GB741479A - Improvements in or relating to trichlorodinitrobenzene - Google Patents

Abstract

Trichlorodinitrobenzenes are made by nitrating a trichlorobenzene with a nitrating agent comprising nitric and sulphuric acid, the composition of which is adjusted to give a spent nitrating agent containing 3 to 10 per cent, preferably 6 to 7.5 per cent, of water. A preferred process comprises nitrating 1 : 2 : 4-trichlorobenzene at 100 DEG -150 DEG C. with 1-1.5 times the theoretical amount of a nitric acid/sulphuric acid nitrating agent adjusted to give 6-7.5 per cent of water in the spent nitrating agent. The products are purified by heating a trichlorodinitrobenzene phase with a phase comprising a mixture of nitric and sulphuric acids containing not more than 15 per cent water at 70-135 DEG C., separating the organic phase and allowing it to solidify. The process is suitably applied to the nitration of a dehydrochlorinated benzene hexachloride. The products are used as fungicides, insecticides and plant growth regulants (see Group VI). In examples the above nitration process is used for the nitration of (1)-(5) 1 : 2 : 4-trichlorobenzene to give as the main product 1 : 2 : 4-trichloro-3 : 5-dinitrobenzene; (6) a mixture consisting mainly of trichlorobenzenes obtained by dehydrochlorinating benzene hexachloride to give a product containing a large proportion of dinitro derivatives, the main product being 1 : 2 : 4 - trichloro - 3 : 5 - dinitrobenzene, and (7) 1 : 2 : 3-trichlorobenzene to give the 4 : 6-dinitro derivative. An example of the purification of 1 : 2 : 4 - trichloro - 3 : 5 - dinitrobenzene by heating with a mixture of nitric and sulphuric acids is also given.ALSO:Plant growth regulant, fungicidal and insecticidal compositions comprise a minor proportion of 1 : 2 : 3-trichloro-4 : 6-dinitrobenzene produced by the nitration of the corresponding trichlorobenzene (see Group IV(b)) and a major proportion of a diluent together with a minor amount of an inert surface active agent. The invention also comprises compositions comprising a minor proportion of 1 : 2 : 3-trichloro-4 : 6-dinitrobenzene with a major proportion of 1 : 2 : 4-trichloro-3 : 5-dinitrobenzene, in which the 1 : 2 : 4-trichloro-3 : 5-dinitrobenzene is preferably present in an amount not exceeding 95 per cent, such compositions being produced by nitration of mixed trichlorobenzenes. The active materials may be used in the form of a water suspension disposed by means of a wetting agent, or in solution in organic solvents such as hydrocarbons, ketones, chlorinated solvents, p esters, alcohols and mono- and diethylene glycol monoethyl ethers, or the active materials may be mixed with solid diluents such as talc or clay to give dusts. Examples of aqueous dispersions, solutions and powders incorporating 1 : 2 : 3-trichloro-4 : 6-dinitrobenzene and mixtures thereof with 1 : 2 : 4-trichloro-3 : 5-dinitrobenzene are given.