DE2137992A1 - Herbicidal agents - Google Patents

Description

Patent Attorneys 21 Dlpl.-Ing. R. B E E T Z ββη. * I Dlpl-Ing. K. LAMPSSCHT

Dr.-lng. R. B £ ■: ίϊ T Z Jr. 8 monks 22, Steinsdorfetr. tO

503.1-17.355P July 29, 1971

PEPRO, Societe pour le Development et la Vente de Specialites Chimiques, LYON, (France)

Herbicidal agents

The invention relates to herbicidal compositions for selective weed control in crops such as grain, cotton and soybeans, which are characterized by a content of N- (4-Ieopropylphenyl) -N, N ¹ -dimethylurea as an active ingredient in a mixture with fillers or Carriers and usual additives.

The N- (Jf-isopropylphenyl) -Ν ·, N'-dimethylurea used according to the invention corresponds to the formula:

-NH-CO-N

970) -Nö ~ r (i5) -Vest + DOR

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Dimethylated phenylureas have been used for a long time Time spent fighting harmful plants. In practice it is especially:

- the N- (3,4-dichlorophenyl) -N «, N'-dimethylurea (Diuron);

- the N- (4-chlorophenyl) -N ', N'-dimethylurea (Monuron); and

- the N- (3, ll-dichlorophenylJ-N'-methyl-N'-butylurea (Neburon),

those in the usual way for weed control in cultivated plants be used. The former have relatively few selective properties and are in every way for the control of wild plants in grain fields unusable. The Neburon, on the other hand, has this selectivity and is widely used in weed control Grain fields, especially wheat, applied.

Investigations by the applicant have now shown that the N- (4-isopropylphenyl) -N ', N ¹ -dimethylurea (which is hereinafter referred to as IPU for the sake of simplicity) has an effectiveness which, viewed overall, is at the same time remarkable for its selectivity

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Cultivated plants, such as gramineae and dicotyledons, and in particular special to rice, wheat, corn, peanut, cotton and soy, which is equivalent to or often superior to that of the most active of the aforementioned ureas.

That the IPU, in principle, has a herbicidal effect, can already be seen in US Pat. No. 2,655,7 , where it is mentioned alongside a large number of other phenylureas. However, the herbicidal effect of the phenylureas described there has only been demonstrated for some representatives of Agropyrum repens and Sorghum halepense , ie. · two Gestrüppbsv bush plants. Their herbicidal action against Un herbs in wheat fields and but sometimes pronounced selectivity in this respect were vacant known · It should be noted, moreover, that indicated only the formula of the IPU in said patent - is, while data on physico-chemical characteristics or biological effects are absent.

Anmeiderin has now succeeded in first synthesizing this substance and demonstrating that the 1-company - contrary to the information in the patent mentioned, according to which the phenylureas indicated there seem to have the same effects and for the selective weed-

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control in cereal fields either because of a lack of herbicidal effect or an extremely effective against the crops themselves appear unusable surprisingly clearly differs from its homologues, as the following examples show.

The compound used according to the invention can by Reaction of p-isopropylphenyl isocyanate with dimethylamine be obtained in benzene solution. The isocyanate itself is accessible in two ways: either by Acylation of cumene and oxidation of the p-isopropylacetophenone obtained and subsequent cyanate formation in the p-isopropylbenzoyl radical obtained in this way (in the form of the chloride) or by nitration of cumene and subsequent catalytic reduction and action of phosgene on the so obtained p-Ieopropylaniline.

Example 1 ι Synthesis of I, P.U,

0.1 mol of dimethylamine dissolved in 25 ml of anhydrous is added Benzene into a prepared 0.04 mole of p-isopropylphenyl isoeyanate dissolved in a flask containing 100 ml of anhydrous benzene

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Boiling heated. When simply cooling down, the urea falls in the form of white crystals, which are washed and dried in vacuo. The implementation takes place with a Yield of $ 92. The melting point of the crystals obtained is at 157 C, and were used in the elemental analysis achieved the following results:

# C # H # N

calculated 69.90 8.73 13.59

found . 69.6A- 9.18 13.62

The herbicidal properties and selectivity of the action of the IPU have been demonstrated by various tests in which its homologues were used for comparison.

Pots measuring 10 × 10 × 15 cm were filled with French soil which had not yet been subjected to any herbicide treatment. Grains of different plant species were placed on this soil, the sensitivity of which to the herbicidal products to be tested was to be demonstrated. The seeds were covered with a layer of soil, the thickness of which was the same as the diameter of the seeds

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was dependent ¹ . The herbicidal composition to be tested was then sprayed onto these pots. This was formed from a wettable powder that was produced by mixing the following ingredients together for one minute in a knife grinder:

Active substance to be tested. 20 #

Dissolving agent (calcium lignite sulphate): 5 ^

Wetting agent (sodium alkyl aryl sulfonate): $ 1

Filler (Aluminum Silicate) :? 4 #

This wettable powder was then mixed with the amount of water calculated for spraying at the desired dose per hectare.

In the individual tests , an untreated comparative plant was checked in parallel in order to be able to identify any growth inhibition as well as a lack of germ formation or growth disorders of the plants as a result of special circumstances or conditions.

The pots thus treated were kept in the greenhouse for some time under constant conditions of humidity, temperature and lighting. After 5 weeks were

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the results were recorded and, in particular, the percentage of destruction of the individual plant species compared to the reference plant was determined.

Of course, in the experiments after germination, the herbicide was sprayed on only after germ formation, at a stage in which the plant species developed two real leaves.

The following cultivated and wild plants were used for the investigations:

Plant species scientific name symbol

Wild oats Ävena fatua AV

Wheat Triticüm vulgar BL

Corn Zea mays MA

Thistle Echinochloa crus-galli PA

Barrel hole.

« LoIium italicum RA

Rice Oryza sativa RI

Black foxtail
» Alopecurus myosuroides VU

amaranth

Amaranthus retroflexus AM

Goosefoot ■ ■■ -.

' Chenopodium album CH

Mustard Sinapis alba MO

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Cotton soybean

- if -

Polygonum fagopyrum Gossypium hirsitum Glycine max

SA CO so

In each experiment the IPU was mit.einigen the ureas described in US Patent No. 2 655 ^ 7 and compared with the best known of the current commercial herbicidal ureas,

Example 2; Testing before germination

The results obtained are summarized in the table below , in which the percentage destruction of the plant species used for the test is given for the individual products examined. The following symbols were used for the active ingredients:

Really
atoff dose
Ha BL MA RI SO CO AV RA PA VU AT THE CH MO SA h kg 0 0 0 0 4o 100 100 100 100 100 100 100 100 I.P.-U. 2 kg
1 kg 0
0 0
0 0
0 0
0 0
0 100
100 100
98 100
98 100
98 100
98 100
100 100
98 100
100 0.5 kg 0 0 O 0 0 98 90 95 50 98 100 70 75

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Really
material dose
Ha BL MA RI SO CO AY RA PA VU AT THE CH MO SA 4 kg 98 100 - 100 98 100 100 100 - - 100 100 100 A. 2 kg 98 98 - 100 20th 98 100 100 - - 100 100 100 1 kg 80 80 - 98 10 60 98 98 - 100 98 85 4 kg 95 100 - 100 80 100 100 100 - - 100 100 100 B. 2 kg 95 100 - 100 80 100 100 100 - - 100 100 100 1 kg 50 50 - 95 10 98 98 100 - - 100 100 95 4 kg 0 0 - 10 •
0 0 0 95 25th 100 100 100 98 C. 2 kg 0 0 - 0 0 0 0 75 10 98 98 98 95 4 kg 85 1 00 - 100 0 100 100 100 100 100 100 100 100 D. 2 kg 50 100 - 100 0 98 100 100 75 100 100 100 95 4 kg 0 10 - 90 60 30th 55 10 50 95 90 90 100 E. 2 kg 0 0 - 20th 0 10 10 0 20th 90 80 70 85 1 kg 0 0 - 20th 0 0 5 0 10 0 80 25th 6o 8 kg 0 0 2 0 90 15th 5 88 10 97 100 98 95 F ·· 2 kg 0 0 0 0 80 0 0 0 0 85 100 25th 5

Example 3? Check after germination *

The results obtained are in the following Table summarized in the values for the percentage

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Destruction of the plant species examined in connection with the individual tested products is stated are. The symbols already given have been used for the active ingredients.

Really
material dose
ha / kg BL MA RI 0 so 0 CO AV RA PA VU AT THE CH MO SA 2 0 0 0 0 10 100 100 100 100 100 100 98 100 I.P.Ü. 1 0 0 0 0 0 100 98 100 100 98 100 98 100 0.5 0 0 100 100 0 98 95 100 90 98 85 95 98 4th 100 100 100 99 20th 100 100 100 100 100 100 98 100 A. 2 100 99 100 99 0 100 100 100 100 100 100 96 100 1 100 80 100 100 0 100 100 100 100 100 100 90 100 4- 100 100 100 100 60 100 1OO 100 100 100 100 99 100 B. 2 99 100 100 95 10 100 100 100 100 100 100 85 100 1 98 70 30 · 40 0 100 100 100 100 100 100 70 100 4th 0 0 0 10 98 2 50 60 85 99 100 9.7 100 E. 2 0 0 0 0 95 0 40 50 25th 95 99 85 70 F. 2 0 0 55 0 15th 65 0 98 97 95 96

Example 4; Testing in the open air

During the winter and spring of 1970/197 | became the

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I.P.U. subjected to numerous investigations in the open field. These were used to demonstrate the possible applications under practical conditions with the participation of different people Factors ^ such as soil type and atmospheric conditions that are suitable for use in greenhouse studies results obtained thoroughly. to change and which cannot be taken into account when testing under greenhouse conditions "

ρ These investigations were carried out on plots of 20 m

before and after germination starting from © inem wettable Powder of the following composition:

IPU $ 50

Wetting agent (alkylnaphthalenesulfone) ^: $ 1

Deflocculant (lignosulfite) 5 i »

Filler (silicon dioxide + kaolin) kk #

carried out, which was diluted with a sufficient amount of water prior to treatment to the desired for testing workest off inenge per hectare to achieve. "

k a: imen examination before the Auske;

The treatments were carried out between the ages of 20 and 30.

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October at - depending on the parcel - between the 16th and 23rd October sown wheat. The doses used ranged from 0.5 to 3 kg per hectare.

From a dose of 0.5 kg / ha onwards, very good results were achieved with foxtail (Alopecurus) (percentage Annihilation over, $ 85). Starting from 2 kg / ha, a Almost complete destruction of all wild gramineae (wild oats, foxtail, ryegrass, lolch and windstalk) obtain. In all investigations and all doses, the selectivity or low effect was compared to wheat perfectly satisfactory.

U b; Check after germination:

The treatments were carried out between February 23 and April 1 on crops sown between October 18 and 28, where the wheat had saplings for 2 to h . According to these investigations, doses between 1 and 3 kg / ha can completely destroy any wild gramineae (foxtail, lolch, windstalk and wild oats). the

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Selectivity towards wheat was 'always' very good, apart from that of a slight effect sometimes observed in calcareous soil at a dose of 3 kg / ha compared to the Wheat.

In these post-germination tests, for comparison with the I.P.U. used two related products, commonly used for this type of application be, namely:

the N- (3-chloro-4-methylphenyl) -N'-N'-dimethylurea of the formula

NH-CO-N

Cl

and the N- (3-chloro-4-methoxyphenyl) -N'-N ¹ -dimethylurea of the formula

In all of these tests, the doses required by the IPU to achieve satisfactory distribution

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rate the weeds by $ 30 to $ 50 lower than the doses required for the other two compounds.

The significance of the herbicidal agents according to the invention clearly show their effectiveness in relation to wild plants or weeds always at least equal to that of the most active ureas is and their selectivity or weakness in relation to Cultivated plants is at least equal to that of Neburen. If one * more in detail the X.P.U. compare with Neburon, in particular, a better effectiveness of the I, P.U. against the most common weeds in grain fields firm, as opposed to ryegrass, wild oats, thistles (Panisse) and Foxtail (Alopecurus).

It is also noted that the I.P.U. through application possibility both before and after the plants have sprouted. Taken together, it makes a difference it differs from the ureas known so far due to its remarkable selectivity and weakness of action against some crops such as wheat, rice, maize, Cotton and soy, along with excellent effectiveness on most weeds in these crops. The previously known ones are under the same conditions

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Urea is either very herbicidal but insufficiently selective compared to the same crops or insufficient effective against the harmful plants.

In a practical application, the I.P.U. can be applied in doses, depending on the type of treatment to be carried out Treatment and the Types and Development ^ Stages of existing weeds - range from 0.2 to 5 kg / ha.

The I.P.U. is commonly used in the herbicide industry commonly used procedures formulated; The purpose of such compositions is that To make means available to users, their use as simple as possible and their effectiveness in relation to the too destructive plants is maximal.

For this purpose one generally gives to the pure Active ingredients a number of fillers or carriers and various additives are added - depending on the type of the intended Recipe and the result to be achieved.

These formulations or recipes can be liquid or «liquids (emulsions, real solutions, Pastes, suspensions, etc.) that are ready to use or

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- 10 - -

still need to be diluted with water or in solid forms (as wettable powders, granules, etc.) that are known as such are applicable or are diluted in a liquid medium before use.

These compositions then generally contain inert fillers and / or organic, mineral or mixed solvents and / or emulsifiers, additives to prevent caking, deflocculants, etc.

Details of such compositions can also be found in the book by FRYER and EVANS: "Weed Control Handbook ¹¹ , 5" edition, pages 101 ff.

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Claims (2)

Claims 1. Herbicidal agents for selective weed control in cereals, cotton and soybeans, characterized by a content of N- (4-isopropylphenyl) -N \, N ¹ -dimethylurea as an active ingredient, mixed with fillers or carriers and customary additives. 2. A method for selective weed control in cereals, cotton and soybeans, characterized in that these crops are before or after treated germinating with a herbicidal amount of an agent according to claim 1. -