IL30292A - N-phenyl urea compounds,their preparation,and herbicidal compositions containing them - Google Patents

Description

†n33n , *m Vaa-N maiain ut N-phenyl urea compounds, their preparation, and herbicidal compositions containing them FARBENFABRIKEN BAYER AKTIENGESELLSCHAPT C:28569 - - ■ \ ■ ψ better selective herbicidal effect than have the compounds Suitable amine starting materials are, for example, methyl amine, dimethyl amine, and butyl amine* As diluents, there ma be used, for example, water or inert organic solvents · Preferred organic solvents are, for example, 30292/3 - 3a - ether, such as dioxan; hydrocarbons such as benzene; and chlorinated hydrocarbons such as chlorobenzene.

The reaction temperatures can be chosen within a fairly wide range; in general, the process is carried out at 10-80°C, preferably at 20-50°C.

Preferably, about equimolar amounts of isocyanate and amine are used, but an excess of amine is not detrimental.

The reaction mixture can be worked up by conventional operations.

The active compounds of the invention can be used for the destruction of weeds in the widest sense, i.e. plants which grow amon cultures or in other places where the are not desired. Whether the active compound of the inventio act as total ' or ground- synthetic minerals, such as highly-dispersed silicic acid or silicates.

Preferred examples of emulsifying agents include non^-ionic and anionic emulsifers, such as polyoxyethylene-fatty acid esters, polyoxyethylene-fatty alcohol ethers, for example alkylarylpoly- glycol ethers, alkyl sulphonates and aryl sulphona es ; and preferred examples of dispersing agents include lignin,. sulphite waste liquors and' methyl cellulose.

The active compounds according to the invention- may be present in the formulations in admixture with other active com- . • pounds . .

The formulations, contain,, in general, from .1 to 95, preferably from 0.5 to 90, per cent by weight of active compound. · · ■ The active compounds may be used as such or in the form of their formulations or of the application forms prepared therefrom, such as readyr-to-use solutions, emulsions, suspensions, powders, pastes and granulates. Application may be made in the usual manner b spraying, atomising, watering, dusting or scat-' tering.

■The active compounds can be applied according to the pre- emergence method but with particularly good results according , to the post-emergence method.

The concentrations of active compound in the ready-to use . preparations may vary within fairly wide ranges. - They depend, among other things, on whether the active, compounds are used as total herbicides or as selective herbicides. In general the concentrations of active compound are , from 0.005 - to 10#, preferably from 0.01 to 1#, by weight. .

In particular, the amount of active compound per unit area is different according to the purpose intended and the mode of application. In general, between 0.5 and 10 kg of active The invention also provides a her ici a compos on con-taining as active ingredient a compound of the invention in . admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

The invention also provides a method of combating weeds which comprises applying to the weeds or a" weed habitat a compound of the invention alone- or in the form of a composition containing as active ingredient a compound of the invention in . admixture with a solid or liquid diluent or carrier.

The invention also' provides crops protected from damage by weeds by being grown in areas in which immediately prior to and/or during the time of the growing a compound of the invention was applied alone or in admixture with a solid or liquid diluent or carrier.

The activity of the compounds of the invention1 is illustrated by the following Examples', Λ-and J3. .

Example A Pre-emergence test , ' Solvent: 5 parts by weight acetone Emulsifier: 1 part by weight alkylaryl polyglycol ether To produce a suitable preparation of active compound, 1 part by weight of active compound is mixed with the stated amount of solvent, the stated amount of emulsifier is added and the concentrate is then diluted with water, to the desired concentration. · Seeds of the test plants are sown in normal soil,and, after 24 hours, watered with the preparation of the active compound. It is expedient to keep constant the amount of water per unit area. The concentration of the active compound in the preparation is of no importance, only the amount of active compound applied per unit area being decisive. After three weeks, the degree of damage to the test plants ie determined and characterised b the values 0- which have he f 0 no effect . 1. slight damage or delay ' in growth 2 marked damage or inhibition of growth 3 heavy damage and only deficient development or only 50$ emerged 4 plants partially destroyed after . germination or only 25$ emerged plants completely dead or not emerged.

The active compounds , the amounts applied and the results obtained can be seen from Table A.

Example B Post-emergence test Solvent: 5 parts by weight acetone Emulsifier l -part by weight alkylaryl polyglycol ether.

To produce a suitable preparation of active compound, 1 part by weight of active compound is mixed with the stated . amount of solvent, the stated amount of emulsifier is added and the concentrate is then diluted with water to the desired concentration.

Test plants which have a height of about 5-15 cm. are sprayed with the preparation of the active compound until -just dew moist. After three weeks, the degree of damage to the plants is determined and characterised by the values 0-5» which have the following meaning: 0 no effect 1 a few slightly burnt spots 2 marked damage to leaves 3 some leaves and parts of stalks partiall dead '.. · plant partially destroyed plant completely dead .

The active compounds, their concentrations and the results obtained can be seen from Table B.

Solven : . 5 parts by weight acetone ·'':·'·: ·"·> · ; Emulsifier: .1 part by weight alkylaryl polyglycol . ethe To produce a suitable preparation of the particular active compounds 1 part by weight, of such active compound is mixed with the stated amount of solvent, the stated amount, of emulsifier is then added and the resulting concentrate ie diluted with water to the desired final concentration.

Seeds of the test plants are sown in normal soil and, . after 24 hours, . watered with the given active . oompound pre-;, paration. It is expedient to_¾eep constant the amount of water per unit area. The concentration of the aotive compound . in the. preparation is of no importance, only the amount of aotive compound applied per unit area being decisive.- After three weeks j the degree of;. damage to the test plants is determined and characterized by the values 0-5 which have the ■ following meaning: . , .'.·'"';■·· ·.'■.',': ■ no effect. .. .·.'■'"'■ ; - ..' ' ., 1 slight/damage or delay in growth. ■'; · *"■ :\'-.- 2 marked damage, or inhibition o growth ; ··· ■" ...3 heavy damage and only deficient development or only 50$ emerged 4 plants partially destroyed after . ·.··■:";. ' [ germination or only 25$ emerged plants completely dead or hot emerged The particula aotive compounds tested, the amounts applied ' and the results obtained can be seen from the .follov/ing Table C - 18 - 30292/1 Example 2 12 g of 4-trifluoromethylthio-phenyl isocyanate are added dropwise at room temperature to 50 ml of a 20 aqueous solution of dimethyl amine. The temperature is allowed to rise to about 35°C, the reaction mixture is stirred until the reaction subsides, and the crystalline product is filtered off with suction. 10 g of Ii-(4-trifluoromethylthiophenyl)-N' tW -dimethyl urea, of m.p. 148-149°C are obtained.

The 4-trifluoromethylthio-phenyl isocyanate starting material is obtained in a particularly favorable manner from 4-trlchloromethylthio-phenyl isocyanate (n^ : lf6l25) by reaction with anhydrous hydrofluoric acid under pressure at temperatures of up to 110°C as water clear liquid of boiling point 91-92°C/l7mm lg and refractive index ^0 : 1.5104.

In an analogous manner there can be prepared; Example 3 Prom equimolar amounts of 4-t ifluoromethylthio- methyl phenyl isocyanate and either/amine or di-tert.-butyl amine, the corresponding urea compounds, amely : (a') K'-(4-trifluoromethylthio-phenyl)-N,-methyl urea; and (b» ) N-(4-trlfluoromethylthio-phenyl)-N' ,Ν' -di-tert.-butyl urea, can be prepared by the process described in Example 2.

V - 19 - 30292/2

Claims (13)

1. tt-phenyl urea compounds of the general formula in which one of X.^ and X≥ is trlfluoromethylthio and the other one chlorine or hydrogen, R1 is hydrogen or alkyl with 1 to 4 carbon atoms, and 1¾2 is alkyl with 1 to 4 carbon atoms.

2. The compound of the formula

3. · N-aryl urea compounds according to Claim 1, as described herein.

4. · A process for the preparation of compounds according to Claims 1, 2 or 3 in which the isocyanate of the formula is reacted with an amine of the formula in the presence of a diluent, where X^', 2> R1 and Rg have the same meanings as in Claim 1.

5. A process according to Claim 4, in which the reaction is carried out at 10-80°C, preferably at 20-50°C. - 20 - 50292/2

6. A process according to Claim 4, substantially as described herein.

7. , Herbicidal compositions containing as active ingredient an N-phenyl urea compound according to Claim 1, 2 or 3 in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

8. Compositions according to Claim 7, containing from 0.005 to 95$ by weight of the active compound.

9. · A method of combating weeds which comprises applying to the weeds or a weed, habitat an N-phenyl urea compound according to Claims 1, 2 or 3 by itself or in the form of a composition according to Claims 7 or 8.

10. A method according to Claim 9 in which a composition containing from 0.005 to 10 by weight of the active compound is used.

11. A method according to Claim 10, in which the N-phenyl urea compound is applied in an amount of 0.5-10 kg per hectare of cultivated land.

12. A method according to Claims 9» 10 or 11, in which the N-phenyl urea compound is applied to oat, wheat, maize or cotton culture lands.

13. Crops protected from damage by weeds by being grown in areas in which immediately prior to and/or during the time of the growing a urea according to Claim 1, 2 or 3 has been applied by itself or in admixture with a solid or liquid diluent or carrier.