A substituted diphenyl ether herbicide(MC-4379) was studied on the decomposition by some environmental factors; sunlight, microorganisms, and the crude enzyme in rice plant extract.
All the decomposition products were confirmed by means of TLC, GLC, and IR. The parent compound and the decomposition products were put to the test for the effect on the growth of some plants. The results obtained are summarized as follows:
1. Photolysis
Amino-MC-4379, 2,4-dichloro-3´-carboxyl-4´-nitrodiphenyl ether, Nitrofen, 2,4-dichloro-3´-carboxyl-4´-amino-diphenyl ether, amino-Nitrofen, 3-carboxymethyl-4-nitrophenol, p-nitrophenol, p-aminophenol, etc. were confirmed as photoproducts, in addition to a relatively small amount of an unknown compound. It was confirmed that the solution-phase photolysis of MC-4379 was accelerated much more by the aid of a photosensitizer benzophenone.
2. Degradation by the crude extract of germinating rice seeds
Nitrofen was confirmed as a major degradation product, in addition to a relatively small amount of and unknown compound. Most of the parent compound remained unchanged.
3. Degradation by microorganisms
Nitrofen and amino-MC-4379 were confirmed as the major products, in addition to a small amount of an unknown compound.
4. The germinating rice seeds and soybean were grown in the 1,000 ppm emulsions of some chemicals, respectively. The effect on rice plant growth was in the inhibitory order of p-nitrophenol $gt; C-6989$gt; Nitrofen$gt; amino-Nitrofen $gt; MC-4379. The effect on soybean was in the order of Nitrofen $gt; amino-Nitrofen $gt; MC-4379.
Two weeds, Amantus blitum and Setaria viridis were grown in the 500 ppm emulsions containing the compounds, respectively. After incubation for 3 days, it was observed that all the shoots had been dead.
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