GB658976A - Improvements in or relating to the manufacture of cyclo-trimethylenetrinitramine - Google Patents

Abstract

Cyclo-trimethylenetrinitramine (cyclonite) is obtained in substantially pure, granular form from mixtures obtained by nitration of hexamine or hexamine dinitrate with concentrated nitric acid, by adding the nitration mixture gradually and continuously with stirring to water, or dilute aqueous nitric acid, previously heated to and maintained during the addition at between 40 DEG and 90 DEG C. in such proportion that the diluted liquor contains 50-70 per cent (by weight) of nitric acid. A substance such as a metallic nitrite or paraformaldehyde which reacts with the nitric acid at the temperature obtaining to produce oxides of nitrogen may previously be added to the diluting water or acid. Alternatively the decomposition may be initiated by heating the dilution medium before the addition of the nitration mixture to a temperature between 75 DEG and 90 DEG C. In this case the temperature may rise above 90 DEG C. in the initial stages of the addition but is then reduced and maintained by cooling within the desired range. The diluting agent may comprise 50-70 per cent aqueous nitric acid to which the nitration mixture may be added simultaneously with water in such proportions that the strength of the acid in the diluting vessel remains substantially constant and in a continuous process the volume of the decomposing diluted acid solution is kept substantially constant during the addition of the nitration mixture and water by drawing off continuously a mixture of diluted acid and cyclonite. In examples: (1) hexamine is added to nitric acid at 20 DEG C. and the cyclonite mixture is then added slowly to 50.2 per cent nitric acid heated to 50 DEG C. and to which a small amount of sodium nitrite or paraformaldehyde had been added. The temperature is kept by cooling at 65 DEG to 75 DEG . After cooling and allowing the mixture to stand the cyclonite is filtered off; (2) as in (1) except that the reaction mixture is added to 70 per cent nitric acid heated to and then maintained at 70 DEG C.; (3) as in (1) except that water is added simultaneously with the reaction mixture; (4) hexamine is nitrated and the mixture added to water at 87 DEG C. The temperature rises initially to 98 DEG C. and is then reduced by cooling to below 90 DEG C. and then maintained at 70 DEG to 75 DEG C. During the further addition of the nitration mixture water is added at intervals; (5) hexamine is nitrated in a continuous manner at 20 DEG to 25 DEG C. and the mixture of hexamine and nitric acid overflows into a diluter filled with 55 per cent nitric acid at 90 DEG C. and dilution water is fed in to maintain the acid concentration constant while the temperature is lowered and then maintained at 75 DEG C. The suspension of cyclonite in mother liquor overflows and after cooling the cyclonite is filtered off and washed with water.