DE1717106A1 - Stabilization of biocidal phosphoric acid esters - Google Patents

Description

Stabilization of biocidal phosphoric acid esters

The present invention relates to the stabilization of biocidal phosphoric acid esters, which are characterized by low toxicity to warm blooded animals and as such, as well as in the form of solutions, emulsion concentrates, dusts, Granules etc., excellently suited for combating insects, spider mites and nematodes on plants and animals are.

The biocidal phosphoric acid esters often have a short shelf life, so that especially after long periods of storage at higher temperatures, such as occur in tropical areas, a more or less pronounced drop in the Active ingredient content and as a result davjjn a corresponding Reduction of the biological or pesticidal effectiveness can be determined. The degraded pesticides can no longer be used properly, be it that the effectiveness has decreased, be it that the warm-blooded titer toxicity through the formation of pyrophosphate has increased, be it that they can no longer be emulsified satisfactorily in water, or that they can no longer be emulsified satisfactorily

New documents (An7 jtAb ", 2 nm u * sdmh * m * g *> m " 4. -. T * ;,> 109832/1633

SAIfNAL INSPECTEO

130-2618

cause precipitation or unpleasant odors through undesired decomposition phenomena. The technical usability this phosphoric acid ester is therefore very limited.

Since this reduced stability, which is also positive with regard to the residue problem in the cultivated plants rate, especially the particularly valuable insecticidal phosphoric or thiophosphoric acid esters with very low If warm-blooded toxicity adheres, processes for stabilizing emulsion concentrates by adding them are already in place stabilizing agents became known. Such stabilizers are e.g. epichlorohydrin, acetic anhydride, Glycols, glycol ethers, alkyl sulfate, etc. However, these known stabilizers are not suitable in all cases, to remedy the deficiencies mentioned, in particular they are not suitable for stabilizing (thio) phosphoric acid esters the 2-hydroxyquinoxaline and other {thio) phosphoric acid esters.

It has now been found that one can obtain stable pesticides obtained when phosphoric acid esters of the general formula I

where R is a methyl or ethyl group and Z is oxygen or sulfur, with 0.5 to 30 %, preferably 1 to 20 % (based on the weight of the phosphoric acid ester) of a compound of the formula II

R-N = C-X

II

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wherein X is an oxygen atom or the = N-R group, R is hydrogen or a radical A- (Y) », A is an alkyl radical, a cycloalkyl radical, a phenyl-substituted alkyl radical, a isocyanate-substituted alkyl radical or an optionally halogen- or isocyanate- or alkyl- or alkyl-isocyanate-substituted Aryl radical, Y -CO- or -SOp- and η denote 1 or 2, mixed. Compounds of formula II are e.g .: n-butyl isocyanate, benzyl isocyanate, phenyl isocyanate, 4-chlorophenyl isocyanate, 3,4-diehlophenyl isocyanate, N.N'-di-o-tolylcarbodiimide, N.N'-bis- (2.6-diethy! Phenyl) -! carbodiimide, cyanamide, hexamethylene diisocyanate, tolylene diisocyanate and especially cyclohexyl isocyanate and N, N'-dicyclohexylcarbodiimide. I.

The invention relates to the stabilization of biocidal \

Phosphoric acid esters of the formula I by mixing with 0.5-30%, preferably 1-20%, of a compound of the formula I

mel II. I

The phosphoric acid esters can be used alone or in a mixture with one another or with other pesticides. Of the phosphoric esters of the formula I, 0.0-dimethyl-0-quinoxalyl- (2) -thionophosphate and \ OO-diethyl-0-quinoxalyl- (2) thionophosphate may be mentioned.

In addition to the compound of the formula II, the phosphoric acid esters can also be mixed with suitable solvents, carriers, j Add emulsifiers etc.

Storage stability of organophosphate increases by a _multiple: The addition of the compounds of formula II which is.

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In the following examples, parts are parts by weight, percentages are percentages by weight, and temperatures are given in degrees Celsius.

example 1

a) An active ingredient concentrate A suitable for emulsification in water, consisting of 25 parts of OO-diethyl-O-quinoxalyl- (2) -thionophosphate, 10 parts of emulsifier and 65 parts of Shellsol R (registered trademark) [aromatic hydrocarbon reaction, bp. 203-289 °] 20 days stored at 7O ⁰ in sealed glass bottles. After storage, the content of OO-diethyl-0-quinoxalyl- (2) -thionophosphate has fallen to 6 parts; the preparation has become very dark and has almost completely lost its emulsifiability.

b) An analogous preparation in which 3 parts of Shellsol R have been replaced by 3 parts of phenyl isocyanate, shows, after exactly the same storage, 24 parts of the named active ingredient. It still looks bright and can be emulsified perfectly.

In the table below, analogous preparations are listed which are obtained by using the in example 1 described active ingredient concentrate A corresponding amounts of Shellsol R by the amounts given in the table n-butyl isocyanate or cyclohexyl isocyanate or 4-chlorophenyl isocyanate, and N.N'-dicyclohexyl-carbodiimide, respectively replaced. The new preparations are after exactly the same storage as in Example 1, i.e. after 20 days at 70 ° in Glass bottles, still light, easy to emulsify and still contain the following amounts of active ingredient:

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at
game stabilizer Stabilisa
gate crowd Active ingredient
salary* 1 a
2
4th
5 η-butyl isocyanate
Cyclohexyliso-
cyanate
4-chlorophenyl
isocyanate
N.N'-dicyclo-
hexylcarbodiimide. . Part 1
2 parts
3 parts
3 parts 6.0 parts
24.3 parts
24.3 parts
23.0 parts
24.5 parts

* Initial value 25 parts of active ingredient
Example 6

a) An emulsifiable active ingredient concentrate B, consisting of 25 parts of 0.0-dimethyl-O-quinoxalyl- (2) -thionophosphate, 10 parts of emulsifier, 55 parts of xylene and 10 parts of Shellsol R, are kept in sealed glass bottles for 5 days stored at 70 °. After storage, the 0.0-dimethyl-0-quinoxalyl (2) thionophosphate content is 13.7 Parts sunk.

b) An analogous preparation in which 3 parts of xylene through 3 parts of butyl isocyanate have been replaced, after exactly the same storage still has 23 parts of the above Active ingredient on.

Example 7

A mixture of 100 parts of 0.0-diethyl-0-quinoxalyl- (2) ~ thionophosphate and 2 parts of dicyclohexylcarbodiimide are stored in a sealed bottle at 50 ° for 4 weeks;

·) ■■,

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ORIGINAL INSPECTED

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the analysis of the brown liquid shows a content of 0.0-diethyl-0-quinoxalyl- (2) -thionophosphate of 95 #, ie taking into account the residual content of bicyclohexylcarbodiimide, the degradation is only about J>%>. If the same active ingredient is heated in exactly the same way without dicyclohexylcarbodiimide (4 weeks at 50 °), a black product is obtained which has completely solidified and which still shows 42 % active ingredient content on analysis.

Example 8

A mixture of 100 parts of 0.0-diethyl-0-quinoxalyl- (2) -thionophosphate and 2 parts of cyclohexyl isocyanate is heated to 50 ° for 4 weeks, as described in Example 7. The analysis of the still clear brown oil shows 95 % active ingredient content (degradation = J>%), while the active ingredient without cyclohexyl isocyanate is a black solidified mass which only contains 42% active ingredient.

Example 9

A mixture of 5 parts of 0.0-dimethyl-O-quinoxalyi- (2) -thionophosphate, 0.5 part of emulsifier as in Example 1, 1 part of cyclohexyl isocyanate and 13 * 5 parts of Shellsol R is used in 65 parts of dry ether dissolved; with this solution will be 80 parts of pumice granules soaked evenly and on top the ether evaporates; 100 parts of granules are obtained, which are suitable, for example, for soil treatment. It will be in a sealed glass bottle heated to 50 °. After 4 weeks, an analysis of the content of O.O-dimethyl-0-quinoxalyl thionophosphate of 4.15 parts found. An analogous preparation without cyclohexyl isocyanate provides evidence Exactly the same heat treatment does not contain 0.0-dimethyl-O-chloroxalyl-thionophosphate more on.

ORiGmAL INSPECTED 109832/1633

Claims (1)

Claim: Stabilized insecticide of general formula I. where R _{1 is} a methyl or ethyl group and Z is oxygen or sulfur, characterized in that it is 0.5 to ^ O %, based on the weight of the phosphoric acid ester, of a compound of the formula II as a stabilizer R-N = C = X II contains where X is oxygen or the = N-R group, R Hydrogen or a radical A- (Y) ,, A an alkyl radical, a cycloalkyl radical, a phenyl-substituted alkyl radical, an isocyanate-substituted alkyl radical or an optionally halogen or isocyanate or alkyl or alkyl isocyanate-substituted aryl radical, Y -CO- or -SOp- and η is 1 or 2. 5700 / HT / KST New documents (Art. 7 ξ 1 Paragraph 2 No. Τ Sentence 3 of the Xrrferunoaoes. Ν 4 109837/1633