GB886425A - Herbicidal compositions and benzyl and substituted benzyl mono- and di-thiocarbamates for use therein - Google Patents

Abstract

The invention comprises a halogen-substituted benzyl thiocarbamate having the general formula <FORM:0886425/IV (b)/1> in which each X is an oxygen or sulphur atom, at least one being sulphur, R1 and R2 are hydrogen atoms or alkyl, alkoxyalkyl, carboxyalkyl, carbamylalkyl, cycloalkyl, alkenyl or haloalkenyl groups having up to 7 carbon atoms or together represent a group of the formula CnH2n in which n is an integer from 4-8 and which may be interrupted by an oxygen atom or by a group of the general formula -NY- in which Y is a hydrogen atom or an alkyl or hydroxyalkyl group having not more than 5 carbon atoms and R3 is a halogenated benzyl group containing 2, 3 or 4 nuclear halogen atoms and a process for the preparation thereof which comprises condensing an alkali metal or ammonium salt of a thiocarbamic acid having the general formula <FORM:0886425/IV (b)/2> in which R1, R2 and X are as above defined and M is an alkali metal atom or ammonium group, in aqueous solution with a halogen substituted benzyl halide containing 2, 3 or 4 nuclear halogen atoms. The products are employed as active ingredients in herbicides (see Group VI). Substituted benzyl radicals specified include 2-halogeno-, 2,4- and 2,6-dihalogeno-2,4,5-, 2,4,6- and 2,3,6-trihalogenobenzy. Specific products described include trichlorobenzyl N,N-di-n- and di-iso-propyl, N,N-diethyl and N,N-diisobutyl thiol carbamates, N,N-bis(2-methoxy-ethyl)-, N-(3-chloro-2-butenyl)N-cyclohexyl-, N-(2-carbamoylrthyl)N-cyclohexyl-, N-(2-chloroalkyl)- N-isopropyl- and N-(carboxymethyl)N-methyl dithiocarbamates, o-sodium salt of 2,3,6-trichlorobenzyl N-(carboxymethyl)-N-methyl-dithiocarbamate dihydrate and a similar compound in which the positions of the chlorine atoms in the benzene nucleus are unknown, trichlorobenzyl N-(b -hydroxy-ethyl) piperazine- and 5-ethyl-2-methyl-1-piperidine-carbodithioate. Mono- and di-thiocarbamic acids for use in the process are prepared by adding carbon oxysulphide or disulphide to appropriate secondary amines representative of those specified being alkyl), bis(b -methoxyethyl) amines, N-methyl-and N-cyclohexyl a -amino-acetic and -b -amino-propionic acids, N-ethyl-a -aminoacetamides, N-allyl-N-iso propyl amines, pyrrolidine, piperidine, piperazine, N-ethyl and N-(b -hydroxyethyl)-piperazines and morpholine. Examples are furnished. Trichlorobenzyl chloride is produced by chlorinating dry toluene in the presence of iron to obtain trichlorotoluene which is then treated with caustic soda solution and filtered through clay or distilled to remove the iron and further chlorinated under ultra-violet light.ALSO:A herbicidal composition comprises a major proportion of a carrier and a minor proportion of a benzyl thiocarbamate having the general formula <FORM:0886425/VI/1> in which each X is an oxygen or sulphur atom, at least one being sulphur, R1 and R2 are hydrogen atoms or alkyl, alkoxyalkyl, carboxyalkyl, carbamylalkyl, cycloalkyl, alkenyl or haloalkenyl groups having up to seven carbon atoms or together represent a group of the formula CaH2n in which n is an integer from 4-8 and which may be interrupted by an oxygen atom or by a group having the general formula -NY- in which Y is a hydrogen atom or an alkyl or hydroxy-alkyl group and R3 is a benzyl, methyl-benzyl dimethylbenzyl or a halogen substituted benzyl group containing not more than four nuclear halogen atoms (see Group IV (b)). Specific active substances described include trichlorobenzyl N,N-di-n- and di-iso-propyl, N,N-diethyl- and N,N-diisobutyl-thiol-carbamates, N,N-bis-(2-methoxyethyl)-, N - (3 - chloro - 2 - butenyl) - N - cyclohexyl-, N-(2 - carbamoyl ethyl) N - cyclohexyl-, N - (2-chlorallyl)-, N-isopropyl- and N-(carboxymethyl) N-methyl dithiocarbamates, o-sodium salt of 2,3,6-trichlorobenzyl N-(carboxymethyl)-N-methyl dithiocarbamate dihydrate and a similar compound in which the positions of the chlorine atoms in the benzene nucleus are unknown, trichlorobenzyl N - (b - hydroxyethyl) piperazine- and 5 - ethyl - 2 - methyl - 1 - piperidine-carbodithioate. Organic solvents for the thiocarbamates specified include acetone, chloroform, ethanol, ethyl acetate, benzene, ether and heptane. The thiocarbamates may be directly dispersed in water or a solution in organic solvent may be dispersed in water with a wetting agent. Wetting agents specified include soft or hard sodium and potassium soaps, alkali metal and amine salts of alkylated aromatic sulphonic acids such as sodium dodecylbenzene sulphonate and dibutylammonium dodecylbenzene sulphonate, the alkali metal p salts of sulphated fatty alcohols such as sodium lauryl sulphate and non-ionic wetting agents such as ethylene oxide condensation products of alkylphenols, tall oil and higher mercaptans.