIES OF ORGANIC COMPOUNDS FROM MOLECULAR STRUCTURE USING SPARC
Hilal, S H. PREDICTION OF CHEMICAL REACTIVITY PARAMETERS AND PHYSICAL PROPERTIES OF ORGANIC COMPOUNDS FROM MOLECULAR STRUCTURE USING SPARC. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-03/030 (NTIS PB2004-101167), 2003.
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.
The computer program SPARC (SPARC Performs Automated Reasoning in Chemistry) has been under development for several years to estimate physical properties and chemical reactivity parameters of organic compounds strictly from molecular structure. SPARC uses computational algorithms based on fundamental chemical structure theory to estimate a variety of reactivity parameters. Resonance models were developed and calibrated on more than 5000 light absorption spectra, whereas electrostatic interaction models were developed using more than 4500 ionization pKas in water. Solvation models (i.e., dispersion, induction, dipole-dipole, hydrogen bonding, etc.) have been developed using more than 8000 physical property data points on properties such as vapor pressure, boiling point, solubility, Henry's constant, GC retention times, Kow, etc. At the present time, SPARC predicts ionization pKa (in the gas phase and in many organic solvents including water as function of temperature), carboxylic acid ester hydrolysis rate constants (as function of solvent and temperature), E(1/2) reduction potential (as function of solvents, pH and temperature), gas phase electron affinity and numerous physical properties for a broad range of molecular structures.
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Record Details:Record Type: DOCUMENT (PUBLISHED REPORT/REPORT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
ECOSYSTEMS RESEARCH DIVISION