Permanganate oxidation is an attractive
environmental remediation
strategy due to its low cost, ease of use, and wide range in reactivity.
Here, permanganate reactivity trends are investigated for model organic
compounds and organic contaminants. Second-order permanganate reaction
rate constants were compiled for 215 compounds from 82 references
(journal articles, conference proceedings, master’s theses,
and dissertations). Additionally, we validated some phenol rate constants
and contribute a few additional phenol rate constants. Commonalities
between contaminant oxidation products are also discussed, and we
tentatively identify several model compound oxidation products. Aromatic
rings, alcohols, and ether groups had low reaction rate constants
with permanganate. Alkene reaction sites had the highest reaction
rate constants, followed by phenols, anilines, and benzylic carbon–hydrogen
bonds. Generally, permanganate reactivity follows electrophilic substitution
trends at the reaction site where electron donating groups increase
the rate of reaction, while electron withdrawing groups decrease the
rate of reaction. Solution conditions, specifically, buffer type and
concentration, may impact the rate of reaction, which could be due
to either an ionic strength effect or the buffer ions acting as ligands.
The impact of these solution conditions, unfortunately, precludes
the development of a quantitative structure–activity relationship
for permanganate reaction rate constants with the currently available
data. We note that critical experimental details are often missing
in the literature, which posed a challenge when comparing rate constants
between studies. Future research directions on permanganate oxidation
should seek to improve our understanding of buffer effects and to
identify oxidation products for model compounds so that extrapolations
can be made to more complex contaminant structures.