CS244748B1 - A method for obtaining silver ions from acidic waste solutions of silver ions from acidic waste solutions d - Google Patents

Abstract

A method of obtaining silver from acidic waste solutions of dichromate, resulting from the determination of COD, in which chloride ions are added to the reaction mixture in an amount of 0.6 to 12 g/l and the resulting precipitate of silver chloride is separated from the reaction mixture, dissolved in ammonia and the resulting solution of silver amocomplex is subjected to electrolysis at a voltage of 2 to 4 V and a current density of 0.01 to 0.2 A/cnt^.

Description

HORYNA JAROSLAV ing., JENÍKOVICE, 'HOLUB MIROSLAV prom. ped. , OVČÁRY u Kolín, 'MACH KAREL, PARDUBICE (54) Preparation of technical 4-sulfophthalimide ammonium

Process for the preparation of technical 4-sulfophthalimide with 3-sulfoisomer and ammonium sulphate from reaction mixtures formed by sulfonation of phthalic anhydride after dilution with water and neutralization with ammonia by reacting the reaction mixture containing the trivalent ammonium salts of isomeric 4- and 3-sulfophthalic acid 0 to 9.5: 0.5 to 3, and ammonium sulfate, heated to 200 to 370 ° C for 2 minutes to 2 hours, the reaction mixture being dehydrated by evaporation before entering the reaction chamber at 200 to 370 ° C. C or directly in this space.

The present invention relates to a process for the preparation of technical ammonium 4-sulfophthalimide with an addition of 3-sulfoisomer and ammonium sulphate and to thermal cycling of technical triammonium sulfophthalic acid salts obtained from the reaction mixture after sulfonation of phthalic anhydride.

Sulphophthalimides and their salts do not yet belong to the category of bulk tonnage intermediates. According to the literature, for example, the ammonium salt of 4-sulfophthalimide can be prepared from the bivalent ammonium salt of 4-sulfophthalic acid by heating it to 190 ° C, another method of synthesis is starting from 4-sulfophthalic acid treated with ammonia at 190 ° C. However, the technical level of these methods of preparation does not give rise to the introduction of rational production of sulfophthalimide, since the formation of the phthalimide ring is slow and incomplete.

According to the present invention, technical ammonium 4-sulfophthalimide with an admixture of 3-sulfoisomer and ammonium sulfate can be prepared from reaction mixtures resulting from phthalic anhydride sulfonation after dilution with water and neutralization with ammonia by reacting the reaction mixture containing the triammonium salts of isomeric 4- and 3-sulfophthalic acids. a weight ratio of 7.0 to 9.5: 0.5 to 3 and ammonium sulfate, heated to 200 to 370 ° C for 2 minutes to 2 hours, wherein the reaction mixture is dehydrated by evaporation before entering the 200 ° C reaction space. up to 370 in this space.

^J C or directly

Said thermal cyclization of the ammonium salts to the phthalimide moiety can be carried out either in batch, for example by heating a solid salt evaporator while passing the salts through a reaction zone of 200 to 370 ° C with a residence time of 2 minutes to 2 hours. According to the invention, it is possible to evaporate the totally neutralized reaction mixture after sulfonation of phthalic anhydride immediately before entering the reaction zone of 200 to 370 ° C or directly in the zone, preferably in a continuous embodiment. The thermal cyclization leading to the formation of the phthalimide moiety is unexpectedly affected by the presence of ammonium sulfate, which is likely to act as a heat transfer agent in the endothermic cyclization process. Surprisingly, the conversion of ammonium salts of sulfophthalic acid to technical sulfophthalimide is accelerated at a temperature range of 200 to 370 ° C, and an almost 100% conversion to sulfophthalimide is achieved after a few minutes of ammonium salt residence in the temperature range of 350 to 370 ° C.

The necessary mixtures of ammonium salts of sulfophthalic acid and ammonium sulfate can be easily obtained according to AO 236 112. During their processing, the evaporation process of the water from the ammoniacal reaction mixtures after sulfonation of phthalimide hydride can be combined with the phthalimide cyclization itself, for example of the type of spray or fluidized bed driers and the like, wherein at a hot gas temperature of 200 to 370 ° C, thermal cyclization immediately after the previous evaporation of the water follows to form a phthalimide ring.

If it is desired to produce technical 4-sulfophthalimide from solid mixtures of sulfophthalates and ammonium sulfate in a batch design, the salt mixtures are heated to temperatures of 200 to 370 ° C. For large-scale production, it is preferred that solid ammonium salt mixtures formed into a thinner layer are continuously shifted through a reaction zone of 200 to 370 ° C, for example, in a heated horizontal rotary reactor or in an agitated pulverulent mass or other known reactor used to process solids. bulk materials at elevated temperatures.

According to the process of the invention, a solid phase is formed from the starting solutions or the free-flowing ammonium salts, which remains as a bulk material up to 280 ° C; at temperatures above 280 ° C, the pulverulent mass may aggregate into a particulate material, but it is easily crushed.

It is therefore preferable to disperse the ammonium salt solutions into the hot gas stream or to introduce solid ammonium salt homogenates into rotary reactors with a mobile crushing charge when operating above 280 ° C.

The new production method achieves almost quantitative yields, based on the employed triammonium salts of sulfophthalic acids, and cyclization is incomparably faster in the defined temperature range of 200 to 370 [deg.] C. than in the previously described processes. The product is obtained in the form of slightly brownish or greyish powders or pieces and is a mixture of ammonium salts of 4- and 3-sulfophthalium (2,47,748) with an isomer ratio in the range of 7.0 to 9.5: 0.5 to 3.0 and ammonium sulfate, optionally with a small amount of impurities either introduced into the product by the starting technical ammonium salts or formed during the synthesis.

As such, the mixtures obtained are suitable for the production of some significant tar colorants or more noble semi-finished products.

Example 1

Weigh 14.00 g of a 45.8% technical mixture of triammonium sulfophthalic acid salt (with a ratio of 4- and 3-sulfoisomers 86: 14) with ammonium sulfate, which was obtained by evaporating the aqueous solution of the reaction mixture after sulfonation of phthalic anhydride into a porcelain crucible. totally neutralized ammonia. The crucible with the handle is placed in a fireclay furnace equipped with an electrical resistance heater and heated to 280 ° C within 50 minutes; is maintained at 280 ° C for 40 minutes. The product crucible is then transferred to a desiccator and weighed after cooling; 12.89 g of a powdery powdery product is obtained, which is slightly off-white and is a mixture of 85% 4- and about 15% ammonium 3-sulfophthalimides with ammonium sulphate. The sample is labeled A for the analysis described below.

In a comparative experiment, 1.550 g of 93.5% pure tri-ammonium salt of 4-sulfophthalic acid was weighed into a 19.0 mm diameter platinum crucible, heated to 280 ° C and held at this temperature for 20 minutes. 1.226 g of product were obtained. The sample for analysis was designated B.

Analysis:

According to the NMR spectra of samples B and ¹³ C (measured in DMSO-Dg), the CONHCO hydrogen signal is 11.4 and the Nflt group hydrogens exhibit triplet and extended triplet 114 ^{4 respectively} due to J (NH). Comparison of experimental and calculated chemical shifts using substitution chemical shifts valid for SOgNa grouping in the DMSO-Dg system was used to determine the sulfo group position. Values for carbon atoms indicated by the following scheme I (I)

-O ₃ s 3

CO are shown in tabular form.

designation 1 2 3 4 5 6 7 8 13 experimentally (C) and and 120.0 153.6 and 123.3 169.0 169.0 found calculated (^ C) 133.4 132.3 120.4 153.5 131.8 123.5 -

and ... 132.9 (2xC) or 131.6

The obtained product is practically pure ammonium salt of formula I in terms of NMR spectra.

IR spectrum (in KBr) was recorded from product B. In the range of 1,650 to 1,800 cm, the peak assembly is identical to that of the phthalimide moiety, and in the range of 1,000 to 1,300 cm, the sulfo group frequencies are characteristic.

»» ·

For the product designated as A, the ammonium salt of 4-sulfophthalimide and the ammonium salt of 3-sulfophthalimide (85:15 ratio) were found by NMR spectra as the main organic component. The 3-sulfoderivative shows (CO) = 168.8 and 166.9, respectively; (C-SO3) = 144.4 (calc. 142.1); its ^J content was determined from C signal intensities.

Example 2

A batch of 14.00 g of an ammonium salt technical composition of the same composition as in Example 1 was gradually heated to 370 ° C in a porcelain crucible over 1 hour, then the crucible was transferred to a desiccator and allowed to cool freely. 12.75 g of a compact gray mass is obtained, which is a mixture of ammonium salts of 4- and 3-sulfophthalimides and ammonium sulfate.

Example 3

Using the procedure of Example 1, 14.00 g of a technical mixture of ammonium salts of the above composition are heated and after heating to 200 ° C the crucible is kept at 200 ° C for 2 hours. 12.92 g of a powdery powdery product of a light gray color are obtained, which is a mixture of ammonium salts of 4- and 3-sulfophthalimides and ammonium sulfate.

Example 4

A 50% aqueous solution prepared from a 47% technical mixture of triammonium sulfophthalic acid salts (with a ratio of 4- and 3-sulfoisomers of 95: 5) and an ammonium sulfate content was dispersed into a spray drier heated to 280-10 ° C by flue gas. From the dryer separator, a powdery greyish product is obtained which is a mixture of ammonium salts of 4- and 4-sulfophthalimides with ammonium sulfate.

Example 5

The technical triammonium salt of the composition as in Example 1 is passed through a rotating horizontal cylindrical reactor having an internal temperature of 300 ° C. Pass through 1.2 kg of raw materials / 10 minutes. The lumpy product obtained in an amount of 1.1 kg / 10 minutes has similar properties as in Example 1.

Claims (1)

OBJECT OF THE INVENTION A process for the preparation of technical ammonium 4-sulfophthalimide with 3-sulfoisomer and ammonium sulphate from reaction mixtures resulting from phthalic anhydride sulfonation after dilution with water and neutralization with ammonia, characterized in that the reaction mixture contains trivalent ammonium salts of isomeric 4- and 3-sulfophthalic acids ratio of 7.0 to 9.5: 0.5 to 3 and ammonium sulfate, heated to 200 to 370 ° C for 2 minutes to 2 hours, the reaction mixture being dehydrated by evaporation before entering the reaction chamber at 200 to 370 ° C. 370 ° C or directly in this space.