CS235587B1 - Process for the preparation of diuitrot3-tetrahydroimidazo [4,5-d] imidazole-2,5 (1H, 3H) -diphenyl - Google Patents

Abstract

The invention relates to 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-dimidazole-2,5 (1H,3H]-dione with nitric acid, while urea nitrate is added to the reaction system in the production process gradually or all at once in an amount of 0.01 to 25 wt. % per weight of the nitrated substance. The process according to the invention increases the economy and quality of DINGU production.

Description

The 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 urea nitrate in the reaction system.

The state of the art is the yield and safety of the nitrolysis and / or amine 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, e.g., the author's certificate and number 206 382, 213 509, 214 311 and others). The probable mechanism of action of some of these additives has been discussed in some publications, e.g. in MS. author's certificate no. 206 382; they are basically third generation catalysts.

According to the present invention, a method for producing dinitrotetrahydr oimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione by nitration of tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione is fuming % nitric acid in the presence of 0.01 to 25 wt. % urea nitrate, preferably in the presence of 0.3 to 20 wt. urea nitrate in the reaction mixture, calculated on the weight of the nitrated substance, wherein urea nitrate is added to the reaction system gradually or simultaneously.

An advantage of the present invention is to increase the process yield by a technically available additive whose presence in the reaction system generally also increases process safety. Another advantage is to increase the stability of the nitration product in the presence of an additive.

The process according to the invention has not been published so far and is documented by the following example, which in no way excludes the possible variability of the process.

Example

Up to the present 200 volumes of 96.1% nitric acid containing 0.3 wt. of analytical nitric acid, cooled to 18-20 ° C, is added with stirring and cooling, 20 wt. parts of the nitrated substance, i. j. tetrahydroimidazo [4,5-djimidazol-2,5 (1H, 3H) -dione, so that the temperature of the reaction mixture was 23-25 ° C. The reaction mixture is then heated to 63-66 ° C with stirring for 35 minutes. The nitration is terminated by pouring the reaction mixture into 1000 volumes, parts 65-70 ° C warm water, the resulting suspension is stirred for 30 minutes and filtered after cooling to 24-20 ° C.

The filter cake is dried at 90 ° C for 2 hours after washing five times with 20 volumes of part water. This basic procedure results in 24.5 wt. parts of 1,4-dinitrotetrahydroimidazo [4,5-d] imidazol-2,5- (1H, 3H) -dione, code-named DINGU, is a 75% yield over theory.

Said basic procedure is repeated with the application of a starting substance containing 0.299% w / w. urea nitrate (i.e. 0.3 wt.% per weight of nitrated substance) and then repeated, with 4 wt.% dissolved in the present nitric acid prior to introduction of the starting substance into the reaction system. parts of urea nitrate (i.e., 20% by weight of the nitrated substance). In the first case, 25.7 wt. parts of DING (i.e. 78.7% vs. theory), in the second 27.0 wt. parts of DING (i.e., 82.65 percent versus theory).

Using a non-isothermal differential thermal analysis operating at a linear temperature rise rate of 5 ° C. min ^-1 ·, with a measuring range of 1 mV per scale and weighing 80-90 mg of the sample, the foundations of exothermic decomposition were found in DING from nitration without additive at 149.9 ° C, in DING from nitration with additive 0.3 wt. at 151.1 degrees C and DING from nitration with 20 wt. additive at 154.9 ° C.

SUBJECT

A method for producing dinitrotetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione by nitration of tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione by nitric acid, characterized in that in the production process

Claims (1)

A method for producing dinitrotetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione by nitration of tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione by nitric acid, characterized in that in the production process, urea nitrate is added to the action system gradually or simultaneously in an amount of 0.01 to 25% by weight, preferably in an amount of 0.3 to 20% by weight. to a tetrahydroimidazo [4,5-d] imidazol-2,5 (1H, 3H) -dione weighing weight.