Effect of nonionic surfactants on the photochemistry of 3-(4-chlorophenyl)-1,1-dimethylurea in aqueous solution

Phototransformation of linuron and chlorbromuron in aqueous solution

“…3 The presence of non-ionic surfactants eliminates ring hydroxylation and enhances reductive dechlorination. 5 The same e †ect was observed when methanol was added to the solution. 2 The main photoproducts identiÐed by Tanaka et al6 in the photolysis of diuron in aqueous solution resulted from the substitution of Cl by OH, and elimination or oxidation of the methyl group.…”

“…Previously it was observed with diuron and monuron when the solution contained organic substances such as alcohol7 or surfactants. 5 It is attributed to a substitution involving the formation of a radical after electron transfer from the solvent substitution), more efficient with (SN 2 . ET .…”

Reviews of Environmental Contamination and Toxicology

“…These observations suggest that the aryl moiety ofmonuron may be either dissolved in or absorbed on the surface of the micellar lipophilic core, away from any oxygen source. The important observation of this study is that photochemical reactions occur in the organic phase ofthe micelles rather than in the aqueous phase (Tanaka et al 1979). Again, the products of photoreaction 22 were identified using MS, and alternative structures such as 91 and 92, and 94 and 95 can be assigned to products 83 and 90, respectively (discussed below).…”

“…Under environmental conditions, monuron is applied as a formulation which may include surface-active agents (Worthing and Walker 1983); therefore, there would be a need to determine the effect of surfactants on its photolytic degradation. Tanaka et al (1979) tried to define the quantitative and qualitative effects of surface-active agents by irradiating 170 ppm aqueous solutions of monuron (76) containing 0.2, 0.4, I, and 2% (wjw) of surfactants such as Triton X and Tergitol TMN series of nonionic surfactants with aryland alkyl-substituted polyoxyethylene glycols. Monomethyl monuron (77), fenuron (1,1 ,dimethyl-3-phenylurea) (88), monomethyl fenuron (l-methyl-3-phenylurea) (89), monuron dimer (83) Only dealkylation, coupling and reductive dehalogenation processes were observed in the presence of surfactants.…”

“…In summary, results show a nonparticipation of oxygen in the photoreaction ofmonuron in the presence of surface-active agents. According to Tanaka et al (1979), the addition of surfactants to aqueous monuron eliminates the ring hydroxylation and enhances the reductive dechlorination reaction (compare Reactions 21 and 22). These observations suggest that the aryl moiety ofmonuron may be either dissolved in or absorbed on the surface of the micellar lipophilic core, away from any oxygen source.…”