SU1535865A1 - Method of producing nonsinterable pulverulent and/or crystalline hexamethylene tetramine - Google Patents

Abstract

This invention relates to methods for making non-agglomerated powdered and / or crystalline hexamethylenetetramine. The method of manufacturing non-agglomerated powdered and / or crystalline hexamethylenetetramine consists in crystallization, combined with separation and / or processing it with anti-sintering additives in the reaction solution and / or subsequent manufacturing phases, also by refining, which is added as an anti-sintering additive one-time or gradually soluble and / or insoluble condensation products of urea, catalyzed by acid or acids, with formaldehyde from the group: trimethyl entetramurea, hexamethylenediamine and / or 2-keto-5-carboxamide-1,3,5-perhydrotriazine in the amount of 0.001 - 15 parts by weight, calculated per 100 parts by weight solid phase, followed by homogenization. 3 tab.

Description

The invention relates to a process for the manufacture of non-agglomerating and / or crystalline products by crystallization, which are used as absorbers, artificial fertilizers and intermediate products in the manufacture of explosives using anti-sintering impurities.

The formation of agglomerates is a disagreeable property of some substances used in the manufacture of explosives, artificial fertilizers and powdered absorbers, which occurs during storage, as well as during mechanical operations with these substances.

The number of lumps, as well as their strength, is due to various factors, most often the size of the crystals, their shape, humidity, pressure at which the product is stored, storage time, temperature fluctuations, electrical conductivity or the possibility of static electricity, etc.

Most often, the agglomeration of particles or sintering is promoted by the moisture of crystalline surfaces, and the resulting solution is gradually stripped and binds the original powder or crystalline substance to a hard recrystallized phase.

To prevent lumpiness of substances, the addition of other substances is largely used.

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These additives can be divided into substances capable of adsorbing or absorbing moisture even more than a crystalline or powdered product.

Partially water-soluble or at least swelling in water substances are used against sintering hexamethylenetetramine (Copyright Certificate Czechoslovakia 205440, cl. C 07 D 187/18, 1980). However, their use is significantly limited only to hexamethylene tetramine. However, for some special applications of hexamethylene tetramine, optimal non-toxic and available anti-sinter additives cannot be specified.

The manufacture of non-agglomerating powdered and / or crystalline products using relatively universal anti-sintering additives can be carried out according to the method according to the invention.

According to the proposed method of manufacturing non-agglomerating powdered and / or crystalline products by crystallization, coupled with the separation and / or processing of these products by modifying with anti-sintering additives in the reaction solution and / or in subsequent manufacturing phases, it is also possible by refining, as an anti-sintering additive soluble or / and water-insoluble condensation products of urea catalyzed by acid or acids with formalde at one time or gradually idom from the group trimetilentetramovechiny, hexamethylene geptamocheviny and / or 2-keto-5-amide karboks- 1,3,5 pergidrotriazin in an amount of 0.001-15 mae.ch. calculated on 100 mae.ch. solid phase followed by homogenization.

The proposed method is characterized by technically readily available anti-caking agents, their universal use. The method does not require technically sophisticated additional equipment and products are obtained with a minimum ash content. In addition, the anti-caking additives practically do not contaminate hexamethylenetetramine, since they are similar in chemical composition and reactivity.

In accordance with the invention, the notion of subsequent manufacturing phases is understood to mean drying, concentrating

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crystallization, recrystallization, refining, operations during the drying process, after drying, before packing, during filling, before the expedition.

According to the invention, the added anti-caking additives are the reaction products of urea and formaldehyde in an acidic medium. Consequently, it is extremely important mixtures of trimethylene tetraureas to hexamethylenheptamoceain, possibly cyclic polycondensates. Starting from a molar ratio of rovechin to formaldehyde of 0.8-1.8, preferably 1.0-1.3 in the presence of 0.001-0.010 mol of mineral acid per 1 mol of urea in the presence of 0.004-0.005 mol of mineral acid per 1 mol of urea and at reaction temperatures up to 70 ° C. The most effective form of separation of these condensates (in terms of their uses according to this invention) is to dry the reaction mixture in a spray dryer. This produces a fine-grained product with a large specific surface, practically insoluble in water and slightly soluble in common organic solvents.

Example 1. A formaldehyde condensation product of urea is prepared as follows: 800 mash. ureas (for example, 13.320 mol) are dissolved in 1800 wt.h. water. To this solution, 900 mas was added at 7 ° C. formaldehyde aqueous solution containing 40.7 wt.% formaldehyde (for example, 12.198 mol of formaldehyde). To the mixture was added 27.93 wt.h. nitric acid with a concentration of 20.3 wt.% (for example, 0,072 mol of nitric acid). After 18 pins from the start of the reaction, the reaction mixture acquires a maximum temperature of 68 ° C. Then the reaction mixture is cooled to 50 ° C. The pH of the mixture was adjusted to a value of 4.5 with an aqueous solution of sodium hydroxide at a concentration of 20% by weight. Next, the neutralized reaction mixture is introduced into a spray dryer with an initial temperature of 200 ° C; the mixture is metered at such a rate that the temperature of the outgoing gases is 85-90 ° C. Obtained 920 mas. product in the form of fine powder, and a further 25 ma.h. trapped from the stream of gases exiting the dryer.

Using differential thermal analysis (DTA), working with weights of about 0.1 g and a linear rate of raising the temperature at 6 ° C / min, the product has the following characteristics: the beginning of the first endothermic change in the solid phase at 114.4 ° C with a peak at 125 , 0 ° C; the onset of endothermic decomposition in the solid phase at 240.0 ° C with a peak at 253.9 ° C.

Pripe 2. Condensation product of urea with formaldehyde II is prepared as follows: 800 mash. Urea (for example, 13.320 mol of urea) is dissolved in 1800 mas. water and to this solution was added 780 mas. an aqueous solution of formaldehyde specified in Example 1 (i.e., for example, 10.571 moles of formaldehyde). Then, at a temperature of 17 ° C, 22.3 wt. H. Are added to the mixture of solutions. nitric acid concentration of 20.3 wt.% (for example, 0,057 mol of nitric acid). After 45 minutes from the start of the reaction, the mixture acquires the maximum temperature, i.e. 56 C. After cooling to 32 ° C, the liquid components of the mixture are removed, resulting in 1407.1 wt.h. filter cake with a content of 48.6 May. % water. After drying this filter cake at 70-74 ° C for 48 hours (thin layer), the product is obtained in the form of lumps, easily disintegrating into a fine powder.

Using DTA, as in Example 1, the following characteristics are determined for this condensate: the beginning of the first endothermic change in the solid phase at 104.4 ° C with a peak at 110.0 ° C; the beginning of the second, inexpressively long change (endothermic) in the solid phase at 115.5 ° C with a peak at 124.6 ° C, and the beginning of endothermic decomposition in the solid phase at 234.5 ° C.

Example 3. 25 kg of crude technical hexamethylenetetramine with a content of 1.31% by weight of water are treated by adding 2% by weight of urea condensate with formaldehyde in Example 2. The mixture thus obtained is dried at 100-105 ° C and placed at the laboratory temperature in polyethylene packaging. The 4 polyethylene packages thus prepared are tied up with a string, stacked on each other and stored.

5 months there is no sintering of hexamethylenetetramine.

Example 4. To an aqueous suspension with a temperature of 60 ° C and a concentration of 50% by weight of hexamethylenetetramine from the degree of compaction of the reaction mixture after ammoniation of the formaldehyde solution for every 500 mash. suspensions added 7.7 wt.h. a filter cake of urea formaldehyde condensate prepared relative to example 2. After removing the mother liquors and washing the filter cake with a saturated solution of hexamethylenetetramine (hexamine), followed by drying in a dryer using an air stream with a temperature of 65-70 ° C, a product with content of 1 , 9% of night formaldehyde condensate II.

The filtration precipitate of urea-aldehyde condensate is first stirred in a small amount of suspension, and only after this mixture is added to the supply groove before the centrifuge. When filtering or centrifuging, mother liquor is obtained which is cloudy due to the presence of condensate that passes through the filter cloth.

EXAMPLE 5 To 1000 kg of hexattetramine in a homogenizer, 3% by weight of trimethylene tetraurea are added. After that, the mixture is homogenized for 1.5 hours. Then, 500 kg of the product is transferred through a sieve into automatic packaging scales and the packaged product is placed on a pallet. The remainder is milled in a mill. The ground hexamethylenetetramine from the mill is carried by air into a cyclone, in which the hexamethylenetetramine is separated and fed to an automatic packaging balance and the packed product is placed on a pallet. The product on the pallets does not bake even with immediate storage.

Example 6. 1000 g of hexamethylenetetramine is suspended and, as an anti-caking agent (reflux condenser), various types and amounts of urea derivatives or condensation products of urea and formaldehyde are added in the form of aqueous solutions in an acidic medium. Sample processing is similar to example 3.

The results are summarized in table. one.

Example 7. Nitrolysis of hexamethylenetetramine, containing 0.21% by weight of water, is carried out on processing equipment consisting of a first nitrator, a second nitrator, a crystallizer, a slurry cooling apparatus, permanent filters and apparatus for stabilizing the product.

Nitric acid of 99.09% with a content of 0.09% by weight of analytical nitric acid and hexamethylenetetramine with a content of 0.21% by weight of moisture are continuously fed into the first nitrator. Dosing of raw materials is carried out in such a way that at 1 ma.h. hexamethylamine atramine accounted for 10.7 mach. nitric acid. The temperature in the first nitrate was kept in the range of 17–22 ° C by cooling. The contents of the first nitrator are continuously transferred to the second nitrator with a maximum operating temperature of 24 ° C. The total delay of both nitrators is 44 min. From the second nitrator, the nitrating mixture is introduced into the crystallizer, where the temperature is maintained at a value of 70-80 ° C and at the same time washing water is fed from the permanent filters in the amount of 4.7 parts by volume. on 1 ma.ch. reactive hexamethylenetetramine. From the crystallizer, the product suspension in 54.8% nitric acid through the mixer and the refrigeration unit, where it is cooled to CS-40 ° C, goes to continuous (chamber filters, where the nitric acid is separated and the product is washed with water. With a continuous filter ( filter of continuous operation; the filter cake of the product, washed off with water, and the final suspension is pumped through a steam ejector to a stabilization apparatus, where when heated with live steam the acidity of the crystals decreases to less than 0.05 wt.% az After isolation by filtration, 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) is found in the amount of 1,177 parts by weight of dry residue per 1 part by weight of hexamethylenetetramine reacted, t. e. 74.3% of theoretical.

When replacing the metered hexamethylenetetramine of the indicated quality with the processed according to Example 1 according to the invention 1.3 wt.% Urea-aldehyde condensate from 1 wt.h.

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the treated hexamethylenetetramine is 1.25 wt.h. RDX, which is 78.76% of the product yield to the weight of the treated hexamethylenetetramine and 80.01% of the theoretical value calculated for the content of hexamethylenetetramine in the weight,

The beneficial effect of the treated hexamethylethramine on the urea-formaldehyde condensate was also observed under various conditions of nitrolysis on the yield of 1,5-endomethylene-3 7-dinitro-1,3,5,7-tetraazacicycloooctane (DPT) and 1, 3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMH). This higher yield of cyclic nitroamines is attributed to the insertion effect of carbammonium ions and the good solubility of the treated hexamethylenetetramine.

Example 8. Two samples of hexamethylenetetramine, treated with an additive based on urine-formaldehyde condensates prepared in accordance with Example 1, are available. One sample contains 0.38% by weight of this additive, 0.42% by weight of moisture and 0.0053% by weight % ash. Another sample contains 1.06% by weight of an anti-sintering additive, 0.43% by weight of moisture and 0.0057% by weight of ashes. From each sample, under the same conditions, a press piece of 28x28 mm is pressed. The pressing is carried out with both a pre-dried sample and a sample dried for 1 hour at 60 ° C in a layer 4 cm thick. In the press article, the weight, the residue after burning the tablet (i.e., the weight of ash) burning and heat of combustion, then the quality of the edges of the press product.

The results are presented in table. 2

Technical hexamethylenetetramine containing 0.24 May. % moisture and 0.0062 May. % ash, complies with the requirements imposed on the press product 1 m, after 2 hours of drying. The edges of the press products made of hexamethylenetetramine with an anti-caking additive do not crumble, the edges of the press products made of their technical hexamethylenetetramine are easily crumbled. Press products made from hexamethylenetetramine with a content of 1.06% by weight of the additive are relatively more fragile than press products from technical hexamethylenetetramine or from hexamethylenetetramine containing 0.38% by weight of the additive.

The burning of tablets with additives passes calmly, without flying off the burning pieces.

Example 9. Two samples of hexamethylene tetramine are available, namely, the content of the anti-caking additive is 0.05 May. and 0.10 May. 2

Time dependency results

The edges are sufficiently resistant to crushing and the drying time can be reduced by 0.5-1 hours.

Claims (1)

Invention Formula The method of manufacturing non-agglomerating powdered and / or crystalline drying and the quality of the final press-molding of hexamethylenetetramine by means of lithium are presented in Table 3. The crystallization connected to the separation of the mass of the press-products of undried cakes and / or the processing of its anti-baking samples is 78.0 g of the mass of extrusion products, dried hexamethylenetetramine with a content of 0.05 wt.% in the reaction solution and / or in the subsequent phases of production, and also by refining, about one liter - 89 ± 0.5 g, and for the press products of dried hexamethylenetetramine with a content of 0.10 May. / additives - 90 + 0, 7 years Hexamethylenetetramine with a content of 0.05% by weight of the additive does not differ significantly from technical hexamelegylenetetramine, as regards the quality of the press article, the edges of the tablets compressed from it have 20 due to the fact that, as an anti-caking additive, soluble and / or water-insoluble condensation products of urea, catalyzed by acid or acids, with formaldehyde from the group of: trimethylene tetraurea, hexamethylene heptamine and / or 2-keto-5 -carboxamide-1,3,5 clone to crushing, drying time is 25 perhydrotriazine in the amount of 0.001 - to be at least 1.5 h.15 parts per hour, calculated for 100 parts per hour. In press products from hexamethyleneteramide with a content of 0.10 wt.% Of addition of a solid phase, followed by homogenization. The edges are sufficiently resistant to crushing and the drying time can be reduced by 0.5-1 hours. Invention Formula processing and / or processing of its anti-baking additives in the reaction solution and / or in the subsequent phases of manufacture, and also by refining, tolling and / or treating it with an antisexing due to the fact that, as an anti-caking additive, soluble and / or water-insoluble condensation products of urea, catalyzed by acid or acids, with formaldehyde from the group of: trimethylene tetraurea, hexamethylene heptamerea and / or 2-keto 5-carboxamide-1,3,5 solid phase, followed by homogenization. Condensation product I Co-Sensing Product II Trimethylenstramouchevi and Hexamethylene Heptamoche 2-keto-5-carboxamide-1,3, 5-perhydrase Table one After 10 days began agglomeration Not started within 5 months Also Not started within 5 months. Same Mass, g Min. 80 80 Residue, g after szh95 80 96