CS210824B1 - Method of stabilization of 1,5-endomethylen-3,7-dinitroso-1,3,5,7-tetraazacyclooctane - Google Patents

Abstract

The purpose of the invention is to provide a method of stabilization 1,5-endomethylene-3,7-diisole- -1, 3,5,7-tetraazacycloctane produced nitrosolysis of hexamethylenetetramine weakly acidic environment. This purpose is achieved by converting 1,5-endomethylene-3,7- -dinitroso-1,3,5,7-tetraazacycloctane, isolated from an acid nitrosolysis mixture to the suspension to which the neutralizing agent is treated with sodium hydroxide or hexamethylenetetramine with ammonia. It is applied to form a suspension water and / or aqueous neutralizing solution reagents. The method of stabilization according to the invention allows to increase the capacity of nitrosolysis, improves working environment of insulation and drying 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, saves auxiliary raw materials and is an important starting point for production liquidation of mother liquors from nitro - lysis.

Description

The present invention relates to a process for stabilizing 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane produced by nitrosolysis of hexamethylenetetramine in a weakly acidic medium, wherein the stabilization conditions are selected to facilitate recovery from the nitrosolysis of the parent of lye.

Nitrosation cleavage of hexamethylenetetramine in weakly acidic environment with the aid of alkali metal or calcium nitrite is the most industrially viable method of production

1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, also known as Ν, Ν'-dinitrosopentamethylenetetramine, and referred to as DNPT.

The by-products of the reaction remaining in the mother liquors after the isolation of the final product are inorganic salts, some of the starting nitrite, formaldehyde, ammonium ions, or even small amounts of organic substances corresponding to the by-products of hexamethylenetetramine synthesis. In the event that nitrosolysis is terminated by neutralizing the entire reaction mixture with alkaline hydroxide (German Patent Specification No. 1,004,618) or ammonia (Japanese Pat. No. 21,533} Japan. Kokai 76 80 898; 191 379), in addition to the already mentioned compounds and the neutralizing agent, products of formative and N-Mannich condensations, in particular hexamethylenetetramine, but also small amounts of polyols (C C and C?) and sugars (C ^ a and Oγ) are present in the mother liquors. .

The application of an alkaline hydroxide to neutralize the entire nitrosolysis mixture results in a local temperature increase at the dosage, resulting in thermal destruction of the final product and thus the possibility of reducing the yields of 1,5-endomethylene-3,7-dinitroso-1,3,5, Of 7-tetraazacyclooctane.

Contact with alkaline or caustic soda also causes decomposition. Alkaline hydroxide, as well as formaldehyde occluded in the product crystals or adsorbed on its surface, can never be completely removed under industrial conditions, resulting in a decrease in the stability of 1,5-endomethylene-3,7-dinitroso-1,3, 5,7-tetraazacyclooctane. Furthermore, adsorbed formaldehyde deteriorates the working environment, especially during product isolation and drying.

From the standpoint of product stability as well as the improvement of the working environment during its isolation and drying, the use of ammonia as a neutralizing agent while eliminating the acidity of the whole nitrosolysis mixture is very advantageous. However, the ammoniacalization of the whole nitrosolysis mixture is only of importance if the resulting mother liquors are further used as a solvent for the raw materials for the production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacycloctocane. Japan, Kokai 76 80 898) or for the manufacture of fertilizers, in particular based on rhodium-ammonium nitrate complex.

Intending to process mother liquors from the production of 1,5-endomethylene-3,7-dinotroso-1,3,5,7tetraazacyclooctane into pure inorganic salt and aqueous formaldehyde solution is one of the most important conditions for obtaining this high purity salt as much as possible to reduce the organic content not volatile substances in the mother liquors. Minimizing the content of these substances is also achievable by modifying the nitrosolysis termination method, resp. a process for isolating the product, including a process for stabilizing 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane.

According to the present invention, the stabilization of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraaza, cyclooctane, is produced by nitrosation cleavage of hexamethylenetetramine using alkali metal or calcium nitrite and dilute mineral acid solutions, and isolated from acidic nitrosolysis mixtures, carried out for 5 to 40 minutes by treatment with 1,5-endomethylene-3,7-dinitroso-1,3,5,7-teiraazaeyklookten suspended in water or in a solution of any of the aforementioned agents, with sodium hydroxide or ammonia and hexametbylentetramine.

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The neutralizing agent is used for stabilization such that 0.007 to 0.10 kmol of the reagent is added per 1 mole of hexamethylenetetramine to be reacted. To form a suspension of acid 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, 300-1,700 liters of water and / or neutralizing agent solution are applied per mole of nitrosolysis of the hexamethylenetetramine taken.

According to the invention, only the acidic filter cake is practically neutralized

1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane will save the neutralizing agent. The relatively large dilution of the neutralizing agent reduces its degradation effect, both thermal and chemical. Furthermore, the application of an ammonia-containing hexamethylenetetramine solution improves the working environment for product isolation and drying, since ammonia reacts readily with adsorbed formaldehyde to hexamethylenetetramine and thereby perfectly removes formaldehyde from 1,5-endomethylene-3,7-dinitroso-1 crystals. 3,5,7-tetraazacyclooctane.

The application of the present invention in practice is an important starting point for the processing of mother liquors from the production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane to a pure inorganic salt and a solution of formaldehyde or methylal by: According to the present invention, acidic mother liquors result in further processing in this sense, saving the mineral acid required for decomposition of the nitrite and hexamethylenetetramine present, and for a longer time minimizing the formation of organic substances of the polyol and sugars type, respectively. N-Mannich bases.

Neutralization of the entire nitrosolysis mixture is most conveniently realized directly in the nitrosator. By stabilizing the 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane of the present invention, i.e. outside the nitrosator, it is possible to increase the production capacity of said substance.

It follows from the foregoing that the present invention not only results in savings of auxiliary raw materials and possibly an increase in the nitrosation cleavage capacity of hexamethylenetetramine, but also has a secondary effect in the field of environmental protection, in particular when ammonia is applied as part of the neutralization solution.

Example!

The nitrosation cleavage of hexamethylenetetramine was reported in a process nitrosator, which was equipped with cooling coils, stirring, nitric acid supply below the reaction mixture level (into the stirrer space) and had a conical bottom with an outlet. The mixing intensity of the reaction mixture was such that the excreted product was kept at the level of the mixture by the escaping gas of the reaction.

The reactor was charged with 553 liters of a solution of hexamethylenetetramine containing 375 g of substance per liter (ie a total of 1.496 kmol) and 774 liters of a technical solution of sodium nitrite of 360 g of substance per liter and 120 g of sodium nitrate per liter (ie a total of 4.037 kmol). sodium nitrite). The present mixture of solutions was cooled to 8 to 5 ° C and at this temperature, with stirring and brine cooling, an inlet of 910 liters of 21.6% nitric acid (i.e. 3.509 kmol of nitric acid) was started so that the temperature of the reaction mixture did not exceed 12 ° C. ° C; the acid influx time was 25 minutes. After all nitric acid was introduced, the reaction was carried out for 10 minutes at 12 to 9 ° C.

The reaction mixture was then neutralized to pH = 9.4 by the addition of 87.5 L of a 20.07% aqueous sodium hydroxide solution (0.535 kmol of sodium hydroxide). After stirring for 15 minutes, the nitrosator content was pumped into the pressure filter cartridge (which took 6 minutes). Using a pressure filter, the product was separated from the mother liquors, washed with water, then with a surfactant solution and dried to a moisture content of 10% by weight. air purging.

The yields of this nitrosolysis process ranged from 83.5% to 85.0% of theory. Filtration on a pressure filter resulted in 2,035 liters of mother liquors, each containing 1.6 g of sodium hydroxide, 32.4 g of sodium nitrite, 188.9 sodium nitrate, 5.8 g of hexamethylenetetramine and 25.48 g of formaldehyde.

Example 2

Nitrosolysis of hexamethylenetetramine was conducted as in Example 1. However, after 10 minutes of reaction at 10 to 7 ° C, the nitrosolysis mixture was filtered on a suction cup with a stirrer. After suctioning off the mother liquors, the acidic filter cake was stirred in 2000 liters of water and 6 liters of 18.45% aqueous ammonia (i.e. 0.0604 kmol of ammonia) were added to the resulting suszpension.

After stirring for 20 minutes, the slurry was pumped into a pressure filter container and further processed as in Example 1. Filtration of the acidic nitrosolysis mixture resulted in 1,960 liters of mother liquors, each containing 0.01 g of nitrous acid, 18.03 g of sodium nitrite, 196.9 g. sodium nitrate and 32.25 g of formaldehyde. Filtration of the ammonia slurry on a pressure filter yielded 1,690 liters of filtrate containing 0.26 g of sodium nitrite, 3.37 g of sodium nitrate, 0.43 g of hexamethylenetetramine and 0.22 g of ammonia per liter.

Example 3

The nitrosation cleavage of hexamethylenetetramine was carried out as in Example 1; acidic filtration of the nitrosolysis mixture was carried out at 11 ° C. The nug product cake was slurried in 2400 liters of a solution prepared from 1600 liters of the ammoniacalized filtrate in Example 2, followed by 790 liters of water and 10 liters of 20.88% aqueous ammonia (i.e. a total of 0.133 kmol of ammonia and 0.0049). hexamethylenetetramine).

After stirring for 5 minutes, the slurry was pumped into a pressure filter cartridge (which took 6 minutes) and worked longer as in Example 1. Filtration resulted in 2,350 liters of filtrate (without washings), in one liter containing 0.40 g of sodium nitrite. 44 g of sodium nitrate, 0.69 g of hexamethylenetetramine and 0.63 g of ammonia.

Example4

Nitrosolysis of hexamethylenetetramine was conducted as in Example 1. Filtration of the acidic nitrosolysis mixture (as in Examples 2 and 3) was carried out at 5 ° C. The acidic filter cake of the product was slurried in 2100 liters of the filtrate after the ammoniacalization in Example 3. 0.01 kmol of hexamethylenetetramine and 0% were used to neutralize acidic 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane. , 77 kmol of ammonia.

After stirring for 20 minutes, the resulting slurry was pumped into a pressure filter cartridge and further processed as in Example 1. Filtration resulted in 2060 liters of filtrate (without washings) containing 0.69 g of sodium nitrite, 8.56 g of sodium nitrate per liter, 1.09 g of hexamethylenetetramine and 0.17 g of ammonia.

Example 5

Nitrosolysis of hexamethylenetetramine was conducted as in Example 1. Filtration of the acidic nitrosolysis mixture was carried out at a temperature of 12 ° C. The acidic filter cake was slurried in 1900 liters of water and 21 liters of a 20.07% aqueous sodium hydroxide solution (i.e. 0.1285 kmol of sodium hydroxide) was added to the resulting suspension. After stirring for 10 minutes, the suspension was pumped into a pressure filter cartridge (which took 6 minutes) and treated as in Example 1.

Example 6

775 liters of sodium nitrite solution containing 360 g of substance and 98.1 g of sodium nitrate per liter (i.e. 4.0429 kmol of sodium nitrite) and 553 liters of a solution of hexamethylenetetramine containing 375 g of substance per liter were charged to the nitrosator as in Example 1 ( i.e., 1.496 kmol). The present solutions were cooled to 2 ° C and then an inlet of 503 liters of 30.18% sulfuric acid (i.e., 1.889 kmol of sulfuric acid) was started. The acid was metered in such a way that the temperature of the reaction mixture did not exceed 14 ° C and lasted about 20 minutes.

After the acid was added, a 10 minute post-reaction was performed at 14-12 ° C. The thus obtained suspension of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane and sodium sulfate decahydrate was filtered according to Examples 2, 3, 4 and 5 at 14-16 ° C. The filter resulted in 1,430 liters of mother liquors. The filter cake in a volume of approximately 570 liters was slurried in 2200 liters of water at 40 ° C warm and 21 liters of 20.07% aqueous sodium hydroxide solution (i.e. 0.1285 kmol sodium hydroxide) were added to the resulting suspension.

After stirring for 5 minutes, the suspension was pumped into a pressure filter cartridge. Filtration on a pressure filter resulted in 216.3 kg of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane cake having a moisture content of 11% by weight. The yield of the product here is 79% compared to theory.

Claims (2)

SUBJECT OF THE INVENTION Process for stabilizing 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacycloctocane produced by nitrosation cleavage of hexamethylenetetramine with alkali metal or calcium nitrite and dilute aqueous mineral acid solutions and isolated from an acidic reaction mixture at temperatures of -5 to 30 ° C, characterized in that the isolated 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane recovered from the reaction mixture is converted into a suspension to up to 40 minutes, preferably 11 to 27 minutes, with a neutralizing agent, such as sodium hydroxide or hexamethylenetetramine with ammonia, in an amount of 0.007 to 0.10 kmol of neutralizing agent, preferably at 0.086 kmol of neutralizing agent per mole for nitrosolysis of the taken hexamethylenetetramine , with subsequent isolation of neutralized 1,5-endomethylene-3,7-dinitroso-1,3,5,5-tetraa-acyclooctane by filtration and washing off the neutralizing agent residue from the residue eating the filter cake with water. 2. A process according to claim 1, characterized in that water and / or a neutralizing agent solution is used in an amount to convert the 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane into the slurry. 300 to 1,700 liters, preferably 334 to 1,577 liters of water and / or neutralizing agent solution per kmol for nitrosolysis of the taken hexamethylenetetramine.