CS235585B1 - Process for producing dinitrotetrahydroimidazo [4,5-d] imidazole-2,5- (1H, 3H) -dione - Google Patents

Abstract

The invention deals with the production of dinitrotetrahydroimidazo[4,5-d]imidazole-2,5 (1H,3H)-dione, known under the code name DINGU, by nitration of tetrahydroimidazo[4,5-d]-imidazole-2,5-(1H,3H)dione with nitric acid, during which dicyandiamide is added to the reaction system in the production process, either gradually or all at once 0.01 to 15% by weight per weight of nitrated substance. The process according to the invention increases the economy and safety of DINGU production.

Description

The present invention relates to a process for the preparation of dinitrotetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) dione by nitration of tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) dione with nitric acid in the presence of dicyandiamide in reaction system.

The state of the art is the yield and safety of the nitrolysis and / or nitration process, respectively. amides, to cyclic nitramines favorably affected by the presence of urea, urea-formaldehyde condensates, aminoguanidine sulfate and the like. in the respective reaction mixture (see for example the author's certificate No. 206 382, 213 509,

214,311 and others). The probable mechanism of affecting some of the above-mentioned additives has been discussed in some papers, e.g. in MS. author certificate no. 206 382; they are basically third generation catalysts.

According to the present invention, a process for the preparation of dinitrotetrahydr oimidazo [4,5-d] imidazol-2,5 (1H, 3H) dione is nitrated by tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) dione by fuming nitric acid in the presence of 0.01 to 15 wt. % dicyandiamide, preferably in the presence of 0.3 to 11 wt. dicyandiamide in the reaction mixture, wherein the dicyandiamide is added sequentially or simultaneously to the reaction system.

An advantage of the present invention is to increase the yield of the nitration process by a technically available additive with secondary effect in the field of increasing the stability of the reaction mixture.

The process according to the invention is illustrated by the following example, which in no way excludes the possible variability of the process.

Example 1

Up to 200 vol. % by weight of nitric acid 96.1% by weight and 0.3% by weight. Analytical nitric acid, cooled to

5 to 20 ° C, 20 wt. parts of tetrahydroimidazo [4,5-d] imidazol-2,5- (1H, 3H) dione such that the temperature of the reaction mixture was in the range of 23-25 ° C. The reaction mixture is then heated to 62-65 ° C and held there for 35 minutes with stirring. The nitration is terminated by pouring the reaction mixture into 1000 volumes, 65-70 ° C warm water; the resulting suspension is stirred for 20 minutes, then cooled to 20-24 ° C and filtered. The filter cake is washed 5X and washed 20 volumes. with water and dried for 2 hours. at 90 ° C. This basic procedure results in 24.5 wt. parts of crude 1,4-dinitrole tetrahydrofuranimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione, code-named DINGU, which is 75% yield from theory.

Said basic procedure is repeated once with the application of tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) dione containing dicyandiamide (0.299% by weight of dicyandiamide, i.e. 0.3% by weight of the substance) and then once, before starting the nitration, 2.2 wt.% dissolved in the starting nitric acid at 10 to 11 ° C with good stirring and cooling. parts of dicyandiamide (i.e., 11 · wt.% per weight of nitrated substance). In the first case, 25.1 wt. parts of DING (i.e. 76.8% against theory), in the second 26.5 wt. parts of DING (i.e. 81.1% vs. theory).

Using a non-isothermal differential thermal analysis (DTA) operating at a linear temperature rise rate of 5 K. min ^-1 , measuring range 1mV per scale scale and weighing 80-90 mg of sample, found the onset of exothermic decomposition in DING from nitration without additive at 149.9 ° C, DING from nitration with 0.3 wt. additive at 151.8 C and ^Q DINGU nitration of a 11% by weight. additives at 152.0 ° C.

Claims (1)

SUBJECT A method for producing dinitrotetrahydroimidazo [4,5-d] imidazole-2,5- (1H, 3H) dione by nitration of a tetrahydroimidazo [4,5-d] imidazole-2,5 (1H, 3H) dione with nitric acid, characterized by that, in the production process, di-cyanediamide is added sequentially or simultaneously to the reaction system in an amount of 0.01 to 15% by weight, preferably 0.3 to 11% by weight. to the weight of the starting tetrahydroimidazo [4,5-d] imidazole-2,5 (1H, 3H) -dione.