SK50402011A3 - Process for synthesis of cyclic nitramines using raw materials recovered from reaction medium - Google Patents

Abstract

It is described a method based on the recuperation of raw materials present in the reaction solutions, during the preparation of cyclic nitramines, converting them on hexamethylenetetramine dinitrate which after the isolation replaces of significant proportion of raw materials needed for their production.

Description

Technical field

The invention relates to a process for the production of cyclic nitramines, represented by high-risk explosive, hexogen (RDX) and an intermediate for the production of also high-risk explosive, octogen, dinitropentamethylenetetramine (DPT), from raw materials recovered from their reaction environment. production.

BACKGROUND OF THE INVENTION

For the production of the best-known, industrially produced cyclic nitramines: 1,3,5 trinitro

1,3,5 cyclohexane-hexogen triaza (RDX), 1,3,5,7 tetranitro 1,3,5,7 cyclooctane octogene tetrazole (HMX) and 1,5 dinitro 1,3,5,7 tetraza 3,7 Endomethylene cyclooctane dinitropentamtylenetetramine (DPT) has been built up considerable production capacities in the middle of the last century mainly in the USA and Canada, making use of various variations of the nitrolysis process by HMT nitric acid in acetic anhydride with ammonium nitrate addition. This process, also referred to as the Bachman process, requires the investment of a costly complex manufacturing ketene chemistry complex and other service plants to regenerate acetic anhydride and acetic acid. In particular, corrosion and other problems are a major drawback, especially in relation to the processing of by-products and waste. Therefore, limited production for commercial purposes in the peaceful period is used only to a limited extent.

On an industrial scale, cyclic nitramines hexogen and octogen are currently produced mainly by the method of continuous guided nitrolysis, in the case of hexogenous hexamethylenetetramine in the abbreviation HMT and in the case of octogen dinitropentamethylenetetramine in the abbreviation DPT in or without concentrated nitric acid.

Ammonium nitrate to 10% by weight of the acid, followed by controlled thermal decomposition of the by-products of nitrolysis in waste acid.

Since the yields of the reactions leading to the formation of the products are not high, a larger proportion of the feedstock molecule, in the case of hexogen production of about 67%, is lost in this process without any benefit. Since the decomposition products are, in addition to carbon dioxide, nitrogen oxides, their uptake through the absorption system and recovery in the form of dilute nitric acid cause further losses and complications.

In the case of dinitropentamethylenetetramine, in addition to the nitro-urea-based process hitherto used, production has recently been introduced by nitrolysis by HMT with nitric acid, followed by dilution with water and successive neutralization of the reaction solution with ammonia. Depending on the choice of reaction conditions in nirolysis, a proportion of RDX is formed in addition to the DPT precursors, which is generally separated from the reaction solution after completion of the nitrolysis by filtration. DPT is formed at the conclusion of a controlled course of ammonia neutralization of the filtrate and is separated when the pH of the environment reaches a value of about 5.6. The reaction solution solution contains about 40% ammonium nitrate and about 9% formaldehyde. Its composition is adjusted with respect to the desired conditions of deposition and utilization by further neutralizing and increasing the alkalinity of the solution to pH 9-11, typically with ammonia gas, to produce an equivalent amount of HMT. The final reaction solution thus obtained is used as a liquid fertilizer with fungicidal effects.

SUMMARY OF THE INVENTION

The incentive to invent a new process for the production of cyclic nitramines with substantially lower raw material consumption than conventional processes used hitherto has been developed during laboratory tests conducted to increase the ammonium nitrate content of the final reaction solution in the preparation of DPT, subject to limited RDX formation. The reaction solution after neutralization and alkalization was used to dilute the primary reaction solution after nitrolysis and post-reaction in place of water. The laboratory verification of the above process has surprisingly found that the isolation of RDX from the reaction solution after prior dilution with the final reaction solution generally yields a greater amount of product than would be expected based on commonly obtained yields. However, the product thus obtained after washing with hot water again showed a weight of only the usual RDX yields.

Subsequent analyzes showed that the product isolated from the reaction solution after addition of the alkalized final solution recycled from the previously carried out nitolysis contained, besides hexogen, a considerable amount of about 50-70% of a white water-soluble crystalline product which was subsequently identified as hexamethylene tetramine dinitrate, also abbreviated as hexadi. This compound is known in the literature that, instead of the equivalent amount of HMT and nitric acid contained therein, the RDX yield of nitrolysis is increased by up to 5%, which has been confirmed by subsequent laboratory tests. During further laboratory testing, it has been shown that by recycling a portion of the final reaction solution originating from the previous production phase to the primary reaction solution after HMT nirolysis, hexadiate can be obtained in an amount corresponding to about 95% yield from the amount of HMT contained in the recycled final reaction solution. a significant, up to about 50%, proportion of HMT of the amount required to effect nitrolysis, without any additional means. At the same time, an equivalent amount of nitric acid corresponding to the amount of hexadiene recovered at a concentration of up to 100% is obtained from the reaction solution. Recycling part of the final reaction solution also reduces the amount of ammonia needed to neutralize the reaction solution.

An additional amount of nitric acid can also be recovered from the primary reaction solution after nitrolysis and post-reaction by adding HMT in the form of an aqueous solution, preferably prepared from aqueous formaldehyde solution and ammonia, or in solid form in the amount required to form the recycled reaction solution. hexadi to ensure full production run. By adding HMT to the process in the form of an aqueous solution prepared from basic raw materials, the cost is reduced by about half compared to using HMT supplied in solid, crystalline form.

The selection of the recycle fraction of the total amount of the final reaction solution determines the proportion of HMT recovered from it in the form of hexadiene, while the amount of the outgoing final reaction solution is always equal to the sum of the feed materials.

Another benefit of recycling the final reaction solution, especially at higher ratios above 50%, is also an increase in the ammonium nitrate content of the final reaction solution exiting the process up to 55 to 60%, while reducing the amount of HMT contained therein. This also creates favorable conditions for the isolation of the hexadiene from the final reaction solution leaving the process in a conventional manner, adding the necessary amount of nitric acid, isolating the hexadiate by filtration, and then neutralizing the ammonia to the alkaline region. A treated solution with an increased NH 4 NO 3 content and without HMT may also be better appreciated on sale.

The present invention provides a process for the production of cyclic niramines, RDX, and DPT by nitrolysis of their raw materials hexamethylene tetramine, or hexamethylene tetramine dinitrate and nitric acid alone, or containing up to 10% ammonium nitrate, wherein the production process comprises recovering the raw materials from the reaction solutions of the final reaction solution from the previous production stage to the primary reaction solution after completion of the nitrolysis in the current production stage, the reaction between nitric acid in the primary reaction solution after completion of the nitrolysis and the HMT present in the final reaction solution forms a hexadenate. used as a raw material replacing HMT and a portion of HNO3 in nitrolysis. The present invention also provides a process for the production of cyclic niramines, RDX and DPT, by nitrolysis of their feedstocks in nitric acid alone, or containing up to 10% ammonium nitrate, wherein the production process comprises recovering a portion of nitric acid from the primary reaction solution after addition. HMT in crystalline form or in the form of an aqueous solution, most preferably prepared from a solution of formaldehyde and ammonia gas, the reaction between the nitric acid in the primary reaction solution after completion of the nitrolysis and the HMT added to the solution produces a hexadiate which is isolated as the raw material , replacing HMT and a portion of HNO3 in nitrolysis.

-4Overview of drawings

1 is a block diagram of a process for producing hexogen according to the present invention; Individual blocks in the form of squares in the direction of the left-to-right arrows indicate the individual operations as they follow each other. The raw material flow comes from the top, the products leaving the process are marked at the bottom of the scheme.

Recycled streams are indicated by a dashed line.

The names of the operations and the brief characteristics of the currents are given directly in the figure.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

In the first batch of batch preparation of RDX according to the invention to 42 g of nitric acid calculated at 100% above 98%, 10 g of HMT was metered over two hours with vigorous stirring at 18 to 22 ° C. This temperature was maintained with stirring for an additional 45 minutes.

Then, after completion of the nitrolysis, the reaction solution was stirred at a temperature of up to 25 ° C with a previously prepared solution of 34.55 g ammonium nitrate, 2.66 g HMT and 29.26 g water. The RDX precipitated from the solution was separated on a filter and washed with 4.5 g of water, the product after drying weighing 8.66 g.

To an equal amount of the solution of the above composition was mixed an aqueous HMT solution prepared from 13.86 g of 37% formaldehyde solution and 1.7 g of ammonia gas containing about 26.7% HMT and then gradually added to the filtrate at a temperature of up to 25 ° C. after RDX separation.

Pritone was formed to form hexadiene and precipitate out of solution in an amount of about 15.9 g. After a short reaction, the hexadiate was separated by filtration, the filter cake was thoroughly aspirated, and the hexadiate was dried with a stream of air at a temperature of up to 45 ° C.

The filtrate was neutralized with 7.67 g of ammonia gas until the solution was alkalized at a pH of 9 to 11, with the ammonia formalin present in the solution being reacted to HMT.

In total, an alkalized final reaction solution of 177.0 g was obtained during the process, of which 75% was intended for recycling to dilute the primary reaction solution after re-reaction during the next batch of RDX and 25%, 44.4 g as the output stream. containing about 43.7% water, 52.3% ammonium nitrate, and 4.0% HMT, was used to obtain the missing amount of hexadi for the next batch by adding concentrated nitric acid in an amount of 6 to form the hexadiene and acidify the solution. , 12 g. The hexadiene from the suspension was filtered and after aspirating and drying at 3.2 g, the total amount of hexadiene obtained was 19.1 g. The nitric acid present in the final reaction solution was neutralized and the pH of the solution was adjusted to 8-9 with ammonia gas in an amount of 1.2 g. 48.3 g of a 59% ammonium nitrate solution were obtained as a by-product.

In the next batch of RDX preparation, the amount of nitric acid used was reduced by the amount contained in hexadiene, so that up to 33 g of nitric acid calculated at 100% above 98% was charged with 19 g of hexadiene. The primary reaction solution after completion of the nitrolysis was mixed with 66.5 g of the alkaline final reaction solution to be recycled from the previous batch, and an equal amount of 66.5 g of the alkaline final reaction solution from the previous batch was added to the filtrate after RDX separation. In addition to the above changes, the course of the second batch was identical to the course of the first batch.

4.52 g of 100% nitric acid, 1.22 g of ammonia gas and 0.39 g of formaldehyde in a 37% aqueous solution were used to produce 1 g of hexogen, 3.32 g of ammonium nitrate as 59% were obtained as a by-product. aqueous solution.

Example 2

In the first batch of batch preparation of RDX according to the invention to 42 g of nitric acid calculated at 100% above 98%, 10 g of HMT was metered over two hours with vigorous stirring at 18 to 22 ° C. This temperature was maintained under stirring for an additional 45 minutes.

Then, after the nitrolysis, the primary reaction solution was stirred at a temperature of up to 25 ° C with a previously prepared solution of 22.5 g of ammonium nitrate, 2.4 g of HMT and 32.0 g of water. FROM

The 6X solution precipitated by RDX was separated on a filter and washed with 4.5 g of water, the product after drying weighing 8.66 g.

An equal amount of a solution of the above composition to which 6.0 g of crystalline HMT was previously added was gradually added to the filtrate at a temperature of up to 25 ° C. This produced hexadiene and precipitated out of solution in an amount of about 19.5 g. After a short reaction, the hexadiate was filtered off, the filter cake was thoroughly aspirated, and the hexadiene was dried with a stream of air up to 45 ° C. The amount of hexadiene 19.5 g obtained covers the amount needed to carry out the next batch of RDX preparation with little reserve.

A 25% aqueous ammonia solution was added to the filtrate after separating the hexadiate until a pH of between 9 and 11 was reached in an amount of about 28.6 g. 166.7 g of the alkali-final reaction solution were obtained, of which 68% was intended for recycling to the primary reaction solution after completion of the nitrolysis in the next cooker in two batches of 56.7 g each. The by-product, 53.3 g of a solution containing 39.5% NH 4 NO 3, 4.2% HMT and 56.2% water, was intended to be disposed of as a liquid fertilizer.

In the next batch of RDX preparation, the amount of nitric acid used was reduced by the amount contained in hexadiene, so that up to 33 g of nitric acid calculated at 100% above 98% was charged with 19 g of hexadiene. The primary reaction solution after completion of the nitrolysis was mixed with 56.7 g of the alkaline mother liquor to be recycled from the previous batch, and an equal amount of 56.7 g of the alkaline mother liquor from the previous batch was added to the filtrate after RDX separation. In addition to the above changes, the course of the second batch was identical to the course of the first batch.

3.82 g of 100% nitric acid, 0.825 g of ammonia in the form of a 25% solution and 0.7 g of crystalline HMT were used to produce 1 g of hexogen, 2.43 g of ammonium nitrate as 39.5% were obtained as a by-product. aqueous solution.

Example 3

In the first batch of discontinuous preparation of DPT according to the invention into 40 g of nitric acid calculated to 100% at a concentration of 88%, 10 g of HMT were dosed over two hours with vigorous stirring at 18 to 22 ° C. This temperature was maintained under stirring for an additional 45 minutes.

Thereafter, after the nitrolysis was complete, the primary reaction solution was stirred at a temperature of up to 25 ° C with a previously prepared solution of 21.53 g of ammonium nitrate, 3.36 g of HMT and 27.4 g of water. The RDX precipitated from the solution was separated, washed with 1.5 g of water on the filter, and the product weighed 2.0 g after drying.

An equal amount of 52.2 g of a solution of the same composition in which 3.5 g of crystalline HMT was dissolved was gradually added to the filtrate. This produced hexadiene and precipitated out of solution in an amount of about 19.4 g. After a short reaction, the hexadiate was filtered off, the filter cake was thoroughly aspirated, and the hexadiene was dried with a stream of air up to 45 ° C. The amount of hexadium obtained covers the need for carrying out the next batch of DPT preparation with little reserve, with HMT replaced by hexaden fully, and the nitric acid feed reduced by 9 g.

A 25% aqueous ammonia solution was added to the filtrate after separation of hexadiene at a temperature between 8-12 ° C in an amount of 7.0 g, an additional 3.5 g was added in 60 minutes, and another 5.2 g in 150 minutes at the same temperature. range. After the addition of about 11 g of solution, precipitation of DPT from the solution as a pale yellow precipitate began. The ammonia solution was added until the pH of the solution reached the desired value of about 5.6. After 15 minutes of reaction, the DPT was filtered off, washed with water and dried at a temperature of up to 45 ° C, weighing 4.9 g. The filtrate was adjusted by the addition of 12.33 g of a 25% ammonia solution and had a pH of about 10.5. In total, an alkalized final reaction solution of 160.0 g, consisting of 41.2% NH4O3, 6.7% HMT and 52.4% H2O was obtained. Of this, 65%, i.e. 104.5 g, was used to dilute the primary reaction solution in the next batch, and 56.3 g was disposed as liquid fertilizer.

For 1 g of total production of RDX and DPT, 4.48 g of 100% nitric acid, 1.04 g of ammonia in the form of a 25% solution and 0.505 g of crystalline HMT were used, and 3.34 g of ammonium nitrate were obtained as by-product. % Aqueous solution.

Claims (8)

PATENT CLAIMS A process for the production of cyclic nitramines: hexogen and dinitropentamethylenetetramine by reacting hexamethylene tetramine and concentrated nitrate bed alone or containing up to 15% ammonium nitrate to form a primary reaction solution, characterized in that the feedstocks: hexamethylene tetramine and nitric acid are recovered solutions in the form of hexamethylene tetramine dinitrate by recycling a portion of the final reaction solution obtained by successive dilution, neutralization and alkalinization of the primary reaction solution with ammonia after separation from the solution of the gradually precipitated foams: hexogen, hexamethylene tetramine dinitrate, possibly also solution to form and then isolate hexamethylene tetramine dinitrate from solution. Method for producing cyclic nitramines according to claim 1, characterized in that the hexamethylene tetramine content of the recycled final reaction solution is increased by adding hexamethylene tetramine in crystalline form or in the form of an aqueous solution, preferably prepared from formaldehyde solution and ammonia gas, before addition. into, during the next stage of producing the primary reaction solution formed to form and subsequently isolate hexamethylene tetramine dinitrate from the solution in the required amount to carry out the next batch. A process for the production of cyclic nitramines according to claim 1, characterized in that the reaction of hexamethylene tetramine with concentrated nitrous oxide is carried out in the production of hexogen in a batch, batch mode. A process for the production of cyclic nitramines according to claim 1, characterized in that the reaction of hexamethylene tetramine with concentrated nitric acid is carried out in the production of hexogen at a weight ratio between nitric acid and hexamethylene tetramine equal to 4 "1-7'1. -95. Process for producing cyclic nitramines according to claim 1, characterized in that the recycled proportion of the final reaction solution is 45-80%. The process for producing cyclic nitramines according to claim 1, characterized in that the reaction of hexamethylene tetramine with concentrated nitrous oxide is carried out in the production of dinitropentamethylene tetramine in a continuous, continuous mode. 7. A process according to claim 1 wherein the amount of hexamethylene tetramine and nitric acid is added to the reaction solution after reaction of hexamethylene tetramine and nitric acid, in aqueous solution or in solid form, so that the total amount of hexamethylene tetramine dinitrate produced is added. The present invention, when reacted with nitric acid, fully covered the need for hexamethylene tetramine. A process for producing cyclic nitramines according to claim 1, characterized in that the separation of hexamethylene tetramine dinitrate is carried out from the reaction medium at a nitric acid concentration in the range of 17.5-21%. The process for producing cyclic nitramines according to claim 1, characterized in that an additional amount of hexamethylene tetramine dinitrate is obtained from the final reaction solution by adding nitric acid in an amount necessary to form the dinitrate and to achieve a nitric acid concentration in the solution of 18.5-20. 5%, by separating hexamethylene tetramine dinitrate and then neutralizing the final reaction solution with ammonia to a weakly alkaline region around pH 8.