DD298473A5 - Means of combating ill-health - Google Patents

Abstract

The invention relates to the preparation and use of agents for combating weeds, especially in beta-bees, by removing a carbamate in a acid amide. By the addition of stabilizers in the form of Essigsaeurealkylestern, acetic acid and alcohols or mixtures thereof, a recrystallization of the carbamate active ingredient is delayed in the emulsion and achieved an increase in herbicidal activity in the amount of about 20%.

Description

Application of the invention

The invention relates to the preparation and use of emulsifiable active substance concentrates with the herbicidal active ingredient 3- (methoxycarbonyl-aminophenyl-N (3-methylphonyl) carbamate (Phenmedipham) for controlling undesired plant growth in agricultural and horticultural crops, preferably in beetroots.

Characteristic of the known technical solutions In many cases, emulsifiable active substance concentrates consist of an active substance, organic, which is present as a solid Solvents such. B. isophorone (DD 69641) and emulsifiers. It should be the active ingredient used in the organic Solvent should be readily soluble, but the solvent on the other hand should have the lowest possible water solubility,

to prevent crystallization of the active ingredient in diluting the active ingredient concentrate with water and the

To ensure formation of a stable emulsion. Also, in the patent literature, for formulating drugs Solvents from the series of short-chain, limited water-soluble acetic acid alkyl esters and dimethylformamide u.a. in

the patents DD 100137, DD 101539, DD 104691, DD 105711 and DD 117974 mentioned.

Alkylacetates of longer alkyl chain length sometimes have very low water solubility, but are very

bad solvents for Phenmedipham.

Dimethylformamide is immiscible with water indefinitely and has long been considered an excellent solvent for Phenmedipham

known.

This can be about 110g Phenmedipham dissolved in 100g of dimethylformamide. Thus, the DDR patent 152271 describes that the Phenmediphamkonzentration in a variety of solvents

can be increased to 40% by the addition of dimethylformamide or dimethylacetamide, which is based on the information from

Table 1 is easy to explain. The disadvantage of such highly concentrated solutions, however, is that they dilute

strongly with water tend to recrystallize the active ingredient in the emulsion. The formulation of phenmedipham by solubilizing the active ingredient in longer-chain acetic acid alkyl esters is also extremely problematic since phenmedipham has only a very low solubility therein (Table 1).

The use of concentration with an active ingredient content of 1-3% is economically unreasonable, although the use

of ester-based solvents due to the relationship to plant growths of interest.

The use of phenmedipham dissolved in dimethylformamide is also not possible because it dilutes one Phenmediphamlösung with water due to the water solubility of dimethylformamide for an immediate deposition of

fecrkristallinem Phenmedipham comes and the herbicidal action drops sharply.

Object of the invention

The aim of the invention is the formulation of Phenmedipham-containing emulsion concentrates which give dilute with water for several hours stable spray liquors with minimal recrystallization tendency, which have an increased herbicidal activity and make additional stabilization of the drug against decomposition dispensable.

Explanation of the essence of the invention

The invention has for its object to formulate by choice and combination of ingredients, drug concentrates, meet the requirements listed above. Surprisingly, it has been found that the recrystallization from water-diluted Phenmediphamlösungen can be greatly delayed if the phenomethane dissolved in dimethylformamide, stabilizers, preferably alkylacetate of the alkyl chain length C ₈ -C ₈ or mixtures thereof, are added in amounts of at most 10-50%, preferably 15 -30% of the Phenmedipham contained in the concentrate are able to dissolve. The strongest crystallization inhibition is observed with alkyl acetates whose solubility is lowest for Phenmedipham. A particularly pronounced and unexpected crystallization inhibition with comparable emulsifying properties is achieved by adding a technical hexyl octyl acetate mixture 1: 1 with a proportion of up to 15% of an alcohol mixture and 0.25-0.75% of free acetic acid. By adding such an ester-alcohol mixture in an amount which would be able to dissolve only 20% of the Phenmodiphams contained in the concentrate, can be produced after dilution of the concentrate with water in the ratio 1:50 emulsions, which still after well over 2 For a long time no recrystallization phenomena can be recognized (Table 1). Thus produced active substance concentrates show no change in the biological effect after heating for 18 hours at 50 ° C. and are storage-stable for at least 2 years.

Table 1

Components of solubility solubility formulations -% 3 4 5 10 6 7 8th 10 active ingredient concentrates in HjO from PMP Wt. 2 10 10 10 10 10 10 g / 100gH ₂ O g / 100 gLsgm. 1 10 10 10 10 10 Phenmedipham (PMP) 0.0008 - 10 10 dimethylformamide 110 10 25 60 n-Butyl acetate 2.3 6 60 n-Hexylazetat 0.2 3 n-Octylazetat 0.2 2 45 60 techn. Mischester Hexyl Octylazetat 1: 1 1.0 3 12.5 10% alcohol mixture 0.25-0.75% vinegar. 15 5 55 acetophenone 0.5 13 20 47.5 20 isophorone 1.2 32 35 20 20 20 20 xylene 0.02 0.1 60 20 emulsifiers 20 Beginning recrystallization after dilution 145 160 NEN of the active ingredient concentrate with water 75 65 30 10 in the ratio 1:50 10 T = 22 ⁰ C min 5

Formulations according to the invention also make it possible to use those alkyl acetates which are normally not used in active substance concentrates with phenmedipham owing to their poor phenolic drug solubility. An additional unanticipated advantage of the ester mixture used compared to other solvents is that the free acetic acid present in the ester mixture is sufficient to stabilize the carbamate active during normal storage of the active ingredient concentrate against i., ..Olytic decomposition while under conditions, the one Hydrolytic decomposition of the active ingredient also favor the hydrolysis of the solvent and the release of acetic acid to a greater extent, which counteracts further decomposition of the active ingredient. An additional stabilization such as u.a. in DD 80898 and '¹ BRD-OS 3325444 shown, therefore unnecessary. In the stabilization of carbamate-based solvents by acetic acid, as described in another context in US Pat. No. 2,954,936, such interactions are not possible. It was further surprising that the alcohol content of the mixed ester in a size up to 15% has no visible negative effects. In Photosyntheseuntersuchungen with formulations of the invention was also found, surprisingly, that the electron transport in the photosynthetic apparatus of plants in the presence of alkyl acetates with an alkyl chain radical from 5 carbon atoms is significantly reduced, suggesting herbicidal activity. The following examples serve to illustrate the invention.

example 1

At 11 sites, the biological effect of a formulation according to the invention (Table 1, Formulation 8) was compared with a commercial formulation containing 16% Phenmedipham. The testing took place a) with comparable application rates, b) with comparable amounts of active substance, c) at 3 different stages of development of the weeds. This makes it possible to compare the recipes according to the aspects a, b and c as well as the relationship between them. The results obtained are shown in Tables 2 and 3.

Table 2

Residual weeds (untreated control = 100%) at 3 different stages of development of the weeds and different amounts of drug wio

AS Concentrate l / ha AS X 300 X Developmental stage of the weeds 3-4 sheets 5-6 sheets 3 g / ha 400 1-2 sheets 22.4 33.4 handelsübl. 4 480 480 11.0 18.4 30.4 formulation 5 640 600 5.9 15.9 24.3 6 800 640 4.4 16.9 20.4 960 800 3.4 18.4 27.1 3 960 6.2 25.7 33.3 invention. 4 11.2 22.4 32.4 formulation 4.8 10.0 20.0 24.8 6 6.8 17.8 20.7 6.4 6.1 18.6 21.7 8th 6.4 12.7 19.7 9.6 3.9 10.4 15.8 3.9 18.3 24.1 6.8

Table 3 Residual weed after application of different application rates {untreated control = 100%) AS Concentrate

l / ha

AS g / ha

Developmental stage of the weed egg

1-2 sheets 3-4 sheets 5-6 sheets

handelsübl. Formulation according to the invention. formulation

3-6

3-6 4.8-9.6

720

450 720

18.4

21.6 15.4

27.1

27.8 20.5

The analysis of the determined residual weeds revealed that the respective effects correspond to:

at the date of the 1st application = 3l / ha commercial formulation

3 l / ha of the formulation according to the invention

6l / has.oben = 7.8 l / ha of the formulation according to the invention

to the date of the 2nd application

3 l / ha commercial formulation = 4.9 l / ha of the formulation according to the invention

6 l / ha commercial formulation = 7.8 l / ha of the formulation according to the invention

to the date of the 3rd application

3 l / ha commercial formulation = 3 l / ha of the formulation according to the invention

6 l / ha commercial formulation - 6.3 l / ha of the formulation of the invention

On average over deadlines and application rates, 0.95 l / ha of active ingredient concentrate are required for the formulations according to the invention in order to achieve the same herbicidal action as in the case of the commercially available formulation. However, since the active ingredient content differs in both formulations, for the same effect in the inventive formulation χ = 550g / ha of active ingredient and in the commercial formulation χ = 720g / ha drug required. The drug savings with the Formulieru invention. ig is thus 23%.

Function equations for the commercial formulation:

to date 1 y = 85 + 2,13

to the appointment 2 y = 76 + 2,12 to the appointment 3 y = 57 + 3,8

Function equation for the formulation according to the invention:

for appointment 1 for appointment 2 for appointment 3

y = 86 + 1.15 y = 72 + 2.13 y = 60 + 2.66

Example 2

Results of photosynthetic measurements Biological testing was performed on isolated chloropiasts of Vicia faba. The influence of esters and ketones and of the technical hexyl octyl ester mixture described in more detail in Table 1 on the electron transport in the photosynthetic apparatus was measured.

The Löeungsmittelkonzentration was 2 10 ~ ⁴ mol / l in the drug-free treatment solution.

The emulsion concentrates underlying the treatment solutions consisted of

70% solvent Table 4 electron transport 10% dimethylformamide and solvent (untreated control = 100%) 20% emulsifier. 149.8 1. ethyl acetate 98.8 2. n-butyl acetate 95.4 3. n-hexyl acetate 28.9 4. n-Oytyl acetate 37.0 5. technical ester mixture 215.5 6. phenylacetone 225.7 7. Cyclohexanone 175.2 8. Isophorone 105.5 9. Acetophenone 85.2 10. Propiophenone

The solvents 3,4,5 and 10 inhibit the electron transport in the photosynthetic apparatus of Vicia faba under the given experimental conditions.

This proves that the technical ester mixture (# 5, Table 4) contained in the formulation of the invention as a stabilizer inhibits photosynthesis.

In contrast, isophorone (solvent of the commercial formulation) an increase in photosynthesis was determined. This difference is also evident in connection with phenmedipham in the herbicidal properties of the formulation according to the invention and of the commercial middleid (Example 1, Tables 2 and 3).

Claims (5)

1. Emulsifiable carbamate active substance concentrates dissolved in acid amides, characterized in that are added as crystallization-inhibiting stabilizers acetic acid alkyl ester or mixtures thereof and acetic acid and alcohol. 2. emulsifiable active substance concentrates according to claim 1, characterized in that the acetic acid alkyl esters used as crystallization-inhibiting stabilizers b ^ w. Ester mixtures have an alkyl chain length between 5 and 10 carbon atoms. 3. Emulsifiable active substance concentrates according to claim 1 and 2, characterized in that the acetic acid alkyl esters or ester mixtures used as stabilizers contain 0.25-0.75%, preferably 0.5-0.6% of free acetic acid. 4. emulsifiable active substance concentrates according to claim 1 and 3, characterized in that the acetic acid alkyl ester or Essigsäurealkylestergemische used as stabilizers can contain up to 15% of an alcohol or alcohol mixture. 5. emulsifiable active substance concentrates according to claim 1, characterized in that as carbamate preferably 3- (methoxycarbonyl) -aminophenyl-N (3-methylphenyl) carbamate - (Phenmedipham) - is used.