GB603338A - Improved process of preparing chlorites from chlorine dioxide - Google Patents

Abstract

In the preparation of chlorites from chlorine dioxide in an alkaline medium in the presence of water and a reducing agent, the reducing agent employed is ammonia, one or more organic or inorganic compounds containing an NH2 radicle, or secondary or tertiary amines, or compounds containing the -C­N group. Examples are hydrazine, hydroxylamine, urea, amines, e.g. diethylamine, nitriles, cyanocompounds, e.g. calcium cyanamide. Catalysts consisting of compounds of, say, nickel, manganese, copper and especially silver may be present. Increased or reduced temperatures and pressures may be used. The reducing agent may itself constitute the basic compound, e.g. in the case of calcium cyanamide and ammonia. The latter part of the reaction may proceed under the influence of a stronger reducing agent than the second; thus, ammonia may be employed followed by hydrazine. The chlorine dioxide may be added as a solution, or as a gas diluted with an inert gas, e.g. air. When adding chlorine dioxide to an ammonia solution, its free concentration should not exceed .01 molar. Sodium hydroxide and potassium carbonate are also specified as alkaline substances. Specifications 460,374, 460,375 and 495,289 are referred to.ALSO:In the preparation of chlorites from chlorine dioxide in an alkaline medium in the presence of water and a reducing agent, the reducing agent employed is inter alia, one or more organic compounds containing an -NH2 radicle, or secondary or tertiary amines, or compounds containing the -C­N group. Examples are hydrazine, hydroxyclamine, urea, amines, nitriles. The reducing agent itself may constitute the basic compound in which case the chloride of the amine &c. employed, e.g. diethylamine, is obtained. Catalysts consisting of compounds of, say, nickel, manganese, copper and especially silver, may be present. Increased or reduced temperatures and pressures may be used. The latter part of the reaction may proceed under the influence of a stronger reducing agent than the second; thus, ammonia may be employed followed by hydrazine. The chlorine dioxide may be added as a solution, or as a gas diluted with an inert gas, e.g. air. Specifications 460,374, 460,375 and 495,289, [all in Group III], are referred to.