CS206619B1 - Method of stabilization of 1,5-endomethylen-3,7-dinitroso-1,3,5,7,-tetraazacyclooctane - Google Patents

Description

The invention deals with the stabilization of l-5-eadometyléa 3 »7dinitrózo-l, 3,5,7 ^w tctr69.2aoyklooktanu, realized by means of ammonia on acidic substance, resulting from nitro * · ionization cleavage of hexamethylenetetramine with the aid of aqueous solutions of alkali nitrites or nitrite calcium and dilute aqueous mineral acid solutions.

Hitrozacní cleavage hexamethylenetetramine in a weakly acidic medium with the aid of alkali nitrites or calcium nitrite is an industrial most viable methods of producing _L> 5end «netylán 3» 7-dinitroso-l, 3 »5» 7-tetraazaoyklooktanu, also known as the H, N ~ di-nitrosopentamethylentiramine (codename DIPPT). A byproduct of this reaction, which remains in If, γ-dinitrosopentaraexylenetetramine, is 1,3,5-trinitroso-1,3,5-triazacyclohexane, also called the R-salt. The by-products remaining in the mother liquors after isolation of the final product are, in particular, an inorganic salt, formaldehyde and a certain excess of the starting nitrite, which is also taken into account as a buffering and catalyzing additive.

In the event that nitrosolysis is stopped by neutralizing the entire reaction mixture with alkaline hydroxide (Ger. S. 1,004,618) or ammonia (Japanese Patent No. 21,533 i Japan. Kokai 76 80,898} USSR Authorial Certificates No. 191 379 and 193 221 M-Manniohe condensation products and formation reaction products are present in the mother liquors, in addition to the excess neutralizing agent and the above-mentioned substances, and the amount and composition of the side reaction products of nitrososolysis of hexamethylenetetramine greatly affects the thermal stability of the final product through its adsorption sites. 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane crystal, in this sense, significant destabilizers are alkali metal hydroxides and formaldehyde

When alkali hydroxides are applied to neutralize the entire nitrosolysis mixture, the temperature is localized and thus the thermal destruction of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazaoyclooctane occurs.

From the point of view of perfect removal of occluded and adsorbed formaldehyde from 1,5endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, ie from the point of view of increased product stability and improvement of working environment during its isolation and drying, ammonia application is very advantageous as a neutralizing agent. However, the ammoniacalization of the whole nitrosolysis mixture is of importance only if the resulting mother liquors are further used as a solvent for the raw materials for the production of N, f-dinitrosopentamethylenetetramine (Czechoslovakia Certificate No. 191 379 | Japan. Kokai 76 80,893) or for the production of fertilizers, in particular a urea-ammonium nitrate complex.

The intention to obtain 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclooctane from the mother liquors is a pure inorganic salt and an aqueous formaldehyde solution (see, for example, CSSR Authorized Certificate No. 185 888) is one of the most important conditions suppressing the formation of nonvolatile organic compounds in these leaches. Minimizing the content of non-volatile organic fractions is also achievable by modifying the nitrosolysis process, in particular by isolating the product from the acidic reaction mixture # which then raises the problem of reliable, economically and ecologically effective neutralization of the acidic product.

According to the invention, the stabilization of 1,5-endomethylene-, 3,7-dinitroso-1,3,5,7-tetraazaoyclooctane resulting from the acidic filtration of the nitrosolysis mixture is carried out in an aqueous dispersion containing 150 to 350 liters of water, preferably 150 up to 190 liters of water per kilomol by reacting the taken hexamethylenetetramine, at a temperature of 0 to 30 ° C, preferably 10 to 15 ° C, for 10 to 60 minutes, preferably 10 to 30 minutes, with ammonia in an amount of 0.06 to 0 0.60 kilomol, preferably 0.07 to 0.10 kilomol per kilomol, by reaction of the hexamethylenetetramine. Since ammonia easily reacts with adsorbed and occluded free formaldehyde in the product crystals to hexamethylenetetramine, this operation results in a formaldehyde-free odorless product # resulting in improved thermal stability of the final product and improved working environment for isolation and drying of 1,5-endomethylene-3 , 7-dinltrose-1,3,5,7-tetraazacyclooctane ·

The application of the present invention in operational practice is an important starting point for the treatment of mother liquors into pure inorganic salt and aqueous formaldehyde solution. According to the present invention, acidic mother liquors resulting from the present invention will save the mineral acid required for decomposition. nitrite and hexamethylenetetramine present, and further to minimize the formation of nonvolatile products of the formation reactions.

Neutralization of the entire nitrosolysis mixture is most conveniently feasible directly in the nitrosator. By performing the neutralization of the product within the meaning of the invention, ie outside the nitrosator, it is possible to increase the capacity of the nitrozae proper.

It follows from the above that the present invention not only results in savings of auxiliary raw materials and possibly an increase in the nitrosative cleavage capacity of hexamethylenetetramine, but its secondary effect is an increase in the stability of 1,5-endomethylene-3,7-dinitroso-1,3,5,7tetraazacyclooctane and protection of work and the environment in relation to the production of the substance.

Example 1

To a 750 ml sulfonaonic flask equipped with a stirrer, a mercury thermometer and a jacket cooling was added 28 g of hexamethylenetetramine (0.200 mol) in the form of its

37.5% aqueous solution and 38 g sodium nitrite (0.550 mol) as its 30% aqueous solution. After cooling the mixture to 5 ° C, dosing of 132 ml of 20.16% nitric acid (0.4722 mol) was started so that its inlet time lasted for a minimum of 9 and a maximum of 12 minutes and the temperature of the reaction mixture did not exceed 10 ° C. After 10 minutes of reaction at 10-14 ° C, the reaction mixture was filtered and the acidic product was charged to a sulfoaation flask in which a solution of 1 ml of 26.4% aqueous ammonia (0.014 mol) in 30 ml of water was presented. After stirring vigorously for 10 minutes at 15-20 ° C, filtration was performed, the product on the filter was washed twice with 20 ml of water and dried at 60-70 ° C. This resulted in 29.1 g of N, N-dinitrosopentamethylenetetramine, which is 78.92% of theory.

Using a differential thermal analysis (DTA) operating at 0.1 g sample weight and a linear temperature rise rate of 5 ° per minute, it was found that the onset of exothermic decomposition of the product was 129.7 ° C and the R-salt content was 0.31% wt.

The nitrosolysis resulted in 297 ml of mother liquors and from the ammoniacalization of the acid product 29 ml of the first portion of ammonia (wash) waters.

Example 2

Nitrosolysis of hexamethylenetetramine was conducted as in Example 1, but a 31% aqueous hexamethylenetetramine solution was applied. To the acid product ammonia carried out as in Example 1, a first portion of the aqueous ammonia washes of Example 1 was used, to which 5 ml of water and 1.5 ml of a 26.4% aqueous ammonia solution (0.021 mol of ammonia) were added.

The reaction resulted in 29.2 g of product, which is 79.01% of theory. Using DTA as in Example 1, an onset of exothermic decomposition of the product at 127.8 ° C and an R-salt content of 0.30% by weight were found.

312 ml of mother liquors and 34 ml of the first portion of the ammonia washings were removed from the nitrosolysis.

Example 3

Hitrosolysis of hexamethylenetetramine was conducted as in Example 1 but using a 26.47% aqueous hexamethylenetetramine solution. To the ammoniacalization of the acid product, as in Example 1, a first portion of the ammonia washings of Example 2 was used, to which 5 ml of water and 1.5 ml of a 26.4% aqueous ammonia solution were added. (0.021 mol) and its own ammonia was 30 minutes.

The reaction resulted in 28.9 g of product, which is 78.17% of theory. By DTA as in Example 1, an onset of exothermic decomposition of the product at 127.3 ° C and an R-salt content of 0.85% by weight was found.

328 ml of mother liquor was removed from the nitrosolysis and 38 ml of the first portion was washed with ammonia water.

Example 4

The mother liquors of Examples 1, 2 and 3 were combined with the first portion of the ammonia water wash of Example 3. This resulted in 975 ml of waste which, after standing for 30 hours at a temperature of 20 to 22 ° 0 per 1000 ml, had the following composition: 29.9 g of formaldehyde, 16.0 g of sodium nitrite and 119.7 g of sodium nitrate and their pH was 6.0. After decomposition of sodium nitrite with nitric acid, the mixture was used as a solvent for the preparation of a urea solution, from which a liquid fertilizer based on the urea-ammonium nitrate complex was prepared.

Example 5

A solution of 28 g of hexamethylenetetramine (0.199 mol) and 42.5 g of potassium nitrite (0.499 mol) in 140 ml of water was placed in a nitrosator as in Example 1j, the jacket cooling was carried out with a mixture of methanol and solid carbon dioxide. After cooling the nitrosator content to -10 ° C, a solution of 41 ml of 35.2% hydrochloric acid (0.465 mol of hydrogen chloride) in 88 ml of water was added with vigorous stirring so that the acid influx did not exceed 3 seconds. After the acid was added, the reaction mixture was cooled to a temperature not exceeding + 10 ° 0. After the rapid temperature rise ceased, a ten-minute post-reaction was carried out at a temperature of maximum +10 ° C. The acidic reaction mixture was then filtered, the acidic filter cake was transferred to a nitrosator, where it was stirred in a solution of 1.6 mL of 20.1% aqueous ammonia (0.02 mol) in 30 mL of water. After stirring for three minutes at 10 to 15 ° C, filtration was performed, the product on the filter was washed three times with 40 ml of water and dried at 35 to 45 ° C for 36 hours.

24.1 g of product were obtained, which is 65.2% of theory. By OTA as in Example 1, an onset of exothermic decomposition of the product was found at 124.1-125.8 ° C and an R-salt content of at most 3.0% by weight.

Example 6

Nitrosolysis of hexamethylenetetramine was conducted as in Example 5 and in the nitrosator of Example 1, only potassium nitrite was replaced with 32.3 g of calcium nitrite (0.244 mol). The isolation and ammoniacalization of the acid product was carried out according to Example 5, the same as water washing and subsequent drying product. This resulted in 25.1 g of N, Hdinitrosopentamethylenetetramine, which is 67.9% of theory. By OTA as in Example 1, an onset of exothermic decomposition of the product at 122.1 to 124.8 ° C and an R-salt content of max.

Example 7

The nitrosation cleavage of hexamethylenetetramine was conducted in a process nitrosator equipped with cooling snakes, stirring, feeding nitric acid below the level of the reaction mixture (into the stirrer space) having a conical bottom with a discharge, stirring the reaction mixture such that the excreted product was escaping gaseous products held at the level of the reaction mixture.

553 liters of a solution of hexamethylenetetramine containing 375 g of substance per liter (total of 1.496 kilomol) and 774 liters of technical solution of sodium nitrite containing 360 g of substance per liter (total of 4.037 kilomol) and further containing 120 g of sodium nitrate per liter were introduced into the nitrosator. The present solutions were 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 (3.509 kilomol) was started so that the temperature of the reaction mixture did not exceed 12 ° C. The acid was 24 minutes. After all of the nitric acid had been introduced, the reaction was carried out for 10 minutes at 12 to 9 ° C.

The reaction mixture was then neutralized with ca 20% aqueous sodium hydroxide solution to a pH of 8-9. After stirring for 15 minutes, the nitrosator content was pumped to a pressure filter where the product which had been washed with water was recovered in triplicate by dry weight ΪΓ, Ν -dinitrosopentamethylenetetramine, fluid-dried.

Five experiments were carried out according to this procedure and the quality of the resulting products was determined using DTA as in Example 1 for quality}.

Try number Onset of exothermic decomposition (° C) 1,3,5-trinitroso-1,3,5-briazacyclohexane content (% by weight) 1 127.5 * 0.5 2.9 2 128.0 * 0.0 2.8 3 127.0 * 1.0 2.2 4 123.5 * 2.0 2.6 5 133.5 * 0.5 3.2

The products from all five trials were clearly able to smell the product of Experiment # 4 after formaldehyde even after drying.

Example 8

The nitrosolysis of hexamethylenetetramine was carried out as in Example 7. However, after 10 minutes of reaction at 10 to 7 ° C, the nitrosolysis mixture at 5 to 10 ° C was filtered on a stirrer-shaped vertical bowl. After filtering off the acidic mother liquors, the filter cake was stirred. in 277 liters of water and 13.8 liters of 20.01% aqueous ammonia (0.149 kilomol) was added to form Suzpenz. After stirring for 20 minutes at a temperature of 10-15 ° C, the suspension was pumped onto such a filter and further processed according to Example 7. Five experiments were carried out and the resulting products were specified by DTA as in Example 1 for quality; The results are presented in the following table:

Try number Beginning exothermic decomposition (° 0) 1,3,5-Trinitroso-1,3,5-triazaoyclohexane content (% by weight) 1 128.1 * 0.2 1,8 2 130.5 * 1.5 2.7 3 133.0 * 1.2 1.7 4 127.5 * 1.5 1.5 5 134.0 * 3.4 1.3

Products from all five trials were virtually odorless.

Claims (1)

SUMMARY OF THE INVENTION A process for stabilizing 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazaeyclooktane resulting from the nitrosative cleavage of hexamethylenetetramine in the form of its 26.5-37.5% aqueous solution by 27.4-36%. 3% aqueous solutions of alkali metal nitrites or calcium nitrite and dilute aqueous solutions of mineral acid, characterized in that to 1,5'-endomethylene-3 ', 7'-dinitrozo-1,3,5,7'-tetraazacyclooctane obtained by filtration of the reaction mixture, at a temperature of 0 to 30 ° C, preferably at a temperature of 10 to 15 ° C, for 10 to 60 minutes, preferably for 10 to 30 minutes, in aqueous suspension containing 150 to 350 liters of water, preferably containing 150 to 190 liters of water per kilomol for nitrosolysis of the taken hexamethylenetetramine, treated with ammonia in an amount of 0.06 to 0.60 kilomol, preferably at 0.07 to 0.10 kilomol of ammonia per kilomole for the nitrosolysis of the taken hexamethylenetetramine.