JPS62273902A - Method for preparing herbicidal aqueous solution - Google Patents

Abstract

PURPOSE:To obtain a safe and effective herbicidal aqueous solution having pH in a specific range, by adjusting an aqueous solution of a herbicidal composition comprising a bipyridinium quaternary salt as an active ingredient and an aqueous solution of a basic compound to pH in specific ranges, respectively, and blending both the aqueous solutions. CONSTITUTION:In obtaining a herbicidal aqueous solution which consists of (A) a herbicidal composition comprising a bipyridinium quaternary salt shown by formula I and/or formula II (l and m are 1, 2; group shown by formula III is anion; [Y]<m-> is anion; R is alkyl which may be replaced) as an active ingredient, (B) a basic compound and water and has 1-5.7pH, when pH of the aimed herbicidal aqueous solution is Z, pH of the aqueous solution of the component A is adjusted to (Z-1)-(Z+1), pH of the aqueous solution of the component B to (Z-1.3)-(Z+0.8) and both the aqueous solutions are blended in such a way that the pH is 1-5.7. The herbicidal aqueous solution keeps stability by maintaining acidity in an acidic atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preparing five herbicidal waters containing bipyridium quaternary salt as the main active ingredient.

Herbicides based on bipyridinium quaternary salts have a long history (invented in 1955, and have continued to be used for more than 30 years due to their broad herbicidal spectrum, strong effects, and safety). In other words, as with general agricultural chemicals, if sprayed according to the handling specifications, the agricultural chemical composition will not cause any harm.

However, even if the agricultural chemical composition is safe for agricultural use, it may have serious effects on the human body if misused, especially if swallowed by mistake, and various measures have been taken to prevent such misuse. There is. That is, lower aliphatic carboxylic acids as disclosed in JP-A No. 52-90631, natrahydrothiophene as disclosed in JP-A-52-114021, and JP-A-49-7.433. One of the methods is to use an odorant such as an alkylpyridine, which is disclosed in the No. 3 issue, to prevent accidental ingestion or misuse due to its odor.

Furthermore, if someone drinks, there are ways to make them spit out what they have swallowed: 11! It is being proposed. That is, S-) lyazolopyrimidine conductors disclosed in Japanese Patent Publication No. 56-35641 and tripolyphosphates and birophosphates disclosed in Japanese Patent Application Laid-Open No. 56-61301 correspond to this. These preventive measures can be effective.

Through such various means, herbicides containing bipyridinium quaternary salts as main ingredients are used in various fields as safe and effective agricultural chemicals.

However, when preparing a herbicidal aqueous solution containing a safe and effective bipyridinium quaternary salt as its main component, it is often preferable to maintain its acidity in an acidic atmosphere (1° The reason for this is to maintain the stability of active ingredients or various additives.

In particular, when it is necessary to add a basic compound as an additive, maintaining its acidity becomes a major problem.

Therefore, the present inventor conducted extensive research with the aim of preparing a stable and effective herbicidal aqueous solution containing a bipyridinium quaternary salt as a main component by adding such a basic compound, and as a result, arrived at the present invention. That is, the present invention is based on the following general formula (1) (where l represents an integer of 1 or 2, and [X) le represents an anion. ] and/or a herbicidal composition containing at least one bipyridinium quaternary salt represented by the following general formula (If) as an active ingredient, a basic compound, and water, the herbicidal composition having a pH in the range of 1 to 5.7. When preparing a herbicidal aqueous solution, when the pH value of the target herbicidal aqueous solution is 2, the pH of the aqueous solution of the herbicidal composition is (Z-1) ~
(An aqueous solution of the basic compound prepared within the range of Z+1) has a pH of (Z −1,3) to (Z + o,a)
This is a method for preparing a herbicidal aqueous solution, which is characterized by mixing the rainwater solution so that the pH thereof is in the range of 1 to 5.7.

Next, the method of the present invention will be explained in more detail.

The method of the present invention has the following advantages.

(1) When preparing a herbicidal aqueous solution containing bipyridinium quaternary salt as the main active ingredient, fluctuations in acidity are very small and it is easy to adjust the desired pH. There is almost no heat generation due to the addition of the basic compound, and the stability of the drug's activity is rarely affected.

(2) There is little change in acidity due to the addition of basic compounds, and it does not become neutral or alkaline even in extreme areas, so there is no harm to active ingredients and additives that are unstable in INK under alkaline conditions. This can be mentioned.

(3) Other advantages of this method include the fact that there is no need to re-adjust the pH, and the final pH measurement can be estimated, which has great industrial significance.

(4) Furthermore, one of the features of the present invention is that it is extremely effective when setting the acidity of the herbicidal composition containing a basic compound near the neutralization titration point of the basic compound, and the desired acidity can be set extremely accurately. In other words, if the acidity is set near the neutralization point of a basic compound, the presence of a small proportion of base or acid will greatly change the acidity pH, but this does not occur. It is stable and can be easily prepared.

As mentioned above, in the method of the present invention, the pH of the aqueous solution of the herbicidal composition and the pH of the aqueous solution of the basic compound are adjusted such that the pH of the final herbicidal aqueous solution is within the range of 1 to 5.7. Therefore, when the pH of the desired herbicidal aqueous solution is 2, the pH of the former aqueous solution is: (Z −1) ~ (Z +
1) In the range f), the pH of the latter aqueous solution (Z
-1,3) to (Z+0.8), the above-mentioned advantages can be achieved. is more effective. In addition, for more accurate pH control, K,
The pH of the aqueous solution of the herbicide composition was adjusted to (Z-0,8) to (Z-0,8) to (
It is more effective to set the pH of the aqueous solution of the basic compound in the range of (Z-t, t) to (Z+0.7).

In addition, since the amount of the aqueous solution of the herbicidal composition to be mixed is generally larger than the amount of the aqueous solution of the basic compound, the pH of the aqueous solution of the herbicidal composition is.

It is easier to operate if the pH (Z) is closer to the target herbicidal aqueous solution than the pH of the basic aqueous solution. Although any mixing method may be used, it is generally preferable to add the aqueous solution of the basic compound to the aqueous solution of the herbicidal composition.

Next, the bipyridinium quaternary salt in the present invention will be explained.

One of the bipyridinium quaternary salts of the present invention has the following general formula CI
).

(However, in the formula, ! indicates an integer of 1 or 2, and (X)le indicates an anion.) Here, the selection of 7 anions is made appropriately based on, for example, price. As an anion.

Those that yield salts with suitable water solubility are preferred. Examples of anions that can be monovalent or polyvalent include acetate radicals,
Benzene sulfonic acid radical, benzoic acid radical, bromate radical, bromide ion, acetic acid radical, chloric acid radical, chloride ion, citric acid radical, formic acid radical, fluorosilicate radical, fumaric acid radical, fluoroboric acid radical, iodide ion, lactic acid radical, malic acid radical, maleic acid radical , methyl sulfate, nitrate, propionate, phosphate,
Mention may be made of salicylate, sulfaminoate, succinate, sulfate, thiocyanate, tartrate and p-)luenesulfonate. Preferred are bromide, chloride, iodide or methyl sulfate.

Examples of compounds of the above general formula CI) include [11,1'
-ethylene-2,2'-bipyridinium dichloride (
Diquat diglomide) (diquat dibr)
omide )(-11,1'-ethylene-2,2'-
Bipyridinium dichloride (c) 1,1'-ethylene-2,2'-bipyridinium cyphiotide and the like can be mentioned.

The method for producing such a compound is not particularly limited. For example, when diquat dichloride is used as this compound, K is preferably produced by quaternizing pyridine as a raw material using 22' bipyridyl dimerized with a Raney nickel catalyst and ethylene bromide. The invention is applied.

On the other hand, other bipyridinium salts are represented by the following general formula CI).

As the anion in the bipyridinium quaternary salt of the general formula (1), the same anions as those explained in the general formula CI) can be used.

Examples of such compounds of general formula (U) include:

) l,1'-dimethyl-4,4'-bipyridinium dichloride (baraquat dichloride) (e)
1,1'-di-2-hydroxyethyl-4,4'-bipyridinium dichloride () 1-(2-hydroxyethyl) -1'-methyl-4,4'-bipyridinium dichloride ())
1,1'-di(carbamoylmethyl)-4,4'
-Bipyridinium dichloride i 1,1'-bis-N,N-dimethylcarbamoylmethyl-4,4L-bipyridinium dichloride (su) 1,1'-bis-N,N'-diethylcarbamoylmethyl-4,4'-bipyridinium・Dichloride k) 1.1'-Diacetonyl-4,4'-bipyridinium dichloride & IJ 1,1'-jethoxycarbonylmethyl-4
, 4'-bipyridinium dichloride sec) 1.1'-diallyl-4,4'-bipyridinium dichloride (711,1'-dimethylthio-4,4'-bipyridinium dichloride, etc.).

The compound of general formula (II) can be produced, for example, by the method shown in the following reaction scheme, that is, by reacting dipyridine with furkyl halide.

The active ingredients in the herbicidal composition of the present invention are:

The general formula (1) or [■], or CI) and (II
), but in consideration of stability, it is recommended that it contain a diviridinium quaternary salt of CI) as an active ingredient. That is, (1) alone or (I
The effects of the present invention are significantly superior when a herbicidal aqueous solution is prepared using a herbicidal composition containing a mixture of (1) and (1) as an active ingredient.

Especially when using a mixture of CI) and (I[), preferred combinations include [-, for example, Bi)-].

Examples include (b)-(i), (i)-(i), (p)-(i), (i)-(g), or (b)-(g).

In the herbicidal aqueous solution of the present invention, it is desirable that the amount of cations in the bipyridinium quaternary salt is at a concentration of 20 to 40011/j.

The basic compound of the present invention refers to a substance that is water-soluble, reacts with protons in its aqueous solution, and is capable of accepting protons.

Such basic compounds may be either organic or inorganic compounds. Such basic compounds include surfactants and rust preventives.

Includes stabilizers, emetics, bittering agents, 9 odorants, 1 colorant, and other substances used for various purposes.

For example, in Example 1, which is preferably used, it is used as an odorant substance such as an agricultural chemical or a pH adjusting substance. Examples of such tLiLi-forming compounds include aliphatic amines, alicyclic amines, aromatic amines, and heterocyclic amine compounds.

Specific examples of such basic compounds include aliphatic amines such as methylamine and ethylamine.

Purpylamine, dimethylamine, diethylamine, alicyclic amines such as cyclohexylamine and cyclopentylamine, aromatic amines such as aniline, and heterocyclic amines such as pyrrolidine, piperidine, piperazine, pyridine, a, and β.

Examples include r-picoline, lutidine, trialkylpyridine, pyridandine, pyrimidine, pyrazine, cinnoline, phthal7dine, quinazoline, quinoxaline, and mixtures thereof.

However, the invention is not limited to these examples.

゛ The type of basic compounds used is determined by the needs of the target product. In general, amounts ranging from several tens of ppm to several tens of vt percent are usually used in herbicidal aqueous solutions.

Adjusting the aqueous solution of the basic compound to the above pH,
A desired herbicidal aqueous solution is prepared by mixing this with an aqueous solution of a herbicidal composition prepared separately. The preparation and mixing may be carried out continuously, or intermittently, or semi-continuously and semi-intermittently.

In the present invention, in addition to the above-mentioned two active ingredients, an emetic agent, in order to avoid disasters such as misuse, especially accidental ingestion,
Alternatively, it is also possible to create a safer herbicidal aqueous solution by adding additives such as a stabilizing agent or a bittering agent.
That is generally preferable and there are some cases. In the present invention, the emetic agent 9, odorant, bittering agent, etc. are not particularly limited as long as they satisfy the conditions in the method of the present invention.

However, when the emetic agent 2 odorant, bittering agent, etc. is an organic type, and is a furkyl type or a heterocyclic type compound, it may be used in a preferable manner.

In addition to these warning substances, additives commonly used in aqueous solutions for curtain removal can also be added. That is, alkyl sulfates, alkyl sulfonates, and lignin sulfonates.

Polyoxyethylene glycol ethers, polyoxyethylene alkyl 7-aryl ethers.

It is prepared using one or more of surfactants such as polyoxyethylene sorbitan monoalkylate and dinaphthylmethane disulfonate, emulsifiers or dispersants; various auxiliaries such as carboxymethyl cellulose and gum arabic.

The method of the present invention will be described in detail below with reference to Examples.

Example 1 (Preparation of aqueous solution of herbicidal composition) 45.012+
Concentrated aqueous solution of 1% 1,1'-dimethyl-4,4'-bipyridinium dichloride (pQ'c4)! 13.9
1, 41. ON:l%f) 1,1'-4-L/7-2.2'-Bipyridinium dichloride (DQ-Brt) was mixed with 20.7 Jil of a concentrated aqueous solution, and a nonionic surfactant (alkyl phenyl ether type) 2.09 and polyoxyethylene alkyl heptamine type surfactant 1.05! 1. Heterocyclic emetic agent 0.05,
? and high concentration salt fi 0.3 aj or pH 4.0
An aqueous solution of the herbicidal composition was prepared by FA. The composition of this composition aqueous solution was as follows.

Examples 2 to 4 In the same manner as in Example 1, only the amount of hydrochloric acid added was changed, and the pH was 3.0 (Example 2).
Aqueous solutions of herbicidal compositions of 3.5 (Example 3) and 4.5 (Example 4) were prepared.

Example 5 - Alkylpyridine mixture based on flutidine 47.
5.9 was heated with highly concentrated hydrochloric acid (35%) 37.5.9 to prepare an aqueous solution of a furkylpyridine mixture of pl(4,0). and pH 3.0 (Example 6) and pH 5, respectively.
0 (Example 7) was prepared.

Examples 8 to 16 and Comparative Example 1 The aqueous solutions of herbicidal compositions obtained in Examples 1 to 4, the aqueous furkylpyridine mixtures obtained in Examples 5 to 7, and the aqueous herbicidal solutions intended for dyes. pH (target value) K
They were selected and mixed accordingly. The results are shown in the table below.

On the other hand, the furylpyridine mixture water of Examples 5 to 7? #
Instead of liquid, benzylamine (Example 14), n-propylamine (Example 15) or piperidine (Example 1)
The results of preparing and using the aqueous hydrochloric acid solution of 6) are also shown in the table below.

In Comparative Example 1, an aqueous herbicidal composition solution prepared in the same manner as in Example 1 was used, except that hydrochloric acid was used to adjust the pH to 1.22.

Claims (1)

[Claims] The following general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・
[I] (In the formula, l represents an integer of 1 or 2, and [X]^l^■ represents an anion.) and/or the following general formula [II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・・
[II] [However, in the formula, m represents an integer of 1 or 2, and [Y]^m^■ represents an anion. The two R's are the same or different alkyl groups having 1 to 5 carbon atoms, and the alkyl groups include a hydroxy group, a lower alkoxy group, a lower thioalkyl group, a lower alkylcarbonyl group, a lower alkoxycarbonyl group, a carboxy group, and a carbonylamide group. , may be substituted with a halogen group. ] In preparing a herbicidal aqueous solution with a pH in the range of 1 to 5.7 consisting of a herbicidal composition containing at least one type of bipyridinium quaternary salt as an active ingredient, a basic compound, and water, the objective and When the pH value of the herbicidal aqueous solution is defined as Z, the pH value of the aqueous solution of the herbicidal composition is (Z-1) to (
The pH of the aqueous solution of the basic compound was adjusted to be in the range of (Z-1.3) to (Z+0.8), and the pH was adjusted to be in the range of 1 to 5.7. A method for preparing a herbicidal aqueous solution, which comprises mixing both aqueous solutions.