Patent GB-886426-A (GB)
Title: Herbicidal compositions and substituted benzyl dithiocarbamates for use therein
IPC: C07C333/18
Filed: 1958-05-06
Abstract: The invention comprises a halogen-substituted benzyl-thiocarbamate having the general formula <FORM:0886426/IV (b)/1> in which R1 and R2 are alkyl and alkenyl groups having up to seven carbon atoms and R3 is a halogen substituted benzyl group containing two, three or four nuclear halogen atoms, of which one is present in the 2- or 6-position when the group contains three halogen atoms, and a process for the preparation thereof which comprises condensing an alkali metal or ammonium salt of a dithiocarbamic acid having the general formula <FORM:0886426/IV (b)/2> in which R1 and R2 are as defined above and M is an alkali metal atom or ammonium group in aqueous solution with a nuclear halogen substituted benzyl halide containing two, three or four nuclear halogen atoms of which one is present in the 2- or 6-position when the group contains three halogen atoms. The preparation is described in examples of 2,4,5- 2,3,6-, 2,3,4-trichloro- and 2,5-dichlorobenzyl N,N-diisopropyl dithiocarbamates by reacting the corresponding benzyl chlorides with sodium N,N-diisopropyldithiocarbamate.  The halogen substituted benzyl-thiocarbamates of the invention are employed in herbicidal compositions (see Group VI). p  2,4,5-Trichlorobenzyl chloride is prepared by reacting 2,4,5-trichlorotoluene with sulphuryl chloride in the presence of benzyl peroxide.  2,4,6-trichlorobenzyl chloride is prepared by chlorinating 2,4,6-trichlorotoluene at 190 DEG C.-198 DEG C. 2,3,6-Trichlorobenzyl chloride is prepared similarly. 2,3,4-Trichlorobenzyl chloride is similarly prepared, the reaction mixture being irradiated. 2,5-Dichlorobenzyl chloride is similarly prepared.  Dithiocarbamic acids employed in the process may be prepared by adding carbon disulphide to appropriate secondary amines, e.g. from dimethyl to diisobutylamines, methyl ethyl and N-allyl-N-isopropylamines and diallylamines.ALSO:A herbicidal composition comprises a major proportion of a carrier and a minor proportion of a benzyl thiocarbamate having the general formula <FORM:0886426/VI/1> in which R1 and R2 are alkyl or alkenyl groups having up to seven carbon atoms and R3 is a methyl benzyl, dimethylbenzyl or halogen substituted benzyl group having up to four nuclear halogen atoms of which one is present in the 2-or 6-position when the group contains three halogen atoms (see Group IV (b)). Benzyl thiocarbamates specified include o-, m- and p-chloro, 2,4-, 2,6- and 3,4-dichloro-, 2,3,6-, 2,4,5- and 2,4,6-trichloro-, 2,3,4,5- and 2,3,5,6-tetrachloro-benzyl N,N-diisopropyldithiocarbamates.  The active substances may be dispersed directly in water or a solution in an organic solvent may be emulsified in water with the aid of a dispersing agent. Dispersing agents specified include soft and hard potassium soaps, alkali metal and amine salts of alkylated aromatic sulphonic acids, e.g. sodium or dibutyl-ammonium dodecyl benzene sulphonate, alkali metal salts of sulphated fatty alcohols, e.g. sodium lauryl sulphate and non-ionic wetting agents such as ethylene oxide condensation products with alkyl phenols, tall oil and higher mercaptans.  Solid carriers specified include talc, clay, pyrophillite, silica or fuller's earth.  Dry compositions may comprise a wetting agent.