Oxidation of aniline and other primary aromatic amines by manganese dioxide

Journal Article · Thu Mar 01 00:00:00 EST 1990 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00073a012· OSTI ID:5452506

Laha, S; Luthy, R G ^[1]

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1. 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), Vol. 24:3; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
01 COAL, LIGNITE, AND PEAT
ANILINE
OXIDATION
POLYCYCLIC AROMATIC AMINES
CHEMICAL REACTIONS
MANGANESE OXIDES
PH VALUE
REDOX REACTIONS
WATER
AMINES
AROMATICS
CHALCOGENIDES
HYDROGEN COMPOUNDS
MANGANESE COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
010900 - Coal
Lignite
& Peat- Environmental Aspects