GB413722A - Improvements in the manufacture of oxychlorides of copper and of anticryptogamic products containing them - Google Patents

Abstract

Copper oxychloride is obtained by acting on copper or materials containing it, at temperatures say up to 50 DEG C. and in the presence of an air current or oxygen with a solution of a chlorine compound capable of forming "chlorine of an oxidizing character," together with bodies or compounds promoting the formation of such chlorine in such amount that no free chlorine is formed or liberated. "Chlorine of oxidizing character" is defined to mean chlorine which in solution and in the presence of a body having an affinity for oxygen will act on the water and either form peroxides such as hydrogen peroxide or liberate oxygen, and it may be furnished by a chlorine compound of a heavy metal or metalloid, but preferably from aqueous solutions of hydrochloric acid or an alkali metal chloride. Compounds promoting its formation may be chloric, perchloric, permanganic, persulphuric, or chromic acids or their salts; or preferably nitric acid or an alkali metal nitrate which are used in such quantities that no free nitrogen oxides appear in the solution. The solution for attacking the copper may contain hydrochloric and nitric acids in respective concentrations of 50--80 and 2--10 grms. per litre and the attack may proceed in an acid, neutral, or basic medium, whilst in a modification, the copper is attacked in a basic medium in the presence of mother liquors from the manufacture of copper sulphate, whereby a mixture of oxychloride and basic sulphate of copper is produced. In the said modification, the attack may proceed in a first phase in the presence of sulphuric acid to form copper sulphate, and be continued with the mother liquors from such formation without further addition of sulphuric acid. The process may be carried out in a tower fitted with a false bottom, which, for the joint production of copper sulphate and the oxychloride-basic sulphate mixture, is connected to crystallizing vessels, the solution circulating continuously between the tower and crystallizing vessels during the copper sulphate production. For use as a fungicide, the oxychloride or mixed oxychloride-basic sulphate product is oxidized, mixed with lime preferably in the form of calcium oxide, dried if necessary, neutralized by carbon dioxide, and mixed with an inert substance and/or a substance having high adhesive power such as dextrin. Specifications 323,115, [Class 1 (iii)], and 413,721 are referred to.ALSO:For use as a fungicide, copper oxychloride or a mixture thereof with basic sulphate of copper is oxidized, mixed with lime preferably in the form of calcium oxide, dried if necessary, neutralized by carbon dioxide, and mixed with an inert substance and/or a substance having high adhesive power such as dextrin. Specifications 323,115, [Class 1 (iii)], and 413,721, [Group III], are referred to.