GB949574A - Improvements in or relating to benzene dicarboxylic acid chlorides - Google Patents

Abstract

Di-acid chlorides of phthalic acids are prepared by mixing an a ,a 1-hexachloroxylene and a phthalic acid in a molar ratio of 0.85-2.0:1.0, heating the mixture to between 100 DEG and 250 DEG C. whereby hydrogen chloride is evolved and the di-acid chloride is produced and separating the di-acid halide; the reaction being carried out in a single step when the molar ratio of hexachloro-xylene to acid is greater than 1 and the reaction being carried out in two steps when the ratio is no greater than 1, the first step comprising reacting all of the acid and from 80% to 98% of the stoichiometric quantity of hexachloro-xylene to form the di-acid chloride and a polymeric residue, and separating the di-acid chloride; the second step comprising adding the balance of hexachloro-xylene to the residue and reacting the two to produce a distillable product comprising di-acid chloride, a trichloromethyl-benzoyl chloride and unreacted hexachloro-xylene, which may be recycled. Catalysts such as zinc and iron chlorides may be used in the reaction. The isophthaloyl and terephthaloyl chlorides prepared by this method may be used in fungicidal and nematocidal compositions (see Division A5). In examples the preparation of isophthaloyl and terephthaloyl chlorides is described.ALSO:Fungicidal and nematocidal compositions comprising, as essential active ingredient, isophthaloyl or terephthaloyl chloride obtained by reacting the corresponding acid with an a ,a 1-hexachloro-xylene (see Division C2) are described. The compositions may contain solid diluents such as Attaclays, diatomaceous earth, synthetic silica and flours, e.g. walnut shell, redwood, soyabean and cotton seed flours. The compositions may also contain liquid diluents and surface-active agents such as sodium and potassium oleates, sulphonated fish and castor oils sulphonated petroleum oils or acyclic hydrocarbons goulac, alkyl-naphthalene sodium sulphonates and alkaryl polyether alcohols. In examples, aqueous acetone solution of isopathaloyl and terephthaloyl chlorides containing 0.01% of an alkaryl polyether alcohol are used to control nematodes (Panagrellus redivivus) in vitro and rust fungus (Uromyces phaseoli) in soil. Specified forms are sprays, emulsifiable concentrates, wettable powders, granules, pellets, solutions and suspensions.