Patent GB-573712-A (GB)
Title: Improvements in or relating to the production of pest control agents
IPC: C07C23/10
Filed: 1943-12-08
Abstract: Chlorinated cyclohexanes, containing from 5 to 7 atoms of chlorine per molecule and melting below 30 DEG  C., may be obtained by the prolonged chlorination, at low temperatures, of cyclohexane or monochlorocyclohexane in the presence of actinic radiation. The crude chlorinated product may be fractionated.  In one group of examples, cyclohexane was chlorinated at 0 DEG  C. for 48 hours in sunlight, the white crystals consisting of tetrachlorocyclohexane filtered off, and the liquid heated under vacuum to remove free chlorine.  The final product was a clear viscous liquid containing 71.2 per cent Cl and consisting of a mixture of penta- and hexachlorocyclohexanes. Further chlorination of this liquid gave, on filtration, white crystals of hexachlorocyclohexane of m.p. 145 DEG  C., and a syrupy liquid which, on fractionation under reduced pressure, gave a liquid mixture of hexa- and heptachlorocyclohexane, and heptachlorocyclohexane.  In a further example, the later stages of chlorination were conducted in presence of iron filings and ultra-violet light, and five fractions were obtained, the first four consisting of hexachlorocyclohexane and the last of a mixture of hexa- and heptachlorocyclohexanes.  In a last example, monochlorocyclohexane was chlorinated and four fractions were obtained, the first three having compositions approximating to that of heptachlorocyclohexane, the fourth being a mixture of hepta-and octachlorocyclohexane.  The last two fractions crystallized on standing and had a m.p. of 20 DEG  to 25 DEG  C.  In a statement of prior art, the prior production, by chlorination of cyclohexane and intensive cooling, of fine white needles having the empirical composition of benzene hexachloride and melting at 130 DEG  C., which on fractional sublimation gave plate-like crystals melting at 145 DEG C., is referred to.  Specification 573,689 is referred to.ALSO:A pest control composition comprises chlorinated cyclohexane containing from 5 to 7 atoms of chlorine per molecule and melting below 30 DEG C., and a carrier material or diluent.  The chlorinated hydrocarbons may be mixed with a solid diluent, such as chalk, gypsum, anhydrite, slate-dust or talc, or used in solution in a solvent such as acetone, or made up as a dispensible powder with an agent such as soap or "goulac," or as a liquid dispersible in water by solution in a solvent, e.g., methanol, together with a suitable dispersing agent, or may be emulsified with water, preferably containing a wetting agent, after solution in methanol or carbon tetrachloride.  They may also be used with a bait material.  The chlorinated cyclohexanes may be obtained by the prolonged chlorination, at low temperatures, of cyclohexane or monochlorocyclohexane in the presence of actinic radiation.  The crude chlorinated product may be subsequently fractionated to isolate a fraction having an improved pest control activity.  In one group of examples, cyclohexane was chlorinated at 0 DEG C. for 48 hours in sunlight, the white crystals consisting of tetra-chlorocyclohexane filtered off, and the liquid heated under vacuum to remove free chlorine.  The final product A was a clear viscous liquid containing 71.2 per cent. Cl. and consisting of a mixture of penta- and hexachlorocyclohexanes.  Further chlorination of this liquid gave, on filtration, white crystals of hexachlorocyclohexane of M.P.145 DEG C., and a syrupy liquid which, on fractionation under reduced pressure, gave a liquid mixture of hexa and heptachlorocyclohexane B, and heptachlorocyclohexane C. For killing locusts 1 part of product A may be mixed with 18 parts by weight of molasses, 76 parts by weight of water and 500 parts by weight of bran, or products A. B. C may be used with bran alone.  For killing grain weevils the products may be mixed with talc and dusted on wheat.  In a further example, the later stages of chlorination were conducted in presence of iron filings and ultraviolet light, and five fractions were obtained, the first four consisting of hexachlorocyclohexane and the last of a mixture of hexa and heptochlorocyclohexane.  In a last example monochlorocyclohexane was chlorinated and four fractions were obtained, the first three having compositions approximating to that of heptachlorocyclohexane, the fourth being a mixture of hepta and octachlorocyclohexane.  The last two fractions crystallised on standing and had a M.P. of 20 to 25 DEG C.  In a statement of prior art, the prior production, by chlorination of cyclohexane and intensive cooling, of fine white needles have the empirical composition of benzene hexachloride and melting at 130 DEG C., which on fractional sublimation gave plate like crystals melting at 145 DEG C., is referred to.  Specification 573,689 is referred to.