SU537086A1 - Method of producing ion exchangers - Google Patents

Description

one

This invention relates to the field of obtaining iopites, selective with respect to cations of polyvalent metals, as well as apionites possessing enhanced heat resistance in OH-form.

Nowadays, in ion hydrometallurgy, ion-exchange chromatography, and analytical practice, ionites having a high sorption capacity for polyvalent metal cations, for example, IO, are widely used. The most widely used phosphorus-containing ion exchangers for this purpose have been found.

However, using known phosphorus-containing IONITES, for example, cation exchangers with phosphonyl groups, it is not possible to solve the technical problem of the separation of polyvalent metals in nitric acid media.

The separation coefficient of the UOl cations from rare earth cations (REE) is 3-7, and U02 from is no more than 5 and is insufficient for using this type of cation exchangers to solve the indicated technical problem.

It is also not possible to achieve the separation of cations in nitric acid supplements and with the aid of known amphoteric ion exchangers, for example, an ion exchanger with pyridine and phosphonic groups (separation coefficients are 3-7).

Another important technical task is the creation of highly basic materials with enhanced thermal stability in OH-form. The existing highly basic anion exchangers withstand short-term heating in the OH-form at a temperature of 60 ° C. At higher temperatures (90-100 ° C) complete destruction of groups of quaternary ammonium bases occurs, with their transition mainly to tertiary ones.

A known method of producing ion exchangers by chloromethylation and phosphorylation of styrene and divinylbenzene copolymers with a mixture of chloromethyl reagent and phosphorus trichloride in the presence of, for example, anhydrous tin tetrachloride, anhydrous zinc chloride.

Cation exchangers of this type exhibit an increased sorption capacity with respect to the UOl cations, rare earth elements (REE) during sorption from nitric acid media, and the distribution coefficient in, for example, reaches 70,000. However, as already noted, using these cation exchangers is not possible during sorption from nitric acid media. to separate polyvalent metal cations (,) from REE (separation factor 3-7) and to divide these polyvalent metals among themselves (separation factor not more than 5).

The purpose of this invention is to increase the selectivity with respect to cations of polyvalent metals and the increased heat resistance of the ion exchanger in the OH form.

This goal is achieved by the fact that chloromethylation and phosphorylation are carried out until (the content of chloromethyl groups is 0.4-0.9 for an aromatic core, and after hydrolysis, the resulting phosphorus-containing cationite is subjected to amination.

Ammonia, primary, secondary and tertiary amines, di- and triamines (for example, ethylenediamine, diethylenetriamine) are used as the amyping agent.

The proposed method allows not only to vary the functionality of the introduced amino groups over a wide range, but also to easily vary the ratio between the introduced amount of phosphorus and nitrogen containing, their groups and, thus, other physical and chemical properties of ion exchangers, in particular, heat resistance, in addition to sorption ones.

Thus, an amphoteric ionite obtained by the proposed method and containing about 10-20% of methylenephosphonic groups of the total number of functional groups and containing quaternary trimethylammonium groups as anion-exchange, has an anion-exchange capacity of 1 n. 1.5 mg / eq / g NaCl solution, which is fully preserved after heating the OH-form ion exchanger at 100 ° C for 50 hours, while the ion exchanger containing only trimethylammonium groups, under similar conditions, completely loses its ability to splitting neutral salts. Thus, amphoteric ion exchangers obtained by the proposed method can be used as anion exchangers having enhanced heat resistance in OPform.

The invariability of the structure of the ion exchanger after heating under the indicated conditions is confirmed by the complete identity of the IR spectra of the ion exchangers before and after heat treatment.

Using ion exchangers obtained by the proposed method and containing approximately equal amounts of phosphorus and nitrogen-containing groups, the degree of separation of polyvalent and rare-earth elements (the separation factor increases from 3-7 to 1200) and polyvalent metals with each other, for example, UOV -Fe + (separation factor from 5 increases to 50).

The amount of free chloromethyl groups to be used in the amination process is controlled by the amount of catalyst. To obtain an amphoteric ion exchanger with a predominant anion-exchange function, a catalyst is used (anhydrous

SnCU, ZnCla) in an amount of 0.2-0.3 mol per basolom copolymer. To obtain amphoteric ion exchangers with an approximately equal ratio of heteropolar groups, the amount of catalyst on the basis of the copolymer reaches 0.7 mol. Chloromethylation and phosphorylation are carried out with a mixture of monochlorodimethyl ether and phosphorus trichloride mainly in a molar ratio of 1: 1 (an excess of one or another component can be used). The reaction temperature is 45-60 ° C, the duration is 4-12 hours, depending on the structure of the starting copolymer. After carrying out the chloromethylation and phosphorylation, the product is hydrolyzed and a cation exchanger is obtained with a content of methylenephosphonic groups from 0.1 to 0.5 per aromatic nucleus and 0.9-0.5 chloromethyl group per aromatic nucleus. The obtained intermediate product is aminated by chloromethyl groups and an amphoteric ionite is obtained, containing, depending on the synthesis conditions, polarized functional groups in different ratios.

As aminating agents, ammonia mono-, di- and triethanolamine, di trimethylamine, pyridine, di- and triethylamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, etc. are used.

The structure of the obtained ion exchangers, in addition to the elemental analysis data, which is given in the examples, is confirmed by potentiometric titration data: ion exchangers with approximately equal content of heteropolar groups are characterized by one pKa value equal to 6.6-6.8, and IR spectroscopy: the presence of bands, absorption in areas 900, 1060 and IZO-1180 cm which can be referred

About to vibrations of bonds in the ion —P-OH, that

It is also known for intra salt forms of polyampholytes, as well as the presence of absorption bands in the region 1620 and 3200-5500, which characterize the vibrations of the amino groups.

Example 1. 50 g of a macroporous styrene copolymer with 10% divinylbenzene, prepared in the presence of 100% isooctane, incubated for 30 minutes to swell in a mixture of monochlorodimethyl ether (200 ml) and phosphorus trichloride (175 ml), a mixture of 50 ml monochlorodimethyl ether and 11 ml of anhydrous tin tetrachloride, increase the temperature of the reaction mixture to 45-50 ° C and incubated with stirring for 4 hours

Claims (2)

A mixture of 24 ml of anhydrous tin tetrachloride and 75 ml of phosphorus trichloride is then added and the reaction mixture is kept at this temperature for 8 hours. The resulting product is filtered, hydrolyzed and washed successively with water, 4% NaOH, water, 6% HC1 and water until there is no C1-ion in the filtrate. After drying, the product is analyzed. The content of CI is in the form (-CHgCl groups) of 8.5%, P is 6.5%, the static exchange capacity (SOY) is 0.1 n. NaOH solution, 4.1 mEq / g. Then, the resulting cation "it, containing chloromethyl groups, is aminated in dioxane medium with an excess of hexamethylenediamine (50 g) at a temperature of 55-60 ° C for 10 hours. The resulting ion exchanger is washed similarly to the product of chloromethylation and phosphorylation and analyzed after drying. The content of P is 4.7%, N 3.6%, EOI of 0.1 n. a solution of NaOH 2.8 mEq / g; SOY 0.1 n. HCl solution 1.6 mEq / g. Polyampholyte has the following separation factors a in 0.1 n. HNOs solution (determined using radioactive tracers for cation concentrations of 10–3–10–4 mol / l): o, p. QFe3 + / E3 + -55; ° 2 / RES + 23; / EuZ + 1240. The distribution coefficient (Kp) for UO2 reaches 40,000 under these conditions. Example 2. 20 g of the copolymer specified in Example 1 is chloromethiated and phosphorylated as indicated in Example 1. After hydrolysis, washing and drying the product is aminated in dioxane medium with an excess of trimethylamine (20% alcohol solution, 100 ml) at a temperature of 50-55 ° C for 10 hours. The ion exchanger is washed, dried and analyzed. The content of P 5.0, N 3.2%, SOY 0.1 n. NaOH solution 1.9 mEq / g; SOY 0.1 n. HC1 solution of 1.5 mEq / g. Polyampholyte has the following values a, defined in the conditions of example 1: I G +, Fe3 + / gu3 + 8; . ° 2 380; ,, 04, „a,„ iog / pg3 + 50 (with Cr according to UO2 2700). Example 3. 50 g of a styrene copolymer containing 2% divinylbenzene were incubated for 30 minutes to swell in a mixture of monochlorodimethyl ether (200 ml) and phosphorus trichloride (225 ml), a mixture containing 3.5 ml of anhydrous tin tetrachloride and 20 ml of phosphorus trichloride, heat the reaction mixture to 55-60 ° C and incubated for 3 hours. Next, a mixture containing 5.5 ml of anhydrous tin tetrachloride and 30 ml of phosphorus trichloride is added and kept at the indicated temperature for 3-4 hours. Next, the product is treated as indicated in the example 2. The content of P is 1.0%, N 3.0%; The OH-form of the OH-form of the C1-ion (determined for 1N NaCl solution) is 1.5 mg-eq / g. After holding the OH form of the ion exchanger for 50 hours at 100 ° C, the EOE of the C1 ion does not change. Example 4. 20 g of the copolymer specified in example 1, chloromethylated and phosphorylated, as indicated in example 1, using as catalyst anhydrous zinc chloride in the amount of 17.1 g. Next, the product is hydrolyzed, washed, dried and aminated with diethanolamine (100 ml) at a temperature of 70-75 ° C for 6 hours. Next, the ion exchanger is processed as indicated in Example 1. The content of P is 4.7%, N 2.6%, and SOY at 0.1 g. a NaOH solution of 3.0 mEq / g; SOY 0.1 n. HCl solution 1.2 mEq / g. Polyampholyte has the following values for a pair of cations: Fe3 + / Eu + 27; 26; UO | + / Eu3 + 720 (for Kr and U02 + 38000). The method of obtaining ion exchangers by chloromethylation and phosphorylation of styrene and divinylbenzene copolymers with a mixture of chloromethylation reagent and phosphorus trichloride in the presence of catalysts selected from the group of anhydrous tin tetrachloride, anhydrous zinc chloride, and with the aim of aiming to increase the concentration of anhydrous zinc chloride and anhydrous zinc chloride. cations of polyvalent metals and obtaining highly basic ion exchangers with increased heat resistance in the OH form, chloromethylation and phosphorus ation is carried out until the content of OH groups chloromethyl-0,9 on the aromatic nucleus, using said catalysts in an amount of 0,7-0,2 mole per osnovomol of the copolymer, respectively, and phosphorus obtained after hydrolysis are subjected to cation exchanger amination.