CS251537B1 - Process for producing 1,5-metano-3,7-dinitroso-1,3,5,7-tetraazacycloctane - Google Patents

Abstract

The essence is that the suspension after nitrosation cleavage is treated with alkali metal carbonate to a pH of 6.5 to 12.

Description

The invention relates to a method for the production of 1,5-methano- _3,7-1 ^dinitroso -1,3,5,7-tetraazacyclooctane, wherein the conditions are chosen so as to substantially affect the yield and quality of the product without affecting the economy.

Nitrosation cleavage of hexamethylenetetramine in a weakly acidic medium using alkali metal nitrates, alkaline earth metal nitrates or ammonium nitrite is the most industrially feasible method for the production of 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, also known as N,N'-dinitrosopentamethylenetetramine (DNPT).

The minor impurity that remains in 1,5- ^methane -3,7-dinitroso-1,3,5,7-tetraazacyclooctane is 1,3,5-'trinitroso-1,3,5-triazacylhexane, also called R-salt'.

In the current production of 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, its aqueous suspension is treated after nitrosation with a concentrated solution of sodium hydroxide or potassium hydroxide (Ger. Pat. No. 1 004 618). Alkalization of the suspension with strong bases is accompanied by a violent release of gases, with subsequent flotation of the product to the surface of the reaction mass, and the formation of a persistent, difficult-to-mix foam. The increase in temperature during neutralization promotes the exposure decomposition of the nitroso compound into formaldehyde and nitrous gases, which catalyze further decomposition. In the case of suction of mother liquors and the subsequent action of strong bases, spontaneous ignition of the products and the formation of a fire or explosion may occur.

It is known from the patent literature that, in addition to neutralizing the reaction mixture with an alkaline hydroxide, ammonia can be used for neutralization and stabilization in the final stages of the production process of 1,5-methano-3,7-dihydroiso-1,3,5,7-tetraazacyclooctane (Japan, No. 21 533; Japan. Kokai No. 76 80 898; CSSR AO No. 206 619) or basic reacting compounds of alkaline earth elements and ammonium compounds (ČSSR AO No. 19-3 2121). The use of ammonium compounds threatens to reduce the thermal stability of the product under certain conditions.

The above-mentioned shortcomings are solved by the present invention, according to which the method for producing 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane by nitrosation cleavage of hexamethylenetetramine by the action of nitrite, in an acidic medium at a temperature of 0 to 40 °C, combined with the separation of the product, is carried out in such a way that the suspension after nitrosation cleavage, preferably at least after partial suction of the mother liquors, is treated with alkali metal carbonate to a pH of 6.5 to 12.

Among the advantages of the process according to the invention, it is necessary to include in particular the fact that the application of technically and economically readily available substances will increase the yield of the process and thus the economy of production. In addition to increasing production as a result of better use of raw materials, the purity and quality of the desired product will increase. Work safety will increase because there is no corrosion of the operator. The ignition of products in the acid filtration node associated with the possibility of fire or explosion is eliminated. In this way, the emission of nitrous gases into the air will be further suppressed, thereby achieving an improvement in the working and living environment. The aggressiveness and toxicity of wastewater will be reduced without losing the importance of their further effective industrial use.

Efficiency can be achieved by using alkali carbonates, which due to their quality are not suitable for other applications and are an industrial waste. For example, it is advantageous to use sodium carbonate solutions, with a concentration of 19 to 22% by weight and a content of sodium carbonate admixture not exceeding 5% by weight, from the production of cyclohexanone, which saves time, energy and material required for the isolation of pure raw material.

The superior effect according to the present invention has not been previously described in the literature and is documented by the following examples. Example 1

Into a 750 ml glass flask equipped with a stirrer, mercury thermometer and jacket cooling, 28 grams of hexamethylenetetramine (0.2 mol) in the form of a 37.5% aqueous solution and 38 g of sodium nitrite (0.55 mol) in the form of a 30% aqueous solution are introduced. After cooling this mixture to 0 °C, 132 ml of 20.16% nitric acid (0.47 mol) are added so that the addition lasts 10 minutes and the temperature of the reaction mixture does not exceed 10 °C. After a ten-minute reaction at 10 to 15 °C, the reaction mixture is filtered and the acidic product is subsequently treated with 20% aqueous potassium carbonate solutions to achieve pH 12. After stirring this mixture for 5 minutes at 15 °C, the product is filtered off and washed twice with 20 ml of water and dried at 60 °C. This results in 29.0 g of 1,5-methano-3,7-dinitroso-1,5-tetraazacyclooctane, which is 78.6 percent of theory.

Example 2

The nitrosative cleavage of hexamethylenetetramine is carried out in a commercial nitrosator equipped with cooling coils, stirring, and the supply of nitric acid below the level of the reaction mixture (into the space of the stirrer). The intensity of the stirring is such that the separating product is kept afloat at the level of the reaction mixture.

To the nitrosator, 553 liters of hexamethylenetetramine containing 375 g of the substance per liter (total 1.5 kilomoles) and 774 liters of technical sodium nitrite solution containing 360 g of the substance per liter (total 4.0 kilomoles) and further containing 120 g of sodium nitrate per liter are introduced. The solutions are cooled to 5 °C and at this temperature, stirring and cooling with brine are started with the addition of 3.5 kilomoles so that the temperature of the reaction mixture does not exceed 10 °C; the acid addition time is 25 minutes.

After the entire amount of nitric acid has been added, a 10-minute reaction takes place. Then, after suctioning off approximately 1/4 of the mother liquors, the reaction mixture is neutralized in the neutralizer with a 22% sodium carbonate solution containing 5% by weight bicarbonate from the cyclohexanone production to a pH of 6.5.

After 15 minutes of stirring, the contents of the nitrosator are pumped to a pressure filter, where the isolated product is washed with ammonia water (3% by weight NH3) and finally a solution containing 1% by weight of Slova-pon N (a surfactant based on a mixture of oxyethylated fatty alcohols). The yield is 78.9% according to theory.

Example 3

Into the flask, as in Example 1, are added 213 ml of water, 41 g of hexamethylenetetramine (0.29 mol of hexamethylenetetramine) and 55 g of sodium nitrite (0.8 mol of nitrite). After the mixture is cooled to -15 °C with intensive stirring and cooling,

The neutralizing agent H- is dosed in one go with 165 ml of 23% nitric acid (0.69 mol of nitric acid). The temperature of the mixture is maintained at 5 to 10 ^° C by cooling until the exothermic reaction subsides. After a 15-minute reaction at a temperature of 10 to 15 ^° C, the reaction mixture is neutralized with a neutralizing agent (see Table 1) to a pH value of 7.6 to 9 (depending on the alkalinity of the agent) and after stirring for 10 minutes at a temperature of 15 to 18 °C, the product is isolated by filtration and then washed with 30 ml of water. The isolated 1,5-methano-3,7-dimerozo-1,3,5,7-tetraazacyclooctane (DNPT) is dried for 30 hours in a thin layer at 22 to 24 °C.

Using differential thermal analysis (DTA), operating with a linear temperature rise rate of 5 °C/min, a measuring range of 1 mV per scale division and sample weights of approximately 50 mg, the stability of the manufactured product is specified.

The following table No. 1 gives an overview of the applied neutralizing agents, the corresponding yields and thermal stabilities of DNPT.

number 1

Chemical essence Applied amount (g) of the substance itself Applied in the form of the pH of the reaction mixture after neutralization Sodium Hydroxide 1.8 40.6% aqueous solution 8.98 Ammonia 6.0*) 26.4% aqueous solution 8.51 Sodium bicarbonate 4.3 powder 7.65 Sodium carbonate 2.3 18.3% aqueous solution 8.23 Calcium Hydroxide 1.9 powder 8.20 Hydr-coal- 5.0 powder 7.60

potassium chitosan

DNPT Extract DTA Results ;(%) Beginning First peak (g) -OpRoti ex-o-roz- exo-roz- theory Ikla-du positive (°C) ro

44.4 81.7 126.1 ± 1.3 169.3+0.9 45.3 83.4 129.8 + 0.8 170.1 ± 0.8 46.3 85.2 132.7 ±1.1 170.6 + 0.9 45.9 84.5 130.1 ± 1.4 169.9 ± 1.1 44.9 82.7 129.2 ± 1.3 169.1 + 0.8 46.4 85.4 132.3 ± 1.2 170.7 + 0.8

Note:

*) neutralization and simultaneous conversion of the formaldehyde present to hexamethylenetetramine — after 60 minutes of standing and the filtrate after isolation of DNPT from the reaction mixture, its pH value drops to 6.7.

Claims (2)

OBJECT What is claimed is: 1. The preparation of 1,5-meso-3,7-dinitrole-1,3,3-tetraazacyclodectane by nitrosation of hexamethylenetetramine by treatment with a disodium, in an acid medium at 0 to 40 [deg.] C., associated with the separation of prolduct, that the alkali metal carbonate is brought to pH 6.5 to 12 by the cleavage suspension, preferably at least partially sucking off the mother liquors. 2. A process according to claim 1, wherein sodium bicarbonate is used for neutralization, with a concentration of 19 to 22% by weight. with a content of bicanbonate containing 5% by weight of cyclohexanone. Severografia, n. P., Závod 7, Most Price 2,40 Kcs