DD145053A5 - HERBICIDAL COMPOSITION - Google Patents

Abstract

The invention relates to a herbicidal composition for the selective weed control in crop plants, for example cereals, corn, cotton, soybean. According to the invention, 3-W-trifluoromethyl-4-ethylphenyl-N'N'-dimethylurea is used as active ingredient in the new herbicidal compositions, together with customary carriers and / or surface-active agents.

Description

Berlin _t d.27.11 * 1979 AP C07C / 214 581

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Herbicidal composition Field of application of the invention

The invention relates to a herbicidal composition containing a novel substituted phenylurea, its preparation and a method for selective weed control in certain crops by means of these compositions.

The invention also relates to 3-trifluoromethyl-4-ethylaniline, its preparation and use as an intermediate for the production of chemical compounds.

Characteristic of the known technical solutions

It is known that certain trisubstituted phenylureas possess interesting herbicidal properties. In particular, BE-PS 594,227 describes herbicidal compositions which contain as active ingredient the 3-N-trifluoromethylphenyl-U ^f N ^f -dimethylurea. which is useful as total or selective herbicide postemergence to 2 _S 5 kg / ha maize · since then, this was Ver ~ bond used commercially only for cotton, since the selectivity margin is judged at other crops too narrow ·. ,

Moreover, ^ -alkylphenyl-N ¹ N ⁸ -dimethylureas with good selective herbicidea properties in crop plants are known in particular to getroid species However, their selectivity was never applied to cotton since the results of the outdoor experiments did not confirm those of the tests in the greenhouse »

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Furthermore, FR 2,001,791 describes a family of substituted phenylureas whose substituents cover those of the compounds of the invention _. however, this family comprises a considerable number of possible compounds (more than 100,000), and the single subgroup j, which is actually illustrated by pysicochemical properties, does not concern the products having a trifluoromethyl group on the phenyl nucleus. When the selectivity of certain compounds, in particular the chlortoluron N (4-methyl-3-chlorophenyl) -N ¹ N * -dimetefluorourea, in cereals is explained in the biological sector, their behavior in cotton is not shown in any experiment and even in the case of cotton Description of this patent not mentioned

The aim of the invention is the provision of a herbicidal composition with improved herbicidal activity and broad selectivity spectrum.

Explanation of the essence of the invention

The invention is based on the object _? finding a compound _f having improved herbicidal action, has a wide spectrum of selectivity and is suitable as an active ingredient in herbicidal compositions.

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According to the invention in herbicidal compositions as active ingredient 3-N-trifluoromethyl ~ 4-ethylphenyl ~ N ^f N ¹ -diinethylharnstoff of the formula

KHCON

applied"

The invention further relates to a method for selective weed killing in a large number of crops by means of these compositions.

It has now surprisingly been found that the 3-fluoromethyl-1-ethylphenyl-H'N'-dimethylurea would be cumulated in place of the reduced selectivity properties on cereals, corn and cotton as evidenced by the simultaneous presence of the substituents trifluoromethyl in 3-position and lower-alkyl in the Λ-position of the phenyl ring would have an accumulation of better selectivities, which are much better than the mentioned urea derivatives.

The compounds according to the invention can be prepared by processes known per se.

First, 3-trifluoromethyl-4-ethylphenyl isocyanate can be condensed with dimethylamine according to the following scheme:

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N = C = O + .HN. - £ C ₀ H ₁ - (ί)> - NHCON

This reaction is effected in an organic solvent medium which is inert under the reaction conditions, for example in an aromatic solvent such as toluene or chlorobenzene, at ambient temperature, preferably with stirring.

The isocyanate used can be obtained in a manner known per se by reaction of phosgene with 3-trifluoromethyl-4-ethylaniline, the reactants being in the form of a solution in an inert organic solvent, for example in an aromatic solvent which is inert under the reaction conditions, such as toluene . or chlorobenzene at a temperature between 0 ⁰ C and added to the boiling point of the LösLingsraittel a relatively elevated temperature favors the development of hydrogen chloride that is released during the reaction;

+ COCl ₂ -> C ₀ H ₁ T-Zf IV-N = C = O + 2HCl

Another method of preparation consists of hexametapil and CO ₂ -GaS with 3-TriflUQrmethyl- ~ 4-ethylaniline according to the following scheme

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NH - COH

3 ρ + co ₂

POH

in the presence of pyridine at a temperature between 15 and 100 ⁰ C siu? To bring reaction.

Finally, the compound according to the invention can also be prepared by reacting dimethylcyclohexyl chloride with methyl-4-ethylaniline according to the following scheme

ClCON

/ ^0H 3

NHCON. + HCl

in the presence of an acid acceptor such as triethylamine "

The 3 "" ^f ^ ifl ^ ormethyl "is 4-ethylaniline" which is distilled a liquid product at 96-97 ⁰ C under 16 mm Hg. Is is a novel synthesis intermediate, which is obtained by catalytically © hydrogenation of the corresponding nitro derivative in the presence of beispielsf ^ öise palladium on activated carbon in methanolic medium according to the scheme:

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CF ₃

can produce. The nitro derivative can be prepared by nitration of orthotrifluoromethylethylbenzene by means of a sulfuric acid-nitric acid mixture according to the following scheme

H ₂ SO ₄

CH ₃ -CH

be prepared "" The Orthotrifluormethyläthylbenzol can be obtained by catalytic hydrogenation of Orthotrifluormethyl-2 ^{t i} 2'2 "trichloro-'äthylbenzol in the presence of palladium on carbon in methanol! seh-alkaline medium according to the following scheme

^3E0H * ^H 2

CH ₃ -CH ₂

CF,

+ 3

The trichloro derivative can be obtained by reaction of dichlorovinylidene on a halide, in particular diasonium chloride of 2-trifluoromethylaniline in the presence of copper (II) chloride in acetone according to the following scheme:

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MH ₂ + HCl +

water

CF.

-N = N ⁺ Cl "" +

-N = N ⁺ Cl "

CH ₂ -CCl ₃ +

For use in practice, the compound of the invention is seldom used alone. It is usually part of formulations which generally contain from 0.5 to 95% by weight of the active material according to the invention, a carrier and / or surface-active agent (generally in an amount of from 0 to 10% by weight, preferably 0, 1 to 10%) * The term "carrier" for the purposes of the present specification refers to an organic or mineral, natural or synthetic material with which the active material is associated, to its application on the plant, on the seeds or the soil or facilitate its transport or handling. The carrier may be solid (clay, natural or synthetic silicates, resins, waxes, solid fertilizers) or fluid (water, alcohols, ketones, petroleum fractions, chlorinated hydrocarbons, liquefied gases).

The surfactant may be a emulsifier, dispersant or wetting agent, any of which may be ionic or nonionic. For example, mention may be made of the salts of polyacrylic acids, the salts of phenolsulfonic acids or naphthalenesulfonic acids, polycondensates of ethylene oxide with fatty alcohols, fatty acids or fatty amines.

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The inventive compositions may granules _s solutions, emulsifiable concentrates, emulsions, concentrates are produced in suspension and aerosols in the form of wettable powders, dusting powders., *

The wettable powders are generally prepared such that they contain from 20 to 95% by weight of active material _9, and they usually contain, in addition to a solid support, 0 to 5% by weight wetting agent, 3 to 10% by weight of one or more Stabilizers and / or other additives such as penetrants, adhesives or anti-caking agents, adhesives, glues, etc. For example, the composition of a wettable powder may be as follows

Active material (compound 1) 50%

Calicium lignosulphate (deflocculant) 5 % sodium isopropylnaphfchaline sulphonate (anionic

Wetting agent) 1 %

Silica against clumping " 5%

Kaolin (filler) 39 %.

To be placed on the granules, which are intended to the ground _s are usually prepared so that they have dimensions of between 0.1 and 2 mm, and they can be produced by agglomeration or impregnation "In general, contain-die.Granulate. 0.5 to 25 % active material and from 0 to 10% by weight additives such as stabilizers, slow release modifiers, binders and solvents,

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The emulsifiable concentrates which are applicable by atomization usually contain, apart from the solvent and if necessary, a co-solvent of 10 to 50% w / v of active material, from 2 to 20% w / v of suitable additives such as Stabilizers, penetrants, corrosion inhibitors, dyes and adhesives.

As an example, the composition of an emulsifiable concentrate is given below, the amounts being expressed in g / l:

Active material (Compound No. 1) 400 g

Alkalidodecylbenzenesulfonate 20g

Oxyethylated nonylphenol with 10 moles of ethylene oxide 10 g

Cyclohexanone 200 g

aromatic solvent top up to 1.1

The concentrates in suspension, which are also applicable for atomizing, v / ground prepared so as to obtain a flüides stable, non-sedimenting product, and they usually contain from 10 to 75 wt -.%>'Active material, 0.5 to wt Ϊ5 .- # surfactant, 0.1 to 10 wt »H & thixotropic agents, 0 to 10 wt .-% of suitable additives such as antifoams, corrosion inhibitors, stabilizing agents _$ penetrants and stickers, and as carrier, water or an organic liquid in which the active material is substantially insoluble:

Certain solid organic materials or mineral salts may be dissolved in the carrier to prevent sedimentation thereon or as an anti-gels to the water.

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Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or emulsifiable concentrate according to the invention by means of water, are also included within the general scope of the invention. Emulsions may be of the water-in-oil type or of the water-in Oil-in-water type, and they may have a tough texture like that of a "mayonnaise".

The compositions of the present invention may also contain other ingredients, for example, protective colloids, adhesives or thickeners, thixotropic agents, stabilizing or sequestering agents, and other known active materials having pest control properties, especially insecticides or fungicides.

sb el sgiel.

The following examples are intended to further illustrate the preparation and herbicidal properties of N- (3-trifluoromethyl-4-ethylphenyl-N'N'-dimethylurea.

Preparation of 3-trifluoromethyl-4-ethylphenyldimethylliarn substance according to the first method!

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A solution of 35 S (0.162 mol) of 3-fluoromethyl-4-ethylphenyl isocyanate, dissolved in 100 ml of toluene, is poured dropwise onto a solution of 8.1 g (0.18 mol) of dimethylamine in 15 ml of toluene Stirring at a temperature of about 15 ^° C. for 4 hours results. Evaporation of the solvent gives a precipitate which is recrystallised from a mixture of methanol / water 30/70. The product obtained in a yield of 63% melting at 105 to 106 ⁰ C. The NMR analysis by means of a spectrograph 60 Mz In hexadeuterisiertem dimethyl sulfoxide with tetramethylsilane as an internal reference, shows that there · 'is 3-trifluoromethyl "4 ~ äthylphenyldimethylharnstoff is.

The 3-trifluoromethyl-4-ethylphenyl isocyanate used above was prepared in the following manner.

A solution of 39.7 g (0 _s 21 mol) of 3-trifluoromethyl-4-ethylaniline, dissolved in 400 ml of toluene, is poured dropwise onto Bine solution of 83.2 g (0.84 mol) of phosgene dissolved in 600 ml Toluene ·. '·. ,

The reaction is effected with stirring at a temperature of about 0 ⁰ C. After completion of the pouring of the aniline solution, the medium is allowed to come to room temperature, then slowly heated to boiling. After completion of the gas evolution of the hydrogen chloride formed and the excess phosgene is held for one hour at 'reflux. The toluene is then evaporated to give a liquid of boiling point 50 to 51 ⁰ C under 1 mm Hg in a yield of 95% ·.

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NMR analysis of the compound confirms the structure sought.

Preparation of the compound of the invention by the two-th method

In a three-necked flask equipped with condenser _t ^ Gaseinleitlungsrohr which dips to the bottom of the piston and! is provided with a stirrer, leading to 8.1 g (0, (H27 mol) of 3 ~ trifluoromethyl ~ 4-ethylaniline, 7.0 g (0.0427 mol) Hexametapil ZTCHo) ₂ MS ⁵ and 22 ml previously ge

dried pyridine. ' The temperature is set at 60 ⁰ C, and allowed to pass the C0 _o gas stream for 6 hours. After evaporation to dryness and picking up in 20% ethanol precipitates the urea. By recrystallization in a mixture of methanol / water 50/50 is obtained in a yield of 69% 7 * 7 S 3-N-trifluoromethyl - ^ - ethylphenyl-N'N'-dimethylurea of F = 105 ⁰ O, its structure confirmed by NMR analysis.

Preparation of 3-trifluoromethyl-4-ethylaniline

It is carried out under a pressure of 10 bar hydrogen in a heated to 48 to 50 ⁰ G mixture of 43.8 g (0.2 mol) of 2 ~ trifluoromethyl ^ nitroethylbenzene, 2 _S 5 g of palladium on carbon to 5 % i before moistened with 1 ml of water was _t and 350 ml of methanol a «

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The reaction is effected for 30 minutes with stirring. Then it is cooled and filtered. After evaporation of the methanol to obtain a liquid product in an overall yield of 85%, which distills at 96 to 97 ⁰ C below 16 mm Hg.

The 2-trifluoromethyl-4-nitroethylbenzene is obtained by the following procedure.

The mixture is poured dropwise, the mixture of 70.7 g of 92 / oiger sulfuric acid and 47.5 g of 100% pure nitric acid per 80 g (0.46 mol) of 2-trifluoromethyl ~ ethylbenzene. The reaction temperature is kept at 38 to A ^L 0 ⁰ C. After pouring the sulfuric acid-nitric acid mixture, the mixture is kept under stirring for one hour. The mixture is then poured into 2 1 crushed ice. It is extracted with an organic solvent such as methylene chloride. The methylene chloride extracts are washed and then dried over anhydrous sodium sulfate. After evaporation of the solvent gives a colored liquid welche.bei f 5 ⁰ C crystallized j, the total yield is 87.6%.

The 2-trifluoromethyl-ethylbenzene is prepared as follows:

In a 1000 ml autoclave, 70 g (0.25 mol) of 2-trifluoromethyl (2 ^t 2 ^t 2 ¹ -trichloräthyl) benzene, 4 g of palladium on carbon to 5% »was previously moistened with 5 ώΐ water 'and 300 ml of methanol. A solution of 44 g (0.785 mol) of potassium hydroxide in a mixture of 350 ml of methanol and 35 ml of water is then added. Hydrogen is introduced under a pressure of 4 bar, the temperature

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of the environment at 28 to 30 ⁰ C during the entire duration of the hydrogen absorption is maintained, the methanolic solution is then filtered and then diluted with 6 1 of water. The organic phase is decanted and the aqueous phase is treated with methylene chloride. The organic phase and the methylene chloride extracts are combined, washed with water and dried over anhydrous sodium sulfate. After evaporation of the methylene chloride to obtain a liquid product which distills at 40 to 41 ⁰ C under 15 mm Hg 5 the total yield is 91 % *

The 2-trifluoromethyl (2 ^t 2'2 * trichloro-ethyl) benzene is obtained as it were!

first prepare the diazonium salt by diasotising 2-trifluoroethylaniline. A solution of 69 g (1 mol) of sodium nitrite in 10 ml of water and the solution of 197 »5 S (1 mol) of 2-trifluoromethylaniline hydrochloride in 5OO ml are poured simultaneously Water to 13Ö ml 1 L hydrochloric acid, After the reaction at a temperature between 0 and 5 ⁰ C to obtain a clear pale yellow solution of 2-trifluoromethylbenzenediazonium chloride.

This solution, which is further maintained at 0 to 5 ⁰ C, is poured onto a mixture of 116.4 g (1.2 mol) of dichlorovinylidene, 1 1 acetone and 10 g Kuprichloriddihydrat dissolved in 50 ml of water, the reaction is maintained at a temperature \ ^r on 27-28 ⁰ C ,, the entrained by the nitrogen evolution Dichlorvinyliden is in the ⁰ to -10 G cooled by Sirkulieren brine cooler condensed. After flowing in the solution of Diazoniuiasalzes holding the stirring and heating to 30 ⁰ C until the end of the

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Nitrogen evolution upright. The reaction mixture is then diluted in 5 liters of water. The organic phase is decanted, washed with water and dried over anhydrous sodium sulfate. After filtration, a lightly colored liquid is obtained, which distills at 108 to 110 ^° C. under 15 mm Hg, in a yield of 78 %.

Herbicidal activity in the pre-emergence and in the emergence of crops and pests

In pots of 9x9x9 cm, which are filled with light field soil, you sow a certain number of seeds according to the type of plant and the size of the grain.

The seeds are then covered with a layer of earth about 3 mm thick.

After moistening the soil, the pots are treated by macerating a quantity of spray mixture corresponding to a volume of 500 l / ha per pot containing the active substance at the dose considered.

The spray mixture is prepared by adding an emulsifiable concentrate having the following composition by weight.

active substance to be tested 20% emulsifier ethoxylated nonionic phenol with

17 ethylene oxide 10%

Solvent (xylene) 70 %

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diluted with water to the desired dilution containing the active material in the desired dose. The experiments were carried out for active material doses of 0.25 kg / ha to 8 kg / ha.

The treated pots are then placed in carrying _$ intended _f to obtain the irrigation water, by sub-irrigation and the pots during 35 days at environ-. temperature kept below 70 % relative humidity *

After 35 days, the "record of the degree of destruction with respect to a control sample which under the same conditions was treated with a sputtering dispersion but which did not contain any active material is effected.

For the postemergence test (postemergent) proceed as before, except that the treatment is effected at the stage of the second leaf in the development for the grassy plants and of two developed cotyledonous leaves with terminal broken bud for the dicotyledons.

The tested plant species, both the crops and the pests, were the following

Corn (Zea mays) MA

Grain (Triticum vulgare). BL

Cotton (Gossypium barbadense) CO

Soy (Glycine max) SO

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pests

Wild oats (Avsna fatua) 'FA

Fingergrass (Dlgitaria sanguinalis) DI millet (Eohinochloa crus-galli) .PA

Raigrasj V / iesenlolch (Lolium multiflorum) RA

Giant Tail (Setaria faberii) SE

Foxtail (Alopecurus myosuroides) "VU

Goosefoot (Chenopodium album) CH

Nightshade (Solanum nigrum) MR

Mustard (Sinapis alba) _t. Mo

Starwort (Stellaria media) ST

The compounds sampled as active material are the following?

3 ~ Trifluoromethyl-4-ethylphenyldimethylurea (Compound of the invention, Example 1)

3-trifluoroethyl-4-butylphenyl-dimethylurea (Compound A)

3-trifluoromethyl-4-butylphenylmonomethylurea (Compound B)

3-trifluoromethyl-phenyldimethylurea (compound known under the name of fluometuron).

The compounds were prepared according to the procedure of Example 1 '.

The results given below are expressed in kg / ha and denote:

f. Ct 4 '

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a) In the case of crops, the threshold of selectivity, which indicates the maximum dose tolerated by the crop without detriment. According to this evaluation, a plant with a selectivity threshold of 4 kg / ha has a selectivity twice as high as that of a plant with a threshold of 2 kg / haj

b) in the case of harmful plants, the activity threshold, ie the minimum dose necessary for complete destruction (> 90 %) , of the type in question. According to this evaluation, a compound with an activity threshold of 1 kg / ha A selective herbicide will therefore be the better, the higher its selectivity threshold (eg at least 4 kg / ha) and the lower its activity threshold (for example at most = 1 kg) are twice as effective as those with an activity threshold of 2 kg / ha / ha) are ä h f, the margin between activity and selectivity, is the bigger, with greater safety, the herbicide of the crop plant is contemplated ver;..? endbar "

The results are summarized in the following tables:

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preemergence Tree wool soy Uachauflauf Tree wool Crops compounds Grain corn > 8 2 Grain corn 4 I according to the invention 4> 8 4 4

A -> 8> 8> 8> 8> 8> 8> 8

B> 8> 8> 8> 8> 8> 8> 8

Fluometuron 0.5 0.5 4 0.5 1 2> 8

This table clearly shows that the compound I according to the invention has a selectivity far above that of fluometuron. On the other hand, it is below compounds A and B, but the selectivity of these compounds corresponds to a general inactivity, including to harmful plants, as shown in the following table:

Table Ha, «. Activity threshold in kg / ha on weevils in pre-emergence.

Certified pollination patches

Connections ^{ΈΑ DI PA M SE W CH MR M0 ST;}

I invented 1 <o 25 O, VJI 1 0 , 5 1 < 0.25 <0 125 4 <Ό 25 Droppings according to

A inactive at 8 kg / ha

B inactive at 8 kg / ha

Fluome-. , , ,

turon 0,50 0,50 0,50 1 0,50 1 <0 _? 25 0,50 0,50 <O, 25

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Table IIb ^ activity swell in kg / ha post-emergence of weeds

Tested connections

Harmful Plants DI PA RA SE YU CH MR MO ST

I according to the invention

2 1 0,50 2 4 0,50 1

Pluometür on

inactive at 8 kg / ha with the exception of mustard inactive at 8 kg / ha

> 8

4 0,50 8

From these two tables, it is significantly evident that Compound I has eerbicid activity substantially equivalent to that of fluoinaturon in the forerun and incomparably higher postemergence

Incidentally, the herbicidal activity of this compound X is clearly much higher than that of the compounds A and B, both in the pre-run and postemergence, the latter being inactive at 8 kg / ha, with the exception of compound B, which destroyed the mustard plant at 8 kg / ha postemergence.

Biese examples show very well the surprising herbicidal behavior of the compound according to the invention both towards its homologous 4-alkyl-3-trifluoromethylphenyldimethylharn.-substances and towards fluoineturon *

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The invention 3 ~ N-trifluoromethyl ^ - ~ ethylphenyl - N ^t li ^s is dimethylurea as the active material in compositions for the selective Ilnkrautbekäiiipf ung of useful plants and in particular cereals (corn, barley), maize, cotton and soya usable.

For the herbicidal treatments by means of the compound according to the invention, the dose of active material to be used may vary from 0.25 to 8 kg / ha, in particular depending on the type of crop and the nature of the soil. Preferably, this dose is between 0.5 and 5 kg / ha *

Claims (1)

Herbicidal composition for selective weed control in crops, especially cereals. Cotton and soybean, characterized in that it contains 0.5 to 95% of 3-N-i-trifluoromethyl-4-ethylphenyl-II- ^t ] Sf ". -Dimethylurea as an active material together with customary carriers and / or surface-active agents. ; · Process for the selective control of weeds of cereals, maize, cotton and soya ₅ , characterized in that a pre-emergence or postemergence composition is used in accordance with point 1 ''