Laser flash photolysis study of the photoinduced oxidation of 4-(dimethylamino)benzonitrile (DMABN)

Investor logo

Warning

This publication doesn't include Faculty of Economics and Administration. It includes Faculty of Science. Official publication website can be found on muni.cz.
Authors

LERESCHE Frank LUDVÍKOVÁ Lucie HEGER Dominik KLÁN Petr VON GUNTEN Urs CANONICA Silvio

Year of publication 2019
Type Article in Periodical
Magazine / Source PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
MU Faculty or unit

Faculty of Science

Citation
Web Full Text
Doi http://dx.doi.org/10.1039/c8pp00519b
Keywords laser flash photolysis
Description Aromatic amines are aquatic contaminants for which phototransformation in surface waters can be induced by excited triplet states of dissolved organic matter ((DOM)-D-3*). The first reaction step is assumed to consist of a one-electron oxidation process of the amine to produce its radical cation. In this paper, we present laser flash photolysis investigations aimed at characterizing the photoinduced, aqueous phase one-electron oxidation of 4-(dimethylamino) benzonitrile (DMABN) as a representative of this contaminant class. The production of the radical cation of DMABN (DMABN(center dot+)) after direct photoexcitation of DMABN at 266 nm was confirmed in accord with previous experimental results. Moreover, DMABN(center dot+) was shown to be produced from the reactions of several excited triplet photosensitizers (carbonyl compounds) with DMABN. Second-order rate constants for the quenching of the excited triplet states by DMABN were determined to fall in the range of 3 x 10(7)-5 x 10(9) M-1 s(-1), and their variation was interpreted in terms of electron transfer theory using a Rehm-Weller relationship. The decay kinetics of DMABN(-+) in the presence of oxygen was dominated by a second-order component attributed to its reaction with the superoxide radical anion (O-2(center dot-)). The first-order rate constant for the transformation of DMABN(center dot+) leading to photodegradation of DMABN was estimated not to exceed approximate to 5 x 10(3) s(-1).
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.