CH384283A - Herbicides - Google Patents

Description

       

      Weedkillers Trifluoromethyl group-containing herbicidal substances have already been produced on various occasions. Thompson et al. describe z. For example, among the numerous compounds developed on behalf of the Chemical Warfare Service (Bot. Gaz. [1946], Vol. 107, pages 476 to 507), four substances containing trifluoromethyl groups, whose effect, however, is in some cases far below the effect of the known phenoxyacetic acids .

   In Weeds, Vol. 2 (1953), page 58, the herbicidal effect of isopropyl - N-3- (trifluoromethylphenyl) - carbamate is also mentioned, which is about three times less than that of isopropyl-N-3- (chlorophenyl ) carbamate (CIPC). Al.

   Abel describes in Chemistry and Industry (1957), page 1106, the action of N- (4-trifluoromethylphenyl) -N ', N'-dimethylurea or N- (3-trifluoromethylphenyl) N' using Hill's reaction , N'-dimethylurea. As a result of the high production costs or the insufficient inhibition of the photolysis of the water, which is vital for the carbon change in the plant, neither of these two preparations has been able to gain practical importance.

   In none of the numerous N-aryl-N ', N'-dialkylureas developed for herbicidal purposes are active ingredients containing trifluoromethyl groups written or even claimed. As an examination of N- (3,5-bis-trifluoromethylphenyl) -N ', N'-dimethyl urea by the inventors showed, this urea lacks any useful activity. N ', N'-diarylureas containing trifluoromethyl groups (Swiss Patent No. 315 319; Austrian Patent No. 185 814 or

   French patent specification No. 1 158 430) only have an insecticidal effect on keratin-eating insects.



  Surprisingly, it has now been found that the N-phenyl-N'-alkylureas of the following formula, which are halogen-substituted in the phenyl nucleus and contain trifluoromethyl groups
EMI0001.0047
    where R is a low molecular weight alkyl group, R1 is a hydrogen atom or the same radical as R, X is an oxygen or sulfur atom, Hal is halogen and n is 1 or 2, excellent herbicidal effects are available.



  As herbicides, those compounds of the formula given above are preferred which have the formula
EMI0001.0053
    correspond, in which X, R and R1 have the meaning given above. Among the compounds of the formula mentioned last, preference is again given to those in which X is oxygen and, among these, those in which R is a methyl or ethyl group and R is hydrogen or a methyl or ethyl group.



  The compounds which correspond to the formulas given can be prepared using methods known per se, it being possible in principle to use all of the methods customary for the preparation of urea or thiourea derivatives.

   In the following some processes are listed schematically, without a complete list being given: (For the halogen-substituted phenyl radical containing trifluoromethyl groups, the designation Ar is chosen and for R and R1 the Muthyl group.)
EMI0002.0005
    Instead of isocyanate, isocyanate formers or releasing agents can also be used.
EMI0002.0009
    As arylamines that can be used for the preparation of the new compounds are, for. B.

    mentioned: 3-trifluoromethyl-4-chloroaniline, 2-chloro-5-trifluoromethylaniline, 2-trifluoromethyl-4-chloroaniline, 2,5-dichloro-4-trifluoromethylaniline, 3-trifluoromethyl-4-bromaniline u. a. m.



  As aliphatic amines, the z. B. to react with the aromatic isocyanates are, for. B.



       Monomethylamine, monoethylamine, dimethylamine, methylethylamine, methylpropylamine, methylbutylanün, diethylamine called.

   Among the numerous active compounds, the following are examples: N-3-trifluoromethyl-4-chlorophenyl-N ', N'-dimethyl urea, N-3-trifluoromethyl-4-chlorophenyl-N'-methyl-N' -n-butylurea, N-3-tritluoromethyl-4-chlorophenyl-N'-methyl urea and N-2,5-dichloro-4-trifluoromethylphenyl-N ', N'-dimethylurea.



  For their practical application, the new compounds are processed into preparations which are the subject of the present invention. The active substances can in emulsified or dispersed or dissolved form or in dusts on their own or together with other weedkillers, such as.

   B. tri- and tetra-substituted aryl-alkyl-ureas, halogenated phenoxy-alkanecarboxylic acids, halogenated benzoic acids or phenylacetic acids, halogenated fatty acids or their salts, esters and amides, with borax or other inorganic salts such as waste salts, with calcium cyanamide, urine fabric and other fertilizers, or pesticides such.

   B. chlorinated hydrocarbons or phosphoric acid esters, who applied the. On the other hand, basic active substances such as tertiary or quaternary amines with herbicidal action are also suitable for combination, such as. B.

    dodecylhexamethyleneimine or its salts, 1,1'-ethylene-2,2'-dipyridilium dibromide. Herbicidal carbamates or thiol carbamates or dithiocarbamic acid esters or derivatives of s-triazine can also be processed into these agents. Likewise, herbicidal heterocycles such. B.



  2-chlorobenzothiazole, 3-amino-1,2,4-triazole, maleic hydrazide, 3,5-dimethyl-tetrahydro-1,3,5,2-H-thiadiazine-2-thione, but also simpler herbicides Substances such as pentachlorophenol, dinitrocresol, dinitrobutylphenol, naphthylphthalamic acid or methyl isothiocyanate can also be used.



  For the production of directly sprayable solutions come z. B. Mineral oil fractions from high to medium boiling range, such as diesel oil or kerosene, also coal tar oils and oils of vegetable or animal origin and hydrocarbons, such as alkylated naphthalenes, tetrahydronaphthalene, possibly using xylene mixtures, cyclohexanols, ketones,

      also chlorinated hydrocarbons, such as tetrachloroethane, trichlorethylene or tri- and tetrachlorobenzenes.



  Aqueous application forms are prepared from emulsion concentrates, pastes or wettable spray powders by adding water. As emulsifiers or dispersants nonionic products come into consideration, for. B.

   Condensation products of aliphatic alcohols, amines or carboxylic acids with a long-chain hydrocarbon radical of about 10 to 30 carbon atoms with ethylene oxide, such as the condensation product of octadecyl alcohol and 25 to 30 mol of ethylene oxide,

      or that of soy fatty acid and 30 moles of ethylene oxide or that of technical oleylamine and 15 moles of ethylene oxide or that of dodecyl mercaptan and 12 moles of ethylene oxide. Among the anion-active emulsifiers that can be used, the sodium salt of the dodecvl alcohol sulfuric acid ester,

      the sodium salt of dodecylbenzenesulfonic acid, the potassium or triethanolamine salt of oleic acid or abietic acid or mixtures of these acids or the sodium salt of a petroleum sulfonic acid. Quaternary ammonium compounds, such as cetylbyridinium bromide or dioxyethylbenzyldodecylammonium chloride, are suitable as cationic dispersants.

    



  For the production of dust and grit, talc, kaolin, bentonite, calcium carbonate, calcium phosphate, but also coal, cork flour and wood flour and other materials of vegetable origin can be used as solid carriers. It is also very useful to manufacture the preparations in granulated form. The various application forms can be provided in the usual way by adding substances which improve distribution, adhesive strength, rain resistance or the ability to penetrate; as such substances, fatty acids, resins, glue, casein or z.

   B. also alginates u. a. m.



  The compositions according to the invention are suitable both for the selective killing of weeds under crop plants and for the total killing and destruction of undesired vegetation. In this context, weeds are also understood to mean undesired crops, that is to say crops grown in advance or in the vicinity.



  <I> Example 1 </I> 20 parts of N-3-trifluoromethyl-4-chlorophenyl-N ', N'-dimethylurea and 80 parts of talc are ground very finely in a ball mill. The mixture obtained in this way serves as a dust.



  <I> Example 2 </I> 20 parts of N-3-trifluoromethyl-4-chlorophenyl-N ', N'-dimethylurea are in a mixture of 48 parts of diacetone alcohol, 16.5 parts of xylene and 16 parts of a condensation product of ethyl lenoxide with higher fatty acids, e.g. B. that of soy fatty acid and 30 moles of ethylene oxide dissolved. This concentrate can be diluted with water to form emulsions of any desired concentration.

   N-3-trifluoromethyl-4-chlorophenyl-N'-methylurea can also be used.



  <I> Example 3 </I> 80 parts of N-3-trifluoromethyl-4-chlorophenyl-N ', N'-dimethylurea or equal parts of N-3-trifluoromethyl-4-chlorophenyl-N'-methylurea are mixed with 4 Sharing a wetting agent, e.g. B. the sodium salt of butylnaphthalenesulfonic acid, 1 to 3 parts of a protective colloid, e.g. B. sulphite waste liquor, and 15 parts of a solid inert carrier such as kaolin, chalk or kieselguhr, mixed and then finely ground.

    The wettable powder obtained can be mixed with water before use and gives a ready-to-use suspension.



  <I> Example 4 </I> 15 parts of N-3-trifluoromethyl-6-chlorophenyl-N ', N'-dimethylurea are dissolved in 90 parts of coal tar oil, diesel oil or spindle oil.



  <I> Example 5 </I> N-3-trifluoromethyl-4-chlorophenyl-N ', N'-dimethyl urea destroyed, given in an amount of 10 to 20 kg in 1000 liters / ha, in a plant with weeds occupied courtyards within a few weeks all of the Unhraut.



  <I> Example 6 </I> 10 g of the compounds a, b, c and d are each mixed with 2 g of sulphite cellulose waste liquor and 100 cm3 of water and then subjected to intensive grinding, which results in finely divided, stable dispersions.

        The compounds a, b, c and d correspond to the following formulas:
EMI0004.0002
    <I> Example 7 </I> 80 parts of the compounds a and b from Example 6 are mixed with 16 parts of kaolin and 4 parts of an emulsifier which is supplied by Ninol Inc., Chicago, under the brand name Toximul MP and finely ground. The mixtures can be used as a wettable powder.

    <I> Example 8 </I> Flower pots are filled with soil in the greenhouse and loaded with seeds of the following weed or crop plants: Zea mays, Avena sativa, Setaria italica, Dactylis glomerata, Sinapis alba, Lepidium sativum,

          Calendula chry- santha. The soil is poured on and treated with spray liquors made from the dispersions according to Example 6 on the day of sowing. The application rate for each active ingredient is 10 kg per hectare. 4 weeks after the treatment, with the exception of Zea mays, which was more or less severely damaged, all of the test plants died.

    <I> Example 9 </I> Flower pots are prepared analogously to Example 8. 10 to 14 days after sowing, the plants are sprayed with a spray mixture made from the dispersions according to Example 6, corresponding to an application rate for each active ingredient of 10 kg per hectare. Since the active ingredient is also absorbed through the leaves, the treated plants, with the exception of Zea mays, have died completely or almost completely after just 14 days.



  <I> Example 10 </I> A field that has been cleared of all annual weeds before the start of the experiment is sown with the following weeds and crops: Zea mays, Triticum vulgare, Avena sativa, Setaria italica, Sorghum sudanense, Album cepa, Cannabis sativa, Brassica rapa,

          Sinapis alba, Raphanus raphanistrum, Linum usitatissimum, Soja max, Trifolium pratense, Trifolium repens, Pisum sativum, Beta vulgaris, Phaseolus vulgaris, Daucus carota,

          Spinacia oleracea, Lactuca sativa. On the day of sowing, the field is treated with a dispersion of the compounds a and b prepared according to Example 7, corresponding to an amount of 1.25 to 5 kg of active ingredient per hectare. 30 days after the treatment, all test plants in the field which was treated with 1.25 kg of compound a, except for Zea mays and Pisum sativum, which have only been partially destroyed, have completely or almost completely died. The same effect is achieved with 5 kg of compound b.

   The same applies to the following weeds that have accrued on the test field: Lamium purpureum, Chenopodium album, Capsella bursa pastoris, Galeopsis tetrahit, Senecio vulgaris, Polygonum aviculare, Polygonum convolvulus, Raphanus raphanistrum,

          Chrysanthemum leucanthemum, Ranunculus repens.



  <I> Example 11 </I> A field is prepared and sown analogously to Example 10. 4 weeks after sowing, treatment with the compounds a and b formulated according to Example 7 takes place in accordance with an application rate of 5 kg of active ingredient per hectare. 3 weeks after the treatment, with the exception of Zea mays, which is only damaged by compound b, all test plants have died completely or almost completely.


    

Claims (1)

PATENT CLAIM Agent for weed control, characterized in that it is a compound of the formula as an active component EMI0004.0103 where R is a low molecular weight alkyl group, R1 is a hydrogen atom or a radical identical to R, X is an oxygen or sulfur atom, Hal is halogen and n is 1 or 2. SUBCLAIM Agent according to patent claim, characterized in that it is the compound of the formula as active ingredient EMI0004.0108