LU82129A1 - BASIC SOLUTIONS OF N'-ALOCORY-N'-ALKYL-N-PHENYLUREES - Google Patents

Description

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% v »ι! 5 N * -ALCOXY-N'-ALKYL-N-PHENYLUREA-BASED SOLUTIONS.

The present invention relates to solutions with herbicidal properties! * based on N-phenylureas comprising a substituent of the N'-alkoxy-N'-alkyl type, I these solutions still being in the liquid state at temperatures below 0 ° C.

^ The invention relates more particularly to solutions such as dëfi- | above, stable on storage, which neither solidify nor give rise to the formation of precipitates at temperatures as low as -10 ° C, and which, in addition, confer improved activity on the formulas, containing them,. by comparison with those of the formulas conventionally used for the treatment of soils.

N'-alkoxy-N'-alkyl substituted N-phenylureas form a known class of herbicides studied in particular by Farbwerke Hoechst AG and by the Société Du Pont de Nemours.

1i Among these herbicides, certain compounds such as, for example, "LINURON" ® [N- (3,4-dichlorophenyl) -N'-methoxy-N'-methylurëe] have already been placed in! commercially and are used as herbicides in pre-emergence treatments as well as in post-emergence treatments.

These compounds are very slightly soluble in water, relatively poorly soluble in aliphatic and aromatic hydrocarbons, relatively soluble in water. ethanol and acetone, although the solutions in these latter solvents do not. are not stable over time and, at low temperatures, give rise to precipitates.

These facts make it difficult to prepare liquid formulas based on "LINURON" which, in particular, are stable at low temperatures.

In British Patent No. 1,449,768, in the name of the Swiss Company Ciba-Geigy, a liquid formula is described, consisting of: 35 a) at least one herbicidal compound of general formula:

X - O - CH2 - CH2 - O - R

in which: x is an alkyl or alkoxyethyl radical, and J a R is a hydrogen atom or an alkyl or alkoxyalkyl radical:> | B) another herbicide different from A), in the form of a homogeneous solution; 4 * "% · 2. and, optionally, an aerosol propellant, diluents, surface-active agents, pigments, anti-corrosion agents, etc.

The table on page 6 of this British patent describes a composition containing 4-butoxy-2-ethanol as component A, LINURON ^ and BROMACIL ^ as component B and Sudan Red ( CI: Red Solvent 1) as a co-adjuvant.

The diluents claimed in claims 10 and 11 of this British patent 3 are, inter alia:] - water, j 10 - dimethylsulfoxide, I. - alkyl derivatives of naphthalene, * - benzene, toluene, xylol, i - aliphatic hydrocarbons, {- chlorinated hydrocarbons, ί! 15 - heterocyclic oxygen compounds,! - friends of carboxylic aliphatics, and - esters of alkanoic acids and alcohols having 3 to 15 carbon atoms.

This British patent does not mention the stability of LINURON solutions at temperatures below 0 ° C; it is also not possible to deduce from this patent the solubility of LINURON or of other N'-alkoxy-N'-alkyl-N-phenylureas in the solvents indicated.

i Thus, for example, it is known that LINURON and, in general, j N'-alkoxy-N'-alkyl-N-phenylureas, are soluble in dimethyl sulfoxide in amounts up to 55¾ by weight; at low temperatures, however, the solution becomes solid and, at 0 ° C, forms a tall Cree-4 mass.

It is found that at low temperatures the solutions of N'-alkoxy-N'-alkyl-i 'N-phenylureas in dimethylformamide or dimethylacetamide exhibit a; excellent stability; in these latter solvents, the N-phenylureas are so- | 30 fads at about 40% by weight of the solution, and the solutions prove to be stable even at low temperatures; they are however too expensive to be used when it is desired to put the N-phenylureas in the form of solutions.

. It has been possible to obtain, and this forms the object of the present invention, stable solutions, even at temperatures of the order of -10 ° C, and which; . * are made up of: î î-

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3! - N'-alkoxy-N'-alkyl-N-phenylureas ............ 0.05 to 40% - Solvent A ............... .................. 99.9 to 24% 1— Solvent B ...................... ........... 0.05 to 35%

In these solutions: 5 · Solvent A can be dimethylformamide, dimethylacetamide, dimethyl- | i sulfoxide, while * é - »Solvent B can be a chlorinated hydrocarbon, such as, for example, i Λ • 1,2,3-tri ch1 oropropane; or aromatic hydrocarbons, such as: "| : toluene, xylol, ethylbenzene, styrene; ketones such as: isoforone, methyl ethyl ketone, ethylamyl ketone, cyclohexanone, acetophenone; ! i * | cyclic ethers such as: dioxane, esters of aliphatic or aromatic organic acids such as methylbenzoate, benzylacetate, 2-ethoxyethyl] acetate, diethylmaleate; mixtures of hydrocarbons such as: Solvesso 200 \, (trade name of "Esso Company", for a mixture based on; dimethyl-, ethyl- and tetramethyl-benzene); Shellsol AB (trade name of "Shell Company", for mixtures based on dimethyl-, \ ethyl- and tetramethylbenzene), alone or as mixtures with one another;

In general, A can be any solvent miscible with B, even if it does not have solvent properties with respect to N-phenylureas, with the exception of aliphatic acid alcohols and hydrocarbons.

; The stability of such solutions is surprising in itself because the presence) of Solvent B, in which the N'-alkoxy-N'-alkyl-N-phenylureas are little or! practically poorly soluble, does not reduce at all the solubility which turns out to be approximately equal to that of N-phenylureas, as if the whole of | The solvent mixture was Unmodified Solvent A.

1 Furthermore, while in pure Solvent B the phenylureas are altered at | k storage or tend to form crystalline precipitates in the mixture of Solvents A and B, this phenomenon does not occur in the case of the invention.

Table 1 below shows the stability values of LINURON in t - 30 various solvents and in the solvent mixtures of the invention, after t 5 respectively 7, 14 and 30 days at a temperature of the order of 54 ° C.

IJ The titer is determined by gas-liquid chromatography.

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Obviously, ionic or nonionic surfactants and / or propellants can be added to the solutions according to the invention. they can also be used for the preparation of wettable powders, aqueous suspensions, etc., according to. known methods for obtaining 5 such formulas. It therefore becomes possible to store these compositions or to use them under temperature conditions at which it has not been possible to use them until now. The formulations comprising the solutions according to the invention have an improved activity compared to that exhibited by the herbicidal formulations comprising the same amount of LINURON, as shown in Example 9 below.

s Other advantages and characteristics of the present invention appear? will read the following description and examples given as such; illustrative but not limiting.

EXAMPLE 1 0.05 g of the compound: ^ "/ ° ch3

Cl - / ()) - N —C-NC

i ^ “3 20 is dissolved in a mixture of 99g of dimethylformamide (DMF) and 0.05g of xylol, with constant stirring for 20 min at a temperature of about 25 ° C.

A completely clear solution is thus obtained, 50g of which are maintained for 30 days at a thermostabilized temperature of 54 ° C, while another 50 grams of this solution are kept in a refrigerated enclosure at -10 ° C. It is noted that the two samples having undergone the two abovementioned treatments are not altered.

The analysis of the two samples carried out directly on the solution by liquid-gas chromatography shows that the LINURON® was present in both cases in the solution in a concentration of 0.05¾.

EXAMPLE 2 40 g of-LINURON are dissolved in a mixture formed of 24 g of DMF and 36 g of xylol, and the mixture is kept at the temperature of 25 ° C., with stirring, for 20 minutes. (It should be noted that the dissolution of the substance is very endothermic, and that it is necessary to facilitate it by supplying heat).

J This gives a completely clear solution, 50g of which are placed during s ". 30 days in a thermostabil ized heating enclosure at 54 ° C, while t 6 50g of the solution are placed in a refrigerated enclosure at -10 ° C.

The two samples of solution thus treated prove to be unaltered, j Analysis of the two samples of solution directly removed from the solution

'· Mentioned above, carried out by liquid-gas chromatography shows that the LINURON

5 was present in both cases at a concentration of 40¾ of the solution.

EXAMPLE 3 40 g of LINURON are dissolved in a mixture formed of 24 g of dimethyl sulfoxide (DMSO) and 36 g of xylol, the mixture being kept under constant stirring for 20 min, at a temperature of the order of 25 ° C.

10 (It should be noted that the dissolution of the substance is very endothermic and that the dissolution is facilitated by the supply of heat).

A completely clear solution is thus obtained.

: ". 50g of this solution are placed for 30 days in a heated cell at a thermostabilized temperature of 54 ° C, while another 50 grams of the solution are placed in a refrigerated enclosure at -10 ° C.

The two samples thus treated prove to be unaltered, j The analysis of the two samples of solution withdrawn directly from the solution is carried out by liquid-gas chromatography; this analysis shows ·; that LINURON is present in both samples at a concentration of! 20 40%.

f î EXAMPLE 4

By operating according to the same method as that described in Examples 1, 2 and 3, the solutions described in Table II # below are prepared.

Next, 50 g of each of these solutions are placed in a thermostabilized enclosure at a temperature of the order of 54 ° C, while another 50 grams of the solution are placed in a refrigerated enclosure at -10 ° C.

The two samples thus treated reveal that no alteration has occurred.

30 The analysis of these two samples, carried out directly by liquid-gas chromatography shows that the LINURON is present in the two devolution samples in concentrations equal to the initial concentrations! respective ones.

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8 t EXAMPLE 5

By operating according to the same methods as those described in

Examples 1, 2 and 3 ”a solution consisting of 40 g of LINURON® 25 g of dimethylacetamide and 36 g of xylol is prepared.

5 Two samples of 50 g of the solution are stored respectively for 30 days, at a thermostable temperature of 54 ° C and for 48 hours at -10 ° C, and it is found that the samples thus treated do not undergo any alteration. ;

On analysis by liquid-gas chromatography, it can be seen that the LINURON

10. is present in the solution in a proportion of 40% by weight of the solution.

j | EXAMPLE 6 40g of M0N0LINUR0N® of formula:: o 15 / r \ 11 ^ / OCH3 cl rc “<cHa

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Are dissolved in a mixture formed of 24 g of dimethylformamide and 36 g of xylol, with constant stirring for 20 min at a temperature of the order of 20 of 25 ° C. A completely clear solution is thus obtained, 50g of which are kept at a thermostabilized temperature of 54 ° C for 30 days and t 50g at a constant temperature of -10 ° C for 30 days.

* The two samples thus treated show that no alteration occurs. In both cases, 10 g of a solution are dried under vacuum obtained by mechanical pumping means, at a temperature between 70 and 75 ° C.

4.1g of a dry residue is thus obtained which, after recrystallization, has a melting point of between 70 and 72 ° C (M0N0LINUR0N® Pp = 72 ° C), and; whose IR spectrum coincides with the spectrum of the starting M0N0LINUR0N; 30 this confirms that a percentage of 40% by weight of active substance is used at the start.

EXAMPLE 7 40g of Monobromu of formula: ron 35 _ 0 / λλΧ 11 / och3. i ^ ch3

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1 are dissolved in a mixture formed of 24g of dimethylformamide and i "I: 9 * I 36g of xylol, with constant stirring, for 20 min, at a temperature of 25 ° C.

; 'A completely clear solution is thus obtained, 50g of which are kept for 30 days at a stabilized temperature of 54 ° C and 50g at a temperature of -10 ° C. The samples having undergone these treatments reveal that none! 5 tampering has occurred.

In both cases, 10 g of the solution are dried under a vacuum obtained by mechanical pumping at a temperature between 70 and 75 ° C.

: A dry residue is thus obtained which, after recrystallization, has a melting point of between 94 and 96 ° C (METABR0MUR0N® Pp = 95.5-96 ° C); j. 10 we see that the IR spectrum coincides with the IR spectrum of METABR0MUR0N® | of departure, which confirms the employment at the start of a percentage of 40¾ en | weight of active substance.

I. EXAMPLE 8 | - 15 By operating according to the same method as that described in | 'Example 2, the following formula of an emulsifiable concentrated type is used: | · LINURON t 30, Og I · DMF. î 22.0g · *.

• Xylol% 38.0g 20. TBP EMULSION | 10.0g; On this formula, tests of evaluation of the agronomic properties are carried out. It is noted that the activity obtained is greater than that exerted by the usual formula formed by: \ · LINURON t 50¾ 25 · Kaolin J 20¾ • Silicon Ξ 20¾ - 3- • Ligninsulfonate ~ \ sodium ^ 10¾. * These tests are carried out in the wild, on land in Region 30 of Italy called Emilia-Romagna.

: They are carried out on potato crops (cv. Jaerla), vines (cv, Lambrusco Maroni), fruits (apple trees cv. Starling, cv. Star | Crimson, cherry trees, lemon trees).

I The treatment is a pre-emergence treatment for infestations and! ^ 35 in the case of potatoes, post-sowing, after suitable work ï | of the ground.

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The tests are carried out according to the principle of statistical batches by repetition of the tests (tests) four times on plots of 20 m2 for potatoes and on plots of 5 to 20 ni2 for vines and | fruit trees.

I 5 The results are determined by counting the number: infestants present on the plots. The results are recorded in Table III, below: * TABLEAUin: 10 Frequency = No. = Number of the various infestants / m2.

i 1 <* i ——.....- (- - —— \ î 1 DOSE Euphorbia Chenopodivm Polygonum

Product of substance peplue-patata album-patata aviculum vine active „î (kg / ha) No 'No' __ No '* 1 - - ι · -Il -' —I - - .1-" 'I · "' 1 ' 15 - LINURON OE 30 0.7 3.9 0.2 0.03. .. .. OE 30 1.0 2.9 0.08 0.03: .... OE 30 1.2 1.0 0.08 0 i - LINURON PB 50 0.7 5.7 0, h 0 , 1 day .. .. PB 50 1.0 2.9 0.2 0.1] m .. PB 50 1.2 3.0 0.08 0.03 1 20 - WITNESS ...... - 8.1 2.9 0.8; DOSE Veronica Verorvica Portulaca ί \ persica APPLE persica APPLE oletacea ch.

• active Starling Star Cr.

i (kg / ha) No. No. No.

25 - LINURON OE 30 0.7 3.5 1.8 h, 3 .. .. OE 30 1.0 1.5 1.8 L, 0 .. .. OE 30 1.2 O 0.3 2, 7 - LINURON PB 50 0.7 5.0 1.8 5.6 l - M PB 50 1.0 1.8 2.0 5.3 I "- PB 50 1.2 0.3 2.0 5, 0:30 - WITNESS ...... - 8.0 15.0 50.0

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I CONCLUSIONS B

A new formula of LINURON® with 30% of active principle, used during i * the period of pre-emergence of the infestants in the weeding of crops of fl · jj potato, vine and nursery, gives place, for doses equivalent to a higher herbicidal activity than that of formulas containing commonly used wet powders.

; 4 No negative manifestation was noted on the cultures examined.

The activity ratio between the two LINURON formulas on the cultures tested was as follows: i: * ·; i * 10 '0.750 / 0.800 kg of active substance at 30% LINURON OE corresponds,)', * | with regard to the activity, to 1 kg of active substance of LINURON PB 50,! t OE * = emulsion according to the present invention.

; PB ** = commercial humidifiable powder.

Of course, the present invention is in no way limited to the examples | and modes of implementation described above; it is susceptible of numerous variants accessible to a person skilled in the art, depending on the applications i envisaged and without departing from the spirit of the invention.

%?! 3

Claims (3)

12 * 1. N'-alkoxy-N'-alkyl-N-phenylurea-based solutions stable at storage conditions and at temperatures of -10 ° C, suitable for the preparation • of formulas consisting of: 5. N'-alkoxy-N'-alkyl-N-phenylrees ......... 0.05 to kQ% - Solvent A ................. ............. 99.9 at 2k% - Solvent B ............................ .. 0.05 to 36% in which: - solvent A is formed from dimethylformamide, dimethylacetamide, dimethyl->. , 10 tallow oxide; and ï - the solvent B is any solvent miscible with A, with the exception of alcohols, aliphatic acids and hydrocarbons. 2. Solutions according to claim 1, characterized in that the solvent B consists of aromatic hydrocarbons such as xylol, toluene, dimethyl-, ethylbenzene, tetamethylbenzene, and more generally alkylbenzene, or aliphatic ketones such as isophorone, methyl ethyl ketone , ethylamyl-; ketones, or cyclic ketones such as cyclohexanone, acetophenone or esters of aliphatic or organic organic acids such as; methylbenzoate, benzylacetate, 2-ethoxy-ethyl-acetate, or chlorinated hydrocarbons such as 1,2,3-trichloropropane, or mixtures of several of these compounds such as those sold under the trade names of Shellsol ( a composition based on dimethyl ethyl and tetamethylbenzene), or of Solvesco (a composition based on dimethyl ethyl and tetamethylbenzene). 3. Solutions according to claim 1 or 2, characterized in that they. 25 are added ionic surfactants ^^ __ ^ i! j