CH480799A - Pesticides - Google Patents

Description

  

  



  Pesticides
The preparation of β-alkyl mercaptoethyl thiophosphoric acid esters and the use of these compounds as active ingredients for pesticides is known (DBP 836 349, DBP 850677, DBP 935 432). These known agents have an excellent contact insecticidal and intra-therapeutic insecticidal effect. If such agents are used for a long time, however, as is generally known, the pests get used to the control agents, so that they gradually lose their effectiveness and have to be replaced by other more effective agents.



   It was the purpose and object of the present invention to find new pesticides whose active ingredients have a structure that differs from the above-mentioned active ingredients while being effective.



   It has been found that pesticides which have an s-alkoxy äthylmercapto-) alkyl-thiophosphoric acid dialkyl ester of the formula
EMI1.1
 in which R1, R2, Rg stands for lower alkyl radicals, correspond to the required conditions and have an excellent insecticidal and acaricidal effect.



   These hitherto not yet described compounds can be obtained by the generally known production processes, for example by reacting compounds of the formula HOC, H4SC2H4OR with dialkyl chlorothiophosphates in the presence of acid-binding agents.



   Example I.
80 g of dried, finely powdered potassium carbonate are added to a solution of 90 g of ss-oxy-ss'-oxyethyl diethyl sulfide in 150 ml of benzene. 80 g of dimethyl chlorothiophosphate are added dropwise with stirring at 35 ° C. over the course of 30 minutes, and the mixture is stirred for a further 8 hours at the same temperature. It is then filtered off with suction, washed 3 times with 25 ml of benzene each time, the benzene solution is washed with water and dried over sodium sulfate and the solvent is distilled off.



   At a vacuum of 5 torr and a bath temperature of 90 to 95 ° C., 118 g of 0,0-dimethyl-0,2-fl'-ethoxyethyl mercapto) ethyl thiophosphate remain as distillation residue in the form of a pale yellowish, water-insoluble one Oil. The yield is 86% of theory.



   Example 2
The insecticidal test of 0, 0-dimethyl-0,2- (K-ethoxy-äthylmercapto) -äthylthiophosphats was carried out on flies (Musca domestica), on grain beetles (Sitophilus granarius) and aphids (Aoyrthosiphon pisum, Aphis fabae) dissolved in ether ( Specification of the amount of active ingredient in 1ig / cm2), on rice flour beetle larvae (Tribolium confusum) as the active ingredient in wheat flour (information on the percentage of active ingredient in the flour).



   The degree of effectiveness was determined on grain weevils and flies after eighteen hours of exposure, on leaf lice after six hours and on rice flour beetle larvae after ten days of exposure.



  Use against the amount of active ingredient, efficiency in g / cm2 or 0 / o in O / o M. domestica 1.25 45
12.50 100 S. granarius 13 80
130 100 A. pisum 10 60
100 100 A. fabae 100 100 T. confusum 0.01 60
0.025 100
Example 3
Phaseolus beans infected with spider mites (Tetranychus articae) were treated with a 0.2% above solution of a preparation containing 25% of 0.0-dimethyl-0.2- (ss-ethoxy-ethylmercapto) -ethylthiophosphate, 25% O / o acetone and 50 O / o of an oxethylated alkylphenol.



  When checking after 3 days, an almost 100% control success could be determined.

 

Claims (1)

PATENT CLAIM Pesticides, characterized in that the active component is an (β-alkoxy äthylmercapto) -alkylthiophosphoric acid dialkyl ester of the formula EMI2.1 contains, in which R1, R2, R8 represent lower alkyl radicals.