JPS5948446A - Decoloring of pyrethroid compound - Google Patents

Abstract

PURPOSE:To decolor colored impurities causing contamination of clothes, etc. industrially advantageously, by treating a pyrethroid compound useful as an insecticide against mosquitoes, flies, etc. with a specific oxidative substance or reductive substance. CONSTITUTION:A solution of a pyrethroid compound such as allethrin, resmethrin, etc. in a water-insoluble organic solvent is treated with ( I ) an oxidative substance (oxygen, ozone, sodium perchlorate, sodium percarbonate, etc.), or (II) a reductive substance (sodium thiosulfate, sulfur, hydrosulfite, or a combination of a metal such as iron, lead, etc. and an inorganic acid or organic acid), so that colored impurities contained in it are decolored. The amount of the substance used is 0.1-50wt% based on the pyrethroid compound. EFFECT:Operation is easy, neither purity of the pyrethroid compound nor reduction in effect are brought about.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for decolorizing a pyrethroid insecticide, which is characterized by treating a pyrethroid compound with an oxidizing substance or a reducing substance consisting of the following group.

Pyrethroid compounds are widely used as insecticides for insect pests such as flies, cockroaches, etc., processed into incense sticks, electric mats, aerosols, etc. However, in the case of aerosol types, the insecticide components are directly sprayed indoors. The colored impurities contained in the insecticide ingredients can stain surrounding clothing, furniture, paper, etc. To prevent this, these colored impurities are removed before processing. It is necessary to decolorize it.

Conventional decolorization methods generally involve adsorption of insecticide components using powders such as activated carbon, activated alumina, activated clay, and silica gel. It is industrially disadvantageous because it takes a long time to evaporate after the dyeing treatment, and the decolorizing effect is also low. Under these circumstances, the present inventors conducted various studies on a decolorization method that has a high decolorization effect and is industrially advantageous.As a result, the present inventors developed a method in which a pyrethroid compound is treated with the above-mentioned oxidizing or reducing substance. The present inventors have discovered that this method can decolorize extremely efficiently compared to conventional adsorption methods, and can be carried out with extremely easy operations, making it an extremely advantageous method from an industrial perspective, and has led to the completion of the present invention. Ta.

The pyrethroid compound referred to in the present invention is represented by, for example, the general formula CI) A-C-0-Q 1 .

Here, k and R2 are the same or different and represent a hydrogen atom or a lower alkyl group, and R3 and R2 are the same or different and represent a hydrogen atom, a lower alkyl group, or a general formula or different, a hydrogen atom, a methyl group. Or represents a halogen atom. ) represents a group represented by

Z represents a hydrogen atom, a lower alkyl group, a halogen atom, or a lower alkoxyl group optionally substituted with a halogen atom.

R6 represents a hydrogen atom or a methyl group, and R6 represents a lower alkenyl group or a lower alkynyl group.

R7 represents an allyl group, a propargyl group, a benzyl group optionally substituted with a halogen atom, or a phenoxy group optionally substituted with a halogen atom, and R8 represents a hydrogen atom or a halogen atom. Y is the formula −C,)f,=
A group represented by CH- represents an oxygen atom or a sulfur atom, and k represents a hydrogen atom, an ethynyl group or a cyano group. ] Specific examples thereof include allethrin, resmethrin, tetramethrin, flamethrin, phenothrin, vermethrin, cypermethrin, terrarethrin, fenpropathrin, and fenvalerate.

It is subjected to decolorization treatment as a solution in an organic solvent.

Oxidizing substances used in the present invention include oxygen, ozone, sodium perchlorate, or sodium percarbonate, and reducing substances include sodium thiosulfate, sulfur, hydrosulfide, iron, lead, and aluminum. Examples include combinations of metals such as and inorganic acids or organic acids. Further, if necessary, these may be used in combination with activated carbon, activated alumina, activated clay, etc., and treatments with the above-mentioned oxidizing substances and reducing substances may also be carried out in combination.

These oxidizing substances? The pyrethroid compound and the reducing substance are used as they are or as an aqueous solution thereof, and the amount used is not particularly limited, but is usually in the range of 0.1 to 50% by weight based on the pyrethroid compound.

When carrying out the method of the present invention, the operation is not particularly limited, but is typically carried out as follows.

After stirring and mixing the solution of the pyrethroid compound or its water-insoluble organic solvent and the oxidizing substance, reducing substance, or its aqueous solution, solids are removed by E-filtration or decantation as necessary, and branching is performed. .

The resulting oil layer is washed with water to remove any remaining oxidizing or reducing substances, and then the organic solvent is distilled off if necessary to obtain a decolorized pyrethroid insecticide component.

The method of the present invention is easier to operate than conventional decolorization treatment methods, and even when applied to pyrethroid compounds, which are not very stable chemically, the method of the present invention improves the purity and efficacy of the pyrethroid compounds. This method is extremely advantageous as a decolorization method because it efficiently decolorizes only the target colored impurities without causing a decrease in color.

The present invention will be explained in more detail by examples below.
The present invention is not limited to these in any way.

Example 1 A 10% aqueous solution 509 of hydrosulfide (sodium dithionite) was added to a 40% xylene solution 502 of phenothrin, stirred for 3 hours under conditions of p 1'19-10.10-15°C, and then separated. did. Further, washing with water and liquid separation were repeated twice in the same manner, and then xylene was distilled off. The results of a comparison between the phenothrin that was decolorized in this manner and the phenothrin that was not subjected to the decolorization treatment using the Gardner scale were as follows.

Example 2 Powdered sulfur (3y) was added to d-allethrin dissolved in 40 titoluene (Kl 5 oy), and the mixture was stirred at 40 to 50°C, and then the insoluble matter was removed, and the toluene was distilled off to obtain decolorized d-allethrin. The results of the comparison using the Gardnall scale were as follows.

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Claims (1)

[Claims] A method for decolorizing a pyrethroid compound, comprising treating the pyrethroid compound with an oxidizing substance or a reducing substance from the following group.