CS227911B1 - A method for producing a mixture of monocyclic nitramines - Google Patents

Abstract

The invention relates to the production of a mixture of monocyclic nitramines with a predominant content of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane by nitrolysis of hexamethylenetetramine in an environment of acetic acid and acetic anhydride in the presence of urea-formaldehyde condensate. This mixture is a desired source of octogen designated by the code HMX in technical practice, or is applicable for special purposes.

Description

The invention relates to the production of a mixture of monocyclic nitramines with a predominant content of 1,3,5,7-tetranitro-1,3,5,7-tetraazaoycloctane by nitration of hexamethylenetetramine in an environment of acetic acid and acetic anhydride, whereby the reaction conditions are chosen in such a way that they positively affect the yield of the process.

Nitration cleavage of hexamethylenetetramine, depending on the reaction conditions, yields a binary mixture of monocyclic nitramines, in which either 1,3,5-trinitro-1,3,5-triazacyclohexane, also known as hexogen and denoted by the code RDX, predominates, or 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, called octogen and denoted by the code HMX. The mixture of the second type is a desired source of HMX in technical practice.

As we know (E. Ju. Orlova et al.: Oktogen - termostojkoje zryvčatoje vešchesto, Izdat. Nedra, 1978), the synthesis of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane from hexamethylenetetramine proceeds via 1,5-endomethylene-3,7-dinitro-1,3,5,7-tetraazacyclooctene as an intermediate. From the point of view of ensuring the maximum yield of octogen, it is advisable to realize the nitrolysis of hexamethylenetetramine by first synthesizing 1,5-endomethylene-3,7-dinitro-1,3,5,7-tetraazacyclooctane and then nitrolyzing it to HMX in the next step.

This two-step process can take place with isolation of the intermediate product, but in technical practice it is realized without isolation of 1,5-endomethylene-3,7-dinltro-1,3,5,7-tetraazacyclooctane from the reaction mixture. The first mentioned variant results in almost pure 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, the second then a mixture of HMX and RDX, in which HMX predominates.

According to the latest findings, the formation of cyclic nitramines during the nitrolysis of hexamethylenetetramine is favorably influenced by the presence of urea and/or urea-formaldehyde condensates, or and other acid amides and their derivatives (Czech Republic copyright certificates No. 227 903, No. 206 J82, No. 227 905 and No. 227 906). Urea was applied during the nitrolysis of 1,5-dlacetyl-3,7-endomethylene-1,3»5,7-tetraazacyclooctane in a sulfuric acid environment not i,5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (US Pat. No. 3,926,953), in the production 1,5-endomethylene-3,7-dinitro-1,3,5,7-tetraazacyclooctane (Czech copyright certificate no. 206 382) and during production

1,3,5-trinitro-1,3,5-triazacyclohexane (Czech copyright certificate no. 227 905), other acid amides, or their derivatives were applied in the production of 1,3,5-trinitro-1,3,5-triazacyclohexane (Czech Republic patent no. 227 906) by nitrolysis of hexamethylenetetramine.

Sword formaldehyde condensates increase the yield of hexamethylenetetramine to 1,3,5-trinitro-1,3,5-triazecyclohexene (Czech Republic copyright certificate no. 227 903 and no. 227 905). The mechanism of action of these additives in the nitrate splitting process was indicated in the form of a hypothesis in two works (Czech author's certificate no. 227 903 and no. 227 905). As can be seen from the published data (Czech Republic Pat. No. 97 100 and Czech Copyright Certificate No. 227 903), the presence of urea and/or urea-formaldehyde condensates in the nitrolysis mixture increases their stability, and thus the safety of work.

According to this invention, the method of producing a mixture of monocyclic nitramines of the general formula

N0„

_No.

X

X represents - CH^ - or - CHj - N - CHg - with a predominant content of 1,3,5,7-tetrenitro-1,3,5,7-tetraazacyclooctane by nitration cleavage of hexamethylenetetramine in an environment created by acetic acid and acetic anhydride, carried out in such a way that the nltrolysis process takes place in the presence of urea formaldehyde condensate, preferably of the foam type, such as trimethylene tetra to hexamethylene hepta-ureas and/or 2-keto~5-carboxamide-1,3,5-perhydro-triazine and/or substances of the uronov type, added to the reaction system in an amount of 0.01 to 15.00% by weight, preferably 0.1 to 10.00% by weight, based on the weight of hexamethylenetetramine entering the reaction.

The advantage of this invention, in addition to the possibility of applying hexamethylenetetramine with an anti-scaling treatment (Czech copyright certificate no. 227 902), is an increase in the yield of the process, i.e. an increase in the use of the methylene base of the starting hexamethylenetetramine. In the case of the production of a mixture of nitramines of the title type, this higher effect was not described in the literature, and in the following it is documented depending on the quality of the applied raw materials and, to a certain extent, also depending on the variability of the reaction conditions.

The influence of macrokinetic factors (concrete size and shape, or filling of the reactor) is successfully demonstrated. The influence of macrokinetic factors here appears analogous to the already described influence of these factors in the case of the nitrosative cleavage of hexamethylenetetramine to 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane (Czech copyright certificate no. 182 625). As can be seen from the exemplary part of the application for the invention mentioned below, during nitrolysis in an environment created by serial acetic acid and acetaldehyde, from the point of view of maximum yield of octogen, the most advantageous application is hexamethylenetetramine with a content of approximately 0.2 to 0.6% by weight of water-insoluble urea-formaldehyde condensate. This adltivum in the indicated quantity is a very effective anti-caking additive of hexamethylenetetramine (Czech Republic copyright certificate no. 227 902).

Example

A three-necked sulphonation flask with a content of 750 ml, equipped with a propeller stirrer, a thermometer, court burettes and a shell cooler, is used for nitrate splitting, or heating

The raw materials used are of the following quality: acetic acid 97.9%, acetic anhydride 96.**%, ammonium nitrate with a moisture content of 0.31%, nitric acid 99.15% with a content of 0.19% by mass. of analytical nitric acid, technical hexamethylenetetramine with a content of 0.217% by mass. of moisture, non-caking hexamethylenetetramine (prepared according to the Czech author, certificate, no. 227 902 with the addition of urea-formaldehyde condensate) with a content of 0.201% by mass. moisture and a certain content (table overview) of urea-formaldehyde condensate with a content of 36.7% by mass. nitrogen (preparation, e.g. Czech author, certificate, No. 227 901) and paraformaldehyde with a melting point of 178 to 183 °C.

The procedure is such that 75 ml of acetic acid, 1.5 ml of acetic anhydride and 1.7 g of paraformaldehyde are placed in the bank. At a temperature in the range of 41 to 44 °C, within 15 to 17 minutes, two solutions are rapidly dosed from the burettes, namely a solution of 10.1 g of technical hexamethylene tetramine or hexamethylene tetramine treated with urea-formaldehyde condensate in 16 ml of acetic acid and a solution of 8.7 g of ammonium nitrate in 6.3 ml of nitric acid.

After supplying the mentioned solutions, 6 ml of acetic anhydride is added to the reaction mixture in one go, followed by a further 15-minute reaction at a temperature of 45 to 47 °C. 44.5 ml of acetic anhydride and a solution of 13.2 g of ammonium nitrate in 9.5 ml of nitric acid are then abruptly added to the resulting reaction mixture over the course of 15 to 17 minutes at a temperature of 45 to 47 °C. After delivery and 60 min of reaction at a temperature of 45 to 47 °C, 35 ml of water 75 to 85 °C warmer is added to the stirred reaction mixture. The reaction mixture is then refluxed for 30 minutes and after cooling to 18 to 22°C diluted with 100 ml of cold water.

The reaction product is isolated by filtration and washed with water, then with 50 ml of approx. 5% ammonia water and finally twice with 50 ml of water 75 to 85 °C warmer. The washed product is dried at 80°C.

Table 1 shows the results from the application of three types of hexamethylenetetramine. The extracts given in this table refer to the case where one molecule of hexamethylenetetramine produces 1 molecule of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane and/or 1 molecule

1,3,5-trinitro-1,3,5-triazacyclohexane, in this sense, for a 100% yield of octogen, the utilization of the methylene base of hexamethylenetetramine is 66.66%.

Example 2

A cylindrical reactor with an internal diameter of 71 mm, a height of 172 mm and a bottom with a gut section height of 29 mm is used for nitrate cracking. Mixing, cooling, or heating and dosing of the solutions is carried out as in example 1.

The raw materials are of the same quality as in example 1. Likewise, the nitrolysis itself is conducted as in example 1, with the only difference being that the first batch of solutions lasts 10 minutes at a temperature of 4 to 45 °C and the second takes 8 to 14 minutes at a temperature of 45 to 48 °C.

The results from the application of the same three types of hexamethylenetetramine as in example 1 are shown in table 2. In this table the extracts are sieved with the same spfisob as in example 1.

Example 3

Nitrolysis of hexamethylenetetramine containing 1.23% by mass. of urea-formaldehyde condensate, obtained by curing at 100 °C the pre-condensate from 2.2 moles of formaldehyde and 1 mole of urea, is conducted as in example 2. A weight of 10.1 g of modified hexamethylenetetramine results in 10.4 g of product with a content of 67.52% by mass. octagon, the yield represents 32.94% by mass. of octagon and 21.15 wt.% of hexogen compared to theory, i.e. the utilization of the methylene base of hexamethylenetetramine is 32.53%. Compared to the nitrolysis of technical hexamethylenetetramine, there is a significantly higher yield of octagon.

Example 4

The nitrolysis of technical hexamethylenetetramine is carried out as in example 2, but with the difference that instead of 1.7 g of paraformaldehyde, 1 g of urea formaldehyde condensate with a content of 38.9% by mass is presented with acetic acid and acetic anhydride. of nitrogen (prepared under the Czechoslovak author, certificate, no. 227 901). Reaults 16.6 g of product with a content of 63.14% by mass. of octogen, the yield is 49.18% by mass. of octagon and 38.30 wt.% of hexogen compared to theory, i.e. the utilization of the methylene base of hexamethylenetetramine is 51.93%.

There is a significantly increased yield of both octogen and hexogen compared to the nitrolysis of technical hexamethylenetetramine in the presence of only paraformaldehyde in the reaction mixture.

Example 5

The nitrolysis of technical hexamethylenetetramine and non-sintering hexamethylenetetramine (prepared according to Czech author, osv, no. 227 902) is carried out as in example 2, only the applied acetic acid has a concentration of 99.1% by weight, and acetic anhydride is 97.6%. The first dosing of the solutions takes 10 to 12 minutes at a temperature of 44 to 46 °C, the second then 14 to 16 minutes at a temperature of 43 to 46 °C.

The results from the application of four types of hexamethylenetetramine are shown in table 3. The yields given in this table are calculated in the same way as in example 1,

Example 6

The nitrolysis of technical hexamethylenetetramine is carried out as in example 5, with the only difference that instead of 1.7 g of paraformaldehyde, only 0.6 g of this raw material is presented with acetic acid and then 0.5 g of urea-formaldehyde condensate is presented, the source and quality of which is identical to the urea-formaldehyde condensate in example 4. The result is 17.4 g of a product with a content of 68.70 % mass octogen. The yield represents 56.08% by mass. of octogen and 34.11 wt.% of hexogen versus theor. The utilization of the methylene base of hexamethylenetetramine is therefore 54.44%.

Example 7

The procedure is as in Example 2 with raw materials of the same quality as in Example 2. The difference is that together with the first dosing of hexamethylene tetramine and ammonium nitrate solutions, 24 ml of acetic anhydride is dosed from the third burette. The first dosage is carried out for 7 to 10 minutes at a temperature of 44 to 47 °C and the second for 13 to 14 minutes at a temperature of 44 to 48 °C. The results from the application of piatioh species of hexamethylenetetramine are shown in table 4. The yields in this table are calculated as in example 1.

Example 8

Nitrolysis of hexamethylenetetramine with a content of 0.38% by mass. of the urea-formaldehyde additive is realized as in example 7, only instead of 1.7 g of paraformaldehyde, urea-formaldehyde condensate is presented with acetic acid and acetic anhydride, identical in origin and quality to the urea-formaldehyde condensate in example 4, in an amount of 0.8 g. The result is 17.1 g of product with a content of 81.95% by mass. octogen. The extract represents 65.75% by mass. of octogen and 19.34 wt.% of hexogen compared to theory, the utilization of the methylene base is therefore 53.50%.

Example 9

The kitrolysis of hexamethylenetetramine is carried out in the reactor as in example 2. The types of hexamethylenetetramine, nitric acid and ammonium nitrate used are of the same quality as in example 1.' The nitrolysis environment is created with acetic acid and distilled acetic anhydride (fraction with a boiling point of 137.5 to 139.0 °C). The applied paraformaldehyde has a melting point of 171 to 175 °C.

To the presented 75 ml of Tado's acetic acid, 1.5 ml of ethane anhydride and 1.7 g of paraformaldehyde are mixed at a temperature of 43 to 46 °C. over the course of 13 to 15 minutes, he rapidly (proportionally) dispenses from three burettes: a solution of 10.1 g of hexamethylenetetramine in 16 ml of Tado's acetic acid, a solution of 8.7 g of ammonium nitrate in 6.5 ml of nitric acid and 24 ml of ethane anhydride. After supplying these solutions, 6 ml of ethane anhydride is added once to the reaction mixture and then allowed to react for 15 minutes at a temperature of 44 to 47 °C.

Next, the following are dosed proportionally from two burettes over the course of 8 to 11 minutes at a temperature of 44 to 48°C: 44 ml of ethane anhydride and a solution of 13.2 g of ammonium nitrate in 9.5 ml of nitric acid. After dosing and 60-minute reaction at 44 to 47 °C, 35 ml of water 75 to 85 °C warmer is added to the reaction mixture. The mixture is further refluxed for 30 min under a reflux condenser. It is then diluted with 100 ml of water and cooled to a temperature of 15 to 20 °C with constant stirring. The resulting suspension is filtered and the product on the filter is processed as in example 1. The results of individual experiments with different types of hexamethylenetetramine are shown in table 5.

Example 10

The procedure is as in example 9. Technical hexamethylenetetramine is used. After dosing the first solutions and acetic anhydride and after a 15-minute reaction, 0.05 g of urea-formaldehyde condensate with a nitrogen content of 38.9% by mass is added to the reaction mixture. violet is nitrolyzed in addition to that in example 9. 15.54 g of a mixture of nitramines with a content of 87.12% by mass is formed. octogen. The yield represents 63.55% of octogen and 12.52% of hexogen, compared to the theory, this means the use of methylene base is not 48.63%.

They put '

The procedure is as in example 9, with the difference that paraformaldehyde is replaced by 0.75 g of urea-formaldehyde condensate with a content of 38.9% by mass. nitrogen. Applied is hexamethylenetetramine technical* 15.73 g of a mixture of nitramines is formed, which contains 3.11% by mass.

of 1,5-endomethylene-3,7-dinitro-1,3,5,7-tetraazacyclooctane, 76.28 wt.% of octogen and 20.61 wt.% hexogen. The yield is 56.32% octogen and 20.28% hexogen compared to theory. The utilization of the methylene base of hexemethylenetetramine is 50.30%.

Table 1’ k a 1

Additive content in HMT (56 wt.) HMX content in the product (% wt.) Yield in g Yield vs theory in % on pure HMT HMT methylene base utilization (%) mixture HMX RDX HMX RDX 0.00 71.90 7.2 5.18 2.02 24.31 12.64 22.53 0.38 72.38 7.6 5.50 2.10 25.91 13.19 23.87 1.06 75.04 8.2 6.15 2.05 29.17 12.97 25.93 Focn.: additive - urea formaldehyde condensate Hi-Fi = hexamethylenetetramine Table 2 Additive content HMX content in Extract in β Yield vs. Using the me- in HMT (% wt., product mixture HMX RDX theory in % on tylenol base (% wt., pure HMT HMT (%) HMX RDX 0.00 64.66 10.8 6.98 3.82 32.76 23.91. 33.79 0.38 64.95 12.6 8.18 4.42 38.53 27.76 39.56 1.06 66.19 H.1 9.33 4.77 44.25 30.17 44.60

Fozn.: additive urea formaldehyde condensate HMX > hexamethylenetetremine

Table 3

Additive content in HMT (% by mass) HMX content in the product (% wt.) Yield in g Yield compared to theory in % of pure HMT HMT methylene base utilization (%) mixture HMX RDX HMX RDX 0.00 75.62 10.5 7.94 2.56 37.26 16.02 32.85 0.10 69.71 10.7 7.46 3.24 35.04 20.29 33.50 0.38 68.95 11.6 8.00 3.60 37.68 22.61 36.42 1.06 67.04 15.1 10.12 4.97 47.99 31.43 47.71

Note additive = urea formaldehyde condensate

HMT = hexamethylenetetramine

Table 4

Additive content in HMT (% by mass) HMX content in the product (wt.) Extracts in g Extracts compared to theory in % on pure HMT Use of methylene base ' BMT (%) mixture HMX RDX HMX RDX 0.00 80.30 17.10 13.33 3.37 64.44 21 .44 53.50 0.10 80.08 17.15 13.73 3.42 64.49 21 .42 53.70 0.38 79.31 17.20 13.64 3.56 64.25 22.36 54.01 0.50 79.20 17.30 13.70 •3.60 64.61 22.64 54.39 1 .06 78.76 17.60 13.86 3.74 65.73 23.65 55.64

Note: additive = urea formaldehyde condensate HMT W hexamethylenetetramine

IN

Τ β b u I k a 5

Additive content in HMT (% wt. HMX content in the product (% wt.) Yield in g Extracts compared to theory in % on pure HMT Utilization of methylene mares HMT (%) . mixture HMX RDX HMX RDX 0.00 81.18 14.52 11.79 2.73 55.33 17.09 45.43 0.05 81.40 14.81 12.05 2.76 56.57 17.28 46.35 0.10 83.60 15.70 13.12 2.58 61.62 16.16 49,-16 0.38 85.80 15.80 13.55 2.25 63.82 14.13 49.61 0.50 86.24 15.75 13.58 2.17 64.04 13.65 49.52 1.06 89.10 15.00 13.36 1.64 63.36 10.37 47.42

Note: adltivum = urea formaldehyde condensate HMT = hexamethylenetetramine

Claims (1)

A process for the preparation of a mixture of monoeylic nitramines of the general formula wherein X represents - ch ₂ NO, I ² or - CH, - N - CHg - and a predominant content of 1,3,5,7-tetranitro-1,3,5,7-tetraazaoyclooctane by nitration of hexamethylenetetramine in acetic acid and acetic anhydride media, characterized in that the process is The nitrolysis is carried out in the presence of a urea-formaldehyde condensate, preferably of the foam type, such as trimethylene tetra to hexamethylanehepta-urea and / or 2-keto-5-carboxamld-1,3,5-perhydrotriazine and / or a urone type added to the reaction system. from 0.01 to 15.00% by weight, preferably from 0.1 to 10.00% by weight, based on the weight of the hexamethylenetetramine entering the reaction.