CS214605B1 - Method of treating the mother liquors from the production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7 tetraazycyclooctane - Google Patents

Description

The present invention provides a process for treating mother liquors from the production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazaoyclooctane such that the main processing products are aqueous formaldehyde solution and solid sodium nitrate.

For the β-endayseine production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazaoyclooctane, also known as N, N-dinitrosopentamethylenetetramine (DNPT), the nitrosative cleavage of hexamethylenetetramine is most preferred. In terms of quality, expressiveness and N, t-dinitrosopentamethylenetetramine isolation, the most optimal source of nitrosating agent is a combination of nitric acid and alkali metal nitrites / Gries, Harrowt Ber.laáá, 2L, 2737 f Duden, Scharffj Ann.1895, 288, 218 f Anto Forman, Christian Chemists 1956, 10, 162, French Patent 1,580,636, Czechoslovakia-Aut. 182 625, or calcium nitrite.

Sodium nitrate solutions containing a certain amount of excess sodium nitrite, formaldehyde and ammonium ions are omitted from the application of the non-methylenetetramine-nitric acid-sodium nitrite raw material base. When the reaction is terminated by neutralizing the entire reaction mixture with an alkali hydroxide, hexamethylenetetramine, poles and other products of formation and N-Mannich reactions are also present after the above mentioned substances and neutralizing agent. The polyols and the corresponding N-Mannich bases are also introduced into the reaction mixture by applying the concentrated reaction mixture after the ammoniacalization of formaldehyde instead of crystalline bexamethylenetetramine. The waste mother liquor is a bottle of removable sodium nitrite, but liquidation (CSR aut. Test.185,888), or the use of organic fractions is relatively complicated.The condition of isolation of high quality sodium nitrate is in addition to removing nitrate to reduce the content of organic impurities in mother liquors to a minimum. The occluded proportions of organic compounds, depending on the method and conditions of drying the nitrate, may result in its partial reduction to nitrite.

214 605

214 605

The presence of formaldehyde, ammonium ions, and possibly hexamethylenetetramine in the liquefied liquors from the N, α-dinitrosopentamethylenetetramine production ensures that the decomposition of the nitrite in an acidic environment is complete (see also Z.Anal.Chem.1913, £ 2, 21) Uonatah.Chem 1953, 84, 82 9 Japan (Koksi 74 110,148) J. Am. Concentrating the resulting mixture at atmospheric pressure allows the sulfuric acid to form some of the sodium nitrate present, but the distillate is a highly colored acidic formaldehyde solution. The above drawbacks do not have the method of treating the mother liquors from the production of N, N-dinitrosopentamethylantetramine containing sodium nitrite nitrate, -formaldehyde, ammonium ions, and optionally hexemethylenetetranrine and other formulating and N-Mannich reaction products according to the invention, the essence of which is consists of five stages, the first of which is the acidification of the mother liquors with nitric acid to a pH of 4 to 0, preferably a pH of 2 to 1, at temperatures of 50 to 100 ° C, preferably 90 to 98 ° C, and a contact time of 5 to 60 minutes, and preferably 20 to 40 minutes.) the second step is to adjust the pH of the reaction mixture from the first step to 2 to 7, preferably to 3 to 5) the third step is to distill the formaldehyde at a pressure of 0.1 to 0.5 MPa) the fourth step is to concentrate the distillation residue at a temperature of 50 to 120 ° C, preferably at a temperature of 60 to 80 ° C, to suspend the sodium nitrate from which they are separated in the fifth stage sodium nitrate crystals, wherein the portion I of the lye after crystallization is recycled to the evaporation stage and part is removed from the process. The purity of sodium nitrate can be controlled by the recirculation ratio. In the case of increased requirements for the quality of sodium nitrate or for increasing the degree of its isolation from mother liquors. it can be recrystallized from aqueous solutions into the process, whereby the liquors after recrystallization are returned to the evaporation stage.

The advantage of the invention is that it solves the environmental problems in relation to the production of 1,5-endoraethylene-3,7-dinitroso-1,3,5,7-tetraazacycloctane by evaluating formaldehyde and evaluating a substantial proportion of sodium nitrate contained in the mother liquors of this production.

Example 1.

To 5500 kg.h ^{-1 of} mother liquors from the production of Ν, β-dinitrosopentemethylenetetramine containing 15.09% by weight sodium nitrate, 1.21% by weight sodium nitrite, 2.06% by weight formaldehyde, 0.3% by weight. of hexamethylenetetramine and 0.16% by weight of sodium hydroxide are added 43 * 7.5 kg. h ^'1 21.6% nitric acid to give a pH of 2 zmesi.Reakčná mixture is then nut 30 ml kept at 94 to 96 ° C. Then the pH of this mixture is adjusted to 4.8 with 51% sodium hydroxide solution (23.5 kg.h ^-1 ). The sodium nitrate solution thus obtained, containing 2.09% by weight of formaldehyde, is rectified at a pressure of 0.25 MPs,

Rectification yielded 1004 kg.h ^{-1 of} 12% formaldehyde and a distillation residue of 4851.9 kg.h ^-1 containing 19.28 wt% sodium nitrate, 0.04 wt% formaldehyde and 0.009 wt%. .products of formation reactions.

This distillation residue, together with a long lye after isolation of sodium nitrate crystallized in the evaporation step, is fed to a vacuum evaporator where it is evaporated at 60 ° C.

3519.8 kg · h ¹ vody.Vykrystalizovaný sodium nitrate is separated and part of the liquor kryš.talizácii, in an amount of 797 kg · h ^-1, comprising 52.8% hmotn.dusičňanu solution is discharged from the process and the remainder being returned to the evaporation stage. This gives 514.5 kg.h ^-1 sodium nitrate, which represents 55% isolation efficiency. The cracked sodium nitrate contains only a trace amount of sodium nitrite (causing only a slight coloration of the mixture of beta-naphthol and sulfanilic acid solutions).

Example 2

The mother liquors of the same composition as in Example 1 were treated in the same manner as in Example 1, except that the increase in the re-circulation ratio is achieved by collecting the lyes after crystallization from the process at 358 kg.h. &^lt; ^{-1 &gt}; to 80%. The obtained crystalline sodium nitrate is recrystallized from a saturated aqueous solution at 80 ° C by cooling it to 25 ° C. The mother liquors after recrystallization are added to the vacuum evaporator after washing the sodium nitrate wheel. In this way, it is possible to obtain 748.4 kg.h ^{-1 of} high purity sodium nitrate.

Claims (2)

SUBJECT MATTER 1. Process for the treatment of mother liquors resulting from the production of 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazacyclococtane and containing sodium nitrate, sodium nitrite, free formaldehyde and, where appropriate, formulating products and N- The mannion condensation is characterized in that it consists of five steps, the first step being the acidification of the mother liquors with nitric acid to pH 4 to 0, preferably 2 to 1, at a temperature of 50 to 100 ° C, preferably at temperatures of 90 to 100 ° C. 98 ° C and a contact time of 5 to 60 minutes, preferably 20 to 40 minutes, the second step being to adjust the pH of the reaction mixture to 2 to 7, preferably to 3 to 5, the third step is to distill the formaldehyde at 0.1 up to 0.5 MPa, the fourth step is to concentrate the distillation residue at a temperature of 50 to 120 ° C, preferably 60 to 80 ° C, to suppress sodium nitrate, from which the sodium nitrate crystals are separated in the fifth stage, with part of the mother liquors p about crystallization is recycled to the evaporation stage and part is removed from the process and processed by some of the known processes, 2. The process according to claim 1, wherein the isolated sodium nitrate is recrystallized from aqueous solutions.