CS260416B1 - A method of stabilizing an emulsion concentrate of herbicidal compositions based on substituted biscarbamates - Google Patents

Abstract

Method of stabilizing an emulsion concentrate of herbicidal preparations based on substituted biscarbamates in an organic solvent containing a surfactant and a stabilizer. The essence is that stabilization is carried out with 0.1 to 10% by weight of m- or p-nitrobenzenesulfonic acid.

Description

The invention relates to a method for stabilizing an emulsion concentrate of herbicidal preparations based on biscarbamates of the general formula // *'\ \ Q.CO.Ím·-;' >

Ρ _Ί O'CO,Hn where

R _t , R ₂ represents methyl or R , represents ethyl and R ₂ represents H.

The substances are used in agriculture as herbicides, especially for growing sugar beets. These preparations contain, in addition to the active substances, at least one organic solvent immiscible or only slightly miscible with water, at least one surfactant and a substance stabilizing the content of the active substances in the preparation during its preparation, storage and application.

Since the chemical stability of active substances depends on the pH and composition of the environment, various methods of stabilizing their content are used to prevent a decrease in the content of the active substance in the preparations and thus a decrease in biological effectiveness. The stabilizing effect of, for example, acetic acid, hydrochloric acid, ammonium chloride or ferric chloride and others is known. Later, organic acids such as aliphatic dicarboxylic, aliphatic hydroxycarboxylic, aliphatic and aromatic sulfonic acids were also proposed, citric acid is especially recommended.

So far, the effect of individual stabilizing substances has been evaluated exclusively from the point of view of stabilizing the content of the active substance in the preparation, i.e. from the point of view of maintaining the content of the active substance depending on the time and conditions of storage, while the effect of the individual stabilizing substances mentioned is not comparable. However, the evaluation of preparations containing the mentioned stabilizing substances has not been carried out from the point of view of influencing the physical parameters of the preparation emulsion, which also significantly affect the biological activity and effects of the preparation, especially its selectivity and phytotoxicity.

A new method has now been found for stabilizing an emulsion concentrate of herbicidal preparations based on substituted biscarbamates in an organic solvent containing a surfactant and a stabilizer. The essence is that stabilization is carried out by adding 0.1 to 10% by weight of m-nitrobenzenesulfonic or p-nitrotoluenesulfonic acid.

The addition of these stabilizing substances not only has a fully comparable stabilizing efficiency or even a better stabilizing efficiency compared to known substances, but as has been newly discovered, the required qualitative parameters of the emulsion are also fully ensured, i.e. the practically unchanged biological effectiveness of the preparation is ensured with its reduced phytotoxicity compared to previously known preparations, which was achieved by a suitable choice not only of the stabilizing substance, but also of the surfactants used.

To further clarify the nature of the invention, the following exemplary embodiments are provided:

Example 1

The preparation with the composition of 62.00% isophorone, 10.70% aromatic hydrocarbons C ₈ _ ₉ , 17.1% desmedlpham {ethyl-N-[3-(N-phenyl]-carbamoyloxy]-phenyl]-carbamate, 10.0% surfactants based on calcium dodecylbenzenesulfonate and polyethoxylated castor oil, 0.25% p-nitrotoluenesulfonic acid was stored for 70 days at a temperature of 70 °C, during which the active substance decreased from the original value of 17.1% by weight to 1.6.8% by weight, i.e., a stabilization effect of 98.2 %. During biological evaluation, lower phytotoxicity was found than in the comparison sample.

E x a m p l e 2

A preparation with a composition of 72.6% isophorone, 17.1% phenmedipham, 10.0% surfactants according to example 1, 0.3% m-nitrobenzenesulfonic acid was stored for 70 days at a temperature of 70 °C, during which the active substance decreased from 17.1% wt. to 16.6% wt., i.e. the stabilization effect was 97.0%. During biological evaluation, no phytotoxicity was detected in this sample, while the comparative sample was weakly phytotoxic.

The lower phytotoxicity of the preparation stabilized by the method according to the invention compared to the preparation stabilized with citric acid is evident from the following table:

sample phenmedipham stab. EC fresh g weight % dry matter g % EWRC citric acid 0.84108 21 0.14931 32 7.8 p-nitrotoluenesulfonic acid 2.61799 65 0.30011 65 2.3 desmedipham EC headquarters citric acid 1.08590 27 0.19418 42 7.8 p-nitrotoluenesulfonic acid 3.50644 87 0.36832 79 1.3 control without treatment 4.01458 100 0.46519 100 1.0

EWRC 1... no plant damage, phytotoxicity 9... complete plant destruction

Claims (1)

Subject A process for stabilizing an emulsion concentrate of substituted herbicidal preparations based on substituted biscarbamates in an organic solvent containing a surfactant and a stabilizer, which comprises: The invention stabilizes by adding 0.1 to 10% by weight of an aromatic nitrosulfo acid selected from the group consisting of m-nitrobenzenesulfo acid, p-nitrotoluenesulfo acid.