DE1040542B - Process for the preparation of thionophosphoric acid esters - Google Patents

Description

Thionophosphoric acid esters, in which the residues of two Dialkylthionophosphoric acids are linked to one another via the sulfoxide group, have not yet become known.

It has now been found that this class of substances consists of 0,0-dialkyldithiophosphoric acid disulndants of the following general Formula:

RO,

RO

P —S —S —P '

OR

OR

Process for the preparation of thionophosphoric acid esters

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Gerhard Schrader, Wuppertal-Cronenberg, has been named as the inventor

(See U.S. Patent 2,705,694; R = preferably

low molecular weight alkyl radical) is easily accessible if the oxidation is carried out in such a way that a sulfur atom is eliminated and the remaining bridging or diluent is mixed, sulfur is oxidized to the sulfoxide for use, as can be seen from the following ao.
Formula scheme can be seen: SS

C ₉ ELO.

, p — so - p;

RO S.
ti - S. S.
[| OR - P-. R0 ^y OR

C ₉ ILO

H ₂ O ₂ C, H, O

S S

; p s s ρ

, OC ₂ H ₅

OC ₂ H ₅

-OC ₂ H ₅

RO

RO

OR _ä H ₅ 0

p — so — p:

+ S + H ₂ O insecticidal effectiveness

¹ OR

The oxidation of the disulfides with hydrogen peroxide in suitable solvents in carried out in a weakly acidic medium at temperatures of 40 to 70 ° C. Has proven itself as a solvent especially glacial acetic acid. However, hydrocarbons can also be used as solvents if, for. Am In the presence of small amounts of sulfuric acid this reaction is carried out.

While the disulfides required as starting materials have practically no contact insecticidal effects show, the new sulfoxides are characterized by good contact insecticides and in some cases also systemic Effects (see table below). Flies and caterpillars z. B. can with the compound of the invention can be effectively combated, the new substance class preferably in the one for phosphorus insecticides known way, d. H. with the usual stretching

Flying 0.001%

Aphids 0.001%

Spider mites 0.001%

Cockroaches 0.001%

100% 80% 50% 40%

0.01% 0.01% 0.01% 0.1%

0%

0%

50%

0%

C ₉ H = O

C ₂ H ₅ O

example

P —SO —P,

OC ₂ H ₅

OC ₉ H ₅

74 g of 0,0,0,0-tetraethylthionophosphoric acid disulfide are dissolved in 100 ecm of glacial acetic acid with the addition of 1 ecm 50% sulfuric acid. At 40 ° C, 27 ecm of hydrogen peroxide (37.5%) are then added dropwise with stirring. to. The reaction is self-heating. After the heat of reaction has subsided, the temperature is kept at 40 ° C for 1 hour, then this is taken Crude product in 200 ecm benzene and washes the benzene layer with a 3% bicarbonate solution. To

809 657/465

Claims (1)

the solvent is distilled off after drying over sodium sulfate. The remaining crude sulfoxide is distilled at a pressure of 0.01 mm of mercury at 120 to 122 ° C. Analysis for a molecular weight of 354: Calculated S 27.2 ·> / ", P 17.6 ° / ₀ ; found S 26.6 ° / ₀ , P 18.4 ° / ₀ . DL ₅₀ rat orally 10 mg / kg. Maggots are not killed with aqueous emulsions containing 0.001 ° / ₀ of the active substance. Mosquitoes are killed in 160 minutes at a concentration of 0.01 ⁰ Z ₀ 10O ⁰ Z ₀ Ig. At a concentration of 0.1 ° / ₀ caterpillars are killed more safely. Flies are safely killed at a concentration of 0.001 ⁰ Z _0. Against spider mites, the new preparation acts ig abtötend in a concentration of 0.1 ⁰ ₀ Z 100 ° / _0th P Λ TE N T Λ NSPRCC H. Process for the preparation of thionophosphoric acid esters, characterized in that 0,0,0,0-tetraalkylthionophosphoric acid disulfides are oxidized to corresponding sulfoxides _{by elimination of a disulfide sulfur by oxidation with H 2} O _{2 in an acid medium.} ©! 09 657/465 9. 58