DD158907A1 - METHOD FOR PRODUCING COARSE-COATED ION EXCHANGER RESINS - Google Patents

Abstract

Weakly crosslinked vinylaromatic polymers in aqueous suspension with aromatic monomers, crosslinkers and optionally polymerization-inert materials are subjected to intermesh polymerization. The amount of monomer used can make up 2 to 15 times the amount of carrier. The resulting products can be processed into ion exchangers, resulting in resins with a ball size of about 1.0 to 4.0 mm, which are particularly well used for adsorption purposes, as well as in the form of ion exchangers, in particular gas adsorption, catalytic purposes and hydrometallurgy can.

Description

Process for the preparation of coarse-grained ion exchange resins

The invention relates to a process for the preparation of ion exchange resins which can be used in particular for gas adsorption, for catalytic purposes and in hydrometallurgy.

Characteristic of the known technical solutions

Ion exchange materials are increasingly used to solve environmental problems, on the one hand, and for the extraction and separation of gaseous raw materials, for example, in the sorption of sulfur dioxide, sulfur trioxide, hydrogen chloride, nitrogen oxides, hydrogen sulfide, mercaptans, ammonia,

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Carbon dioxide, acetic acid fumes, hydrogen fluoride, have already been tested in the purification of acetylene, natural gas and the like on a laboratory scale. However, large-scale gas adsorption has not been able to prevail, especially because high flow resistances occur in the adsorption, such. B. Glowiak and Gostomczvk in the journal Staub-Reinhalt. Air, 3and 21 (1973) ,. Pp. 29-32.

This circumstance can be circumvented by using large particles with ion-exchanging properties. For this purpose, so-called ion exchange molded articles were produced, which consist of fine ion exchange granules with a diameter usually below 0.1 mm, which are embedded in an inert material. As Einoettungsmittel Oiefinpolymere are often used, such as. B. in DE-PS 1 285 170, 2 237 953 and 2 343 417 and DD-PS 114 350 is described. However, an important factor of these resins is the low useful capacity of the ion-exchangeable groups, or in other words, the capacity loss caused by the inert plastic.

Gas adsorption could more advantageously be achieved by using large spherical ion exchangers with properties close to the commercially available aromatics-based resin ion exchangers. To achieve more favorable flow resistances, the resin beads should have diameters of at least 1.0 to about 4 mm maximum.

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According to the known suspension process for aromatic vinyl monomers, which lead to starting materials for the ion exchange synthesis, ie usually of styrene-divinylbenzene copolymers, the production of beads in the sizes mentioned so far is not known from a polymerization point of view. The methods proposed in DD-PS 60 888, 66 509 and 71 620, based on the intermesh polymerization, although relate to the certain Brhö'hung the bead diameter by one or more times introduction and polymerization of styrene in unterkörnige, so very small polymer beads, however, are not geared to obtaining patterns of 1.0 to 4.0 mm in diameter in high yield. In this case, an enlargement of the polymer beads by the factor 1.2 to 1.5 is proposed, with prepolymer being treated with a small amount of monomers, which amounts to at most 200 % . This upper limit should not be exceeded, since bad products with rough surface arise, which are not well suited for further processing to ion exchangers. The intermesh polymerization processes described in these patents do not produce the desired result, dissecting spheres with diameters of from about 1.0 to about 4.0, and also in good quality.

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Object of the invention

The aim of the present invention was therefore to develop a process for the preparation of spherical ion exchange beads with a diameter of 1.0 4.0 mm by suitable intermesh polymerization of aromatic polymers with vinyl aromatics and subsequent conversion into ion-exchangeable body. Among other things, the resulting large ion exchange spheres should be well suited for gas adsorption.

Explanation of the essence of the invention

The object of the invention is the development of a method according to which it is possible to produce polymer beads with a diameter of 1.0 to 4.0 mm in high yield with the least possible effort, which are well suited for further reactions to ion exchangers for gas adsorption ,

The essence of the invention is that it vinylaromatic monomers, for. As styrene, with small amounts of crosslinkers, z. B. divinylbenzene copolymerized and the Kopolymerisat modified by a large amount of modification phase by intermesh polymerization, said modification phase contrary to DD-PS 60 888, 66 509 and 71 620 is not limited to 200 %, based on the starting polymer, but in On the contrary, modification amounts of about at least 200 % and about 1500 % maximum are used and worked up the resulting products in a suitable manner to ion exchangers, the products have flawless surface quality and are well suited for the applications mentioned.

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To obtain the polymers for the subsequent intermesh polymerization, the crosslinking component, z. B. the divinylbenzene or else z. B. trivinylbenzene, glycol diacrylates or the like, as well as mixtures of several crosslinkers in amounts of about 0.05 to 0.60 weight percent compared to the vinyl aromatic, z. As styrene used. The copolymerization is carried out in the presence of an initiator and stabilizer in aqueous phase with stirring and heat. In this case, copolymers having a particle size and particle size distribution, as could be used for conventional workup to synthetic resin ion exchangers, are obtained.

These polymers are then treated with other monomers, crosslinkers, initiator and polymerization-inert materials such. As toluene or z. B. aliphatic hydrocarbon fractions preferably having a boiling range of 180 to 220 ^U G suspended in the aqueous phase and polymerized with constant stirring to virtually complete conversion by heat. Aliphatic hydrocarbons are particularly suitable in the process according to the invention and substances or mixtures of this class of substances with boiling points between 60 and more than 250 ° C. can be used successfully. It is quite possible to connect the intermesh polymerization immediately after the preparation of the starting polymers in the same polymerization without isolation of the copolymers, resulting in the economic design of the process.

The mixture of monomers, crosslinker, initiator and inert substance used for the intermesh polymerization can be several times the weight in weight

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Make up spent copolymer. According to the invention it is possible to interme- diate 100 g of polystyrene crosslinked with 0.3 g of divinylbenzene by, for example, 700 to 1200 g of the above mixture, it being possible to obtain polymers having suitable grain size and good surface properties. The amount of crosslinker can vary within the wide limits between 0.5 and 50 % compared to the vinyl monomer, preferably between 3.0 and 25%. This amount influences the properties of the final product and is varied and optimized according to the intended use.

As stabilizers are small amounts of the commonly used stabilizing substances, such as. As polyvinyl alcohol, methoxycellulose, proteins, calcium phosphate, magnesium hydroxide u.a. used. They are used in very small quantities. The addition of surface-active substances has a favorable effect on the stirrability of the suspension and can be added at the beginning or during the polymerization process. As initiators suitable radical-forming substances are used, for. B. azobisisobutyronitrile in an amount of about 0.05 to 1.5%, based on the monomer engemisch.

The phase ratio of water to oil should be about 1.5 to 1 to 4 to 1. The aqueous phase containing the polymer to be intermeshed is introduced. Is added, if appropriate, stabilizer and slowly with stirring Ö! Phase, after which the Intermeshpolymerisation initiated by heat and is conducted at temperatures between 70 and 100 ^U C until practically complete conversion. Thereafter, the polymer is isolated, washed and freed from the inert medium by extraction or 7 / steam distillation.

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The intermesh polymerization can also be carried out in several stages. File can be added several times oil phase and polymerize the mixture.

The resulting polymers can be worked up by known methods to ion exchangers and used for gas adsorption, for catalytic purposes or in hydrometallurgy. The advantages of the process according to the invention are the possibility of producing spherical polymers having a particle size substantially between 1.0 and 4.0 mm, which are well suited for the recovery of ion exchangers for gas adsorption, for catalytic purposes and for hydrometallurgy. The process is easy to do. The mechanical and osinotic stability of the polymers prepared by the process according to the invention are so good that, despite the large polymer dimensions, the conversion into ion exchangers proceeds without problems according to customary methods. As a result of the good polymer properties, ion exchangers with suitable capacity indices are obtained.

Exemplary embodiments Example 1

First, a low-crosslinked base polymer is prepared in the following manner. In a plane ground cup 720 ml V / asser be submitted and related thereto 0.125 % Tylose MH 1000 as a stabilizer,

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and 0.125 % cuprous chloride. The oil phase is added dropwise while stirring, "consisting of 395.2 g of styrene, 4 g of azobisisobutyronitrile and 0.8 g of 50% technical DivinyllDenzol (0.1 % divinylbenzene as a pure component, based on the total amount of the oil phase) is heated to 72 ⁰ C and maintained this temperature for 4 hours; then increased to 90 ° to 95 ⁰ G and 4 hours "stirred at this temperature * The polymer is then filtered off, washed, dried and the sieve fraction of 0.8 to 1.6 mm separated, for further processing by the inventive method is used. 650 g of water and 2 ml of a 1.000 density solution of mersolate are initially introduced. In it are stirred 30 g of the polymer obtained above. Then, the oil phase is added dropwise within one hour, consisting of 174 g of styrene, 24 g of 40% Divinylbenzol, 123 g of an aliphatic Kohlanwässerstoff fraction having a boiling range of 180 to about 220 ⁰ C and 0.4 g Äzobisisobutyronitril. The temperature is raised to 60 C, this is maintained for half an hour, added to 50 ml of a 2% Tylose solution and then polymerized for 4 hours at 75 ⁰ C and a further 2 hours at 95 ° C. The product is filtered, washed, evaporated with steam, dried and subjected to sieving. 145g were obtained with a grain size over 1.5 mm. 100 g of polymer of the sieve size 1.5 to 2.5 mm are chloromethylated with 600 ml Monochlordimethyläther and 10 g FeCl-6 hours at 53 C. The chlorine content was 19.20 SS

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200 g of the Chlormethylates are with 1000 ml of trimethylamine aminated 2 hours at room temperature, 1 hour, "at 20 ⁰ C, 1 hour" at 30 ⁰ C and 4 hours' at 40 ⁰ C. The strongly basic resin obtained has a water content of 57.7 %, a total weight capacity of 4.13 meq / g, a total volume capacity of 1.00 meq / ml and an active capacity of 1.38 meq / g. The total weight and total capacity are determined in the usual way The resin to be tested in the OH form and in the wet state is centrifuged for 1.0 minutes at 1400 to 1600 revolutions per minute, exactly 5 g of the spun resin are transferred to a filter tube and mixed with 200 ml of a 0 The eluate is collected in a 1 lb. aj3 flask and washed with water, making up to the mark, 100 ml of this solution are added with 0.1 η UaOH titrated against methyl orange. The active capacity is calculated according to

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and is obtained in milles per gram of wet resin. The value of 1.38 obtained in this way is very high and at the same time indicates the outstanding properties of the ion exchanger for gas adsorption.

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Example 2

This example is intended to demonstrate the possibility of varying the method in terms of ball size, 65Og of water and 30 g of slightly cross-linked polymer prepared as described in Example 1. With stirring, 100 ml of a 2 % polyvinyl alcohol solution are added followed by the oil phase of 236 g of styrene, 14 g of 50 % ± divinylbenzene, 70 g of an aliphatic hydrocarbon fraction having a boiling range of about 180 to about 220 C and 0.35 g of azobisisobutyronitrile. It is polymerized for half an hour at 60 ⁰ C, 4 hours at 70 ⁰ C and finally 2 hours at 90 ⁰ C. The product is filtered, washed, steamed, dried and sieved. It contains 1 % balls under 1.6 mm in diameter, 10 % with 1.6 to 2.5 mm and 89 % balls with a diameter over 2.5 mm.

Example 3

This example is intended to demonstrate the variation of the process with respect to high levels of crosslinker used, but concurrently with appropriate ball size and active capacity. 650 g of water and 30 g of weakly crosslinked polymer prepared as described in Example 1 are initially introduced. It is 1 drop of Mersolat added, then the oil phase of 250 g of styrene / divinylbenzene mixture containing 15 weight percent of the crosslinker, 120 g of an aliphatic hydrocarbon fraction having a boiling range of about 180 to about 220 ⁰ G and 0.35 g azobisisobutyronitrile within

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One hour with stirring added dropwise. It is polymerized for half an hour at 60 ⁰ C, 4 hours at 72 ⁰ C and finally for 3 hours at 95 ⁰ C. Das'Produkt is filtered, washed, steamed with steam, dried and sieved. The product contains

7.5 % balls less than 1.6 mm in diameter, 50 % with

1.6 to 2.5 mm and 42.5 % balls with a diameter over 2.5 mm.

85 g polymer of the sieve fraction greater than 2.5 mm are chloromethylated with 600 ml monochlorodimethyl ether and 10 g PeCl for 6 hours at 55 ° C. The chlorine content was 15.23 %.

145 g of the chloromethylate are reacted with 700 ml of trimethylamine for 2 hours at 13 ° G, 1 hour at 20 ⁰ C, 1 hour at 30 ⁰ C, 4 hours at 40 ⁰ C and a further 4 hours at room temperature. The strong base resin obtained has an active capacity, determined vd.e described in Example 1, of 1.08. This value indicates suitability for ion exchange processes in gas adsorption, for catalytic purposes and in hydrometallurgy.

Example 4

This example shows the implementation of the process according to the invention by repeated intermesh polymerization.

650 g of water and 30 g of weakly crosslinked polymer prepared as described in Example 1 are initially introduced. 100 ml of a 2% polyvinyl alcohol solution are added followed by 90 g of styrene / divinylbenzene mixture (0.1 % of divinylbenzene, 1 % of azobisisobutyronitrile). It is polymerized for 3 hours

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at 70 ⁰ C and 3 hours at 90 ⁰ C is cooled to 60 ⁰ C, 100 ml of a 2% Polyvinylalkohollö'sung added and added dropwise a mixture of 92 g of an aliphatic hydrocarbon fraction having a boiling range of about 180 to about 220 ⁰ C and 270 g of styrene containing 3 % divinylbenzene and 1 % azobisisobutyronitrile to. Polymerization is again 3 hours at 70 ⁰ C and 3 hours at 90 ⁰ C is cooled again to 60 ⁰ C and a styrene-divinylbenzene mixture is added dropwise (3 % divinylbenzene, 1 % azobisisobutyronitrile) in an amount of 120 g. It is polymerized for 3 hours at 70 ⁰ C and at 90 ⁰ G. The product is filtered, washed, steamed with steam, dried and sieved. It contains 25% balls with a diameter between 1.0 and 1.6 mm, 24 % with 1.6 to 2.5 mm and 51 % balls with a diameter over 2.5 mm.

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Claims (5)

-13-229696 4 2114 invention claim 1 »Process for the preparation of ion exchange resins having a ball size substantially between 1.0 and 4.0 mm in diameter, characterized by suspension copolymerization of vinylaromatics with 0.05 to 0.60 % Vernetzem and subsequent one or more intermethod polymerization of these copolymers in an aqueous medium at a phase ratio of water to oil of 1.5 ' 1 to 4: 1 with an oil phase consisting of vinyl aromatics, Vernetzem in an amount between 0.5 and 50%, suitable radical-forming initiators, optionally suspension stabilizers, optionally polymerization-inert materials, in a Amount of the oil phase of at least 2, Ifachen up to 15 times the weight, based on the starting polymer, polymerization for several hours at temperatures between 55 and 105 ⁰ C, isolation of the polymer, removal of initiators, stabilizers and polymerization-inert materials and optionally soluble polymers to obtain beaded P Ballistic polymers substantially between 1.0 and 4.0 mm in diameter and connected -229695 4 de transfer of the resins in ion exchangers according to known methods. 2. The method according to item!, Characterized by the use of styrene as a vinyl aromatic and divinylbenzene as a crosslinking agent both in the preparation of the weakly crosslinked starting copolymer, as well as in Intemneshgemisch. 3. The method according to item 1, characterized by the use of 1.0 to 25 % crosslinker in Intermeshgemisch, based on the vinyl aromatic. 4. The method according to item 1, characterized by the use of conventional solvents based on aromatics and / or aliphatic solvents and mixtures thereof as Polymerisationsinarte substances » 5. The method according to item 1 and 4, characterized by the use of a substantially aliphatic hydrocarbon fraction having a boiling range of about 180 to about 220 G as a polymerization-inert material.