Verfahren zur Herstellung von Cyanursaeure

摘要

1,265,549. Cyanuric acid. BADISCHE ANILIN- & SODA-FABRIK A.G. 8 July, 1969 [9 July, 1968], No. 34396/69. Heading C2C. Cyanuric acid is made by heating urea and/or biuret at 190-300‹ C. in unsubstituted or a substituted N-cyclohexyl-2-pyrrolidone, e.g. N- cyclohexyl - 4,4 - dimethyl - 2 - pyrrolidone or N - 31 - methylcyclohexyl - 2 - pyrrolidone. The process may be batchwise or continuous, with residence times of 20-60 mins. Atmospheric or sub-atmospheric pressure, e.g. 50-750 mm. may be used. To facilitate removal of ammonia, an inert gas, e.g. nitrogen or carbon dioxide may be passed through the reaction mixture. A coarse-grained cyanuric acid is obtainable by passing into the reaction mixture, with or without the inert gas, hydrogen chloride, hydrogen sulphide, hydrogen and/or phosgene. The deposited cyanuric acid may be isolated by filtering or centrifuging the cooled reaction mixture, to which a diluent, e.g. methanol may be added.