DD212258A1 - METHOD FOR THE PRODUCTION OF SELECTIVE ADSOBENTS ON ACRYLATE BASE - Google Patents

Abstract

The invention relates to a process for the preparation of selective adsorbents of crosslinked polymers of acrylic acid or methacrylic acid amides having at least one primary amino group in the amide part. These amides are obtained by reacting the esters with mono- or polyalkylene polyamines containing at least 2 primary amino groups. This is followed by a further reaction with salts of thiocyanic acid, thiocyanic acid, mustard oils, thioureas, optionally substituted thioureas, acyl isothiocyanates, reaction products of chlorocarbonic acid esters with thiocyanates, carbon disulfide and ammonia and / or amines. As a result, selective absorbents with high capacities for metals, especially for mercury, are obtained. Such adsorbents can be used in wet metallurgy for the enrichment and separation of sulfur metal ions or for the extraction of heavy metals from industrial wastewater.

Description

24577

VEB CHEMICAL COMPANY BITTERFELD Bitterfeld, 2.12.1982

2175

Process for the preparation of selective adsorbents based on acrylate

Fields of application of the invention

Crosslinked polymers with sulfur- and nitrogen-containing anchor groups represent adsorbents with specific properties. Especially those containing thiourea groups have the ability to adsorb metal ions, especially mercury and noble metal compounds. They combine the advantageous properties of adsorbing these metal ions even at high foreign salt concentrations and at low pH values. These properties open up interesting possibilities in the field of isolation and extraction of these metals.

Characteristic of the known technical solutions

The invention relates to new thiourea-containing synthetic resins.

It is known to produce such selective groups-bearing synthetic resins by condensation of thiourea, thiosemicarbazide or thiocarbazide with an aldehyde (DE-OS 2,128,802).

However, such condensation products have insufficient thermal stability and a low adsorption rate

-äDEZ. 1982 * 053 387

245776 4

- 2 - 2175

towards metal ions. To improve these properties, thioureas and aldehydes are preferably cocondensed with substances which give a tough and suitable three-dimensional crosslinking structure. Examples of such substances include phenol compounds and aromatic amines (DE-OS 2,128,802). However, it is always difficult to obtain uniformly constructed condensation products. Non-crosslinked vinylaroratic and vinylaliphatic structures containing not only amino groups but also thiourea groups are described in German Offenlegungsschrift No. 2,312,233. Their use for removing heavy metals from solutions is also described, but the adsorption behavior of these synthetic resins in the strongly acidic pH range is unsatisfactory. These Machteile be overcome when using crosslinked vinyl aromatic polymers of the type of styrene-divinylbenzene (DD-PS 112.277, DE-AS 2,429,944). These polymers must carry a primary or secondary aoba group, which are then reacted with thiocyanic acid, salts of thiocyanic acid, optionally substituted thioureas or mustard oils in the presence of a suspending agent to the polymers containing thiourea groups. The aromatic backbone, as an inert bastard, has an effect thereon System disadvantageous to achieve the highest possible metal capacity. Adsorbents of the same or similar structure are described in SU-PS 523.113 · Chlormethylgruppenhaltige styrene-Oivinylbenzol copolymers or copolymers of 2-chloromethyl-5-vinylpyridine are reacted with aromatic amines or diamines and then in an acidic medium with ammonium thiourea to the thiourea groups Implemented polymers. Adsorbents carrying thiourea groups are likewise described in DE-OS 2,312,233 and 2,326,366. Polymeric backbone here is mainly polyvinyl chloride.

2457 7 6 L, - ³ -

Object of the invention

The aim of the invention is therefore a process for the preparation of thiourea-containing Adsorfaentien with high capacities and pronounced selectivities.

Presentation of the essence the invention

It has now been found that it is possible to prepare thiourea-containing adsorbents which have high capacities and good selectivities, if crosslinked polymers prepared by suspension polymerization with or without the addition of precipitants and / or swelling agents are prepared from acrylates and / or methacrylates with mono- or Polyalkylenpolyaminen containing at least 2 primary amino groups, heated and after washing the aminated polymer this with thiocyanic acid, salts of thiocyanic acid, mustard oils, thiourea, optionally substituted thioureas, Äcylisothiocyanaten, reaction products of chlorocarboxylic acid esters and alkali thiocyanates, carbon disulfide and amines, in the presence of a suspending agent implements. For the preparation of dsr starting polymers , the methyl or the ethyl ester of acrylic or methacrylic acid is preferably used. To crosslink the polymers, polyvinyl compounds are added. Examples which may be mentioned are: trivinylbenzene, divinylphenylmethane, other tri- and divinylhydrocarbons, di- and triallyl compounds, dimethacrylates and further diacrylic compounds. Preferably, however, divinylbenzene is used. Oqv crosslinker content can vary within wide limits. However, preference is given to a content of from 1 to 20% by weight, based on the polymerizable phase. The addition of a precipitating and / or swelling agent which is inert during the polymerization can be utilized in a known manner to achieve a porosity. Examples of such inerting agents are: gasoline fractions of different boiling ranges, alcohols such as cyclohexanol, tert-amyl alcohol, aromatic hydrocarbons such as toluene and diethylbenzene.

2457 7 6 A - * -

The polymers are prepared by known processes of suspension polymerization.

For the preparation of the anion exchangers required as intermediates, both alkylenediamines and polyalkylenepolyamines have proven useful as aminolysis araines. For example, ethylenediamine, propylenediamine, 1,2-diarainopropane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or dipropylenetriamine. The aminolysis of the polymers is preferably carried out in the temperature range from 100 to 200 ° C. It should be noted that the crosslinkable polymerization resins containing primary and / or secondary amino groups which can be used according to the invention are known per se and their use as anion exchangers is described. In carrying out the process according to the invention, the anion exchangers can be used in the salt form (z.3 of the chloride form) as well as in the free amine form. "The process is generally carried out in such a way that the primary and / or secondary amino-containing resin in suspension of a suspending agent, thiocyanic acid, thiocyanates, thiourea, optionally substituted thiourea, acyl isothiocyanates, reaction products of chlorocarboxylic acid esters with alkithiocyanates or carbon disulfide and amines or a mustard oil added to the suspension and then heating the reaction mixture with stirring. In the case of thiocyanic acid, it is also possible to initially load the anion exchanger in a filter tube with thiocyanic acid, then to suspend it in water or dilute thiocyanic acid and to heat the suspension while stirring. For the reaction with mustard oils, acyl isothiocyanates, reaction products of chlorocarboxylic acid esters and alkali thiocyanates, carbon disulfide and amines, the one-pot process is particularly suitable since, according to the process of the invention, these intermediates need not be used in isolated form. They can be synthesized in an upstream reaction and in the same reaction vessel with

2457 7 6 4 " ⁵ "

the anion exchangers are reacted. By-products such as alkali metal halides and others do not disturb the course of the reaction.

The amount of sulfur-containing reaction components used depends on the amount of amino groups contained in the anion exchanger. However, it can be varied within wide limits. So it is possible to work with a multiple upper shot, as well as with a deficiency. In the latter case, exchangers are obtained which, in addition to thiourea groups, also contain amino groups.

The temperature at which the reaction takes place depends on the reactants used. In general, the reaction is carried out at temperatures between 40 and 180 ^° C. In the case of the use of mustard oils, preference is given to working between 30 and 70 ° C. The suspending agents for the reactants include, for example, water, methanol, ethanol, acetone and dioxane.

The following reaction components may be mentioned, for example: inorganic and organic thiocyanates, as well as mixtures of both groups, thiourea, optionally substituted thioureas of the general formula

^R l / ^R 3

R ₂ / I ^X H

wherein R ₁ , R ₉ and R- independently represent a hydrogen atom, a straight-chain or branched alkyl radical or an optionally substituted by halogen, alkoxy or hydroxy-substituted aryl, aralkyl or an acyl radical; Mustard oils of different structure, especially with aliphatic radicals; Acyl isothiocyanates, aromatic or aliphatic carboxylic acids, reaction products of chlorocarboxylic acid ester with thiocyanates. For the reaction with carbon disulfides and amines, aliphatic and aromatic amine components are used

245 7 7 6. 4

- ^s -

possible. The use of ammonia also leads to thiourea groups in good yields.

The adsorbents containing thiourea groups according to the invention have a selective adsorption capacity for mercury, which is largely independent of the pH and foreign ions. Due to the acrylate structure, they have greater adsorption capacity over comparable adsorbents based on styrene-oivinylbenzene copolyesters and the advantage of easy synthesis of the starting resins.

EXEMPLARY EMBODIMENTS;

The following examples are intended to further illustrate the invention without being limited to it.

172 g of macroporous polymethacrylate polymer which is crosslinked with 4.5 % divinylbenzene and has a particle diameter of 0.315 to 0.8 mm, is heated with 800 g of ethylenediamine (98 % strength) for 8 hours at 170 ° C. in an autoclave. After aspirating the excess amine and washing with methanol and water, the finished anion exchanger is converted by means of 5% hydrochloric acid in the chloride form.

98 g of aspirated moist exchanger are refluxed with 52 g of NH ₄ SCN in 300 ml of H ₂ O for 16 h. The finished product is filtered off with suction and washed with water. It is a selective resin of porous structure with thiourea moieties.

Characteristics of the resin: Water content: 77.8 %

Mercury capacity: 8.12 meq / g of dry resin

24 5 7 7 6 L,

-r-

Stirrer, thermometer and reflux condenser are charged with 500 g of diethylenetriamine and 150 g of a macroporous, polymethylacrylate polymer crosslinked with 7.5% divinylbenzene are introduced into a supernatant flask and heated at 170 ^° C. for 8 h. After cooling, the excess amine is separated and subsequently washed with methanol and water. 55 g dry anion exchanger are added to a reaction mixture of 142 g CH ^ J and 100 g KSCN in 350 ml of acetone and heated at 50 C for 10 h. The finished product is filtered off with suction and washed with water. It has methylthiourea groups as a selective group.

Characteristics of the resin: Water content: 49.4 %

Mercury-

capacity: 9.20 meq / g dry exchanger

EtejLs £ iel_3 j_

172 g macroporous Polymethylacrylatpolymerisat, which is crosslinked with 7.4 % divinylbenzene, is heated with SOO g ethylenediamine (98 % ± g) for 10 h at 170 ° C in an autoclave. After aspirating the excess amine and washing with water, the anion exchanger is converted by means of 5% hydrochloric acid in the chloride form. 50 g of dry exchanger are heated with a solution of 178 g of thiourea in 350 ml of water for 16 h at reflux. The resin is separated and washed with water. It has the same structure as the pattern in Seismic Example 1.

Characteristics of the resin: Water content: 50.7%

Ouecksilber-

Capacity: 6.58 meq / g

245775 4-

8 - 2175

In a boiling flask equipped with stirrer, thermometer and reflux condenser, 230 g of thiourea are dissolved in 500 ml of water. 78 g of an anion exchanger in the amine form, which was prepared according to the procedure in Example 2, is introduced into the solution and heated at reflux for 40 h. The pH of the reaction solution is adjusted continuously by means of 5% hydrochloric acid to a value between 4 and 7. The finished product is filtered off with suction and washed with water. It has thiourea groups as selective moieties.

Characteristics of the resin: Water content: 50.75 % mercury

capacity: 8.38 meq / g

800 g of tetraethylene pentamine are placed in a supernatant flask equipped as in Seispiel 2 and 150 g of macroporous Polymethylacryiatpolymeres crosslinked with 7.5 % divinylbenzene registered and heated to 170 ° C for 8 h. After cooling, the excess aroin is separated and subsequently washed with methanol and water.

33 g of dry anion exchanger in the amine form are added to a reaction mixture of 142 g of CH ₃ D and 100 g of KSCN in 400 ml of acetone, heated to 50 C for 15 h. Subsequently, the finished product is separated and subsequently washed with acetone and water. The resin has methyithiourea groups as in Example 2.

Characteristics of the resin: Water content: 34.80 % mercury

capacity: 7.38 meq / g

24 577 5 4

- 9 - 2175

Stirrer, thermometer and reflux condenser are charged with 400 ml of acetone in a boiling flask and 100 g of KSCN are dissolved. 85 g Honochlordimethyläther are added dropwise and reacted at 40 ⁰ C and 1 h at 50 ⁰ C for 3 h. Without isolating the intermediate methoxymethyl mustard oil, 64 g of an anion exchanger having a primary amino group are introduced into the amide part and reacted at 50-55 ° C. for 10 h. It is then washed with acetone and water. In addition to unchanged anion-exchange-active groupings, the end product possesses methoxy-ethyl-substituted thiourea groups. Characteristics of the resin: Water content: 60.4 %

Mercury-

Capacity: 7.50 meq / g

Copper capacity: 2.55 meq / g

A flask equipped with a stirrer, thermometer and reflux condenser is charged with 600 ml of acetone and 120 g of KSCN are dissolved therein. 160 g of benzoyl chloride are then added dropwise and the reaction is carried out at 40 ^° C. for 3 h and at 55 ^° C. for 1 h. Without isolating the intermediate benzoylisothiocyanate, 95 g of an acrylate resin with a Diäthylentriaring in the Araidteil be registered in the same vessel and carried out the actual reaction with the anion exchanger for 10 h at 55 ⁰ C. The reaction product is separated from the reaction medium and washed successively with acetone, methanol and water. It has benzoyl-substituted thiourea groups as a selective group

Characteristics of the resin: Water content: 48.6 % Mercury capacity: 7.73 meq / g Copper capacity: 3.12 meq / g

-10-

245 77 6 4

- 10 - 2175

Example 8:

400 ml of acetone are placed in a supernatant flask of the same equipment as in Example 2, and 100 g of KSCN are dissolved therein. Thereafter, 80 g of acetyl chloride are added dropwise and stirred at 55 ⁰ C for 6 h. In the reaction mixture, 90 g of an anion exchanger, which is obtained by reacting a Polymethy! Acrylates rait ethylenediamine, according to Example 1, and stirred at 55 ⁰ C for 15 h. The solid adsorber is separated from the reaction solution and washed out as in Example 7. He has in addition to basic groups acetyl-substituted thiourea groups

Characteristics of the resin: Water content: 55.8 % Mercury capacity: 7.05 tnval / g Copper capacity: 2.75 meq / g

B_e is £ i el_9 _ ^

In a boiling flask, equipped as in Examples 7 and 8, 100 g of KSCN are dissolved in 400 ml of acetone and then added dropwise 95 g of methyl chloroformate. The reaction is carried out for 3 hours at 40 ⁰ C and 1 h at 55 ° C. Without isolating the intermediate, 80 g of an anion exchanger of the same structure, as in Example 7, registered. The reaction is carried out at 55 ^° C. for 10 h. The mixture is then separated off and washed with acetone and water

Characteristics of the resin: Water content: 49, 9 % Mercury capacity: 9.12 meq / g Copper capacity: 3.38 meq / g

24 5 77 6 4 J3e iS £ iel__10: _

- 11 - 2175

In a sulfonating flask, equipped as in the preceding examples, 200 ml of water are introduced and 114 g of a Äthylendiarainaustauschers, prepared according to Seispiel 1, registered and added 90 ml of carbon disulfide. Subsequently, S h at 25 to 30 ⁰ C and 2 h at 45 to 47 ⁰ C stirred. Thereafter, 300 ml of a 25% ammonia solution are added dropwise rapidly and reacted at room temperature for 24 h. Finally, it is stirred for 15 h at 80 C, separated and washed with water. The final product contains thiourea moieties. Characteristics of the resin: Water content: 39.3 % Mercury capacity: 7.46 raval / g Silver capacity: 3.03 meq / g

-12-

Claims (3)

Cβ ' - 12 - 2175 invention claim 1. A process for the preparation of polymers containing thiourea groups, characterized in that crosslinked polymeric acrylic acid amides and / or methacrylic acid amides containing at least one primary amino group in the amide portion with thiocyanic acid, salts of thiocyanic acid, mustard oil, thiourea and / or substituted thioureas, acyl isothiocyanates, reaction products of chlorocarbonic acid esters with thiocyanates, carbon disulfide and ammonia and / or amines are reacted in the presence of a suspending agent, 2. The method according to item 1, characterized in that are used as crosslinked acrylic acid amides and / or Hethacrylsäureamide copolymers with divinylbenzene. 3. Method according to points 1 and 2, characterized by
that the amide portion of the crosslinked copolymers used can contain at least one primary amino group and any number of secondary amino groups.