Oxidation of aniline and other primary aromatic amines by manganese dioxide
- Carnegie Mellon Univ., Pittsburgh, PA (USA)
This investigation evaluated the redox reaction between a manganese dioxide, {sigma}-MnO{sub 2}, and anilines and other aromatic reductants in aqueous suspensions at pH values ranging from 3.7 to 6.5. The reaction with manganese dioxide may represent a pathway for transformation of aniline and other primary aromatic amines in acidic mineralogical and soil/water environments in the absence of oxygen and substantial microbial activity. The reaction rate with aniline is pH-dependent, increasing with decreasing pH, and first order with respect to {sigma}-MnO{sub 2} and organic solute. Aniline and p-toluidine are demonstrated to be 2-equiv reductants, as is believed to be the case for the other aromatic solutes considered in this study, including the substituted anilines, and hydroquinone and catechol and their alkyl substituents. Ring-bound nitrogen-containing aromatic solutes (methylimidazole, quinoline, and 5,5-dimethylhydantion) were unreactive with manganese dioxide at pH 6.4. The order of the reactivity of para-substituted anilines was methoxy >> methyl > chloro > carboxy >> nitro; the relative reactivity of these compounds correlated with the solute's half-wave potential and Hammett constant.
- DOE Contract Number:
- FG22-86PC90524
- OSTI ID:
- 5452506
- Journal Information:
- Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 24:3; ISSN ESTHA; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010900 -- Coal
Lignite
& Peat-- Environmental Aspects
54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
AMINES
ANILINE
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
HYDROGEN COMPOUNDS
MANGANESE COMPOUNDS
MANGANESE OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PH VALUE
POLYCYCLIC AROMATIC AMINES
REDOX REACTIONS
TRANSITION ELEMENT COMPOUNDS
WATER