Patent GB-812119-A (GB)
Title: New dithiophosphoric acid esters and insecticidal preparations comprising them
IPC: C07F9/165
Filed: 1957-11-28
Abstract: The invention comprises dithiophosphoric acid esters of the formula: <FORM:0812119/IV (b)/1> wherein R1 and R2 are alkyl groups containing not more than 4 carbon atoms.  They may be prepared by reaction between compounds of the formula: <FORM:0812119/IV (b)/2> and compounds of the formula: R2-O-CH2-S-CH2-O-R2, an alcohol of the formula R2OH being split off in the course of the reaction.  The reaction may be carried out at between 20 DEG  and 150 DEG  C., e.g. by heating a mixture of the reactants, if desired in the presence of a solvent, until all the alcohol is split off. Specified starting materials are those in which R1 is methyl, ethyl, n-propyl, isopropyl and butyl and those in which R2 is methyl, ethyl, n - propyl, and isopropyl.  Examples are given for the production of: (1) (CH3O)2P(S).S.CH2.SCH2.OCH3 from the compound CH3OCH2SCH2OCH3 (which is prepared from Na2S and CH3OCH2Cl) and dimethyldithiophosphoric acid; (2) the compound (CH3O)2P(S)SCH2SCH2OC2H5; (3) the compound (CH3O)2P(S)SCH2SCH2O isoC3H7; (4) the compound (C2H5O)2P(S)SCH2SCH2OCH3; (5) the compound (C2H5O)2P(S)SCH2SCH2OC2 H5; (6) the compound (C2H5O)2P(S)SCH2\t SCH2OnC3H7; (7) the compound (isoC3H7O)2 P(S)SCH2SCH2OC2H5; and (8) the compound (n <FORM:0812119/IV (b)/3> The products are stated to be useful as pesticides (see Group VI).ALSO:Dithiophosphoric acid esters of the formula:-  <FORM:0812119/I/1> wherein R1 and R2 are alkyl groups containing not more than 4 carbon atoms (see Group IV(b)) are used in seed disinfectants especially for the treatment of cotton seed.  They may be mixed with active carbon or kieselguhr, an emulsifying agent, gum or methyl cellulose.  In an example equal parts by weight of the compound (CH3O)2 P(S) S CH2 S CH2 OC2 H5 and active carbon are mixed. Six parts by weight of the powdered mixture are mixed with 94 parts of cotton seed.  Cotton plants grown from the thus treated seed are resistant to attack by sucking insects.ALSO:A pesticidal composition comprises as the active ingredient a dithiophosphoric acid ester of the formula:  <FORM:0812119/VI/1> wherein R1 and R2 are alkyl groups containing not more than 4 carbon atoms (see Group IV (b)).  The composition may include an emulsifying agent, e.g. an alkylpolyglycol ether or an alkylphenylpolyglycol ether or a sulphonated oil, and if desired, an organic solvent, e.g. an alcohol, mineral oil, ketone, or aromatic hydrocarbon may also be present.  The composition may also comprise the active ingredient in admixture with a pulverulent in organic material, e.g. active carbon or kieselguhr and gum or methyl cellulose may also be present.  Examples are given of the following compositions: (1) a solution containing the compound (CH3O)2P(S)SCH2SCH2OCH3 and iso - octylphenyl heptaglycol ether; (2) a solution comprising the compound (CH3O)2P(S)SCH2SCH2 OC2H5 and laurylhexaglycol ether in xylene; (3) a powdered mixture of the compound (C2H5O)2P(S)SCH2SCH2OCH3, tertiary dodecyl mercapto-undecaglycol ether, silica gel and kaolin which mixture may be suspended in water to give an aqueous dispersion; (4) a mixture of the compound (C2H5O)2P(S)SCH2 SCH2OC2H5 and talc; and (5) a mixture of the compound (CH3O)2P(S)SCH2SCH2OC2H5 and active carbon which is then mixed with cotton seed to render cotton plants derived therefrom resistant to attack by sucking insects (see Group I).