RU2337902C1 - Method for obtaining ultra fine hexanitrostilbene - Google Patents

Abstract

FIELD: chemistry, explosives.

SUBSTANCE: method of obtaining ultra fine hexanitrostilbene is proposed. Hexanitrostilbene is dissolved at temperature of 50-80°C in dimethylformamide. The hexanitrostilbene is precipitated by adding the obtained solution to a water solution of acid at 5-30°C, with agitation of by compressed air and volume ratio of the water solution of acid to the volume of hexanitrostilbene solution of 4-5. After separation by filtering, the residue is washed in distilled water, and then in a 15-25% water solution of acetone and is then dried in a vacuum.

EFFECT: obtaining ultra fine hexanitrostilbene with particle size less than 1 mcm.

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Description

The invention relates to techniques and technology for explosives (BB) and can be used in ignitors, detonators and other explosive devices where hexanitrostilbene with a high specific surface area (particle size of not more than 1 μm) is required.

A known method of reducing particles of explosives [international application PCT (WO) 93/06065, C06B 21/00, B01D 9/02, publ. 04/01/1993].

A method of reducing the grain size of a crystalline substance, especially hexogen or hexa-containing mixtures, is based on the fact that the explosive is dissolved in an organic solvent, then the dissolved explosive precipitates in the presence of water and crystallizes, and then the recrystallized explosive obtained is separated from the solvent and water, this explosive solution is combined with cold water with turbulent stirring.

However, when using this method, it is possible to obtain particles with sizes of 4 ... 6 μm.

Also known is the "Method of producing finely dispersed octanite" according to the patent of the Russian Federation No. 2281931, C06B 21/00, publ. BI No. 23, 2006

The method is based on obtaining a solution of octanite in dimethylformamide, followed by precipitation of octanite and filtering the resulting suspension. To obtain highly dispersed octanite, dimethylformamide is used and octanite is dissolved at a temperature of 125-135 ° C, and sequential addition of acetone and water are used to precipitate octanite. In this case, the precipitation of octanite from the solution is carried out in two stages.

This method allows to obtain octanite with a particle size of more than 1 μm, which in some cases, in particular to provide an increased susceptibility of the explosive to a shock wave pulse, is not enough.

By technical nature and the problem to be solved, the closest to the claimed method is a method for producing ultrafine hexanitrostilbene according to US patent No. 6844473 B1, 01/18/2005, С07С 205/00 (2006.1).

This method includes the following steps: mixing hexanitrostilbene with n-methylpyrrolidone, heating the mixture to 82 ° C, mixing the heated solution with cold water, filtering the resulting suspension, drying.

The known method according to US patent No. 6844473 B1, 01/18/2005, С07С 205/00 allows you to get ultrafine hexanitrostilbene with a specific surface of the order of 40 m ² / year

The disadvantage of this method of obtaining ultrafine hexanitrostilbene is the need to freeze the resulting suspension during drying. This requires additional equipment, in addition, the duration of the technological cycle increases.

The objective of the present invention is to simplify the method of producing ultrafine hexanitrostilbene.

Using the proposed method provides the following technical result:

- Obtaining ultrafine hexanitrostilbene with a particle size of less than 1 μm (specific surface determined by thermal desorption, 23-26 m ² / g), which makes it possible to control the shock-wave sensitivity of charges based on it.

- Achieving simplicity and low cost of the method through the use of standard equipment.

- Ensuring process safety by the fact that the technology does not have operations of intense mechanical action on explosives and there are no solvents heated to temperatures close to their boiling point.

To achieve the specified technical result, a method for producing ultrafine hexanitrostilbene is obtained, including dissolving hexanitrostilbene in a solvent, filtering the precipitate, drying in which dimethylformamide is used as a solvent, the hexanitrostilbene is dissolved at a temperature of 50-80 ° C, after which it is precipitated by dosing the obtained solution in an aqueous acid solution with a temperature of 5-30 ° C with stirring with compressed air and the ratio of the volume of water the acid solution to the volume of the solution of hexanitrostilbene 4-5, after separating the precipitate by filtration, it is washed with distilled water, and then with a 15-25% aqueous solution of acetone, drying is carried out in vacuum.

The proposed method is as follows.

Example 1

25 grams of hexanitrostilbene are dissolved in 1200 g of dimethylformamide at a temperature of 80 ° C, then the solution is cooled to a temperature of 45 ° C. A precipitating liquid is prepared - in 5200 g of water, 60% phosphoric acid in an amount of 100 ml is added. The temperature of the precipitating fluid is 23 ° C. The resulting solution of hexanitrostilbene in dimethylformamide is dosed into the precipitant with stirring with compressed air with a pressure of 0.5 MPa (5 kg s / cm ² ). The process of crystallization (precipitation) of hexanitrostilbene occurs, after which the precipitate is filtered on a vacuum filter, washed with distilled water in an amount of 500 ml, then with a 20% aqueous acetone solution in an amount of 500 ml and dried at 70 ° C in vacuo.

The specific surface area of the obtained substance by thermal desorption is ~ 26 m ² / g. The average particle size is ~ 0.13 microns.

Example 2

50 grams of hexanitrostilbene are dissolved in 2400 g of dimethylformamide at a temperature of 70 ° C, then the solution is cooled to a temperature of 38 ° C. A precipitating liquid is prepared - in 11000 g of water, 60% phosphoric acid in an amount of 200 ml is added. The temperature of the precipitating fluid is 8 ° C. The resulting solution of hexanitrostilbene in dimethylformamide is dosed into the precipitant with stirring with compressed air with a pressure of 0.5 MPa (5 kg s / cm ² ). The process of crystallization (deposition) of hexanitrostilbene occurs, after which the precipitate is filtered on a vacuum filter, washed with distilled water in an amount of 1 l, then with a 20% aqueous acetone solution in an amount of 1500 ml and dried at 70 ° C in vacuo.

The specific surface area of the obtained substance by thermal desorption is ~ 23 m ² / g. The average particle size is ~ 0.18 microns.

Example 3

20 grams of hexanitrostilbene are dissolved in 1200 g of dimethylformamide at a temperature of 60 ° C, then the solution is cooled to a temperature of 42 ° C. A precipitating liquid is prepared - in 5200 g of water, 60% nitric acid in an amount of 35 ml is added. The temperature of the precipitating fluid is 23 ° C. The resulting solution of hexanitrostilbene in dimethylformamide is dosed into the precipitant with stirring with compressed air with a pressure of 0.5 MPa (5 kg s / cm ² ). The process of crystallization (precipitation) of hexanitrostilbene occurs, after which the precipitate is filtered on a vacuum filter, washed with distilled water in an amount of 500 ml, then with a 20% aqueous acetone solution in an amount of 500 ml and dried at 70 ° C in vacuo.

The specific surface area of the obtained substance by thermal desorption is ~ 26 m ² / g. The average particle size is ~ 0.12 microns.

The experiments showed that the inventive method allows to obtain hexanitrostilbene with a particle size of less than 1 μm. The method is safe and not difficult to execute.

Claims (1)

A method of producing ultrafine hexanitrostilbene, including dissolving hexanitrostilbene in a solvent, filtering the precipitate, drying, characterized in that dimethylformamide is used as a solvent, hexanitrostilbene is dissolved at a temperature of 50-80 ° C, after which it is precipitated by dosing the resulting solution in an aqueous acid solution with at a temperature of 5-30 ° C with stirring with compressed air and the ratio of the volume of an aqueous acid solution to the volume of a solution of hexanitrostilbene 4-5, after separation precipitate by filtration, it is washed with distilled water and then with 15-25% aqueous acetone solution, drying is performed in vacuo.