DD229992A1 - METHOD FOR PRODUCING MACROPOROUS SULPHONIC ACID GROUP-MAKING POLYMERS - Google Patents

Abstract

The invention relates to a process for the synthesis of macroporous polymers containing sulfonic acid groups for the adsorptive separation of organic substances from aqueous or organic solutions and to the use in organic heterogeneous catalysis. Uncrosslinked or crosslinked vinylaromatic polymers such. B. Homopolymers or copolymers of styrene and / or its homologous derivatives are partially chloromethylated in the first reaction step with Monochlordimethylaether and cross-linked in a second reaction step using sulfuric acid in the presence of swelling Inertmitteln Porositaetsbildung and sulfonated.

Description

A-

VEB Chemiekombinat Bitterfeld, 05.12.1984

Bitterfeld 2623

"Process for the preparation of macroporous sulfonic acid group-containing polymers"

Field of application of the invention

The invention relates to a process for the preparation of macroporous sulfonic acid-containing polymers which are particularly suitable for the adsorptive separation of organic substances from aqueous solutions, the adsorptive separation of organic liquid substances or for heterogeneous organic catalysis. Examples are the removal of phenols from aqueous solutions, the separation of aromatic compounds from hydrocarbon mixtures or the catalysis of alkylation, esterification or etherification reactions.

Characteristic of the known technical solutions

It is known to use macroporous cation exchangers in organic catalysis, as described, for example, for olefin reactions and other organic reactions which are catalyzed by H-ions (DE-AS 1,168,808, DE-AS 1,168,909, GB-PS 952,422; DD-PS 147,664). Furthermore, the separation of aromatic compounds from Kohlenwassers toffgemischen means of macroporous cation exchanger in the salt form, for example in DE-OS

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2,356,519; DE-AS 2,364,306 and DD-PS 147.852 described. The preparation of such cation exchangers is generally carried out by sulfonation of crosslinked, macroparlose vinylaromatic polymers, preferably of styrene-divinylbenzene copolymers, such as z.3. in U.S. Patents 3,147,214 and 3,201,357.

The reaction conditions in these descriptions are generally chosen so that as complete or as high as possible Substitu.tionsg rad and thus the introduction of as many sulfonic acid groups in the polymer matrix is achieved.

In DD-PS 208.622 a process for the preparation of sulfonic acid-containing adsorbents based on crosslinked macroporous vinyl and / or polyvinyl aromatic compounds for the dearomatization of hydrocarbon mixtures is described, which is characterized in that crosslinked macroporous polymers with an intrinsic

ren surface of at least 40 m / g dry substance be partially sulfonated.

The features of the known inventions are that the synthesis take place in several steps and with the use of larger amounts of crosslinker and Ine rjrmittel and are energy-consuming and costly by the individual substeps.

Object of the invention

The object of the present invention, while eliminating the disadvantages of known manufacturing processes, the development of a process for the preparation of macroporous «sulfonsäuregruppenhaltigen polymers in energy and less expensive ways.

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Explanation of the essence of the invention

The object of the invention was to produce such polymers on the basis of technical preliminary and intermediate products in an energy-efficient and cost-effective way. The known and described solutions involve the syntheses in at least two steps, wherein the formation of the macroporous polymer by polymerization in the presence of inert agents and crosslinker (eg divinylbenzene) generally> 10% by weight takes place and in a second step, the sulfonation by known methods is carried out. The three steps are carried out separately, with different inerting agents, reaction times and reaction temperatures.

It has now been found that it is possible to produce sulfonic acid group-containing polymers in a simplified and energy-and cost-effective manner, when uncrosslinked or low-crosslinked vinyl aromatic polymers, such as. Perlpolystyren or copolymers of styrene and divinylbenzene partially chloromethylated in a first reaction step and in a second reaction step by means of sulfuric acid in the presence of swelling Inertmitteln further crosslinking with formation of porosity with simultaneous partial sulfonation.

The processes for preparing the starting polymers are known, and it is also possible to synthesize the polymers in the presence of inert agents. The crosslinking agent needs in the inventive method 5-6 wt -. Not to exceed% in general. Particularly cost-effective is the use of uncrosslinked polystyrene. The polymers are prepared in a customary manner by the suspension polymerization method in a particle size of 0.3 to 1.2 mm. A porous structure of the starting polymers is possible by the addition of precipitants or swelling agents or of linear polymers to the polymerizable phase. The use of mixtures of these classes of compounds is possible. As polymerizable compounds are preferably styrene and / or alkylstyrenes and as crosslinkers

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Divinylbenzene used. Other polyvinyl compounds such as trivinylbenzene, polymethacrylates and similar compounds can also be used.

If the starting polymer to obtain a polar structure, the polymerizable phase preferably acrylic and / or Methacry! Acid derivatives are added.

The methods of chloromethylation of the polymers are also known. Advantageously, the introduction of the chloromethyl groups takes place by means of monochlorodimethyl ether. The sulfonation and post-crosslinking takes place according to the invention by means of sulfuric acid in the concentration range from 94 to 100 %. A particularly advantageous variant of the process according to the invention consists in the use of sulfuric acid as the chloromethylation and postcrosslinking catalyst and as a replenishing agent. In general, it is therefore proceeded so that the sulfuric acid is introduced and the starting polymer is suspended therein. An inert swelling agent, mixed with Monochlordimethyläther, is metered and stirred to adjust the swelling equilibrium one to two hours at room temperature. Halogenated hydrocarbons such as dichloroethane and tetrachloroethane are particularly suitable as inert swelling agent. Others are not excluded. After Einquellphase is at temperatures between 40 - 60 C chloromethylation and brought the Nachvernet-wetting and sulfonation at temperatures> 75 ⁰ C. The temperature control can be designed stepwise or continuously. The reaction times for the postcrosslinking reaction are generally between 4 and 15 h and depend on the temperature, After the reaction, the inert medium can be separated together with the sulfuric acid and is then isolated or it is - and that is the more advantageous way by distillation from the reaction mixture away. This variant is particularly suitable for the use of dichloroethane. The final product properties of crosslinking, inner surface and degree of sulfonation can be determined by the batch conditions such as polymer grade and amount, monochloro

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dimethyl ether amount, Inertmittelart and amount and sulfuric acid concentration and amount control.

A second variant of the process according to the invention consists of dissolving the chloromethyl-containing vinylaromatic polymer, e.g. are prepared based on styrene-divinylbenzene copolymers prepared by any known method in the inert medium, after reaching the equilibrium swelling sulfuric acid is metered and by, a stepwise or continuous heating the post-crosslinking, porosity formation and sulfonation is brought about. Again, a distillative recovery of the inert medium is the cheaper way. The recovery rate of the inert medium is very favorable in both variants. A cycle of the Inertmittels is thus easily possible. To achieve higher levels of sulfonation, a temperature increase to 105 - 110 ° C is appropriate. The hydration of the end products takes place in both variants by known methods.

A further advantage of the process according to the invention is that all processes and reactions proceeding, such as swelling, chloromethylation, postcrosslinking, sulfonation and separation of the inert agent take place in a reaction vessel and partly simultaneously. Furthermore, the use of crosslinking component is much lower than known processes or when using polystyrene is not necessary at all.

The inventive method should be further explained by the following examples.

200 ml of sulfuric acid (96 % × g ) are introduced into a boiling flask equipped with stirrer, thermometer and reflux condenser and 5 ml of FeCl 2 (1050 g / l) are slowly added as catalyst. 52 g of a polystyrene (0.3-1.2 mm) crosslinked with 1 % DVB are stirred in this solution and over a period of about 4 h a mixture of 50 ml monochloro

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dimethyl ether, dosed 250 g of dichloroethane. The mixture is then stirred at 40 ° C for 4 h, at 50, 60 and 70 ° C for 1 h and at 80 C for 4 h. The cooled reaction mixture is filtered off, with 60% and 30% H SO., And with sat. NaCl solution, water and methanol. The final product gives the following analysis values: Total weight capacity strongly acidic: '0.83 meq / g Water content: 44.5 %

Inner surface according to BET: 627.0 m ² / g residual chlorine value: 3.2 %

In a similar vial. From armor, as in Example 1, 1000 ml of sulfuric acid (96 % ± g) are introduced and 20 ml of FeCl solution added slowly. Subsequently, 235 g of polystyrene (0.5 - 0.8 mm) are stirred and a mixture consisting of 800 g of dichloroethane and 55 ml Monochlordimethyläther, dosed over a period of about 5 h. Thereafter, the mixture is stirred for a further hour and dosed again 160 ml Monochlordimethyläther and stirred for another hour. Followed by 4 h at 40 C, 1 h each at 50 and 60 ⁰ C, 6 hours at 70 ° C and 2 h at 80 ° C is stirred. The cooled reaction mixture is separated on the suction filter with 60 % ± ger and 30 ° oiger sulfuric acid and washed with water. The analysis of the final product gave the following characteristics: Total weight capacity strongly acidic: 0.56 meq / g

Water content:. 41.2 %

2 BET inner surface: 694.0 m / g

Residual chlorine: 3.4 %

A reaction flask of the same equipment as in Examples 1 and 2 is charged with 210 g of a polymer having a crosslinker content of 5 % divinylbenzene and an internal surface area of 75 m / g and a mixture of 1000 g of dichloroethane and 160 ml of monochlorodimethyl ether 2 h swollen. Subsequently, 800 ml of

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feisäure (96 % ± g) and 20 ml FeCl solution of the same nature, as in Example 1, dosed and 4 h at 40 C, 1 h at 50, 60, 70 ⁰ C and 8 h at 80 ° C stirred. The cooled reaction mixture is separated again on the suction filter and the end product is washed with 60 % strength, 30 % pure sulfuric acid and water. The final product properties are as follows: Total weight capacity strongly acidic: 0.96 meq / g

Water content: 59.1 %

ρ BET inner surface: 587.0 m / g

Residual chlorine value: 3.2 %

j3eis £ ie_l__4j_

In a reaction flask of the same equipment as in the preceding examples, 52 g of a polymer of the same nature as in Example 3, 2 h with a mixture of 250 g dichloroethane and 40 ml Monochlordimethyläther be swollen. Subsequently, 200 ml of sulfuric acid (90.3 % ± g ) are metered and the reaction at 40 ° C for 4 h, carried out at 50, 60, 70 ° C for 1 h and 80 ° C for 4 h. The dichloroethane is distilled off at 88 ° C for 4 h and the final product with 60%, ZO '% i.ger sulfuric acid and water. It has the following end product properties: Total weight capacity strongly acidic: 0.07 meq / g

Water content: 38,8 %

2 BET inner surface: 516.0 m / g

Residual chlorine value: 2.2 %

Be .is JD ie_l_5j_

In a reaction flask, as in Examples 1-4, 52 g of a polymer (0.3 - 1.2 mm) with a divinylbenzene content of 4.5 % and an inner surface of

62 m / g and swollen with a mixture of 220 g of dichloroethane and 37 ml Monochlordimethyläther 2 h. 300 ml of sulfuric acid (96 %) and 5 ml of FeCl 2 solution of the same type are metered in. Subsequently, 4 h at 40 ⁰ C ,. each 1 h at 50, 60, 70 ° C and 8 h at 80 ° C stirred.

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Subsequently, the dichloroethane is distilled off at a temperature increase of within 4 h to 100 ⁰ C. The workup is carried out as in Example 4. The analysis shows the following result: total weight capacity strongly acid: 1.55 meq / g

Water content: 52.6 %

2 BET inner surface: 455.0 m / g

Residual chlorine value: 0.9 %

77 g of a chloromethylated styrene-divinylbenzene copolymer with 16.4 % chlorine and a crosslinker content of 3.5 % in 190 g dichloroethane are swollen for 2 hours in a mixing flask with stirrer, thermometer and distillation attachment. Subsequently, 300 ml of sulfuric acid (98.5 % ± g) are metered. The reaction is carried out at 85 ° C. for 1 h at 40, 50, 60, 70 and 6 h. The dichloroethane is then distilled off within about 4 hours at a temperature increase to 105 ⁰ C. The product separated on the frit is washed successively with 60 % pure, 30% sulfuric acid, NaCl solution and water. The analysis gives the following results: total weight capacity strongly acidic: 3.81 meq / g water content: 42.7 %

Inner surface according to BET: 5.8 m / g

Residual chlorine value: 2.1 %

B e j. s p_i e_l_J7 j_

In a flask of the same equipment as in Examples 1-5, 210 g of a chloromethylated styrene-divinylbenzene copolymer having a chlorine value of 21.3 %, a crosslinker content of 5 % and an inner surface

2 of 50.3 m / g in 800 g dichloroethane for 2 h. Subsequently, 400 ml of sulfuric acid (94.8 % ± g) and 15 ml FeCl ^ - solution are added at a level of 1050 g / l. The reaction is carried out for 1 h at 40, 50, 60, 6 h at 70 and 2 h at 80 ^° C. The excess dichloroethane and the sulfur

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Acid are filtered off with suction, washed with methanol and water. The analysis provides the following characteristics: Total weight capacity strongly acidic: 1.56 meq / g

Water content: 60.6 %

_ ρ

Inner surface to BEi: 635.0 m / g

Residual chlorine value: 2.1. %

a) In an apparatus as in Example 6, 77 g of a chloromethylated styrene-divinylbenzene copolymers having a chlorine value of 20.8 %, a crosslinker content of 5 % and

2 an inner surface of 52 m / g in 200 g of dichloroethane for 2 h. Thereafter, 300 ml of sulfuric acid (98.5 % ± g) are metered. The reaction is carried out at 40, 50 and 60 C for 1 h and at 70 ° C for 4 h and at 85 ° C for 6 h. The dichloroethane is distilled off within 2 hours at a temperature increase of up to 105 ° C. The product separated on the frit is worked up as in Example 6. The following analytical values were obtained: Total weight capacity strongly acidic: 3.42 meq / g

Water content: 58.8 %

2 Inner surface after 3ET: 413.0 tn / g

Residual chlorine value: '2.6 %

b) - c): For the same test procedure, but with an initial sediment value of 18.0 and 14.1 % , the following results are obtained:

Initial chlorine value of the polymer (%) :

Total weight capacity strongly acidic (mval / g)

Water content (%):

_ 2 Inner surface after BEi (m / g):

Residual chlorine value (%):

O) c) 18.0 14.1 3.75 3.09 60.5 49.5 171.0 74.0 0.98 0.89

Claims (1)

- 10 - 2623 claim A process for the preparation of macroporous sulfonic acid-containing polymers based on uncrosslinked or crosslinked vinylaromatic polymers, characterized in that in the first reaction step chloromethyl groups are introduced into the polymer consisting of homo- or copolymers of styrene and / or its derivatives, over in a second reaction step by means of sulfuric acid of a concentration greater than 90 %, optionally in the presence of iron-containing cocatalysts, in the presence of swelling halogen-containing, non-sulfonable inert agents, crosslinking and formation of porosity with simultaneous partial sulfonation is brought about.