DD251276A5 - STABILIZED LIQUID HERBICIDES COMPOSITIONS BASED ON M-BIS CARBANATES AND THEIR USE - Google Patents

Abstract

The invention relates to stabilized liquid herbicidal compositions based on m-biscarbamates. The invention provides stable herbicidal compositions which are also stable upon storage in a concentrated state and when dehydrated with water. The object of the invention is to provide novel compositions which have a strong herbicidal action and have a high stability. Homogeneous liquid herbicidal compositions containing a biscarbamate of the formula (I) in which X is a hydrogen atom or a C 1 -C 3 -alkyl radical and R is a C 1 -C 3 -alkyl radical, characterized in that they contain: - 5 to 500 g / l Active substance of the formula (I), preferably 100 to 250 g / l; -100 to 700 g / l tributyl phosphate; -50 to 300 g / l of a water-miscible organic solvent which has good solubility for the carbamate of the formula (I) -50 to 300 g / l of one or more non-ionic surface-active agents. Formula (I)

Description

Field of application of the invention

The present invention relates to stabilized liquid herbicidal compositions based on m-biscarbamates. It particularly relates to compositions in the form of concentrated emulsifiable solutions. By m-biscarbamates is meant the herbicides of the following formula (I):

NH-CO-O - / S NH-CO-O-R

(D

wherein X is hydrogen or a C 1 -C 3 -alkyl radical and R is a C 1 -C 6 -alkyl radical. Representative examples of herbicides of this class are:

Phenmedipham: common name for the compound of formula (I) in which X and R denote the methyl radical.

- Desmedipham: common name for the compound of formula (I) in which X is hydrogen and R is the ethyl radical. These compounds are generally available in the form of liquid compositions, which are diluted with water prior to use to give spray liquors containing the active ingredient in the required concentration.

Characteristic of the known technical solutions

Numerous types of phenmedipham formulations have been proposed. One of the most common formulations is an emulsifiable concentrate which uses as its solvent the isophorone according to the French patent 1 536108 and an acid type stabilizer according to the French patent 2028876 as well as a surface-active agent.

The disadvantage of these concentrates is associated with the presence of isophorone, and in particular with its toxicity and associated odor problems, and likewise with the fact that these concentrates have a strong tendency to form crystals upon dilution with water.

Furthermore, the isophorone-based concentrates can not have a very high phenmedipham concentration.

Stabilized formulations containing both dimethylformamide or dimethylacetamide and a surfactant such as a phosphate of polyethoxyalkylphenol have also been proposed in both physical and chemical terms (French Patents 2462101 and 2 530122). These compositions are presented as agents which ensure the chemical stability of the active substance and the physical stability when stored in the concentrated state.

As mentioned above, the formation of microcrystals (crystals of size greater than or equal to 40μ) is detrimental to dilution with water, particularly because it results in clogging of the spraying solutions for the spraying solutions used by the agricultural users can; Crystal formation may also be detrimental to the herbicidal activity.

Object of the invention

The object of the present invention is to provide stable compositions from any point of view, also stable when stored in a concentrated state and when diluted with water.

Another object of the invention is to provide compositions with improved activity, i. H. those that give good herbicidal results when used in reduced amounts of active substance.

Another object of the invention is to arrive at concentrates with high content of Phenmedipham.

Explanation of the essence of the invention

The object of the invention is to provide novel compositions which have a strong herbicidal action and a high stability.

These compositions are homogeneous liquids, characterized in that they contain:

- 5 to 500 g / l of active substance of the formula (I), preferably 100 to 250 g / l; the active substance is preferably phenmedipham;

100 to 700 g / ITributyl phosphate;

- 50 to 300g / l of a water-miscible organic solvent for the carbamate of formula (I); usable solvents are, for example, dimethylformamide, cyclohexanone, dimethyl sulfoxide, acetophenone, but preferably N-methyl-pyrrolidone is used;

From 50 to 300 g / l of one or more nonionic surfactants; this surfactant generally has emulsifying properties; if appropriate, other surfactants may be added to it, in particular anionic surface-active emulsifying aids which do not constitute more than 50% of the sum of the nonionic surfactants.

All figures in g / l denote the number of grams of substance under consideration per liter of the liquid composition of the invention to which it is added.

In practical terms, solutions of the invention are homogeneous at least at ambient temperature (20 ⁰ C). Among the nonionic surfactants which can be used according to the invention, mention may be made of the polyethers, in particular the polyethoxylated and / or polyoxypropylated (in particular the derivatives having a C ₈ -C ₁₂ -alkyl group) alkylphenols or polyalkylphenols or polyarylalkylhenols, the aliphatic polyethoxylated and / or polyoxypropylated alcohols (in particular Ce -C ₂ O- and especially Olein- and Ketylalkohol), the polyethoxylated and / or polyoxypropylated esters of fatty acids (especially C ₆ -C ₂ O) / the polyethoxylated and / or polyoxypropylated esters of anhydrosorbitol (= sorbitan), the polyoxypropylene glycols, the polyethoxylated polyoxypropylene glycols, and the copolymers of alkylene oxide and the esters of these polyethers. In the majority of these products, the polyethoxylated or polyalkylene chains generally consist of 2 to 30 ethoxy or oxyalkylene groups.

An anionic surface-active agent having emulsifying properties may be mentioned as the phosphates of polyethoxylated (monophenyl-i-ethyl) phenol of the formula (II):

: O = P- (OCH ₂ -CH ₂ ) _m -O-C ₆ H _5-2 (Ar) ₂ , _(II)

in the

m is an integer between 1 and 80,

Ar is a 1-phenylethyl radical, preferably of 8 to 16 carbon atoms, which may itself be optionally substituted, ζ is an integer equal to 1,2 or 3 and

Y is a radical OH or the group means:

(OCH ₂ -CH ₂ LOC ₆ H ₅ -Z (Ar) ₂

in which m, Ar and ζ have the abovementioned meaning.

Preferably, this surfactant is the monoester or diester of phosphoric acid with the polyethoxylated bis- or tris- (monophenyl-1-ethylphenol.) The monoester of polyethoxylated tris (monophenylethyl) phenol has the formula

OH

O = P- (O-CH ₂ -CH ₂ ) _m - O- (ZV-CH - GH.

^0H OH, -0

As another anionic surfactant (emulsifying aid) may also be mentioned the salts of aliphatic monoesters of sulfuric acid, z. For example, sodium lauryl sulfate, the salts of aromatic sulfonic acids such as calcium or Natriumdodecylbenzolsulfonat, and the Calciumalkylarylsulfonate.

Other common anionic or nonionic surfactants can be used without departing from the scope of the invention.

The amounts of surfactant can vary within very wide limits.

The compositions of the invention are prepared in the form of concentrated emulsifiable solutions. It then suffices to dilute it with a certain amount of water in order to obtain ready-to-use spray liquors.

In addition to the above-mentioned ingredients, the compositions of the present invention may optionally contain various other ingredients or additives common in the field of agricultural product formulation, in particular other solvents, other surfactants, penetrants, corrosion inhibitors, adhesives

The present invention also relates to a process for the herbicidal treatment, in particular of beet crops and especially of sugar beet crops, which consists in treating, after infestation, a field planted with a beet crop with an effective amount of a composition according to the invention which is diluted with water such that it forms a spray mixture. The spray mixture used for this treatment process generally contains 1 to 10 g of active substance per liter of spray mixture applied (diluted with water), preferably 1.1 to 6 g / l. In general, from 120 to 2000 g / ha of the active ingredient of the formula (I) is used according to the same method for the herbicidal treatment according to the invention, preferably 250 to 1000 g / ha.

The examples illustrate the invention and demonstrate possible applications; they do not represent a limitation of the invention:

embodiments

Liquid compositions are prepared in the form of concentrated emulsifiable solutions of the following composition in g / l solution (each of the compositions listed below has a volume of one liter):

Composition No. 1:

Phenmedipham 160 g

Tributyl phosphate 375 g

N-methylpyrrolidone 100 g

Cyclohexanone 200 g

polyethoxylated tris (phenyl-1-ethyl) phenol phosphate (monoester with two free acid functions;

16-18 ethoxy units per mole of phenol) 20 g

Nonylphenyl copolycondensed with ethylene oxide and propylene oxide (in the ratio 3: 1, 42 units

Oxyalkylene) 130 g

Calcium dodecylbenzenesulfonate 45 g

Composition No. 2:

Phenmedipham '200g

Tributyl phosphate 530 g

N-methylpyrrolidone 100 g of polyethoxylated tris (phenyl-1-ethyl) phenol phosphate (equal to that of the composition

NM). 20g

Copolycondensed nonylphenol (equal to that of Composition No. 1) 130 g

Calcium dodecylbenzenesulfonate 45 g

Composition No. 3:

Phenmedipham 200 g

Tributyl phosphate. 580 g

N-methylpyrrolidone 50 g of polyethoxylated tris (phenyl-1-ethyl) phenol phosphate (equal to that of the composition

N.1) 20g

Nonylphenol copolycondensed (equal to that of Composition No. 1) 130 g

Calcium dodecylbenzenesulfonate 45 g

Composition No. 4:

Phenmedipham 225g

Tributyl phosphate 550 g

N-methylpyrrolidone 100 g of polyethoxylated tris (phenyl-1-ethyl) phenol phosphate (equal to that of the composition

No. D 20g

Nonylphenyl, copolycondensed (equal to that of Composition No. 1) 130g

Calcium dodecylbenzenesulfonate 45 g

Composition No. 5:

Phenmedipham 160 g

Tributyl phosphate 395 g

N-methylpyrrolidone 100 g

Cyclohexanone 200 g

Nonylphenol copolycondensed (equal to that of Composition No. 1) 130 g

Calcium dodecylbenzenesulfonate 45 g

Composition No. 6 used is the emulsifiable concentrate based on isophorone, which is commercially available under the name Betanal and contains 157 g / l of phenmedipham. This concentrate corresponds to French patents 1,536,108 and 2,108,876.

storage stability

These six compositions were held at -5 ° C for seven days without the formation of precipitate or crystals being observed. After one month at 50 ° C, no chemical degradation was observed.

Stability when diluted with water

A test was performed to determine the propensity of the compositions to form crystals by dilution with water, the formation of crystals over 40μ in size being considered detrimental.

In 980 ml of water are added within 40 seconds with stirring (for homogenization) 20 ml of the substance to be examined. Forming a precipitate by adding 300 mg of solid phenmedipham is suggested.

After 24 h, it is filtered through a sieve with a mesh size of 40 μ. The precipitate is washed with a jet of water for 1 minute. The precipitate is collected, dried and then weighed.

The above-described test was used to control the spray liquors obtained by diluting the compositions Nos. 1 to 6 with water. On the one hand, the spray mixtures were diluted to the extent that they contained 2.5 g / l of phenmedipham and, on the other hand, that they contained 1.5 g / l of phenmedipham. Such dilutions are on the order of magnitude of the dilution of spray liquors used by farmers in weed control in crops; the concentrated solutions, on the other hand, are those that are stored and handled before dilution to a spray liquor.

In the following, the amount of phenmedipham which forms microcrystals of a size greater than 40 μ is given in% by weight.

Composition no.% Microcrystallized Phenmedipham

Dilution on Dilution on 1.5 g / l 2.5 g / l 6 4 0 0 0.5 0.5 1.5 1 3 2 50 16

Composition No. 6 has much lower values than the compositions according to the invention.

Herbicidal activity

The water-diluted Composition No. 1 was applied to two beet crops affected by various weeds. A comparison was made with Composition No. 6 and the percentage of annihilation was measured. The following results were obtained:

Combined dose percentage destruction,

Activation of an untreated culture

No substance effect on the

in g / ha turnip

I. Culture 2. Culture

Overall effect on the weeds

I. Culture 2. Culture

6 1000 0 5 70 50 0 5 70 50 1 approved dose 0 1 0 70 ' 40 6 750 3 70 40 1 500 375

It is noted that the composition of the invention possesses excellent herbicidal activity and even allows for a reduction in the dose of active substance of about 25% based on the doses of the known commercial product and more particularly on the normal dose approved by the competent agricultural authorities. The selectivity (not destruction of the culture) is completely satisfactory.

Claims (7)

1. Homogeneous liquid herbicidal compositions containing a biscarbamate of the formula: NH-CO-OT ^ I-NH-CO-O-R in which X is hydrogen or a C 1 -C 5 -alkyl radical and R is a C 1 -C ₃ -alkyl radical, characterized in that they contain: From 5 to 500 g / l of active substance of the formula (I), preferably from 100 to 250 g / l; 100 to 700 g / ITributyl phosphate; - 50 to 300 g / l of a water-miscible organic solvent with good Dissolving power for the carbamate of the formula (I); - 50 to 30 g / l of one or more nonionic surfactants. 2. Compositions according to item 1, characterized in that the biscarbamate is the phenmedipham. 3. Compositions according to item 1 or 2, characterized in that the organic solvent is N-methyl-pyrrolidone. 4. Compositions according to one of the items 1 to 3, characterized in that they additionally contain an anionic surfactant which does not constitute more than 50% by weight of the total of the nonionic surface-active agent. 5. A process for herbicidal treatment, characterized in that applying to a field with a beet crop, an effective amount of a spray mixture which is obtainable by diluting a composition according to any one of items 1 to 4 with water. 6. The method according to item 5, characterized in that one uses a diluted with water composition containing 1 to 10g / l biscarbamate of formula (I), preferably 1.1 to 6g / l. 7. Process according to item 5 or 6, characterized in that 120 to 2000 g / ha of the biscarbamate of the formula (I) are used, preferably 250 to 10OO g / ha.