Patent GB-343938-A (GB)
Title: Improvements in or relating to insecticides
Filed: 1929-11-25
Abstract: Mercapto-aralkyl thiocyanates and halides.-Aromatic compounds containing both a thioether group and a CH2.SCN group are prepared by interaction of the corresponding halogen compound with an alkali thiocyanate.  The said halogen compounds are obtained by acting on aromatic thioethers with formaldehyde and a hydrohalide.  The thiocyanate products are useful as insecticides, either alone or in combination with adhesive and wetting agents or in the colloidal state or with the addition of other insecticides. In particular, they may be dissolved in an organic solvent miscible with water and the whole diluted with water to which a wetting agent soluble in the organic solvent may be added. According to the Example, 1-methylmercapto-4-methyl-2-benzylthiocyanate is produced by treating with ammonium thiocyanate in alcoholic solution the corresponding halogen compound, the latter being obtained by methylating p-methylthiophenol with dimethyl sulphate and treating the product with formaldehyde and hydrochloric acid.  A solution of the 1-methylmercapto-4-methyl-2-benzylthiocyanate in acetone, to which an alkylnaphthalene sulphonic acid or its ammonium salt has been added and the resulting solution well diluted with water, is very efficacious for the destruction of green fly. Specification 325,910, [Class 2 (iii), Dyes &c.], is referred to.  The Specification as open to inspection under Sect. 91 (3) (a) describes also the use of any thiocyanate as a reactant and includes the following examples: (1) 1-methylmercapto-4-benzylthiocyanate, prepared from the corresponding halogen compound by means of ammonium thiocyanate in alcoholic solution, is dissolved in acetone to which an acetone-soluble wetting agent is added and the whole diluted with water; (2) 1-methylmercapto-4-chloro-2-chloromethylbenzene, obtained from p-chlorophenylthiomethylether by formaldehydehydrochloric acid condensation, is heated with ammonium thiocyanate in methyl alcohol; the resulting 1-methylmercapto-4-chloro-2-benzylthiocyanate is strongly insecticidal, whether employed alone in aqueous solution or emulsified with the ammonium salt of butylnaphthalene sulphonic acid. This subject-matter does not appear in the Specification as accepted.ALSO:Aromatic compounds containing both a thioether group and a CH2.SCN group are useful as insecticides either alone or in combination with adhesive and wetting agents or in the colloidal state or with the addition of other insecticides.  In particular, they may be dissolved in an organic solvent miscible with water and the whole diluted with water to which a wetting agent soluble in the organic solvent may be added.  According to the example, a solution of 1-methylmercapto-4-methyl-2-benzylthiocyanate in acetone, to which an alkylnaphthalene sulphonic acid or its ammonium salt has been added and the resulting solution well diluted with water, is employed for the destruction of green fly Specification 325,910, [Class 81 (i), Disinfecting &c.], is referred to.  The Specification as open to inspection under Sect. 91 (3) (a) describes also the preparation of insecticides by dissolving 1-methylmercapto-4-benzylthiocyanate in acetone to which an acetone-soluble wetting agent is added and diluting with water, or by emulsifying 1-methylmercapto-4-chloro-2-benzylthiocyanate with the ammonium salt of butylnaphthalene sulphonic acid.  This subject-matter does not appear in the Specification as accepted.