FI92789B - Stabilized liquid herbicide composition comprising methyl- (3-(3-tolyl-carbamoyloxy)phenyl)carbamate (phenmedipham) or ethyl-(3-phenylcarbamoyloxyphenyl) carbamate (desmedipham), a process for its preparation and its use - Google Patents

Description

92789

Stabilized liquid herbicidal composition comprising methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate (phenmedipham) or ethyl (3-phenylcarbamoyloxyphenyl) carbamate (desmedipham), process for its preparation and use of this composition

Stabilizing certain herbicidal compositions, including methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate (phenmedipham) or ethyl- (3-phenylcarbamoyloxyphenyl) carbamate (desmedipham), is preferred for the preparation of the same step. Composition as

The present invention relates to a stabilized liquid herbicidal composition comprising methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate (phenmedipham) or ethyl (3-phenylcarbamoyloxyphenyl) carbamate desmedipham, a process for its preparation and the preparation of this composition. use.

The present invention therefore relates to herbicidal compositions containing herbicidally active phenyl carbamates and other herbicides.

English Patent Publication No. 1,127,050 (claiming priority from German Patent Application No. Sch. 36,854 IVb / 12o, dated April 9, 1965) (to Scering) discloses substituted phenyl carbamates of general formula A of 25 O

! /B

O Cth

Wherein R 1 is an alkyl group, a cycloalkyl group or an aryl group, which aryl group may be substituted by a halogen atom and / or an alkyl group and / or a trifluoromethyl group, R 2 is a hydrogen atom or an alkyl group, or R 1 and R 2 together are nitrogen may form a heterocyclic ring which may contain additional nitrogen and / or oxygen atoms and R 3 is an alkyl, alkenyl or alkynyl group which may be substituted by a terminal halogen atom, which compounds are useful in selective weed control in cultivation areas. The herbicidal effect can be observed both before and after the occurrence of the situations, in which case preparations containing said compound A can be added by any method only. The herbicidal effect is also observed when compounds A are added to the leaves of already established weeds and the compounds are particularly useful in controlling weeds in beet fields, 10 especially as herbicides which are added after emergence in sugar beet fields.

A particularly preferred compound of general formula A is methyl (3- (3-tolylcarbomoyloxy) phenyl) carbamate, which is subsequently given the generic name phenme-15 dipham. Another particularly preferred compound is ethyl (3-phenylcarbamoyloxyphenyl) carbamate, later given the generic name desmedipham Methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate is commercially available under the tradename Betanal and is used in particular as a herbicide, which is applied after the situation has arisen in the weed cultivation of beet crops, in particular sugar beet, at an rate of application of 1 kg va (active substance) / 200-300 liters / ha. Pesticide Manual, A World Compendium, The British Crop Protection Council, 6th Edition, 1979 ) that the compound acts through the leaves with little effect through the cells and the roots.At three months, 71-86% degradation of the active ingredient was observed in the soil after one day of treatment.

25

Danish Patent No. 159653 relates to a process for the preparation of substituted phenyl carbamates of the general formula I in an aqueous medium.

After completion of the reaction, the reaction product, which is very difficult to dissolve in water, can either be isolated and purified in a conventional manner, e.g., by filtration and washing with water and then drying, or it can be removed from the aqueous phase by extraction. 3,92789 as an organic solvent (or solvent mixture) which is substantially immiscible with water or only slightly miscible with water.

Normally, the drying process results in some decomposition of the final product and it is therefore preferable to omit the drying step.

Substituted phenyl carbamates (phenmedipham and desmedipham) can be used either alone or in combination with one or more other herbicides and / or other substances, e.g. fertilizers, for weed control.

These can be used in the form of concentrated compositions intended to be dissolved in water when used.

It has now been found that certain phenyl carbamates, namely phenmedipham and desmedipham, possibly together with other herbicides, can be particularly advantageously formulated in oily preparations as described in more detail below.

In the formation of commercial liquid herbicide concentrates from substituted phenyl carbamates, a solvent capable of dissolving the phenyl carbamate and which facilitates subsequent dissolution of the composition where the composition is to be used is usually included. As already indicated, isophorone is normally used as a solvent in the formation of such compositions because isophorone is a very good solvent because phenylcarbamates and phenylcarbamates are chemically relatively stable in isophorone solution, especially when phenylcarbamates have been washed or treated with acid at pH 2-4 before dissolving them. Another advantage of using an isophorone is that it is only sparingly soluble in water (if a water-soluble solvent were used in the concentrate, it would tend to dissolve in the aqueous phase when the ready-to-use liquid preparation is prepared on site by adding water, which could reduce precipitation of phenyl carbamate and thus biological activity. clogging).

4,92789

Ionic emulsifiers such as calcium dodecylbenzenesulfonate are usually included in commercial isophorone solutions of phenmedipham. The use of salts of phosphoric acid esters as emulsifiers has also been proposed.

As an interesting alternative to phenylcarbamate isophorone solutions, it has been found that in one aspect of the invention it has been found that substituted phenylcarbamates have advantageously high biological activity when phenylcarbamates are "activated" in suspension of compounds in oil and finely ground one or more surfactants, the liquid phase being capable of forming an oil-in-water emulsion or microemulsion when mixed with water in situ for use in preparing a ready-to-use final preparation.

Composition according to the invention, characterized in that the composition is an emulsion comprising phenmedipham and / or desmedipham dispersed in the continuous phase of the oil component, and comprising a) 5-40% by weight of phenmedipham and / or desmedipham having a particle size of less than 10 microns, b) 15-65% by weight of an oil component consisting of one or more mineral and / or vegetable oils, c) 5-40% by weight of a surfactant component comprising one or more surfactants and d ) up to 40% water, the composition being sequenced to form a stable ready-to-use oil-in-water emulsion or microemulsion when dissolved in water in a ratio of one part of the composition to 1 to 10 parts by volume of water.

Il 5 92789

The process according to the invention is characterized in that phenmedipham and / or desmedipham in the form of an aqueous slurry are ground to a particle size of less than 10 microns, and the slurry is then mixed with a mixture of other components with an oil component and surfactant 5 and up to 40% water or components are added separately to form an emulsion.

The composition of the invention is used to control weeds in beets.

Examples of mineral oils include spindle oil, aromatic compounds such as propylbenzene and dodecylbenzene, paraffin oils, etc .; examples of vegetable oils include soybean oil, rapeseed oil, olive oil, etc.

The oil content of the phenyl carbamate suspensions may be 15-65% by weight based on the composition. Surfactants or a surfactant which may be selected from the group consisting of nonionic, anionic, ampholytic and cationic surfactants and mixtures thereof which are normally present in a high proportion, such as 5 to 40% by weight, in particular 10-40% by weight, based on the composition. The amount of phenyl carbamate 1 may be 5-40% by weight based on the composition. In addition to Compound I, the oil component, and the surfactant, the liquid phases of these concentrated compositions may contain one or more ingredients selected from the group consisting of glycols, glycol ethers, and combinations thereof, at concentrations typically in the range of 0.1-15%. , especially 2-10%, based on the weight of the composition. In addition, up to 40% by weight of water can be included. In practice, the chemical stability of the phenyl carbamate in the individual compositions must be taken into account, which will determine the maximum amount of water to be added. If water is included in the oil / surfactant mixture and then the pH should be adjusted to the acidic range, preferably to the optimum range of 2-4 to ensure the optimum chemical stability of the phenyl carbamate.

6,92789 The oil component and surfactant can be selected so that they are soluble with each other and form a stable solution capable of effectively suspending finely divided phenyl carbamates and so that the surfactant effectively emulsifies the oil when water is added to form a ready-to-use final preparation.

5 The surfactant may also promote effective wetting of the sprayed surface with the preparation. The oil component and surfactant and their proportions may also be selected so as to be able to form a microemulsion when mixed with an equal amount of water or even ten times the amount of water (the microemulsion is known to contain oil, an emulsifier). substance) and water in a finely divided state, and is clear and transparent). The microemulsion is stable and cannot normally be separated by centrifugation). The advantage that the oil component and the surfactant are selected to form a microemulsion is m.m. that the phenyl carbamate can be added to the oil component / surfactant in the wet state, it is therefore not necessary that the phenyl carbamate obtained in the process of the invention be completely dried before it is combined with the oil component / surfactant. Another advantage of selecting the oil component and surfactant so that they are capable of forming a microemulsion is that the microemulsion, due to its inherent stability, tends to keep the phenylcarbamate suspension stable during transport and handling of the composition, thus avoiding sedimentation problems. Another advantage associated with the compositions when they are in the form of a microemulsion is that the dilution in water to prepare ready-to-use solutions takes place without such problems as e.g. the formation of aggregates, etc.

Useful surfactants include nonionic compounds such as polyethoxylated alkyl phenols, polyethoxylated higher alkanols, polyethoxylated fatty acids, polyethoxylated amines and amides, monoglycerides, and derivatives thereof. Alkylarylsulfonic acids and phosphoric acid esters and their salts will also be useful surfactants. Phosphoric acid esters can be mono- and diesters of polyethoxylated higher alkanols, polyethoxylated alkylphenols, polyethoxylated distyryl and tristyrylphenols, and non-ethoxylated alcohols. In addition, II: 7 92789 ampholytes are useful surfactants. Other surfactants are described, e.g., in McCutcheon: Detergent & Emulsifiers, International Edition, 1983, Glen Rock, New Jersey 07452, USA. Of course, similar surfactants from other companies are also useful.

5

It is believed that it is preferred to use mixtures of ethoxylated surfactants and anionic surfactants, preferably a nonionic / anionic mixture, when the nonionic components consist of a mixture of surfactants having HLB values of about 9 (emulsifier). and about 12-13 (humectant and dispersant).

10

In preparing a substituted phenyl carbamate composition, the surfactants can be mixed with the oil component to give a clear solution. Coarsely ground dry substituted phenyl carbamate is slurried in this solution. The mixture may be further ground, e.g. in a ball mill, wherein at least 99% of the substituted phenyl carbamate is one having a particle size of less than 10 microns and 50% is one having a particle size of less than 3-5 microns.

When a substituted phenyl carbamate prepared in aqueous solution is isolated as a wet paste, the dry matter content is normally about 65-75% after centrifugation. It is possible to use this substance slurried in an oil / detergent mixture, whereby water penetrates the mixture so that the liquid phase comprises a stable microemulsion which can be further ground in a ball mill. In another embodiment, the herbicidally active compound or compounds in the form of an aqueous slurry may be ground to finely dispense the compound or compounds with a particle size suitable for inclusion in the final composition, optionally with the addition of a surfactant, followed by one or more oily components. surfactants or components, when mixed to form said solution, are added separately. In either case, the resulting liquid phase thus forms an emulsion or a microemulsion. This is considered to be the preferred aqueous slurry obtained in the aqueous phase synthesis described above.

8 92789

Small amounts of glycol ether, e.g. butyl glycol, are expected to have a beneficial effect on viscosity while allowing for a wider blend ratio between the microemulsion and water when the composition is diluted during use. The small amounts of water in the composition often have a viscosity-controlling effect, and glycols such as propylene glycol stabilize mixtures containing limited amounts of water. The dispersion must have the appropriate viscosity. On the one hand, it must be so fluid that it scatters rapidly in the water in which it is diluted, but on the other hand, the viscosity must be high enough to prevent sedimentation of the active ingredients.

10

Many patents and other literature describe the preparation of herbicidal preparations using phenyl carbamates as the active ingredient. However, these can be divided into two groups, namely (1) in which the active ingredient is dissolved in an organic solvent and then emulsified in water with a wide variety of emulsifiers to form ready-to-use solutions, and (2) in which the active ingredient is dispersed in water with various surfactants.

Preparations dispersed in an oily liquid have the same potency as solvent-based preparations and a greater effect than preparations dispersed in water.

An application rate of about 0.3 kg of active agent per hectare has been found to be suitable for selective weed control when two or more additions are made during a single growing season or when the active agent is sprayed through bandpass-25 imaging devices. In other situations, an application rate of about 1 kg of active substance per hectare is normally suitable.

The process described above for the preparation of oil-based compositions is not only suitable for compositions containing substituted phenyl carbamate, but can also be used for the preparation of other compositions containing other types of herbicides and pesticides. Examples of herbicides include II! 9,92789 ta 5-amino-4-chloro-2-phenyl-3 (2H) pyridazinone (chloridiazone), 2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate (ethofumesate), and 4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one (metamitron).

Compositions containing both phenylcarbamates and components containing chloridazon and metamitron are thus preferred in that the active ingredient content can be considered lower because the preferred phenylcarbamates are more effective per unit weight than the other herbicidally active components mentioned above.

10

The above-mentioned metamitron compound is used as a herbicide for beets, normally at doses of about 3-4 kg / ha. Metamitron is recommended in some cases instead of phenylcarbamates 1, although these are only used at doses of about 1 kg / ha, due to the fact that metamitron has a better biological effect on the coil (Galium aparine). against cabbage (Lapsana communis) and blackberry (Solanum nigrum). A much better biological effect is obtained with yellow daisy (Chrysanthemum segetum). wild chamomile (Matricaria chamomilla). in the sparrow of small nettle (Urtica urens) and annual blue grass (Poa annua). Other weed species in 15-20 beets that are common in Denmark can be controlled 20 equally well with phenmedipham and metamitron.

It should be added that doses of 3-4 kg / ha of metamitron are less aggressive (phytotoxic) to beets than doses of 1 kg / ha of phenmedipham.

25

Farmers often prefer to use a mixture of metamicron and phenmedipham in which the dose of both preparations is half the usual dose. In this way, the biological effect is as good as that which would be obtained if metamicron were used alone. The herbicidal mixture is also no more phytotoxic than it would be if metamicron were used alone.

10 92789

Metamitron is normally commercially available as a 70% wettable powder and phenmedipham as a 16% emulsion composition containing isophorone. Until now, farmers have themselves blended the compositions during spraying. However, it is not practical for the user to mix two compositions that are so S different types. Mixing is best performed by diluting each composition separately in a portion of the dilution water and then performing mixing. To biologically activate metamitron, mineral oil is often added after the oil has been emulsified in the spray solution. There is a risk of spraying problems (clogging of the nozzles) if mixing is not carried out carefully. When several products are used, the risk of the products being mixed in the wrong proportions increases. Finally, the present product, characterized in that both phemmedipham and metamitron are dispersed in the oil / surfactant mixture, achieves that, contrary to current practice, the user completely avoids the use of dust and isophorone from the wettable powder as a solvent.

15

An interesting object of the invention is thus a composition containing phenmedipham or desmedipham in an amount of 5-15% by weight, preferably 5-8% by weight, e.g. about 6% by weight, metamitron in an amount of 5-40% by weight, preferably 10-30% by weight %, e.g. about 17% by weight, formed together with an oily component, such as 20 to 65% by weight, e.g. about 30% by weight, of surfactant or surfactants in a mineral oil, e.g. a mixture of substances containing ethoxylated nonylphenol (3-9 ethylene oxide units / molecule) and optionally a salt of a phosphoric acid ester such as Berol® 724, a monoethanolamine salt and / or an alkyl or aryl or alkylarylsulfonic acid salt such as dodecylbenzene or dodecylbenzene C10-C22) sulfonic acid salt (LAS), the total amount of surfactant or mixture of surfactants being 5-40% by weight, e.g. about 40% by weight, of butyl glycol in an amount of 0-10% by weight, e.g. about 7.5% by weight, and optionally water, all amounts based on the total composition. The blend composition can be prepared by mixing a dispersion containing phenmedipham and a dispersion containing metamitron, which dispersion can be prepared separately in liquid phases containing an oil component such as spindle oil 11 92789 in an amount of about 30-35%, a mixture of surfactant formed -li- or aryl- or alkylarylsulfonic acid salts such as dodecylbenzenesulfonic acid-triethanolamine salt, ethoxylated nonylphenol and butyl glycol.

5 The solubility of phenmedipham and metamitron in mineral oil is approximately 0.1%, due to the aromatic content of the oil. In the water-emulsifiable liquids described above, which are solutions containing oil and a surfactant, the solubility of phenmedipham and metamitron is about 3% when the surfactant content of the liquid is of the same order of magnitude as the oil content. When the solubility is about high, there may be a slow development of crystals of phenmedipham and metamitron in the dispersions during storage at different temperature conditions, which means that the compositions are less stable under such conditions. For microemulsions with a water content of about 25%, the dissolution of phenmedipham is reduced by a factor of 10 to about 0.3%. There is no similar reduction for metamitron.

15 In addition, it appears that diluting metamitron dispersions in water is more time consuming than dispersing phenmedipham, probably due to the dissolved fraction of metamitron. However, once emulsions or microemulsions are formed in solution, they are stable.

To reduce the solubility of Phenmedipham and metamitron in a liquid and to counteract that dissolution of dispersions of metamitron compositions in water is so time consuming that the oil content in the liquid can be kept high and the surfactant content correspondingly low and an oil having a less aromatic content can be used. % by weight, preferably less than 25% by weight. (An example of a preferred oil for this purpose is a mineral oil having a boiling point above 200 ° C and a viscosity of less than 100 cSt at 40 ° C and, as mentioned above, an aromatic content of less than 30% by weight, preferably less than 10% by weight.) However, it has been found that if the amount of oil is increased to about 60% and the amount of surfactant is reduced to about 10-15%, the composition has an obvious tendency to separate into rod-like oil and finely divided herbicide sediments when the composition is diluted with water. The proportion of oil emulsified in the aqueous phase also tends to re-separate, like the upper phase.

Thus, in compositions with a high amount of oils with a low aromatic content, there is an obvious need to use a very effective emulsifier (surfactant) system. A sufficiently effective emulsifier (surfactant) to ensure satisfactory emulsification of mineral oils at a relatively low aromatic content can be obtained, for example, by substituting some of the above ethoxylated nonylphenols with ethoxylated dinonylphenols and or an aryl or alkylarylsulfonic acid ester salt, such as a dodecylbenzenesulfonic acid triethanolamine salt, with a total surfactant amount of about 5-20%, e.g. about 10-15%, based on the composition, and a low aromatic mineral oil, e.g. in an amount of, 40 to 65% by weight, e.g. about 60% by weight. Some of the oil can be replaced by a lower boiling petroleum fraction such as kerosene. Thus, the compositions of interest of the invention contain 15-40% by weight, preferably 20-30% by weight of either phenme dipham or metamitron or a combination of phenmedipham and metamitron dispersed in a liquid phase containing mineral oil in an amount of 10-65% by weight, such as about 20% by weight. 50-65% by weight, e.g. about 60% by weight, of a surfactant or a mixture of surfactants containing ethoxylated alkylphenol (containing 3-9 ethylene oxide units) in which the alkyl group contains 4-15, in particular 6-12 carbon atoms and / or ethoxylated dialkylphenol (containing 4-14 ethylene oxide units) in which the alkyl group contains 4-15, in particular 6-12 carbon atoms and optionally a salt of a phosphoric acid ester and / or an alkyl or aryl or alkylarylsulfonic acid salt, surfactant the total amount of the substance or mixture of surfactants is 5 to 25% by weight, preferably 10 to 15% by weight. The mineral oil may, for example, be a solvent-refined mineral oil in an amount of about 50% combined with aromatic-free kerosene (boiling point 190-240 ° C) in an amount of about 10%, ethoxylated dinonylphenol (containing about 9 ethylene oxide units) may be present, e.g. %, ethoxylated nonylphenol (containing 4 ethyl oxide units) may, e.g., be present in an amount

II

13,92789 about 3% and the monoethanolamine salt of the phosphoric acid ester (Berol® 724) may, for example, be present in an amount of about 5%. The amount of dispersed phenmedipham should preferably be 20-40%, more preferably 25-35% of the composition and the amount of dispersed metamitron should preferably be 15-35%, more preferably 20-30% of the composition. The combined compositions can be prepared by mixing dispersions of phenmedipham and metamitron. Dispersions prepared in this way are easily soluble in water. Both phenmedipham and metamitron disperse satisfactorily and the oil phase forms sufficiently stable emulsions in water. In these oil-detergent mixtures, the solubility of phenmedipham and metamitron is about 0.2%.

The compositions are preferably substantially free of water, which increases the chemical stability of the active ingredients.

The invention is described in more detail in the following Examples 4-7 and the preparation, isolation and stability of the compounds prepared by the method of DK Patent No. 159653 in the isophorone are described in Examples 1-3.

EXAMPLE 1

Preparation of methyl (3- (3-tolylcarbomoyloxy) phenyl) carbamate 20

Methyl N- (3-hydroxyphenyl) carbamate (8.35 g, 0.05 mol) (prepared as in Example 1) in water (75 ml) was placed in a 150 ml beaker equipped with a stirrer and the mixture was stirred. Over 3/4 hours, 3-tolyl isocyanate (6.65 g, 0.05 mol) was added via addition funnel without temperature control. During the addition, the pH was maintained at 9.5 by the simultaneous addition of 50% NaOH solution.

After the addition of 3-tolyl isocyanate, stirring was continued for 1 hour. The product, which was a very fine suspended powder, was then filtered and dried to give the title product (14.0 g, 93.3%), m.p. 139-143 ° C.

HPLC analysis showed 94.1% purity, the remaining 5.9% being methyl N- (3-hydroxyphenyl) carbamate and the by-product N, N'-di-3-tolylurea.

Preparation of methyl N- (3-hydroxyphenyl) carbamate 3-Aminophenol (10.9 g, 0.10 mol) in water (100 mL) was placed in a 250 mL beaker equipped with a stirrer, thermometer and pH electrode. . The suspension was stirred and cooled to 10 ° C with external cooling.

Using a separatory funnel, methyl chloroformate (9.45 g, 0.10 mol) was added to the suspension over 1 hour with continuous stirring and maintaining the temperature at 8-12 ° C. During the addition of the ester, the pH was adjusted to 5.3 with the simultaneous addition of 50% NaOH solution.

After the addition of the ester, stirring and pH adjustment were continued for 1A, allowing the temperature to rise to room temperature. The pH was then lowered to 1.9 with 4N HCl for 1/4 hour to dissolve the unreacted 3-aminophenol in its hydrochloride form.

The product, which was a fine suspended powder, was filtered, washed with ice water (2 x 25 mL) and dried to give methyl N- (3-hydroxyphenyl) carbamate (15.0 g, 90%), m.p. 94-95 ° C. Titration of the hydroxyl group with 0.5 N NaOH showed 98% purity.

25 EXAMPLE 2

Solvent extraction of methyl (3- (tolylcarbamoyloxy) phenyl) carbamate 1 liter of the reaction mixture containing about 88 g of methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate was prepared as in Example 1, but the powder was not filtered off. Analysis of the final product formed showed 94% purity.

Il 15 92789

The pH of the reaction mixture was adjusted to 2 by adding hydrochloric acid, and sodium chloride (100 g) was dissolved in the slurry. Isophoron (300 g) was added with stirring and stirring was continued until the solid had dissolved.

The isophorone phase was separated and dried over sodium sulfate. Sodium sulfate was filtered off and acetic anhydride (5.0 g) was added.

Analysis showed that the amount of methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate was 21.6%.

EXAMPLE 3 Stability Tests A isoform solution of methyl (3- (3-tolylcarbamoyloxy) phenyl) carbamate was prepared as in Example 8 and divided into four equal portions. The samples were subjected to storage tests as described in the following table with or without the addition of acetic anhydride, optionally after drying of the sodium sulfate. The tests were performed after 24 hours / 25 ° C, 26 days / 25 ° C and 25 days / 70 ° C.

20 t i

TABLE

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Active substance,% by weight

Added drying

5 and / or stabilizer 24 hours / 25 ° C 26 days / 25 ° C 25 days / 70 ° C

20.68 20.93 20.56 1.0 g AAA / 50 ml 21.32 20.44 19.76

Na 2 SO 4 20.79 20.94 20.67 10 Na 2 SO 4 + 1.0 g AAA / 50 ml 21.56 20.43 19.69 AAA = acetic anhydride 15 EXAMPLE 4

Dispersions of Phenmedipham containing an oil-based microemulsion or solution as a liquid phase Microemulsions I and III and Solution II were prepared without phenmedipham by mixing the ingredients. One part by weight of phenmedipham (technical grade, 95%) was then incorporated into three parts by weight of the liquid phase in each of solutions I, II and III and each of the resulting mixtures was ground in a ball mill equipped with glass spheres (<p 1 mm).

25 The turbidity temperatures of the microemulsions I and III and solution II and the appearance of the microemulsion formed by them with the addition of tap water are shown in Table 1. It should be noted that they all exist as homogeneous liquids which do not separate into their components.

After standing for 3 weeks at 45-50 ° C, all dispersions containing phenmedipham were uniform after moderate mixing.

Il 17 TABLE 1 92789

I II III

5 Water 29.5% 21.0%

Monoethanolamine 2.6%

Berol ™ 724 1) 10.3%

Triethanolamine 2.5% 2.0%

Sulfosoft ™ 2) 5.7% 4.5% 10 Spindle oil 5) 17.2% 28.4% 18.2%

Marlophen ™ 88 H 3) 12.1% 18.5% 12.8%

Berol ™ 26 4) 5.2% 12.8% 8.2%

Butyl glycol 1.7% 7.1% 4.6%

Propylene glycol 3.7% 15____

Total 75.0% 75.0% 75.0%

Appearance Transparent Transparent Transparent yellow solution yellow-brown yellow. solution 20 solution pH (1:10 in aqueous dilution) 2.8 3.4 3.7

Turbidity temperature 60 ° C> 80 ° C 58 ° C

Dilution 1: 1 Transparent Transparent Transparent 25 yellow solution yellow solution yellow. solution

Dilution 1: 1 Slightly cloudy Transparent Transparent after 24 h solution gelatinous solution solution

Dilution 1: 1 Transparent Transparent Transparent slightly turbid solution solution 30 solution

Dilution 1:50 Transparent Turbid, but Transparent solution Transparent faint solution Turbid solution

Technical grade 35 phenmedipham, 96% 25% 25% 25%% phenmedipham * in composition 24% 24% 24% 18 92789 1) Acid phosphoric acid ester (Berol Kemi) 2) Dodecylbenzenesulphonic acid (Berol Kemi) 3) Ethoxylated nonylphenol (8 ethylene oxide units) (Carbon) 4) Ethoxylated nonylphenol (4 ethylene oxide units / molecule) 5 (Berol Kemi) 5) Gravex ™ 19 (Shell) EXAMPLE 5 10 Dispersions of Phenmedipham and metamitron containing an oil-based solution as a liquid phase

Dispersions I and II, the contents of which are shown in the following table, were prepared in the same manner as described in Example 6.

15

Ingredients Dispersion I Dispersion II

Triethanolamine 2.6% 2.5%

Sulfosoft ™ 5.9% 5.7% 20 Spindle oil 29.3% 28.4%

Marlophen ™ 88H 19.1% 18.5%

Berol ™ 26 13.2% 12.8%

Butyl glycol 7.4% 7.1% 25 77.5% 75.0%

metamitron,

Technical quality, 98% 22.5%

phenmedipham,

Technical degree, 96% 25.0%

30 Dispersion pH

(1:10 water dilution) 3-4 3-4

II

19 92789

A combined composition was prepared containing 75% by weight of dispersion I and 25% by weight of dispersion II by mixing the dispersions. The resulting composition would be a viscous composition containing about 6% phenmedipham and about 17% metamicron, which could be diluted with water with somewhat longer stirring and stable dispersions were obtained.

EXAMPLE 6

Dispersion of metamitron containing an oil-based solution as a liquid phase.

10

Solutions I and II were prepared by stirring and one part by weight of metamitron (technical grade, 98%) was incorporated into three parts by weight of the liquid phase in both solutions I and II, and both resulting mixtures were ground in a ball mill equipped with glass spheres (Φ 1 mm).

15

The turbidity temperatures of the resulting solutions I and II and the appearance of the formed microemulsions in the solutions by the addition of tap water are shown in Table 2. It should be noted that they all occur as homogeneous liquids that do not separate into their components.

20 TABLE 2 20 92789

I II

5 Monoethanolamine 2.9% 2.7%

Berol ™ 724 1) 12.6% 13.5% Spindle oil 5) 33.6% 32.4%

Solvesso ™ 1501 3.5% 3.4%

Marlophen ™ 88 H 3) 14.0% 13.5% 10 Berol ™ 26 4) 8.4% 8.1% 60% total alkyl / 3-aminopropanoic acid diethyl glycol solution 0.0% 1.4% 15 Total 75.0% 75.0%

Appearance transparent transparent yellow liquid yellow liquid pH (1:10 in aqueous solution) about 3 about 3

20 Turbidity temp. 45 ° C to 44 ° C

Dilution 1: 1 transparent slightly turbid yellow liquid liquid

Dilution 1:10 transparent cloudy but liquid transparent 25 Dilution 1:50 transparent transparent liquid liquid

Technical quality, metamitron, 98% 25% 25% il 30

Solvesso ™ 150 is a 99% aromatic hydrocarbon, flash point 166 ° C, boiling point 187-210 ° C, available from Exxon Corporation.

21 92789 EXAMPLE 7

Dispersions of metamicron and phenmedipham containing an oil-based solution as a liquid phase.

5

Dispersions I and II in content as indicated in Table 3 were prepared in the same manner as described in Example 6.

22 92789

TABLE 3 I II

5 Hydro Para 19 6) 51.2 47.7

Halpasol ™ 190/240 7) 10.2 9.5

Berol ™ 26 4) 3.1 2.9

Berol ™ 269 8) 5.1 4.8

Berol ™ 724 1) 4.4 4.4 10 Monoethanolamine 1.0 1.0 75.0% 70.0%

Technical grade phenmedipham, 96% 30.0% 15 Technical grade metamitron, 98% 25.0%% phenmedipham in composition 28.8% 20% metamitron in composition 24.5% pH (1:10 in aqueous solution) about 3 about 3 25 1) Acid phosphoric acid ester (Berol Kemi) 4) Ethoxylated nonylphenol (4 ethylene oxide units per molecule) (Berol Kemi) 6) Solvent-enhanced paraffin mineral oil (Norsk Hydro) (4% aromatics, viscosity 19.7 cSt at 40 ° C) II :.

30 23 92789 7) Paraffinic hydrocarbon, <0.1% aromatic hydrocarbons, boiling point 190-240 ° C, flash point> 70 ° C (Haltermann) 8) Ethoxylated dinonylphenol (9 ethylene oxide units per molecule (Berol Kemi) 5

When mixed with water, these oil-containing liquid phases do not form stable transparent microemulsions as described in the previous examples, but form conventional emulsions, from which, however, oil precipitates only very slowly. The attempt to separate oil sediments containing finely ground metamitron 10 or phenmedipham is negligible.

A combined composition in which 77.5% by weight of dispersion I and 22.5% by weight of dispersion II were prepared by mixing the dispersions. The composition contained about 19% metamitron and 6.5% phenmedipham.

15

Dispersion I (metamitron) and the above-mentioned mixture dispersion are both thixotropic. Although they appear to be somewhat viscous, they are easily miscible (emulsifiable and dispersible) in 98-95% water. Mixing is facilitated because the density of the dispersions is lower than that of water.

20

Claims (9)

1. Stabilized liquid herbicidal composition comprising methyl (3- (3-tolyl-carbamoyloxy) phenyl) carbamate (phenmedifam) or ethyl (3-phenyl-carbamoyloxyphenyl) carbamate (desmedifam), characterized in that the composition is an emulsion comprising fenmedifam and / or desmedifam dispersed in a continuous phase of an oil component and comprising a) 5-40% by weight fenmedifam and / or desmedifam of a particle size less than 10 microns, b) 15-65% by weight of an oil component consisting of one or more mineral and / or plant oils, c) 5-40% by weight of a surfactant component comprising one or more surfactants and d) up to 40% water, wherein the composition is arranged to form a stable, ready-to-use oil-in-water emulsion or microemulsion when dissolved in water with a proportion of part composition versus 1-10 parts by volume of water. 2. Herbicidal composition according to claim 1, characterized in that at least 50% of fenmedifam and / or desmedifam is of a particle size of 3-5 microns. Herbicidal composition according to any one of claims 1 or 2, characterized in that it contains water in which the liquid phase is acidic. 30 II 27 92789 4. Herbicidal composition according to claim 3, characterized in that the liquid phase has a pH of 2-4. 5. Herbicidal composition according to any one of claims 1-4, characterized in that it further comprises one or more herbicides selected from metamitron, chloridazone and etofumesate. Process for the preparation of a herbicidal composition according to any of claims 1-5, characterized in that fenmedifam and / or desmedifam are mixed with the other components of the composition and the mixture is subjected to grinding to disperse the fenmedifam and / or desmedifam. a continuous phase of the oil component. Process for the preparation of a herbicidal composition according to any one of claims 1-5, characterized in that the fenmedifam and / or desmedifam in the form of a liquid sludge are pulverized such that the fenmedifam and / or desmedifam have a particle size of less than 10 microns, and the slurry is then mixed with a mixture of the other components in the form of an oil component and the surfactant and up to 40% water or the components are added separately to form an emulsion. 8. A method for selective control of weeds, characterized in that a composition according to any of claims 1-5 is applied to weeds and / or sprayed on weeds during the growing season for weeds or where weeds are expected to grow. 25 Use of the composition according to any of claims 1-5 for controlling weeds in beets.