FI82588B - Liquid herbicide composition - Google Patents

Description

1 82588

This invention relates to a liquid herbicidal composition which contains a carbamoyloxyphenylcarbamate known per se, a stabilizer and at least one emulsifier and an organic solvent as a herbicidal active ingredient. This invention is particularly directed to the selection of said solvent.

Pesticide formulations can be roughly divided into two main groups, solid and liquid formulations. The choice is primarily influenced by the solubility properties of the active ingredient and, on the other hand, by the biological potency of the preparation. Certain active ingredients are so poorly soluble that they do not yield, in practice, genuine liquid formulations that are sufficiently concentrated.

The only possibilities are then solid products or a liquid suspension concentrate in which the active ingredient is still suspended in solid particles in water or another carrier liquid.

These formulations are in themselves advantageous because they generally avoid toxic and flammable organic solvents. But often their biological potency is insufficient because, especially in the case of foliar herbicides, penetration into the plant is required to achieve sufficient biological potency. Hydrolytic decomposition is also often a disadvantage. The active ingredient as a molecule is able to penetrate through the wax and cuticle layers in a real liquid much more efficiently than a solid particle. The most user- and environment-friendly option would be a genuine aqueous solution, but poor solubility or degradation of the active ingredient in water is often an obstacle to the use of this formulation. In this case, the best possible organic solvents must be sought.

2 82588 Almost without exception, water is used as a carrier liquid when spraying the product into the crop. For this reason, the organic solution has to be mixed with water to form an emulsion, which is done with surfactants, i.e. using emulsifiers. Both solvents and emulsifiers are very crucial for the biological efficacy and selectivity of the preparation. Organic solvents dissolve the protective wax on the leaves and surfactants improve the adhesion of the spray droplets to the surface of the leaves, their penetration into the plant and their mobility within the plant. The solvent-emulsifier rice system also has a very decisive effect on the selective biological potency of the active ingredient by influencing the partition coefficient. Therefore, when changing the composition of the preparation, both herbicidal activity and phytotoxicity to beneficial plants must be ensured.

It is known that carbamoyloxyphenyl carbamates of the general formula

_ R

R-O-CO-NH 0 - CO -

'V

wherein alkyl, cycloalkyl or aryl optionally substituted by halogen, alkyl and / or trifluoromethyl, R 1 is hydrogen or alkyl or R 1 and R 2 together with the N atom represent a heterocyclic ring which may additionally contain N and / or O atoms , and R is optionally halogen-substituted alkyl, alkenyl or alkynyl at the terminal 3, has good herbicidal properties (BE patent 679,283). More preferred are those active ingredients in which, in the general formula shown, R 1 = H, e.g. methyl 3-m-tolylcarbamoyloxyphenylcarbamate (= phenmedipham) and ethyl 3-phenylcarbamoyloxyphenylcarbamate (= desmedipham). The two active ingredients are also preferably used in combination with or with other herbicides, such as, for example, 2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-ylmethanesulfonate (- ethofumesate) to extend the effective range of the preparation against weeds. It has also been found that the use of excessive amounts (about 20%) of emulsifier in emulsion concentrate preparations strengthens the biological efficacy (FI patent 44178). In order to be useful and economical, the product should contain a sufficient amount of the active substance, be storable and miscible as an injectable dilution in water. Hitherto, the solvents mentioned, dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, xylene, toluene, isophorone, tetralin, cyclohexanone and cyclohexanol (U.S. Pat. No. 4,452,630 and U.S. Pat. have had either low solubility of the active ingredient and poor storage at lower temperatures, toxicity and, above all, water solubility due to the polarity of the solvent, whereby the dissolved active ingredient crystallizes when the emulsion concentrate is diluted in water to emulsion. Current commercial products use isophorone and its mixtures, however, there is always clearly more isophorone than other solvents. Of the said solvents, isophorone achieves the best non-crystallizing stability in aqueous dilutions. However, visible crystallization begins as early as about 3 hours after dilution with water.

Medical authorities have drawn attention to the toxicity (mutagenicity and carcinogenicity) of isophorone. Due to these considerations, alternative solvents to isophorone have been sought.

It has now surprisingly been found that reducing the water solubility of cyclic ketones and alcohols by methylation or using cyclopentanols or cyclopentanones as solvents provides safer, chemically and physically well-functioning and in some cases even biologically 3-phenylcarbamoyloxyphenylcarbamate or a mixture thereof and containing at least one organic solvent and at least one emulsifier and a suitable stabilizer.

The main features of the invention appear from the appended claim 1.

These solvents are used in admixture with one another and with possible other organic solvents, such as, for example, chlorinated and aromatic hydrocarbons, ketones, cyclic ethers, esters of aliphatic and aromatic organic acids and sulfoxides or mixtures thereof, so that the solvents according to the invention are present in these mixtures. % by weight in the preparation. Of course, in addition to the active ingredients mentioned, other active ingredients may be present in the preparations to extend the range of action of the product.

Known surfactants such as alkyl sulfates, alkyl ether sulfates, alkyl amides, sulfonates, sulfonic acids, alkenoxylated phenols and castor oil, polyglycol ethers and fatty alcohol alkene oxide condensates are used as emulsifiers.

Both inorganic, preferably e.g. sulfuric acid, and organic acids, such as, for example, citric acid, acidic esters, such as, for example, alkylphenol polyalkoxylated phosphoric acid ester, and acidic salts, such as, for example, ferric chloride, can be used as stabilizers.

The solvent is preferably methylcyclohexanone, trimethylcyclohexanone and / or trimethylcyclopentanol. The solvent is particularly preferably a mixture of N-methylpyrrolidone and trimethylcyclo 5,82588 hexanone, and this mixture is preferably about 60-64% by weight of the herbicide mixture, wherein the weight ratio of N-methylpyrrolidone to trimethylcyclohexanone is preferably about 1: 5-7.

The invention is described in more detail below by means of examples.

Parallel liquid formulations were prepared using phenmediphan (methyl 3-m-tolylcarbamoyloxyphenylcarbamate) alone or in combination with desmedipham (ethyl 3-phenylcarbamoyloxyphenylcarbamate) or ethofumesate (2-ethoxy-2,3-dih -dimethyl-1-benzofuran-5-ylmethanesulfonate). The usefulness of the solvents was first checked by their ability to dissolve the active ingredients sufficiently. The product was then formulated by the addition of emulsifiers (dodecylbenzene sulfonate, alkenoxylated phenols and fatty alcohol-alkene oxide cond.) And a stabilizer (p-toluenesulfonic acid) and the physical properties of the preparation were checked for stability, emulsification, crystallization in aqueous dilution. The preparations were generally stored at +40, +20, -20 and -40 ° C in glass bottles and, in addition to physical checks, the active substances were re-analyzed by liquid chromatography after 2 months of storage at + 40 ° C.

The emulsification was checked according to the method of CIPAC MT 36 1.1, paying attention to the spontaneous emulsification in a 5% by volume emulsion and to the deposition on the bottom and / or surface during storage. Crystallization was monitored in 2% v / v emulsions (342 ppm hard water, + 20 ° C) by mixing the beakers 30 times at the start of the experiment and observing the formation of crystals visually and under a microscope. The more dilute the solution, the more sensitive the crystallization is and the most common dilution of carbamoyloxyphenyl carbamate preparations in beets is 2% by volume.

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Biological efficacy was tested by potting experiments in a greenhouse by spraying test plants at 2-4 leaf stages with water dilutions with active ingredient concentrations ranging from 320-1280 g of active ingredient (a.i.) per ha, depending on the conditions, and the amount of water was 200 l / ha. Recommendations for use in field spraying range from 480-960 g a.i./ha. Inspections were performed approximately 6 and 12 days after spraying, at which time plant damage was rated on a scale of 0-10; 0 * no damage, 10 = completely dead. There were 4 replicates and 5 seedlings per jar. Mustard (Sinapis arvensis), yarrow (Stellaria media), foxtail (Amaranthus retroflexus), field horsetail (Spergula arvensis) and safflower (Tripleurospermum inodorum) have been used as experimental plants, as well as sugar beet (Beta vulgaris).

Example 1 Preparation 1 (Comparative) 16.0% by weight of phenmedipham 20.0 "emulsifiers 0.15" stabilizer 63.85 "isophorone

Preparation 2 8.0% by weight phenmedipham 23.0 "emulsifiers 0.15" stabilizer 68.85 "methylcyclohexanone

Preparation 3 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 10.0 "N-methylpyrrolidone 53.85" trimethylcyclohexanone

Preparation 4 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 10.0 "dimethylformamide 53.85" trimethylcyclohexanone 7 82588

Preparation 5 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 15.0 "N-methylpyrrolidone 53.85" trimethylcyclohexanone

Preparation 6 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 20.0 "N-methylpyrrolidone 43.85" trimethylcyclohexanone

Preparation 1 corresponds to currently used preparations in which the toxic isophorone acts as a solvent. Methylcyclohexanone alone is only able to dissolve about 8% of phenmediphar (Preparation 2) so that a cold storage tolerant product is also obtained. Trimethylcyclohexanone is a inferior solvent to methylcyclohexanone. The addition of more polar but more water-soluble solvents to the formulation improves the dissolution properties but reduces the miscibility with water, since the carbamoyloxyphenyl carbamates then crystallize more rapidly from their emulsions. The active ingredient content in the product should preferably be more than 10% so that the amount of product per ha is not too high. In Preparation 6, the solubility of the active ingredient and the storage properties are excellent, but in the aqueous dilution the product started to crystallize as early as 1 hour after dilution, which is not acceptable in view of the practical success of the spraying. The proportion of N-methylpyrrolidone in trimethylcyclohexanone is thus too high in this case. All test members had excellent emulsification and storage properties.

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Biological potency

Preparation Application rate Damage to mustard (0-10) _g a.i./ha_6 pv_10 days 1 640 3 2 2 640 4 4 3 640 3 2 1 1280 5 4 2 1280 6 6 3 1280 5 3

Check - 00

The results show that at a normal dose of 640 g ai / ha the new solvents (N-methylpyrrolidone + trimethylcyclohexanone) achieve at least as good or even better efficacy (methylcyclohexanone) on mustard than isophorone preparation 1. The same trend is with an overdose of 380 ha / ha after 10 days is slightly weaker than the reference product.

Example 2 Preparation 1 (Comparative) 16.0% by weight of phenmedipham 20.0 "emulsifiers 0.15" stabilizer 63.85 "isophorone

Preparation 3 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 10.0 "N-methylcyclohexanone 53.85" trimethylcyclohexanone

Preparation 7 16.0% by weight phenmedipham 24.0 "emulsifiers 0.15" stabilizer 10.0 "N-methylpyrrolidone 49.85" trimethylcyclohexanone 9,82588

Preparation 8 16.0% by weight phenmedipham 18.0 n emulsifiers 0.15 "stabilizer 8.0" N-methylpyrrolidone 57.85 "trimethylcyclohexanone

Preparation 9 (comparison) 13.0% by weight of phenmedipham 3.5 ”desmedipham 20.0" emulsifiers 0.15 "stabilizer 63.35" isophorone

Preparation 10 13.0 wt% phenmedipham 3.5 "desmediphane 20.0" emulsifiers 0.15 "stabilizer 10.0" N-methylpyrrolidone 53.35 "trimethylcyclohexanone Samples were stored for 2 months at + 40 ° C. The active ingredients were analyzed both before and after storage by liquid chromatography.

Content (% by weight)

Phenmedipham Desmedipham

Prepared_Week_2 months_Week_2 months 1 16.4 16.4 3 16.3 16.4 7 16.4 16.4 8 16.7 16.6 9 13.0 13.0 3.3 3.3 10 13.0 13, 1 3.3 3.4

The table shows that the new formulations do not adversely affect the shelf life of the active ingredients.

Thermal storage also does not negatively affect the physical properties of the products. All products also withstand -40eC storage without crystallization. In terms of physical properties, phenmedipham preparations were equivalent depending on the amounts of solvents and emulsifiers. Phenmedipham ίο 82588 + a mixture of desmedipham with new solvents (Preparation 10) was equivalent in physical properties to Isophorone (Preparation 9).

Biological potency

Preparation Application rate Damage (0-10) _g ai / ha_Mustard_Yard star 1 640 4 2 3 640 4 2 7 640 4 2 8 640 41 9 640 7 2 10 640 8 5 1 320 3 1 3 320 2 1 7 320 5 2 8 320 2 0.5 9 320 4 1 10 320 7 1

Check - 00

Inspection of the experiments was performed 11 days after injection. The results show that, as in Example 1, the isophorone-free preparations 3, 7, 8 are equivalent to the isophorone-containing preparation 10 at a normal concentration of 640 g a.i./ha, with the exception of preparation 8 with a yard star. In this case, a lower emulsifier content may affect the result. The same trend is observed at low levels of 320 g a.i./ha, which were thought to be more sensitive to differences in potency. Preparation 8 is weaker than reference 1, but preparation 7 with more emulsifiers is clearly more effective than reference. Formulations 9 and 10, which have both phenmedipharin and desmedipharn in a ratio previously found to be effective, show a clear advantage with the new solvent formulation (Preparation 10) over the old (Preparation 9). Here, it is likely that the partition coefficient of the active ingredient mixture in the solvents is advantageously influenced so as to achieve a clearly improved effect on fractures, in particular mustard.

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Example 3 Preparation 1 (Comparative) 16.0% by weight of phenmedipham 20.0 "emulsifiers 0.15" stabilizer 63.85 "isophorone

Preparation 3 16.0% by weight phenmedipham 24.0 "emulsifiers 0.15" stabilizer 10.0 "N-methylpyrrolidone 49.85" trimethylcyclohexanone

Preparation 11 8.0% by weight phenmedipham 10.0 "ethofumesate 20.0" emulsifiers 0.15 "stabilizer 10.05" N-methylpyrrolidone 51.85 "trimethylcyclohexanone

Preparation 9 (comparison) 13.0% by weight phenmedipham 3.5 "desmedipham 20.0" emulsifiers 0.15 "stabilizer 63.36" isophorone

Preparation 10 13.0% by weight phenmedipham 3.5 "desmedipham 20 0" emulsifiers 0.15 "stabilizer 10.0" N-methylpyrrolidone 53.35 "trimethylcyclohexanone

The physical properties of phenmedipham + ethofumesate preparation 11 were good in all respects and the other preparations with the new solvents (preparations 3 and 10) were equivalent to the corresponding isophorone preparations 1 and 9.

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Biological potency

Preparation Amount of use Damage (0-10) _Mustard Yard star 1 640 4 3 3 640 5 2 11 640 5 7 9 640 4 2 10 640 6 2 1 1280 9 6 3 1280 8 6 11 1280 9 7 9 1280 10 7 10 1280 10 7

Check - 00

The inspection of the experiments was performed 12 days after spraying. The results show that ethofumesate strengthens the efficacy of phenmedipham against these two weeds, it can be further observed that even at overdoses of 1280 g a.i./ha, the preparations with the new solvents are equivalent to the isophorone reference preparations 1 and 9.

Example 4 Preparation 1 (Comparative) 16.0% by weight of phenmedipham 20.0 "emulsifiers and 0.15" stabilizer 63.85 "isophorone

Preparation 7 16.0% by weight phenmedipham 24.0 "emulsifiers 0.15" stabilizer 10.0 "N-methylpyrrolidone 49.85" trimethylcyclohexanone

Preparation 12 6.0% by weight phenmedipham 10.0 "ethofumesate 20.0" emulsifiers 0.15 "stabilizer 10.0" N-methylpyrrolidone 53.85 "trimethylcyclohexanone

Preparation 13 i3 82 588 8.0% by weight phenmedipham 8.0 "ethofumesate 20.0" emulsifiers 0.15 "stabilizer 10.0" N-methylpyrrolidone 53.85 "trimethylcyclohexanone

Preparation 10 13.0% by weight phenmedipham 3.5 "desmedipham 20.0" emulsifiers 0.15 "stabilizer 10.0" N-methylpyrrolidone 53.35 "trimethylcyclohexanone

The phenmedipham + ethofumesate blend formulations with the new solvents (Preparations 12 and 13) were equal in all physical properties compared to the phenophipham isophorone formulation.

Biological potency

Preparation_Damage (0-10)

Yard star- Fox- Field- Mustard Sauna- Sugar _mö_tail hatikka_kukka beet 1 6 1 6 9 4 1 7 6 3 9 9 4 1 12 9 4 7 9 5 1 13 9 3 7 9 3 1 10 7 8 9 9 4 1

Check 000000

The active ingredient amounts were 640 g a.i./ha. The experiments were checked 10 days after injection.

The results show that preparation 7 is clearly more effective against foxtail and field hake with new solvents than reference preparation 1 with isophorone. In other respects, it is on an equal footing with the reference. Etofumesate as well as desmedipham improve the efficacy of phenmedipham on yarrow, foxtail and field acacia.

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Damage to sugar beet, on the other hand, indicates that the new solvents do not increase phytotoxicity to beneficial plants.

Example 5 Preparation 14 16.0% by weight of phenmedipharine 20.0 "emulsifiers 0.15" stabilizer 7.7 "N-methylpyrrolidone 56.15" cyclopentanone

Preparation 15 16.0% by weight of phenmedipharine 20.0 "emulsifiers 0.15" stabilizer 20.0 "N-methylpyrrolidone 43.85" cyclopentanol

Preparation 16 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 20.0 "N-methylpyrrolidone 43.85" methylcyclohexanol

Preparation 17 16.0 wt% phenmedipham 20.0 "emulsifiers 0.15" stabilizer 14.0 "N-methylpyrrolidone 49.85" 2,6-dimethylcyclohexanone

Preparation 18 16.0% by weight phenmedipham 20.0 "emulsifiers 0.15" stabilizer 24.0 "N-methylpyrrolidone 39.85" 2,6-dimethylcyclohexanol li 15 82588

Preparation 19 16.0 wt% phenmedipham 20.0 "emulsifiers 0.15" stabilizer 14.0 "N-methylpyrrolidone 49.85" trimethylcyclopentanol The purpose of this series was to test other cyclic ketones and alcohols for their ability to act as solvents for carbamoyloxyphenyl carbamates. All case studies were satisfactory in terms of physical properties.

Claims (5)

A liquid herbicidal mixture comprising methyl 3-m-tolylcarbamoyloxyphenylcarbamate and / or ethyl 3-phenylcarbamoyloxyphenylcarbamate and at least one emulsifier and an organic solvent and a stabilizer, characterized in that the solvent is a mixture of at least two of the following: cyclic alcohol, cyclopentanol and cyclopentanone with their methylated derivatives and optionally N-heterocyclic cyclopentanone with its methylated derivatives, with the exception of the mixture of cyclopentanol and cyclopentanone. Herbicidal mixture according to Claim 1, characterized in that the solvent mixture is present in an amount of about 30 to 70% by weight of the mixture. Herbicidal mixture according to Claim 1 or 2, characterized in that the solvent is methylcyclohexanone, trimethylcyclohexanone and / or trimethylcyclopentanol. Herbicidal mixture according to one of the preceding claims, characterized in that the solvent is a mixture of N-methylpyrrolidone and trimethylcyclohexanone. Herbicidal composition according to Claim 4, characterized in that the solvent mixture is present in an amount of about 60 to 64% by weight and the weight ratio of N-methylpyrrolidone to trimethylcyclohexanone is approximately 1: 5 to 7.