GB834117A - Thiophosphoric acid esters and process for their production - Google Patents

Abstract

The invention comprises thiophosphoric acid esters of the formula <FORM:0834117/IV (b)/1> wherein R is a C1-C4 alkyl radical, R1 an R2 are identical or different alkyl or aryl radicals, either of which may be substituted, X and Y are oxygen or sulphur, at least one of them being sulphur and each A is a sulphoxide (S(O) group) or sulphone (SO2) group. Compounds in which each A is a sulphoxide group may be obtained by reacting the corresponding sulphide compound in which each A is a sulphur atom with hydrogen peroxide, preferably of 30% strength, whereas compounds in which each A is a sulphone group may be obtained by oxidizing the said corresponding sulphide compound with potassium permanganate in acidic solution, e.g. in an aqueous emulsion containing dilute sulphuric acid. The reaction with hydrogen peroxide is generally carried out at room temperature or lower, e.g. down to about 0 DEG C., and may be carried out in an inert solvent, e.g. an aliphatic carboxylic acid containing 1 to 4 carbon atoms, especially glacial acetic acid. Examples are given for the production of compounds in which X is oxygen, Y is sulphur, R1 and R2 are each ethyl and A is S(O) and SO2 respectively and in which X and Y are sulphur, R1 and R2 are ethyl and A is S(O). Other products specified are those in which X is sulphur, Y is oxygen, R1 and R2 are each ethyl and A is SO or SO2, and the compounds <FORM:0834117/IV (b)/2> and the corresponding sulphone compound, <FORM:0834117/IV (b)/3> and the corresponding sulphone compound, and <FORM:0834117/IV (b)/4> and the corresponding sulphone compound. The products are useful as insecticides (see Group VI). The sulphides (i.e. compounds in which A is sulphur, X is sulphur and Y is oxygen) used as starting materials may be obtained by reacting a compound of the formula (R1SCH2)(R2SCH2) CHOH with a compound of the formula (RO)2P(S)Hal optionally in the presence of an acid binding agent and the sulphides in which X is oxygen or sulphur and Y is sulphur may be obtained by reacting a compound of the formula (R1SCH2)(R2SCH2)CH.Hal with an ammonium or alkali metal salt of the appropriate thiol- or thionothiol-phosphoric acid.ALSO:An insecticidal composition contains as active ingredient one or more thiophosphoric acid esters of the formula <FORM:0834117/VI/1> wherein R is an alkyl radical containing up to 4 carbon atoms, R1 and R2 are identical or different alkyl or aryl radicals which radicals may be substituted or unsubstituted, each A is a sulphoxide or sulphone group and X and Y are oxygen or sulphur, at least one of them being sulphur (see Group IV (b)). The active ingredient may be diluted or extended with solid or liquid carriers or diluents, e.g. talc, chalk, bentonite, clay, water (if necessary with the addition of emulsifiers), alcohols, e.g. methanol or ethanol, ketones, e.g. acetone or methyl ethyl ketone, and liquid hydrocarbons. The compounds may be used in combination with known insecticides and/or fertilizers. A suitable composition is obtained by mixing the compound (C2H5O)2P(O)SCH(CH2S(O) C2H5)2 with acetone and a commercial emulsifier, e.g. benzyl hydroxy diphenyl polyglycol ether, and then diluting with water.