Monuron, photolysis

Tanaka et al. (1981a) studied the photolysis of monuron in dilute aqueous solutions in order to fully characterize a substituted diphenylamine that was observed in an earlier investigation (Tanaka et al., 1977). They identified this compound as an isomeric mixture containing 92% 2-chloro-4, 5-bis(TV, TV -dimethylureido)biphenyl and 8% 5-chloro-2,4 -bis(TV, TV -dimethylureido)-biphenyl. 

The transformation of monuron photosensitized by fulvic acids (X = 365 nm) was shown to yield the same products as direct photolysis or sensitization by hydroquinone [82]. It was concluded that in this case, sensitization was mediated by triplet energy transfer in contrast, the presence of a humic acid induced an H atom transfer and the products were different [82]. The fulvic acid example shows that long-wavelength sensitization may in specific... 

The primary steps of the photolysis of aqueous monuron and diuron were investigated by Canle et al. by means of transient absorption spectroscopy using an ArF laser (X = 193 nm) for excitation [89]. Under these conditions, photoionization occurred with a quantum yield of about 10%. Radical cations were detected after the laser pulse and found to deprotonate to yield neutral radicals [89]. 

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