CS227903B1 - Production of 1,3,5-trinitro-1,3,5-triazacyclohexane - Google Patents

Abstract

The invention relates to the nitrolysis of hexamethylenetetramine led to 1,3,5-trinitro- -1,3,5-triazacyclohexane in the presence urea condensation product with formaldehyde in an amount of 0.01 to 10 wt. counted to hexamethylenetetramine.

Description

The invention relates to the preparation of 1,3,5-trinitro-1,3,5-triazacyclohexane by nitrolysis of hexamethylenetetramine.

Nolysis of hexamethylenetetramine with nitric acid at a concentration above 80% by weight. is one of the most widespread methods of industrial production of 1,3,5-trinltro-1,3,5-triazaoyclohexane. This nitration fission is a complicated set of subsequent and side reactions of nitrolysis, hydrolytic, neutralization and oxidation reactions from a chemical site. The relative proportions of exchanged accidents are determined by the reaction conditions.

Nitrolysis reactions produced! from hexamethylenetetramine not only 1,3,5-trinitro-1,3,5-triazacyclohexane and to a small extent its cyclic haloologist 1,3,5,7-tetranitro-1,3,5,7tetraazaeyklooktan and cyclic ether 3,5-dinitro- 1-oxo-3,5-podzacyclohexane, but also linear nitramines, specifically the nitroesters 1,7-dihydroxy-2,4,6-trnitro-2,4,6-triaazaheptene and 1,9-dihydroxy-2,4,6 , 8-tetranitro-2,4,6,8-tetraazanonan, 5-trimethylolaine and formaldehyde.

The proportion of these products in the reaction mixture depends in particular on the initial molar ratio of nitric acid to hexamethylenetetraamine. the nitric acid applied and the reaction temperature. In recent literature (eg X. Ju. Orlova):

Khimija i technologi i hrizantne vzryvcatych veSestesti. Izdat. Chimija, 1973), the starting molar ratio of nitric acid to hexamethylenetetramine is reported to yield 1,3,5-trinotro-1,3,5-triazacyclohexane raatie as its value increases.

As indicated already in the primary work in this field (Tastes J. W. et al., Canad.

J. Res. 1949, 27 B. 218; Dunning W. et al., J. Chem. Soc. 1952, 1264) is not quite so: there is a certain, optimally-spreading of this molar ratio, depending on the concentration of nitric acid applied and the nitric acid content therein.

For nitric acid of about 96% and more concentrated, the molar ratio of nitric acid to hexamethylenetetremine 21 to 24 is most preferred from the point of view of yield. nitroxonium ions in the reaction mixture.

Hence, the optimum molar ratio range is likely to increase the fraction of hexamethylenetetramine to linear nitramines due to higher nitroonium and respiratory concentrations. nitroxonium ions in the mixture, and the process yield decreases. This is illustrated by an exemplary part of the present invention.

As far as nitric acid concentration is concerned, it should be noted that at least 80% nitric acid has nitrolysis capabilities. Below this concentration value I dominate! in the cleavage of hexamethylene of the tramway hydrolytic process. The presence of water in the applied hexamethylenetetrarine is also favorable for the course of the hydrolytic processes.

I produce neutralization reactions! in the reaction mixture, ammonium lines and the formation of nitroesters from hexamethylene-tetramine-containing fragments of methyl groups, optionally formation of methylenedinitrate from formaldehyde, can be included among them.

Optimally the nitrolysis temperatures of hexamethylenetetramine with nitric acid are in the range of 15-25 ° C. Conducting the process at very low temperatures in addition to the formation of 1,3-dinitro-1,3,5-triazapentane nitrate, 3,5-dinitro-1,3,5-triazaeyclohexane nitrate and methylenebis-1- / 3,5-dinitro- 1,3,5-triazaeyclohexane / as final products (Dunning KW and Dunning WJ: J. Chem. Soc. 1950. 2920; Vroom AH and Winkler CA: Canada..J. Res. 1950, 28 B. 701; Taste WJ et al .: Canad, J. Res., 1948, 27 B. 503) The process control at temperatures above 30 ° C increases the proportion of hydrolytic-oxidation reactions in the consumption of hexamethylenetetramine, thus reducing the yields of 1,3,5-trinitro-1,3. 5-triazacyclohexane and also decreasing process safety

The presence of nitrous acid, resp. nitrogen oxides, in the reaction mixture. Hydrolytic-oxidation reactions cause instability of the reaction mixture after and during nitrolysis. In the literature (V. Kadeřábek and J. Denksteln: Goll. Czeeh. Chem. Commun. 1960, 25, 1070; Czechoslovakia Patent No. 97,100), the stability of the nitrolysis mixture has already been addressed in the literature. these mixtures with increasing storage temperature, increasing starting molar ratio of nitric acid to hexamethylenetetramine, increasing concentration of applied nitric acid and increasing content of nitric acid in the applied. nitric acid.

Since nitrous acid, resp. The presence of these substances in the nitric acid used has a significant negative effect on the stability of the corresponding reaction mixtures.

Substances 1 easily react with nitrous acid, resp. with nitrosonium and on, thus increasing the stability of nitrolysis mixtures. In this sense, hexamethylenetetramine and / or ammonium nitrate (V. Kadeřábek and J. Denksteln) have been proposed to suppress the oxidation reactions in mixtures of this type after nitrolysis. Coll. Czeeh. Chem. Commun. 1960, 25, 1070, in an amount of 0.1 to 80.0 wt. to the original bait of hexamethylenetetramine (CSK Patent No. 97,100).

An analogous method of stabilizing the reaction mixtures, already during the reaction, is conventional in the preparation of n-alkyl nitrates; Here, urea in an amount of 0.5 to 3.0 wt.% is added to the nitric acid or the nitrating acid mixture prior to the start of the reaction. for the weight of nitrating acid (CSR author's certificate 168 189).

The urea stabilization of the nitrolysis mixture can be documented by the preparation of 1,5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane by adding urea to the starting 1,5-endomethylene-3,7-diacetyl-1, 3,5-7-tetraazacyclooctene (U.S. Pat. No. 3,926,953).

Sub-topic of the invention spčsob 1,3,5-trinitro-l, 3,5-triazacyklohexánu nltrolýzou hexamethylenetetramine at -20 to 51.8 * ^{C, and} followed by isolation of the product is that, in the process nitrolýzy was added to the reaction system 0.01 to 10% by weight, based on hexamethylenetetramine, of the urea-formaldehyde condensation product, preferably of the pan type, alone and / or in admixture with the reaction components involved, preferably in admixture with hexamethylenetetramine.

The advantage of the present invention is to increase the stability of the nitrolysis mixtures and the resulting process safety, as well as to significantly affect the yield of 1,3,5-trinitro-1,3,5-triazacyclohexane. In the case of using a mixture of hexamethylenetetramine with urea-formaldehyde condensate, inter alia, due to the fluidity of the system, a ronomer-free, dosing-free dosage is achieved.

Suitable additives during the nitrolysis of the present invention have shown insoluble urea-formaldehyde condensates resulting from the ureability of formaldehyde, preferably in an acidic environment (e.g., US Patent Nos. 227,901, U.S. Pat. Nos. 3,981,845 and 4,081), in water and in organic solvents. 741). Good results are also obtained by the use of water-soluble and organic solvent-soluble condensates suitably chemically and / or thermally modified.

The urea-formaldehyde additives with a large reaction surface give excellent results, which is achieved by using them in foamed form. A relatively wide range of published methods for obtaining various suitable types of diapers is discussed. {Bibliography, Berlin A. A. Sutov F. A. Penopoimers on the Reaction-Warp Oligomer Izdat. Moscow, Khimiya, 1978; Usmáni A.M., Salyer I. 0, Polym., Plast. Technol. Eng., 12 (1), 61-88 (1979)].

When applying urea-formaldehyde condensates to treat hexamethylenetetramine, author certificate 8. 227902, the rate of increase in stability is proportional to the content of these condensates in hexamethylenetetramine.

The presence of urea-formaldehyde condensates in the nitrolysis of the present invention affects the yields of 1,3,5-trinltro-1,3,5-triazacyclohexane. There is a certain optimum content of said condensates in the hexamethylenetetramine used, which increases the process yield, calculated on the unbalance of the treated hexaraethylenetetramine. For nitric acid of at least 96.6% and an optimum initial molar ratio of nitric acid to hexamethylenetetramine of 21.5 to 24.5, according to the present invention the highest recovery is at a content of 1.2 to 1.4% by weight of urea-formaldehyde condensate in the applied hexamethylenetetramine .

When this additive content is exceeded, the yield of 1,3,5-trinitro-1,3,5-triazacyclohexane begins to decrease and the yield level of the hexamethylenetetramine-free process adds to a content of 2.5 to 3.0% by weight of urea-formaldehyde. of condensate in the starting hexamethylenetetramine.

However, in the monitored range of 0.00 to 9.09% by weight, of the urea-monoaldehyde condensate in the applied hexamethylenetetramine, the utilization of the methylene base of hexamethylenetetramine and the additive is higher than in the nitrolysis of hexamethylenetetramine without the additive.

Taking into account published data on the nitrile cleavage mechanism of hexamethylenetetramine (GF Wright, published in H. Feuer, edited by The Chemistry of the Nitro and Nitroso Groups. Part 1. John W.iley, 1969, pp. 653-654), the beneficial effect of urea-formaldehyde condensates on the recovery of 1,3,5-trinitro-1,3,5-triazacyclohexane interpreted as follows: due to the presence of electronegative carbonyl groups in the molecule, urea-formaldehyde condensates in the reaction medium generate carbammonium ions.

These ions could then participate in the equilibrium preceding the cleavage of the hexamethylenetetramine to the undesired products and / or combine with structurally useful hexamethylenetetramine fragments on the perhydro-1,3,5-triazine cycle. For example, other cleavage reactions of hexamethylenetetramine, namely nitrosative cleavage in a weakly acidic environment, are indicative of affecting recovery via equilibrium: here some (optimal) amount of free formaldehyde or free ammonia in the applied aqueous solution of hexamethylenetetramine increases the yields of the 1,5-endomethy product. -3,7-dinitroso-1,3,5,7-tetraazacyclooctane (ČSSR author's certificate No. 191 380).

The method of nitrolysis of hexamethylenetetramine in the presence of urea-formaldehyde condensates based on the converted literature and patent research is new, not yet described in the literature. The following examples illustrate the method as well as the higher effect of the method according to the invention.

EXAMPLE

To 115 parts by volume of 96.9% nitric acid (2.646 moles of nitric acid) having a content of 0.37% by weight. of analytical nitric acid, presented in a stirred nitration apparatus, was charged with 15 wt. % of hexamethylenetetramine containing 2.83 wt. moisture and in the other two experiments still containing urea-formaldehyde condensate. Cooling of the reaction mixture was substantial so that its temperature did not exceed 33 ° C and was generally in the range of 25 to 28 ° C.

After the hexamethylenetetramine was introduced, a 40 minute post-reaction was carried out at a temperature of 25 ° C to 29 ° C. Then, the nitrolysis mixture was poured into 400 parts by volume of water at 60 ° C to warm and after 10 minutes of stirring the resulting suspension, the product was isolated by filtration. After dolconal washing with hot water, 1,3,5-trinitro-1,3,5-triazacyclohexane was dried for 40 hours. at 55 to 60 ° C.

The following tabular dams present the results:

Urea content in urea-formaldehyde condensate in hexamethylenetetramine (% by weight) Number of moles of hexamethylenetetramine dosed yield temperatures mp product (° C) in mass parts in on weighed sample modified hexamethylene tetramine % to pure hexamethylenetetramine 0 0,104 17.1 71,94 74.02 205 to 206 3 0,3 00 16.7 70.26 74.54 206 to 207 5 0,098 16.6 69.84 75.66 206 to 207

The amount of applied raw materials corresponds to mass. ratio of nitric acid to hexamethylenetetramine = 11.477.

EXAMPLE 2 Hexamethylenetetramine with 1.31 wt. humidity, respectively. the same product, treated by the addition of urea-formaldehyde condensate, in an amount of 15 wt. parts are introduced into the stirred and vastly cooled 96.6% nitric acid and containing 0.10% by weight of the composition. nitric acid. The metering and cooling of the nitrolysis mixture is carried out in such a way that the introduction time of hexamethylenetetramine does not exceed 3 minutes while the temperature of the mixture is in the range of 24-29 ° C. After the hexamethylenetetramine is introduced, the reaction is carried out for 40 minutes at a temperature of 24 to 29 ° C and then the reaction mixture is poured into a quadruple volume of water at 60 to 65 ° C as the nitric acid applied. After 1S min. By mixing the resulting suspension, the product is isolated by filtration, washed thoroughly with hot water (three times 100 volumes, in portions) and dried at 55-60 ° C.

The dry product was recrystallized from acetone: 10 wt. parts of the product were dissolved in 100 parts by volume of acetone at boiling point, and after filtering the solution, 50 parts by volume of distilled water were added to the filtrate. After 30 minutes, the resulting suspension was filtered and the product dried at 55-60 ° C. Crystallization yields were 8.1 wt. parts up to 8.4 wt. parts of 1,3,5-trinitro-1,3,5-triazacyclohexane.

An overview of results is presented by tabular dams on p. 31st

On the basis of a graphical comparison of the yield and additive content of hexamethylenetetramine, it was found that from the point of view of recovered on-feed hexamethylenetetramine the optimum amount was 1.2 to 1.4% by weight. of urea-formaldehyde condensate in applied hexamethylenetetramine.

Similarly, based on the graphical confrontation of the yield and the reactant molar ratio, it was found that under the reaction conditions the range of molar ratios of nitric acid to hexamethylenetetramine was optimum to 21.5 to 24.3.

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Example .1

106 parts by volume of 99.09% nitric acid (2.520 moles of nitric acid) containing 0.09% by weight of nitric acid; analytical nitric acid, cooled to 20 DEG C. in the nitration apparatus, and hexamethylanetetramine was introduced in an amount of 15 parts by weight for 3 minutes; hexamethylanetetramine was obtained by drying the hexamethylenetetremine of Example 2 for 48 hours at 50-54 ° C.

The temperature of the mixture at which the hexamethylanetetramine was introduced was kept below + 15 ° C. After addition, a 30-ml post-reaction was carried out at a temperature of 15 to 19 ° C. The reaction mixture was poured into 400 volume parts of water, 60 to 65 ^and C warm. After stirring the suspension for 10 minutes, the product was isolated by filtration and washed three times with 100 volumes of water.

Parallel to nitrolysis, the thermal stability of the resulting nitrolysis mixtures was specified by isothermal differential analysis. The procedure was identical to the nitrolysis procedure except that the dilution of the nitrolysis mixture was not carried out but the nitration apparatus with the reaction mixture was placed in a tempered water bath; the isothermal exposure temperature of the nitrolysis mixture was 51.2 * 0.6 ° C.

For thermal exposure! the coloring of the atmosphere above reaction mixture 6 by Fe-Co ternary cells was visually observed; induction periods of exothermic decomposition were specified; sstotermicteéana the decomposition of the nitrolysis mixture always preceded by a slight coloration of the atmosphere or the level of the mixture of oxygen »! and the time corresponding to this phenomenon was recorded as the induction period of nitrogen oxides. The results of this example are presented in the tabular overview on p. 14th

By graphically confronting the additive content and the yield calculated on the weight of treated hexamethylanetetramine, it was found that the maximum yield of 1,3,5-trinltrose-1,3,5-triazacyclohexane was 1.2-1.4% by weight. of urea-formaldehyde condensate in the applied hexamatylan tetrasine.

In the same way, it was found that, in terms of recovery, nitrolysis of hexamethylanthetramine without the additive was an equivalent of nitrolysis of said substance, with an addition of 2.7% by weight. urea-formaldehyde condensate.

As follows from the tabular overview on p. 14, and extracts of 1,3,5 + trinitro-1,3,5-triazacyclohexane, calculated for the hexamethylanetetramine content in the feed, at the observed range of urea-formaldehyde condensate in the batch weighed higher than the nitrolysis of hexamethylantetramine without the additive.

Thus, within the observed range of additive content in the applied hexamethylenetetramine, the utilization of the mttylene base of hexamethylanetetramine is higher than in nitrolysis in the absence of urea-formaldehyde condensates.

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Example 4

Nitrolysis of hexamethylenetetramine containing 0.21 wt. The moisture was passed through a process apparatus consisting of a first nitrator, a second nitrator, a crystallizer, a suspension cooling apparatus, continuous J brushes and a product stabilizing apparatus.

The first nitrator was continuously fed with 99.09% nitric acid containing 0.09% by weight. % analytical nitric acid and hexamethylanetetramine containing 0.21% w / w; humidity. Feeding of raw materials was conducted so that per 1 wt. % hexamethylenetetramine was 10.7 wt. parts of nitric acid.

By cooling, the temperature in the first nitrate is maintained at 17-22 ° C. The contents of the first nitrator continuously fall into the second nitrator with a working temperature of max. Deň: 18 ° C.

The total retention of both nitrators is 44 minutes. From the second nitrator, the nitrolysis mixture is fed to a crystallizer, where the temperature is maintained at 70-80 ° C, and at the same time water (washing water from continuous filters) is supplied in an amount of ‘4.7 volumes, parts per 1 wt. The reaction was taken up by reaction of the taken hexamethylenetetramine.

From the crystallizer, a suspension of the product in 54.8% nitric acid is passed through a stirred and cooled apparatus, where it is cooled to 30-40 ° C into continuous filters, where nitric acid is collected and the product is washed with water.

From the continuous filter, the filter cake of the product is flushed with water and the resulting suspension is pumped through the steam ejector to stabilization apparatuses where the acidity of the crystals is reduced below 0.05% by weight by direct steam heating. nitric acid. After isolation by filtration, 1,3,5-trinitro-1,3,5-trlazacyclohexane is obtained in an amount of 1.177 wt. parts of dry matter per 1 wt. by hexamethylenetetramine, which is 74.3% of theory.

Example?

The nitrolysis of hexamethylenetetramine was carried out as in Example 4. The feedstock of the starting quality hexaethylanetetramine as in Example 4 was transferred by introducing into the nitrolysis mixture an adjusted content of 1.30% by weight. urea-formaldehyde condensate. From 1 wt. parts of hexamethylenetetramine so treated resulted in 1,248 parts by weight of parts of 1,3,5-trinitro-1,3,5-triazacyclohexane, i.e. 78.76% yield of the product compared to the weight of treated hexamethylenetetramine and 80.01% of theory, calculated on content hexamethylenetetramine in bulk.

The present invention is applicable to all proses of the nitrolysis of hexamethylenetetramine leading to 1,3,5-trinitro-1,3,5-triazacyclohexane. The importance of the essence of the invention and its undemanding design makes it possible for its early use in the production of this widely used explosive in the Czech Republic and abroad.

Claims (1)

Spfls production of 1,3,5-tritro-1,3,5-triazacyclohexane by nitrolysis of hexamethylenetetramine at a temperature of -20 to +51.8 ° C and subsequent isolation of the product, characterized in that, in the process of electrolysis, they are added to the cation system 0, 01 to 10 wt. calculated on hexamethylenetetramine, a urea-formaldehyde condensation product, preferably of the foam type, alone and / or in admixture with the reaction components involved, preferably in a mixture with hexamethylenetetramine.