DD203556A1 - PROCESS FOR THE NETWORKING OF STYRENE DIVINYLBENZEN COPOLYMERISATES - Google Patents

Abstract

The invention relates to a process for the post-crosslinking of slightly crosslinked styrene-divinylbenzene copolymers, optionally containing small amounts of other monomers in the presence of Friedel-Crafts catalysts by means of dihaloalkanes having a number of carbon atoms v. 1 to 18. The reaction is carried out in a suspending agent containing preferably aliphatic and / or aromatic nitro compounds. such as nitromethane, nitropropane, nitrobenzene with metal halides as Friedel-Crafts catalysts, vorzugsw. Aluminum trichloride, carried out at temperatures between 50 degrees C and 1770 degrees C within 10 minutes and 18 hours. The products obtained show a significantly lower swelling capacity corresponding to crosslinked styrene-divinylbenzene copolymers having a divinylbenzene content of up to about 50% and are suitable as starting materials for the synthesis of ion exchangers and non-soluble carriers for peptide syntheses, catalysis resins, polymer reagents and the like.

Description

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VEB CHMiIEKOMBI] JAT BITTERI ¹ EID Bitterfeld, 2. 2. 1982

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Process for the cross-linking of styrene-divinylbenzene copolymers

Field of application of the invention

The invention relates to a process for the crosslinking of styrene-divinylbenzene copolymers with low content of divinylbenzene, wherein the products obtained can be used as starting materials for the synthesis of ion exchangers and insoluble supports for peptide syntheses, catalysis resins, polymer reagents and the like. Furthermore, they can, equipped with certain properties, as Adsorberpolymere, chromatography resins u. a. m. be used.

Characteristic of the known technical solutions

The starting materials for the synthesis of ion exchangers, polymeric supports, adsorber, chromatography resins and the like must be insoluble, since only in combination with the insolubility and the resulting properties products with good performance parameters can be produced. In the art one reaches its insolubility by

-aFEä1982 * 988887

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Copolymerization of a monomer with a translator. In most cases, styrene is used as well as divinylbenzene as a crosslinker. The quantity of incorporated DivinyTbenzens determined decisively leave the structure and the swelling capacity of the copolymers as well as the Io produced therefrom Igeprodukte. The more crosslinker is used, the lower is the swellability, expressed usually as a swelling degree, which represents the recorded amount of Grammege a swelling agent per gram of dry polymer. Depending on the application, the monomer mixture of styrene and divinylbenzene to be copolymerized must contain, for example, 1 to 8% by weight of the Yernetzer (swelling in oil 3.0 to 0.6 g / g) in the case of ion exchange precursors, but also 20 to 50 S and even more in the case of adsorbent polymers, chromatography resins and similar products corresponding to swelling in toluene of 0.5 to 0.2 g / g. Sin crucial disadvantage of crosslinking by copolymerization with divinylbenzene is seen in the high price of this monomer. Furthermore, styrene-divinylbenzene copolymers have structural inhomogeneities due to the different reactivities of the monomers and the production conditions used, which may be disadvantageous in the products produced by polymer-analogous reactions.

These facts have led to numerous attempts to eliminate or mitigate the above-mentioned disadvantages. Two directions of operation can be discerned, one starting from uncrosslinked polystyrene and the other used as starting material with very little divinylbenzene, about 0.1 to about 1.2% by weight, of crosslinked styrene-divinylbenzene copolymers.

When crosslinking uncrosslinked, soluble beaded polystyrene, two different variants can be carried out. Once a pure networking is described and the

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other networking with simultaneous introduction of certain functional groups. The cross-linking of foam polystyrenes with simultaneous sulfonation is described in DK-PS "126 741 and DD-PS 126 738. Similar processes describe the crosslinking of polystyrene with halogen-sulfur compounds or formaldehyde or formaldehyde-emitting substances with simultaneous sulfonation, eg , DE-AS 1 079 326 and DE-AS 1 025 145. Another method describes crosslinking with simultaneous chloromethylation and subsequent crosslinking by heat treatment (E. Hauptmann, Dissertation, Martin-Luther-Universität Halle, 1967). Other crosslinking processes with similar objectives are described in DE-AS 1 495 851, 1 495 792, 1 495 768 and DD-PS 149 673 and DD-PS 149 672 ·

One aspect of all these processes, which use monochlorodimethyl ethers formed directly or as intermediates, is the dangerousness of this substance, which is also harmful to health and, when working with it, the technical equipment is damaged by increased corrosion These methods have the advantage that one fixes themselves by inevitably accompanying chemical modification on a certain class of polyproducts. It is therefore more advantageous to achieve only one crosslinking, since then the usability of the crosslinked polymers is universal. Such a process is described in DD-PS 57 703. It is characterized in that polymers of styrene or styrene derivatives with aliphatic or aromatic disulfochlorides or carbonic acid dichloride are reacted under Priedel-Crafts conditions. The difficulties and disadvantages of this process are the availability and manageability of the materials used, especially in a technical realization.

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In DE-OS 2,206,946 a process for the crosslinking of polystyrene is described, which is characterized in that a part of the aromatic nuclei in the polystyrene is reacted with MonochIordimethylether and then followed by EehydroChlorierung «To maintain the bead shape of the polystyrene is proposed that However, care must be taken that the initial concentration of monochlorodimethyl ether in the seawater mixture is kept at or above 10 l, so that agglomeration of the polystyrene beads is otherwise undesirable Tin Catalyst Used Tin tetrachloride has only a limited influence on the crosslinking by this process and provides products with in some cases still considerable Eestchlorgehalten.

Further possibilities for the preparation of the desired crosslinked polystyrenes are the post-crosslinking of thinly crosslinked styrene-divinylbenzene copolymers. A proposal for this is disclosed, for example, in DE-AS 2 04 5 096, in DD-PS 85 644 and in Juffis, chim , 4JL (1974) 8'1964 - 1967 described on the brook networking of polystyrene with. Compounds of the general formula

ClCH ₂ -

with η = 1, 2 or 3. The most significant disadvantage of this process is the high consumption of crosslinking agent in order to obtain low degrees of swelling or the impossibility of producing substances with very low swelling capacity (J. fiz., chim. 1974) 12, p. 2964 - 2967), as is desirable for many fields of application «

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Sine further Iosting is offered in DD-PS 125 824. It consists in the cross-linking of styrene-divinylbenzene copolymers with xylylene dichloride "with the addition of the cross-linker in a manner which ensures its more complete use." B, in portions or by swelling with little swelling agent. The fraction of this invention is in the portfolio of porosities (or continuous) addition of the xylylene dichloride, that swelling levels of at least 0.7 to 0.8 g toluene / g substance are achieved, although high molar proportions of crosslinking agents are used, namely 50 mol .- $, Another JJachteil said Yerfahrens is in However, because of the limited solubility of the xylylene dichloride in suitable organics, only relatively small amounts of crosslinker can be used, namely, only about 30% of the polymer, and thereby swelling degrees of no less can be achieved as 0.9 g / g .

Also known is a process for Machvernetzung of styrene-divinylbenzene copolymers with monochlorodimethyl ether (Applied Macromolecular Chemistry 29- (1978), S 179), in which the IJachvernetzung is carried out in two stages. The entire amount of monochlorodimethyl ether is swollen and reacted at tree temperature into the polymer in the presence of an equimolar amount of SnCl 2 relative to the polymer. Later, it is once again 1/10 and again an equimolar amount of catalyst to be each time at temperatures of about 5 to 10 Co ⁰ The entire Eeaktionsdauer this first Umsetzungssimfe, -. Wherein in the wesentliehen chloromethylation of the polymer is going on, takes et v / a 16 hours, in the second stage, the chlorinated copolymer is reacted at high temperature for a further 10 hours *

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Disadvantages of the process are the necessary long reaction times, working at low temperatures, which requires suitable equipment on an industrial scale, and the complicated operation. However, the decisive disadvantage of this process is that it is unsuitable for supplying substances with very low swelling degrees , Starting from a styrenic copolymer crosslinked with 0.3 % divinylbenzene, this method yields swelling degrees of about 1.8 ml toluene at both 30 $ and at 50 or 100 % molar crosslinker amount , based on the copolymer! Sat. Substance unsuitable for a variety of applications

Also known is a process from DD-PS 150 218, which, starting from weakly crosslinked styrene-divinylbenzene copolymers, by reaction with monochlorodimethyl ether leads to products having a relatively low degree of swelling ,, when high molar amounts of mono-iodo-dimethyl ether, based on the polymer, For example, when 50 Mo.sub.1-.4 or .gtoreq.10.sup.-1-monochlorodimethyl ether are used, the degree of swelling in toluene is about 0.95 g / g or about 0.50 g / g.

laughlichi1 this method is on the one hand the still relatively high cost of crosslinkers to achieve low swelling and on the other hand that the method is not suitable to produce eztrem low swelling products. Another significant disadvantage vrarde already mentioned elsewhere and consists in the use of the harmful substances and harmful substances Monoehlordimethylether.

Z iel the invention

The aim of the invention is to provide a process for the laclivernetzung of weakly crosslinked styrene-divinylbenzeii copolymers ^ may also contain small amounts of other monomers,

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to develop, which allows the production of polymers with targeted and, if desired, extremely low degree of swelling, which is for many uses of particular advantage. Another object of the invention is the development of a process for the preparation of products having the said properties using technologically easy-to-handle substances that are said to be harmful to health ·

Explanation , the essence of the invention

The object of the invention is therefore to produce crosslinked polymers with desired and, if necessary, very low degree of swelling using only little harmful to health and easy to handle substances »

The essence of the invention is that styrene-divinylbenzene copolymers, optionally containing minor amounts of other monomers, containing from 0.1 to 1.2 percent by weight of divinylbenzene or with degrees of swelling of 10 to 2.5 g / g of a suitable suspending agent and in the presence of a Friedel-Crafts catalyst with dihaloalkanes or mixtures thereof at elevated temperatures.

As suspending agent, various substances such as, for example, dimethylformamide, triethylamine, nitrobenzene, ITitromethan, liitropropan, Methylethylketon.und others, their mixtures: with each other, but also mixtures with other chemically inert substances such as, for example, "B # aliphatic hydrocarbons and similar use. The crosslinkers used are dihalogenated aliphatics, such as, for example, methylene chloride, chlorobromoethane, diiodomethane, dibromoethane, dichloroethane, chlorobromoethane, dichloropropane, dichlorobutane, dibromobutane, higher dihaloaliphatic compounds, and mixtures thereof. Such crosslinkers can be successful

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Such a procedure is in some cases particularly economical owing to the low prices of some dihaloalkanes, such as, for example, dichloroethane. In all these cases, other solvents or swelling agents are required to be used only in small quantities ·

Purely the implementation of the method according to the invention Friedel-Crafts catalysts or mixtures thereof are used, for example, be called sitanetetrachloride, iron trichloride, aluminum chloride, tin tetrachloride. These catalysts are dissolved in a suitable solvent, selected from the organic substances mentioned above, and used for the reaction. Their molar amount may be from 1.5: 1 to 1:10, based on the polymer.

The process is simple and the order of addition of the individual components is not critical to the success of the reaction. Thus, it is possible, for example, first to dissolve the catalyst, then to add the crosslinker and then to enter the polymer Bs but it is also possible to mix the polymer, the crosslinker and the solvent, then add the catalyst and carry out the reaction. The reaction is carried out at temperatures between 50 ⁰ G and 170 ⁰ G, preferably between 60 ⁰ C and 115 ⁰ C, in a period of 10 minutes to 18 hours. However, in almost all cases the reaction is essentially complete after half an hour to eight hours.

The copolymers obtained contain only small amounts of halogen and are well suited for a whole range of applications.

The inventive method is distinguished over known methods by a number of advantages

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On the one hand, the use of dihaloalkanes for the crosslinking of said styrene copolymers leads to the saving of the expensive crosslinking agent divinylbenzene and, on the other hand, eliminates the disadvantages for the quality of the polymer which arise from the different copolymerization behavior of the divinylbenzene with respect to styrene. It can be used as starting materials for the process also copolymers of styrene with divinylbenzene containing small amounts of other monomers. Also in comparison to other (often) used crosslinkers such. B. xylylene dichloride or higher Halogenmethylaromaten represent the dihaloalkanes cheaper raw materials, especially when used according to the invention, for example, as a crosslinking agent and concurrent suspending agent · The method has advantages over the use of the very health and apparate damaging substance monochlorodimethyl ether, if this substance used as a crosslinking agent becomes"

The possibility of using dihaloalkanes with different numbers of methylene groups in the molecule extends the scope of the process in terms of a modification of the structural properties of the end products »

However, a particular advantage of the process according to the invention is on the one hand the degree of swelling controllable by variation of the synthesis conditions and on the other hand the possibility of producing products with extremely low swelling power, as is desirable for a number of applications. Products with swelling degrees below 0.5 g / g to 0.25 g / g, as can be obtained by the process according to the invention, can not be produced at all by the crosslinking processes already described. By copolymerization with large amounts of the expensive divinylbenzene, it is possible to obtain degrees of swelling of this order of magnitude which are in the range of up to 50 % of divinylbenzene in the reaction mixture and above.

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The products obtained by the process according to the invention have only low levels of halogen substitution, which therefore do not adversely affect subsequent products which are released therefrom *

The invention will be explained with reference to examples.

Implementation Ie Example 1;

In a flask, 0.1 mol AlC 1- dissolved in 100 ml Uitromethan, 100 ml of dibromoethane and 10.4 g of styrene-divinylbenzene copolymer with a degree of swelling in sols of 8.14 g / g was added. Bas mixture is stirred for 15 minutes at room temperature, heated to 60 ⁰ C and then stirred for a further 5 hours. The crosslinked product is then filtered off, washed with a mixture of equal volumes of acetone and 5% hydrochloric acid and then with pure acetone until free of chloride. The postcrosslinked copolymer is subsequently dried and analyzed. It shows a degree of swelling in toluene of 2.88 g / s and a halogen substitution degree of only 0.07 $.

Example 2:

In a flask are added 0.1 mol of AlCl 2 dissolved in 100 ml of co-robenzene, 100 ml of diiodomethane and 10.4 g of styrene-divinylbenzene copolymer with a degree of swelling in toluene of 8.14 g / g. The mixture is stirred for 15 minutes at room temperature, heated to 95 ⁰ C and then stirred for a further 8 hours. The product is worked up as described in Example 1. It shows a swelling degree in toluene of 1.90 g / g and a halogen substitution degree of only 0.04.

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Example 3:

In a flask, 0.1 mol of AlCl 2 in 100 ml of Hitrobenzo1 dissolved, 100 ml of chlorobromoethane and 10.4 g of a porous styrene-divinylbenzene copolymer with a degree of swelling in ToIuen of 2.32 s / s was added · The mixture is 15 minutes stirred at room temperature, heated to 74 ⁰ C and then stirred for a further 4 hours »The product is worked up as described in Example 1 · It shows a degree of swelling in ToIuen of 1.50 g / g and a halogen degree of only 0.06« ♦ &

Example 4:

In a flask, 0.1 mol of AlCl 2 dissolved in 100 ml of mtromethane, 200 ml of dibromoethane and 10.4 g of styrene-divinylbenzene copolymer with a degree of swelling in toluene of 9.25 g / g are added. The mixture is added via Sacht Left room temperature, heated to 140 ⁰ C and then stirred for 5 hours at this temperature · The product is worked up as described in Example 1 · It shows a degree of swelling in toluene of 0.36 g / g and a halogen degree of only 0.08 %.

/ Example 5:

In a flask, 0.2 moles of PeCl 2 are dissolved in 200 ml of stitrobenzene, 200 ml of dichloroethane and 20.8 g of styrene-divinylbenzene copolymer having a degree of swelling in toluene of 9.25 g / g added. The mixture is allowed to stand at room temperature for 15 minutes stirred, heated to 95 ⁰ C and then stirred for a further 12 hours. The product is worked up as described in Example 1. It shows a degree of swelling in toluene of 2.52 g / g and a halogen substitution degree of only 0.04 % »

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Example 6:

In a flask, 0.1 mol of AlC 1 dissolved in 60 ml Hitrob'enzen and 80 ml of a mixture of aliphatisolier hydrocarbons having a boiling range of about 180 to about 220 C, 16 ml of dichloroethane and 10.4 g of styrene-divinylbenzene copolymer with a degree of swelling in toluene of 8.14 g / g added "The mixture is stirred for 15 minutes at Saumtemperatur, heated to 90 ⁰ C and then stirred for a further 3'0 minutes" The product is prepared as described in example 1, worked up. It shows a degree of swelling in toluene of 4-22 g / g and a halogen substitution degree of only 0.07 $.

Example 7:

Example 6 is repeated, with the Eealctionstemperatur 18 hours, maintained from 90 ⁰ C · The product exhibits a degree of swelling in toluene of 1.52 g / g and is halogen-free ·

Example 8:

In a flask, 0.05 mol of AlCl ₃ 'and 0.05 mol of PeCl _{3 are dissolved} in 50 ml of nitrobenzene, 50 ml of dichloroethane and 10.4 g of styrene-divinylbenzene copolymer with a degree of swelling in toluene of 8.14 g / g added The mixture is stirred for 15 minutes at room temperature, heated to 95 ⁰ C and then stirred for a further 3 hours. The product is worked up as described in Example 1 ". It shows a degree of swelling in toluene of 2.40 g / g and a degree of halogen substitution of only 0.01 %.

Example 9:

In a flask, 0.5 mol of AlCl _{3 are dissolved} in 500 ml of litrobenzene, added to 5OO ml of dichloroethane and 52 g of styrene-divinylbenzene copolymer with a degree of swelling in toluene of 8.14 g / g. The mixture is kept at room temperature for 15 minutes

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stirred, heated to 110 ^° C. and then stirred for a further 6 hours. The product is worked up as described in Example 1. It shows a degree of swelling in toluene of 0.22 g / g and a halogen substitution path of 0.09 %,

Example .10 ";

In a flask, 0.05 mol of AlClO are dissolved in 200 ml of nitrobenzene, 8 ml of dichloroethane and 20.8 g of a styrene-divinylbenzene-acrylonitrile copolymer containing 2 % of acrylonitrile, with a degree of swelling in toluene of 8.67 g / g added. The mixture is stirred for 15 minutes at Saumtemperatur, heated to 90 ⁰ C and then stirred for another 30 minutes · The product is prepared as described in Example 1, worked up. It shows a degree of swelling in toluene of 1.64 ß / g and is halogen-free ·

Example 11;

In a flask, 0.02 mol of AlCl 2 are dissolved in 100 ml of nitrobenzene, 200 ml of chlorobromoethane and 10.4 g of a porous styrene-divinylbenzene copolymer having a degree of swelling in toluene of 2.32 g / g are added. The mixture is allowed to stand over room temperature at room temperature, heated to 75 ⁰ C and then stirred for 8 hours at this temperature. Das.Produkt, as described in Example 1, worked up. It shows a swelling degree in toluene of 1.50 g / g and a halogen substitution degree of only 0.08 fS »

Claims (8)

237248 7 - 14 - 2216 Invention claim 1 · A process for the crosslinking of styrene-divinylbenzene copolymers in the presence of Friedel-Crafts catalysts, characterized in that weakly crosslinked styrene-divinylbenzene copolymers having a proportion of divinyl benzene of between 0.1 and 1.2% by weight or with relatively high swelling levels, optionally containing small amounts of other Honomer'er, in the presence of! Friedel-Crafts catalysts or mixtures thereof by Lihalogenalkane with a. Number of carbon atoms from 1 to 18 or mixtures thereof at temperatures between 50 and 170 ⁰ C, preferably between 60 and 115 C, be crosslinked in a period of 10 minutes to 18 hours in a suitable suspension medium. 2. The method according to item 1, characterized by the use of a Letallhalogenids as Friede1-Crafts catalyst. 3 · Process according to points 1 and 2, characterized by the use of particular aluminum trichloride as FriedeI-Crafts catalyst. 237 2 48 7 - 15 - 2216 4 * Method according to item 1, characterized by the use of suspending agents containing aliphatic and / or aromatic Fitroverbindungen. 5 * Process according to items 1 and 4 »characterized by the use of bitromethane and / or epitrobenzene in suspension medium 1 6. Method according to items 1, 4 and 5, characterized by the simultaneous use of the halogenalkanes as the main constituent of the suspending agent. 7 «Method according to items 1, 5 and 6, characterized by the use of a mixture of sitromethane, and / or itrobenzene with. Oichlorethane as suspending agent without the addition of further dihaloalkanes » 8 · Method according to points 1 and 5, characterized by the use of a mixture of Hitromethan and / or Ui-crobenzen with aliphatic hydrocarbons as the suspension center 1.