CZ2010543A3 - Preparation process of dinitrodiazophenol - Google Patents

Abstract

Technological process of production of dinitrodiazophenol by diazotization of refined picramic acid, ensuring the formation of rounded crystals called free flowing form with bulk density of about 0.8 g / cm 2 and product purity of up to 98%. The cracker produced in this way has a crystalline shape optimum for the purpose of volume dispensing for both dry and wet production of non-toxic detonator fillers and primers without further modification.

Description

Technical field

The present invention relates to a novel process for the manufacture of dinitrodiazophenol, known as Dinitrodiazophenol (DNDAP), according to recent researches dinitrochinondiazide (DCHD), a historical explosive discovered by Griess in 1858. Interest in this explosive increased only in the early 1930s in connection with by looking for new, less toxic, heavy metal-free explosives.

BACKGROUND OF THE INVENTION

The production of di-nitiazophenol is not a problem for the preparation of this compound as a lacquer, but it is a problem of obtaining crystalline shapes of the compound that are optimal for bulk dosing purposes.

Dinitrodiazophenol is produced by diazotization of picramic acid. The reaction rate of diazotation is enormously dependent on the pH of the reaction medium. When diazotizing in a strongly acidic environment, the product is produced at high speed, high purity and with maximum yield, but absolutely unsatisfactory crystal shape and thus low bulk density (about 0.2 g / cm). These products are light yellow in color.

Thus, the reaction has to be carried out in the opposite way - by adding the acid solution to the reaction suspension or the solution of picramic acid or its salts, which also contains the calculated amount of nitrite. However, if the reaction is not properly controlled, the risk of non-compliant products still exists. These products can also be formed with a local increase in acid concentration, i.e. place it into the reaction mixture. At the elevated acid concentration, the reaction proceeds at such a high rate that it proceeds even in strongly cooled solutions, unless the inlet or dilution of the acid is slowed down accordingly. Therefore, if diazotization will be performed at low temperatures (10 - 15 ° C). which is common practice in the production of diazo compounds, with rapid acid feed and possibly still insufficient mixing of the reaction mixture (low speed or inappropriate shape and location of the stirrer). unsatisfactory products can be expected and, moreover, with a very low yield. However, practical tests have shown that even intensive mixing is not a solution in this case, since the products resulting from these conditions were heavily contaminated with unreacted picramine acid. The authors of the US patents who proposed the use of strongly cooled reaction mixtures have solved this problem by extremely long acid inflows - up to. 300 min.

In order to obtain products of desired properties (high purity, homogeneity, reproducibility, bulk density), it is necessary to conduct the reaction so that dinitrodiazophenol is produced at a sufficient rate even in an environment with low acid concentration and conversely suppress its formation at the site of increased acid concentration. This can be done by increasing the reactivity of the reaction mixture - by increasing the temperature, the intensity and manner of mixing, and using solutions instead of suspensions. In order to disperse the dosed acid in the reaction mixture as quickly as possible, it is necessary to use very dilute acids and it has been proposed to use special atomizers "atomizers" L of this knowledge based on the Smoleński - Pluciňský method. developed in the early 1950s using a suspension of sodium picramine and very dilute HCl. The inflow time is reduced to 120 min.

However, practical laboratory tests have shown that even this method did not provide products of sufficient quality. Nor was the use of atomizers proven. to spray the acid below the level of the reaction mixture - small nozzles sc clogged with the above yellow products.

• vz mi vz vz mi vz vz vz mi mi mi mi mi mi mi mi vz vz vz mi vz vz vz vz vz vz mi φ vz vz φ φ vzmi mi Additions of special compounds acting as growth retarders of the crystal surfaces t1 recommended in many patents (polyphenols, amines, nitro compounds, triphenylmethane dyes, etc.) have also not proved useful. The products were of poor quality, inhomogeneous and often contaminated with unreacted picramine acid.

SUMMARY OF THE INVENTION

It was found that the basic prerequisite for obtaining a sufficiently high-quality product is perfect refining of the basic feedstock - picramine acid. This compound (2-amino, 4,6-dinitrophenol) is produced by partial reduction of picric acid with strong compounds (alkali sulfides) and is only commercially available as its sodium salt. However, commercially produced sodium picramine has been shown to be heavily contaminated with compounds of unknown composition, which may be formed as byproducts in production, but may also be formed in samples of highly refined picramine acid over a period of time. This knowledge fundamentally influenced the solution of the problem of production of dinitrodiazophenol of the required quality.

Sodium picramate is almost insoluble in cold conductor and known polar organic solvents. However, its solubility in water increases substantially with temperature, which can be used for its recrystallization. However, practical tests have shown that even the recrystallization cannot be purified and the only solution was to convert sodium picramate to picramic acid by precipitation from a saturated hot aqueous solution with the calculated amount of mineral acid, in this case hydrochloric acid. After cooling, sedimentation and multiple decantation of the dark-colored solution, picramine acid is further refined by simply dissolving in acetone and precipitating with several times the amount of water. Purified picramine acid is a bright brick-red, crystalline substance crystallizing in the form of long needles. High-quality dinitrodiazophenol can be prepared from this raw material by the method of the invention. If the color of picramine acid turns red or reddish-violet during storage, recrystallization must be repeated before dinitrodiazophenol production to ensure maximum product quality and reproducibility.

For the production of dinitrodiazophenol, we convert picramine acid to a suitable soluble salt, thereby substantially increasing the reaction rate. Among the highly soluble salts of picramine, Mg, Ca or ammonium salts can be selected. An excess of insoluble oxides, hydroxides, or carbonates of these metals must be used in the preparation of MgSO4 salts, the reaction mixture must be heated and the excess of these compounds must be filtered off before the reaction. The simplest was the preparation of the ammonium salt, which is formed by dissolving picramine acid in a small excess of concentrated aqueous ammonia solution. Ammonia is a weak base and therefore a certain excess over the calculated amount not only does not have a negative effect, but practical tests have shown its positive effect on the formation of a more uniform product and an increase in its bulk density. Its overdose, however, causes contamination of the resulting product and high overdose can also lead to product loss during decantation. Thus, the accuracy of dosing is very important and it is necessary to carry out an analytical determination of the ammonia content before the reaction.

The principle of production of dinitrodiazophenol according to this technical solution is as follows:

A metered amount of concentrated ammonia water (known content) and a calculated amount of NaNO 2 are metered into the aqueous suspension of the calculated amount of picramine acid with vigorous stirring. After tempering the reaction solution to the optimum initial temperature and adjusting the speed of the high-speed stirrer to 700 - 1500 rpm, we start dropping very dilute (5.5%) HCl from the separating funnel to achieve the optimum flow rate. The stirring speed, the shape and the location of the stirrer have a fundamental influence on achieving an optimal crystalline shape, the so-called free flowing mold, with the highest achievable specific value. 4 B

4 4 4 »* 44 Weight 0.8 - 0.9 g / cm ² . The centrally located paddle stirrer has a dual function: to perfectly mix the reaction mixture, assisted by a low concentration of reacting components and imparting a high rotation to the liquid, generating a centrifugal force to round the dinitrodiazophenol crystals.

This method makes it possible to produce high quality dinitrodiazophenol with maximum yield in the form with the highest available bulk density, which is most suitable for bulk dosing.

DETAILED DESCRIPTION OF THE INVENTION

1) Conversion of sodium picramine to picramic acid

50 l of distilled or deionized water was introduced into a glass or stainless steel boiler with the possibility of heating and 3000 g of raw sodium picramate (moistened with 20 - 30% water) were dosed. With vigorous stirring and heating at 95-100 ° C, it was completely dissolved. 1500 ml of concentrated 11Cl was added dropwise to the resulting dark colored solution with vigorous stirring. which is almost double the theoretical amount, based on dry picramine. After sedimentation of the precipitated picramic acid and partial cooling of the solution, the product was purified by multiple decantation. The intense coloration of the decanted solution, which changes from red-violet to blue-green-black, indicates the presence of a large amount of contaminants. The last decanting water must not show an acidic reaction.

2) Refining of picramine acid by recrystallization.

The perfectly decanted picramine acid (with the water content reduced to a minimum) now had the appearance of a brown-red amorphous powder and still contained a certain percentage of impurities. Therefore, it was dissolved with stirring in 8-10 times the amount of pure acetone and again, with vigorous stirring, precipitated with 3-4 times the amount of water. After decanting, the product suspension was quantitatively transferred to suction and sucked off several times with water. The product, now in the form of bright brick-red acicular crystals, was dried at normal temperature. Picramic acid has now been prepared for the production of dinitrodiazophenol.

3) Production of dinitrodiazophenol

In a glass apparatus, consisting of a 3000 ml beaker, placed on a water bath with temperature control within ± 1 ° C, equipped with a high-speed, centrically positioned paddle stirrer with speed control within the range of 700 - 1500 ol / min. laboratory thermometer with fine separation and at least 500 ml separating funnel, 2000 ml of distilled water was introduced and after warming to 24-25 ° C, 50 g of refined picramine acid was metered with stirring. then a tempered solution of 18 g NaNO? in 150 ml of distilled water and 21.5 ml of 25% ammonia water. In case of different ammonia content (to be determined eg by titration of 1 N H2SO4 to methyl red) this amount must be recalculated after the conversion of picramic acid into the ammonium salt solution, which resulted in intense darkening of the solution and setting the stirrer speed to min. min. a 5.5% HCl drop-off from the separating funnel was started. for 30 minutes and 0.5 k / s for another 20 - 30 min. The dosing was directed to the inner edge of the air vortex which is formed at full speed of the agitator.

The end of the reaction was indicated by the color of the indicator K1 paper, after which the reaction mixture was allowed to react for 15-20 minutes. Subsequently, the mother liquor was poured and decanted with distilled water until the solution cleared over the sediment, suction filtered and dried at normal or slightly elevated temperature.

The product is dark brown to black colored, has an Ibrma of rounded crystals and has a bulk density of about 0.8 g / cm ² . The reaction yield is about 80% of theory.

Product purity, determined by titration with standard NaNO? in the medium of acetic acid sc fluctuated around 98%.

Industrial use

Dinitrodiazophenol produced by the method according to this technical solution excels in high quality and purity, its crystalline shape and density is optimal for the purposes of volumetric dosing for dry and wet technology of production of non-toxic charges of detonators and primers of eg Sintox type.

Claims (6)

Patent claims A process for the production of dinitrodiazophenol by diazotization of picramic acid, characterized in that the highly refined picramic acid obtained from sodium picramine reacts with a very dilute mineral acid solution added dropwise from the separating funnel at an optimum flow rate while mixing centrically by means of a suitably selected stirrer with speed control which, in addition to thoroughly mixing the reaction mixture, ensures high liquid rotation and centrifugal force influences the formation of rounded particles of the final product. Method according to claim 1, characterized in that picramine acid is obtained by precipitating a saturated hot aqueous solution of sodium picramate with a calculated amount of a mineral acid, preferably hydrochloric acid. A process according to claim 1, characterized in that the high purity of the obtained picramine acid is obtained after cooling, sedimentation and multiple decantation by refining by simple dissolution in acetone and precipitation by multiple amounts of water. A process according to claim 1 wherein the pure picramic acid for the production of dinitrodiazophenol is converted to a suitable soluble Mg salt. Ca, or preferably to the ammonium salt, by dissolving in a small excess of concentrated aqueous ammonia solution. The production method according to claim 1, characterized in that the soluble salt of picramine, preferably ammonium salt, is reacted with a very dilute mineral acid, preferably 2 - 10% HCl, dropped from the separating funnel, where the optimum dosing rate is 1 drop. / sec. for 30 minutes and 0.5 k / s for another 20 - 30 min. 6. The method of claim 1 wherein the mixing of the reaction mixture is carried out by a high speed, centrally located paddle stirrer with speed control in the range of 700-1500 rpm.