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LIGHT PRODUCTION IN ALKALINE MIXTURES OF REDUCING AGENTS AND DIMETHYLBIACRIDYLIUM NITRATE *
Author(s) -
Totter John R.
Publication year - 1975
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1975.tb06737.x
Subject(s) - chemistry , kinetics , hydroxylamine , reducing agent , aqueous solution , nuclear chemistry , ferricyanide , hydroxide , reaction rate constant , light intensity , fructose , inorganic chemistry , organic chemistry , quantum mechanics , optics , physics
— Kinetic studies were made of light production and 0 2 absorption elicited by treatment of dimethylbiacridylium hydroxide [D(OH) 2 ] with reducing agents in alkaline aqueous solutions. D(OH)2 addition stimulated O 2 uptake which proceeded with zero‐order kinetics until nearly all of the O 2 or of the D(OH) 2 was converted to end products. At the termination of the reactions with fructose as reductant the D(OH) 2 was converted to methylacridone and to dimethylbiacridene each compound accounting for approximately one‐half the D(OH) 2 consumed. O 2 was reduced to H 2 O 2 . With hydroxylamine as the reducing agent the emitted light intensity was related to the first power of the D(OH) 2 concentration and the rate of O 2 uptake to the square root of the D(OH) 2 . The disappearance of D(OH) 2 in these circumstances was by a first order or pseudo‐first order rate. Fructose as a reducing agent by contrast resulted in an O 2 uptake nearly independent of D(OH) 2 concentration over a range from 1 × 10 ‐5 M ‐1 × 10 ‐4 M, while the light intensity and disappearance of D(OH) 2 followed a one‐half order rate. O 2 uptake was by zero order kinetics and the oxidation of fructose proceeded at the same rate as was found with ferricyanide as oxidant. The kinetics, quantum yields and temperature dependence of the fructose reactions were compared with similar reactions employing H 2 O 2 as the light eliciting reagent. The results are interpreted as indicating that D(OH) 2 acts as a chain initiator in a manner analogous to better known, radical producing compounds found to accelerate hydrocarbon autooxidations.