GB1062821A - Apparatus for the continuous production of trichloro-cyanuric acid - Google Patents

Abstract

1,062,821. Trichlorocyanuric acid. OFFICE NATIONAL INDUSTRIEL DE L'AZOTE. March 3, 1964 [March 4, 1963], No. 8992/64. Heading C1A. Trichlorocyanurio acid is produced in an apparatus comprising a supply reservoir for delivering a cooled aqueous solution of cyanuric acid and alkali metal hydroxide, a chlorination column comprising means for the chlorination of the cooled mixture, gas supply means for introducing chlorine into the bottom of the column, by-pass means for cycling a portion of the solution from the bottom of the column to the top, means for measuring the redox potential of the reaction mixture, a regulator responsive thereto for controlling the supply of at least the aqueous solution or the chlorine and filtering means for separating product crystals from the mixture of crystals and mother liquor removed from the top of the chlorination column. Preferably means are provided for regenerating chlorine from the mother liquor by acid treatment, the chlorine so produced being introduced into the bottom of the chlorination column. The means for measuring the redox potential is preferably located in the stream of reactants in the by-pass means, and it may also be located in the mother liquor after the crystals have been removed. In the process, the cyanuric acid and the alkali metal hydroxide are mixed together in a molar ratio of at least 1: 3, and the supply of either or both of the cooled aqueous or of the chlorine is controlled in response to the measured redox potential so as to. keep the measured potential within the range of from 1050-1150 mV. and the temperature of the cooled aqueous solution is controlled so that the temperature of the reaction mixture is maintained in the range 0‹ to 16‹ C.