RU2620092C1 - Method for obtaining working fluid of herbicidal agent - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: working fluid of a herbicidal agent is prepared immediately prior to use by means of reacting herbicidally effective amount of substituted sulfonylurea with a trialkylamine containing one alkyl radical with at least 8 carbon atoms, while taken in an equimolar or excess molar quantity with respect to the substituted sulfonylurea, in aqueous medium. The ratio of the trialkylamine containing one alkyl radical with at least 8 carbon atoms and the substituted sulfonylurea is (1-1.05):1, respectively. The trialkylamine is pre-emulsified in water.

EFFECT: simplified process.

4 cl, 4 tbl

Description

This invention relates to agriculture, namely, to a method of using substituted sulfonylureas in the fight against weed and undesirable vegetation in crops of crops.

The fact of the low stability of sulfonylurea preparations in the form of aqueous solutions and emulsion concentrates is well known.

This circumstance contributed to the creation in the system of plant protection chemicals of a high-tech production scheme that is unstable in aqueous and organic media, in particular, substituted sulfonylureas, formulations in the form of dry water-dispersible granules (hereinafter referred to as EDC) and dry fluid suspensions (hereinafter referred to as STS) (List pesticides and agrochemicals approved for use on the territory of the Russian Federation, M., 2011).

Having an obvious technical effect, it should be noted, however, that the technology for formulating EDC, STS itself is quite complex and to some extent affects the economics of using sulfonylurea preparations in agricultural practice (Kuznetsov V.M. Chemical-technological basis for the development and improvement of herbicidal formulations. M. : Chemistry, 2006).

Fundamentally, the possibility of excluding from the chain of production and use of sulfonylurea preparations the technological stage of obtaining the drug in the form of EDC and STS follows from the data given in patent RU 2482676 C1 (publ. 05.27.2013, Bull. No. 15).

According to the well-known patent, a trialkylamine salt of a substituted sulfonylurea, in which one alkyl radical contains at least 8 carbon atoms, has bifunctional properties (biological and surface activity) and is able to be present in an aqueous medium in the state of a micellar solution, the biological activity of which is higher than that of working solutions, cooked in the traditional way.

In this regard, the trialkylamine salt of sulfonylurea, which has surface-active properties, can be directly used to prepare the working fluid for spraying without introducing any additional components into its composition (Table 1).

However, the use of specially synthesized trialkylamine salts of substituted sulfonylureas for these purposes is rather complicated for a number of reasons (amorphous state, extremely low melting point 30-70 ° С).

The present invention is to simplify the process of obtaining a herbicidal agent.

The technical solution, which is the essence of this invention, excludes the stage of preparing formulations in the form of EDC or STS, the technological stage of the synthesis of trialkylamine salts and reduces to obtaining a working fluid for processing directly in the sprayer tank by mixing a herbicidally effective amount of substituted sulfonylurea with a trialkylamine emulsion that contains one an alkyl radical with the number of carbon atoms (hereinafter - C) of at least 8 (hereinafter - TAA), in water, the volume of which is determined by regulatory standards ode working fluid per 1 ha.

This was made possible thanks to two experimentally established facts:

- a sufficiently high reaction rate of the substituted sulfonylurea with trialkylamine, which contains one alkyl radical with at least 8 carbon atoms, in an aqueous medium at ambient temperature;

- the stability of the substituted sulfonylurea during the synthesis of the indicated trialkylamine salt and the salt itself in the aqueous medium for a relatively long time.

The preparation of the working fluid is as follows.

A certain amount of water is poured into the flask with a stirrer (on the basis of l / ha), then an equimolar or excess molar amount with respect to the substituted TAA sulfonylurea is added. Sulfonylurea is added to the resulting trialkylamine emulsion in water. The molar ratio of trialkylamine to substituted sulfonylurea is (1-1.05): 1, respectively.

Given the relative instability of the aqueous emulsion of trialkylamine, it is possible to add 5-10% by weight of a surfactant (e.g., neonol AF 9-9) to the resulting emulsion. on the amount of trialkylamine.

The obtained experimental data are given in table.2.

The stability of aqueous solutions of dimethylalkylamine (DMAA) salts of substituted sulfonylureas (based on the hectare dose of use) over time was evaluated by the change in surface tension on a KRUSS tensimeter.

The obtained experimental data are given in table. 3.

The observed changes in surface tension (48 h for nicosulfuron and 24 h for tribenuronmethyl) unambiguously indicate the beginning of some changes that occur in an aqueous solution of DMAA sulfonylurea salts.

This is due to the fact that during the decomposition of DMAA salts, dimethylalkylamine is released, which has a lower density than water (0.8 g / cm ³ ) and diffuses to the interface (liquid-air), causing a decrease in surface tension to the index ( in the limit) surface tension of pure dimethylalkylamine.

In general, are given in table. Figure 3 shows that aqueous solutions of dimethylalkylamine salts of sulfonylureas are stable in time, which is many times greater than the time required to prepare a working solution and its use.

Finally, the fact of the stability of substituted sulfonylureas during the synthesis of salts and their exposure in an aqueous medium is confirmed by the results of analysis on a high performance liquid chromatograph.

As an example, in table. 4 shows the results of the analysis of an aqueous solution of dimethylalkylamine salt of nicosulfuron.

Thus, the technical solution proposed in this invention significantly simplifies the production chain of the production and use of substituted sulfonylurea preparations due to the exclusion of the expensive and rather complicated stage of formulating the sulfonylurea preparation in the form of VDG, STS, and the process of using substituted sulfonylureas reduces the simple mixing of technical sulfonylurea with water emulsion of trialkylamine, with the receipt of the working fluid for the subsequent processing of agricultural crops.

Claims (4)

1. A method of obtaining a working fluid of a herbicidal agent based on a substituted sulfonylurea having the surface-active properties of a trialkylamine salt, in which one alkyl radical contains at least 8 carbon atoms, in an aqueous medium, characterized in that the working fluid is obtained immediately before use by reacting a herbicidally effective the amount of substituted sulfonylurea, with trialkylamine containing one alkyl radical with a number of carbon atoms of at least 8, while taken in equimolar or an excess molar amount with respect to the substituted sulfonylureas, in an aqueous medium. 2. The method according to p. 1, characterized in that the molar ratio of trialkylamine containing one alkyl radical with at least 8 carbon atoms and substituted sulfonylurea is (1-1.05): 1, respectively. 3. The method according to p. 1, characterized in that the interaction of the substituted sulfonylurea with a trialkylamine containing one alkyl radical with a number of carbon atoms of at least 8, is carried out by preliminary formation of an emulsion of the specified trialkiamine in water, followed by the addition of a substituted sulfonylurea. 4. The method according to p. 1, characterized in that the emulsion of trialkylamine optionally further contains a surfactant in an amount of 5-10% of the mass. in relation to trialkylamine containing one alkyl radical with a number of carbon atoms of at least 8.