Journal article
Reactivity of Alkyl Polyhalides toward Granular Iron: Development of QSARs and Reactivity Cross Correlations for Reductive Dehalogenation
Environmental science & technology, Vol.44(20), pp.7928-7936
10/15/2010
DOI: 10.1021/es1018866
PMID: 20863059
Abstract
Attempts to develop quantitative structure−activity relationships (QSARs) for reductive dehalogenation by granular iron have been hindered by the unavailability of high quality predictor variables, have included relatively few compounds, and on occasion have relied on data lacking internal consistency. We herein investigate the reduction of 24 alkyl polyhalides by granular iron and the better-defined, homogeneous reductants Cr(H2O)6 2+ and an Fe(II) porphyrin. QSARs were constructed with a new set of computationally derived gas phase homolytic carbon−halogen bond dissociation energies and solvated one-electron reduction potentials determined using a quantum chemistry composite method (G3MP2). Reactivity cross correlations between reductant systems were also developed. Reactivity trends were generally consistent among all reductants and revealed pronounced structural influences. Compounds reduced at C−Br were orders of magnitude more reactive than analogues reduced at C−Cl; the number and identity of α- (Br ∼ Cl > CH3 > F > H) and β-substituents (Br > Cl) also influenced reactivity. Nonlinearities encountered during QSAR and cross correlation development suggest that reactions of highly halogenated alkyl polyhalides with granular iron are limited by mass transfer, as supported by estimates of mass transfer coefficients. For species not suspected to exhibit mass transfer limitations, reasonably strong cross correlations and comparable substituent effects are consistent with dissociative electron transfer as the rate-determining step.
Details
- Title: Subtitle
- Reactivity of Alkyl Polyhalides toward Granular Iron: Development of QSARs and Reactivity Cross Correlations for Reductive Dehalogenation
- Creators
- David M CwiertnyWilliam A ArnoldTamar KohnLisa A RodenburgA. Lynn Roberts
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.44(20), pp.7928-7936
- Publisher
- American Chemical Society
- DOI
- 10.1021/es1018866
- PMID
- 20863059
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Language
- English
- Date published
- 10/15/2010
- Academic Unit
- Center for Health Effects of Environmental Contamination; Civil and Environmental Engineering; Public Policy Center (Archive); Chemical and Biochemical Engineering
- Record Identifier
- 9983992095002771
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