DD299030A5 - HERBICIDAL AGENT - Google Patents

Abstract

The invention relates to a herbicidal composition, preferably for selective weed killing in beta-Rueben. Field of application of the invention are the chemical industry and agriculture. The herbicidal agent is characterized in that it contains 5-40% carbamate, 5-40% hydrotrope, 5-70% hydrosoluble fluid and 1-80% surfactant, and nitroaromatics are used as the stabilizer. Preferred nitroaromatics are nitrophenols or nitrobiphenyls such as o-nitrophenol, 2,4-dinitrophenol or * they are added to the concentrate in * preferably * {herbicidal agent; Unkrautbekaempfung; Beta Rueben; chemical industry; Agriculture; Carbamatwirkstoff; hydrotrope; surfactant; Stabilizer; nitroaromatics}

Description

Field of application of the invention

The invention relates to a herbicidal composition, preferably for selective weed control in beta beets. Areas of application of the invention are the chemical industry and agriculture.

Characteristic of the known state of the art

For weed control in beet stocks mainly carbamates are used. An essential representative: this class of substances is methyl-S-ß-tolylcarbamoyloxyl-phenylcarbamate with the common name Phenmedipham, which is the active ingredient of the known herbicide Betanal. It is known that the carbamates decompose depending on the pH, whereby phenmedipham has a hydrolysis resistance as half life at pH 4 of about 135 days, at pH 7 of about 5 hours and at pH 9 of about 10 minutes. Since the decomposition products shift the pH to the alkaline, the use of stabilizers for Unterbir. Young's pH shift required. Therefore, in almost all formulations with carbamate active ingredients for herbicidal purposes, the use of acids in concentrations of 0.1-1.0% in the concentrate. Suitable acids for stabilization are described in the patents US 3898075, DD 80898 among other citric acid, acetic acid, propionic acid and phosphoric acid. In the majority of cases, citric acid is used because of its good stabilizing properties. This is also included in the commercial preparations with Phenmedipham. The commercial Phenmediphampräparate contain as solvent but isophorone. Other solvents used for Phenmedipham such as surfactant ··, cyclohexanone, alkylacetate etc., although it can be used ebanfalls, but added to stabilize acids (including citric acid) cause accelerated crystallization of the active ingredient from the spray mixture. As a result, there is the disadvantage that faster than without addition of acid often the crystals formed lead to nozzle clogging of the application technique and the formulations are unsuitable for crop protection.

Object of the invention

The object of the invention is to find stabilizers for carbamate active ingredients which retard the recrystallization of the carbamates when water enters and which obtain the active ingredient in its starting compound.

Explanation of the essence of the invention

The invention has for its object to produce carbamate-containing concentrates that protect the active ingredients from decomposition, delay the formation of crystals in the spray mixture and maintain and promote the biological effect. The object is achieved in that a mixture consisting of 5-40%, preferably 10-20%, carbamate, 5-70%, preferably 20-40%, of its wasserschwerlöslichen liquid agent, 5-40%, preferably 10- 25%, of a hydrotrope and 1-80%, preferably 20-40%, of surfactant contents, are added as stabilizer nitroaromatics in the amount of 0.01-3%. The carbamate active ingredients used are predominantly phenmedipham, propam and proximpham and the water-sparingly liquid component anonol. The hydrotrope may be any water-soluble solvent that is readily soluble for carbamate actives. However, primarily dimethylformamide or dimethylsulfoxide are used. The surfactants used are usually Fettsäureglycerinesteroxäthylate, Alkylphenylpolyglykoläther or / and fatty alcohols.

As stabilizers nitrophenols or nitrobiphenyls are used in the first place, with ortho-nitrophenol and 2,4-dinitrophenol and 2-hydroxy-3,5-dinitrobiphenyl are particularly suitable. They are preferably added in such an amount that the proportion in the concentrate is 0.1-1%.

Surprisingly, it has been shown that the nitro compounds used according to the invention have a stabilizing effect on carbamate active ingredients. It was also surprising that, in contrast to the acids used hitherto, the crystallization of the carbamates from the spray mixture is not enhanced. The stabilizing effect of the stabilizers according to the invention is demonstrated by determination of the active ingredient content after a certain storage time of the concentrates and blanking of the herbicidal action of the formulations.

Exemplary embodiments |

example 1

Concentrate with stabilizer 10% Phenmedipham 20% Dimethylformamide 35% Anon oil

34% surfactant mixture 1% dinitrophenol

Concentrate without stabilizer 10% Piienmedipham 20% Dimethylformamide 35% Anonol 3F.% Tcnsidgemisch

Height of Phonmedlphamgehaltes Comparison of the two concentrates

Formulation amount of Phenmedipham detected content

in both formulations in%

13.4.88 19.7.88

without stabilizer 8.9 2.9

with stabilizer 9.4 9.9

This proves that Diniti ophenol stabilizes the phenmedipham drug for at least 3 months.

Example 2

Concentrate with stabilizer 15% Phenmedipham 20% Dimethylformamide 30% Anon oil

34% fatty alcohol surfactant with ethylene and propylene oxide groups 1% dinitrophenol

Concentrate without stabilizer 15% Phenmedipham

20% dimethylformamide ·

30% anone oil 35% fatty alcohol surfactant with ethylene and propylene oxide groups

Height of Phenmediphamgehaltes in comparison of the two concentrates

Formulation Amount of the detected phenmedipham content

in comparison of the two concentrates in%

18.12.87 1.8.88

without stabilizer 15 0.9

with stabilizer 15 14.5

This proves that dinitrophenol causes a Phenmediphamstabilisierung of at least 8 Moi ι men.

Example 3

In the crystallization test, the commercial product betanal and the inventive formulations according to Examples 3a and 3b were tested for the beginning of the carbamate recrystallization.

The test was carried out by diluting the emulsion concentrate of each formulation with water from 20 ° dH to 3.2%.

100 ml of this was stirred at 15 ⁰ C with a magnetic stirrer at constant speed of 400 rev / min until the first signs of incipient recrystallization of the active ingredient became noticeable. The time from the start of the experiment to the first appearance of crystals in the emulsion is used as a basis for evaluating the recrystallization properties. The times of incipient recrystallization of phenmedipham determined by this method are listed in the following table:

Recipe 3 a

10% phenmedipham 20% dimethylformamide 34% anone oil

35% alkylphenyl polyglycol ether surfactant 1% dinitrophenol

Recipe 3K

10% phenmedipham 20% dimethylformamide 34% anone oil

35% alkylphenyl polyglylether surfactant 1% citric acid

table

Start of crystal formation of phenmedipham in minutes

Commercial product betanal based on isophorone

undmitZitronensäure

Recipe 3 a Recipe 3 b

75 minutes

clouded after 75 minutes of microemulsion, no crystals for 25 minutes

Thus, it was possible to prove that in formulation 3 a according to the invention the crystallization of phenmedipham is delayed more than in recipe 3b and in betanal.

Example 4

In the greenhouse, the herbicidal action on Ackersenf (Sinapis alba) of the commercial product Betanal was tested as Phenmediphamstandard and the inventive composition according to Example 1 with and without stabilizer. The storage time of the products was 8 months. The success rating was completed after 14 days. According to the notes 1, no effect was awarded until grade 9 = plants totally destroyed. The conversion of the Boniturnoten in herbicidal activity in% was carried out according to the key

Boniturnote iieibicidal activity in% 1 0 2 5 3 19 4 30 5 50 6 70 7 85 8th ϋ5 9 100

The results obtained are listed in the following table: Table

recipe Phenmodipham / ha herbizideV.irkung at Ackersenf in%, 0 from 10Versuchen Commercial product Betanal 400 71.5 inventive formulation according to Example 1 with Stabilir ator 400 91.0 erfindungsgf Permitted formulation Example 1 without stabilizer 400 10.0

This proves that nitrophenol stabilizes the active ingredient and the herbicidal activity is higher than betanol. The absence of nitrophenol (stabilizer) in the formulation according to the invention led to the degradation of the active ingredient (see Example 1) and to the loss of the herbicidal action.

Claims (5)

1. A herbicidal composition, preferably for selective weed control in beta-beets, consisting of carbamate, hydrotrope, a wasserschwerlöslichen liquid agent, a surfactant and a stabilizer, characterized in that it 5-40%, preferably 10-20%, carbamate, 5 -40%, preferably 10-25%, hydrotrope, 5-70%, preferably 20-40%, water-soluble liquid agent and 1-80%, preferably 20-40%, containing surfactant and are used as stabilizer nitroaromatics. 2. A herbicidal composition according to claim 1, characterized in that as carbamate methyl 3- (3-tolylcarbamoyloxy) phenylcarbamate (Phenmedipham) and / or Isopropylphenylcarbamat (prophy) and / or Propanonoximphenylcarbamat (Proximpham), as a hydrotrope dimethylformamide, N-methylpyrrolidone Hexamethylphosphorsäurelriamid or dimethyl sulfoxide, as a water-soluble liquid agent Anonöl and as surfactants Alkylphenylpolyglykoläther, Fettsäureglycerinesteroxäthylate or fatty alcohols. 3. Herbiz'des agent according to claims 1 and 2, characterized in that nitrophenols or nitrobiphenyls are used as stabilizers. 4. A herbicidal composition according to claims 1-3, characterized in that as nitrophenols preferably ortho-nitrophenol or 2,4-dinitrophenol and as nitrobiphenyl 2-hydroxy-3,5-dinitrobiphenyl are used. 5. A herbicidal composition according to claims 1-4, characterized in that the stabilizers account for a proportion in the concentrate of 0.01-3%, preferably 0.1-1%.