DE19954402A1 - Process for the preparation of monodisperse, crosslinked bead polymers with thiourea groups and their use for the adsorption of metal compounds - Google Patents

Abstract

The object of the present invention is a process for the preparation of new, monodisperse, crosslinked bead polymers with thiourea groups and their use for the adsorption of metal compounds, in particular heavy and noble metal compounds.

Description

The present invention relates to a method for producing new, monodisperse, crosslinked bead polymers with thiourea groups and their Use for the adsorption of metal compounds, in particular heavy and Precious metal compounds.

US Pat. No. 4,444,961 discloses a process for producing monodisperse, macroporous Chelate resins known. Here, haloalkylated polymers are aminated and the ami nated polymers with chloroacetic acid to form chelate resins of the iminodiacetic acid type implemented.

Not yet known and are therefore the subject of the present invention monodisperse bead polymers, in particular monodisperse chelate resins, with Thiourea groups are functionalized, a process for their preparation as well their use.

Surprisingly, the monodisperse chelate resins with thiourea group show pen a significantly higher absorption capacity for metal compounds, in particular of heavy and precious metal compounds than those known from US-A 4,444,961 monodisperse, macroporous chelate resins. As a result, it improves Slip behavior in the resin, which leads to smaller residual amounts of metals in the eluate. The better absorption capacity for heavy and precious metal compounds is evident especially with elements of the platinum group, with divalent ions from aqueous Salt solutions or acids, especially in the case of precious metals such as rhodium, gold or Silver or precious metal-containing catalyst residues.  

With the chelate resins according to the invention it is not only possible to use aqueous salt solutions and acids from metal residues can be cleaned. The invention Chelate resins are also used in organic solvents or solutions of liquid or gaseous hydrocarbons or halocarbons materials, especially chlorinated or fluorinated hydrocarbons.

To remove metal ions from liquid solutions, ion exchangers, which selectively take up these ions - so-called selective resins - in practice puts.

The processing of process streams and waste water, especially the galvano and Surface technology, as well as waste water from the chemical industry and the elec electronics industry, continues to gain in importance. she is a essential prerequisite for the continued existence of numerous plants.

A central aspect of the processing of this aqueous or organic Ab water or liquids, but also from landfill leachate and groundwater is the greatest possible removal of metal ions, especially heavy metal ions such as mercury, iron, copper, nickel, arsenic ions, or at least their removal down to very small residual concentrations.

When Naßrauchgaswäsche of waste incinerators and coal-fired power plants and highly saline wastewaters, th significant amounts of heavy metal ions contained. Modern incinerators are using a two-stage washing to separate adsorption of hydrochloric acid at pH <1 and SO ₂ in the alkaline range (father, An, Jekel, water , Waste water 132,1991,10 page 565).

In the acid scrubber, solutions containing hydrochloric acid are obtained, which are combined with a number of Heavy metals are contaminated. In the hydrochloric acid solution of the washer Mercury ionogen dissolved before. Because in many cases a hydrochloric acid extraction the flue gas scrubbing water is sought, mercury must be as large as possible  be removed from this. The macroporous, heterodis used up to now persian bead polymers with thiourea groups, known from DE-A 2429 ß44, are not able to do this to a sufficient extent. Therefore, new types Polymers with improved properties are needed. Here show the fiction according to polymers functionalized with thiourea groups Cleaning effects.

EP-A 0 422 480 describes a process for the partial removal of trace elements described from hydrocarbon mixtures. Are used for this heterodisperse bead polymers with thiourea groups.

However, it is also known that heavy metals and their compounds are not only found in aqueous systems, but also in nature in many organic liquids and gases occur. So contain natural gas and natural gas condensates, natural oils and genes Liquid and gaseous hydrocarbons originating from fossil sources Heavy metals and their compounds such as mercury, iron, nickel, phosphorus, Arsenic and others.

In the petrochemical industry, petroleum and natural gas are different Places of origin processed in numerous different process stages.

These include distillation steps, steam cracking or catalytic Cracking or hydration.

In many cases, catalysts based on Edelme are used such as platinum, palladium, rhodium and others.

The mode of operation of these catalysts depends to a large extent on the Absence of other metal or heavy metal compounds, such as arsenic or Mercury compounds. The presence of these substances can affect the mode of action of the  Reduce catalysts drastically and poison them. One speaks of catalyst poison.

Mercury is a corrosive metal that is caused by amalgam formation in lines and Devices generally have a corrosive effect and cause considerable corrosion damage can call.

So there is also a need for metal or heavy metal compounds Remove hydrocarbon mixtures. The macro used up to now porous, heterodisperse polymer beads with thiourea groups are not in sufficient to do this. The thiourea group according to the invention Polymers containing pen show significantly improved properties here.

For recycling mercury from the wastewater of alkali chloride electrolysis and the purification of this wastewater will be combinations of anion exchange shear and thiourea-containing, macroporous, heterodisperse pearl poly Merisaten used. According to DE-A 22 49 472, the last-mentioned polymer used for fine cleaning.

The thiourea groups according to the invention also show for this application term polymers improved properties. These significantly reduce heavy metals and their compounds from aqueous solutions, but also as described above organic liquids and vapors.

The present invention relates to a process for the preparation of monodisperse, crosslinked bead polymers with thiourea groups, characterized in that

• a) monomer droplets of at least one monovinyl aromatic compound and at least one polyvinyl aromatic compound as well as given if a porogen and / or optionally an initiator or one  Initiator combination, to a monodisperse, cross-linked bead polymer implements
• b) this monodisperse, crosslinked bead polymer with phthalimide derivatives ami domethylated,
• c) the amidomethylated bead polymer to aminomethylated bead polymer implements and
• d) the aminomethylated bead polymer with thiourea, substituted Thiourea or salts of thiocyanic acid can react.

Surprisingly, the monodisperse, thiourea group-containing crosslinked bead polymers prepared according to the present invention show

• - a significantly better removal of heavy metals and precious metals aqueous solutions or organic liquids or their vapors, especially of mercury from aqueous solutions of alkaline earths and Alkaline, especially mercury removal from Alka brine Lichloride electrolysis,
• - A much better removal of heavy metals, especially mercury silver and arsenic, from aqueous hydrochloric acids, in particular from waste water from Flue gas washes, but also from landfill leachate and groundwater,
• - A much better removal of heavy metals, especially mercury silver and arsenic and precious metals, from liquid or gaseous coals Hydrogen such as natural gas, natural gas condensate and crude oil or halo gene hydrocarbons such as chlorinated or fluorocarbons,  
• - a significantly better removal of platinum group elements and gold or silver from aqueous or organic solutions, as well
• - a significantly better removal of rhodium or elements of platinum group as well as gold or silver or rhodium or precious metal-containing Catalyst residues from organic solutions or solvents,

than the polymers known from the prior art.

The bead polymers according to the invention are therefore outstandingly suitable for various fields of application in the chemical industry, the electronics industry, the waste disposal / recycling industry or the electroplating or surface technology.

The monodisperse, crosslinked, vinyl aromatic base polymer according to procedure Step a) can be prepared by the methods known from the literature the. For example, such processes are described in US Pat. No. 4,444,961, EP-A 0 046 535, US-A 4 419 245, WO 93/12167, the contents of which are described herein Registration with regard to process step a) are included.

In process step a) at least one monovinyl aromatic compound and at least one polyvinyl aromatic compound used. However, it is also possible, mixtures of two or more monovinyl aromatic compounds and mixtures of two or more polyvinyl aromatic compounds put.

As monovinyl aromatic compounds in the sense of the present invention who those preferred in process step a) are monoethylenically unsaturated compounds such as styrene, vinyl toluene, ethyl styrene, α-methyl styrene, chlorostyrene, Chloromethylstyrene, acrylic acid alkyl ester and methacrylic acid alkyl ester used.  

Styrene or mixtures of styrene with the aforementioned are particularly preferred Monomers used.

Preferred polyvinyl aromatic compounds in the sense of the present invention for process step a) are multifunctional ethylenically unsaturated compounds such as divinylbenzene, divinyltoluene, trivinylbenzene, divinyl naphthalene, trivinyl naphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacry lat, trimethylolpropane trimethacrylate or allyl methacrylate.

The polyvinyl aromatic compounds are generally used in amounts of 1- 20% by weight, preferably 2-12% by weight, particularly preferably 4-10% by weight, based on gene used on the monomer or its mixture with other monomers. The type of polyvinyl aromatic compounds (crosslinkers) is considered with regard to the later use of the spherical polymer selected. Divinylbenzene is suitable in many cases. For most applications, they are commercial Divinylbenzene grades that, in addition to the isomers of divinylbenzene, also include ethyl contain vinylbenzene, sufficient.

In a preferred embodiment of the present invention, ver step a) microencapsulated monomer droplets are used.

For the microencapsulation of the monomer droplets, they come for use as Complex coacervates known materials in question, especially polyester, natural Liche and synthetic polyamides, polyurethanes, polyureas.

Gelatin, for example, is particularly suitable as a natural polyamide. This is used in particular as a coacervate and complex coacervate. Under Gelatin-containing complex coacervates in the sense of the invention are above all Combinations of gelatin with synthetic polyelectrolytes understood. Appropriate nete synthetic polyelectrolytes are copolymers with built-in units of for example maleic acid, acrylic acid, methacrylic acid, acrylamide and methacrylic  amid. Acrylic acid and acrylamide are particularly preferably used. Gelatin Containing capsules can be hardened with conventional hardening agents such as formaldehyde hyd or glutardialdehyde can be cured. Encapsulation of monomer droplets with gelatin, gelatin-containing coacervates and gelatin-containing complex ko Azervates are described in detail in EP-A 0 046 535. The methods of Encapsulation with synthetic polymers is known. Is well suited for example, phase interface condensation, in which one is in the monomer droplet Chen dissolved reactive component (for example an isocyanate or an acid chlo rid) with a second reactive component dissolved in the aqueous phase (for example an amine) is reacted.

The optionally microencapsulated monomer droplets optionally contain an initiator or mixtures of initiators to initiate the polymerization. Initiators suitable for the process according to the invention are, for example, Per oxy compounds such as dibenzoyl peroxide, dilauryl peroxide, bis (p-chlorobenzoylper oxide), dicyclohexyl peroxydicarbonate, tert-butyl peroctoate, tert-butyl peroxy-2-ethyl hexanoate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane or tert-amylper oxy-2-ethylhexane, and azo compounds such as 2,2'-azobis (isobutyronitrile) or 2,2'- Azobis (2-methylisobutyronitrile).

The initiators are generally present in amounts of 0.05 to 2.5% by weight preferably 0.1 to 1.5 wt .-%, based on the monomer mixture, applied.

As further additives in the optionally microencapsulated monomer droplets Porogens can optionally be used to form spherical polyme risk creating a macroporous structure. Organic solvents are used for this suitable that poorly dissolve or swell the resulting polymer. Examples include hexane, octane, isooctane, isododecane, methyl ethyl ketone, butanol or octanol and called their isomers.  

The terms microporous or gel-like or macroporous are used in the specialist literature have already been described in detail.

Preferred bead polymers for the purposes of the present invention, produced by Process step a) have a macroporous stubborn course.

The formation of monodisperse, macroporous bead polymers can, for example by adding inert materials (porogens) to the monomer mixture in the Polymerization take place. Organic substances are particularly suitable as such, which dissolve in the monomer, but dissolve or swell the polymer poorly (Precipitant for polymers) for example aliphatic hydrocarbons (paints factories Bayer DBP 1045102, 1957; DBP 1113570, 1957).

In US Pat. No. 4,382,124, for example, alcohols with 4 to 10 Carbon atoms for the production of monodisperse, macroporous bead polymers based on styrene / divinylbenzene. Furthermore, an overview of the Manufacturing methods of macroporous polymer beads given.

The optionally microencapsulated monomer droplet can optionally also up to 30% by weight (based on the monomer) of crosslinked or uncrosslinked polymer contain. Preferred polymers are derived from the aforementioned monomers, particularly preferably from styrene.

The average pond size of the possibly encapsulated monomer droplets is 10-1000 µm, preferably 100-1000 µm. The inventive method ren is also well suited for the production of monodisperse spherical polymers.

In the production of the monodisperse bead polymers according to process step a) the aqueous phase can optionally contain a dissolved polymerization inhibitor hold. Inhibitors for the purposes of the present invention are both anor ganic as well as organic matter in question. Examples of inorganic inhibitors  are nitrogen compounds such as hydroxylamine, hydrazine, sodium nitrite and Potassium nitrite, salts of phosphorous acid such as sodium hydrogen phosphite as well sulfur-containing compounds such as sodium dithionite, sodium thiosulfate, sodium sul fit, sodium bisulfite, sodium rhodanide and ammonium rhodanide. Examples of organi inhibitors are phenolic compounds such as hydroquinone, hydroquinone monomethyl ether, resorcinol, pyrocatechol, tert-butyl pyrocatechol, pyrogallol and Condensation products from phenols with aldehydes. Other suitable organic Inhibitors are nitrogenous compounds. These include hydroxylamine vate such as N, N-diethylhydroxylamine, N-isopropylhydroxylamine and sulfonated or carboxylated N-alkylhydroxylamine or N, N-dialkylhydroxyl amine derivatives, hydrazine derivatives such as N, N-hydrazinodiacetic acid, Nitroso compounds such as N-nitrosophenylhydroxylamine, N-nitro sophenylhydroxylamine ammonium salt or N-nitrosophenylhydroxylamine alumi sodium salt. The concentration of the inhibitor is 5-1000 ppm (based on the aqueous phase), preferably 10-500 ppm, particularly preferably 10-250 ppm.

The polymerization of the optionally microencapsulated monomer droplets to spherical, monodisperse bead polymer, as mentioned above, optionally in the presence of one or more protective colloids in the aqueous Phase. Protective colloids are natural and synthetic water-soluble polymers, such as gelatin, starch, polyvinyl alcohol, polyvinyl pyrrolidone, Polyacrylic acid, polymethacrylic acid or copolymers of (meth) acrylic acid and (Meth) acrylic acid esters. Cellulose derivatives are also very suitable, in particular Cellulose esters and cellulose ethers such as carboxymethyl cellulose methyl hydroxy ethyl cellulose, methyl hydroxypropyl cellulose and hydroxyethyl cellulose. Especially gelatin is well suited. The amount of protective colloids used is generally NEN 0.05 to 1 wt .-% based on the aqueous phase, preferably 0.05 to 0.5 % By weight.

Polymerization to spherical, monodisperse, macroporous pearl poly Merisat in process step a) can optionally also in the presence of a  Buffer system can be performed. Buffer systems that adjust the pH Value of the aqueous phase at the start of the polymerization to a value between 14 and 6, preferably between 12 and 8. Under these conditions Protective colloids with carboxylic acid groups in whole or in part as salts. To this The effect of the protective colloids is influenced favorably. Particularly suitable Nete buffer systems contain phosphate or borate salts. The terms phosphate and For the purposes of the invention, borate also includes the condensation products of the ortho- Forms of corresponding acids and salts. The concentration of phosphate or borate in the aqueous phase is 0.5-500 mmol / l, preferably 2.5-100 mmol / l.

The stirring speed in the polymerization is not critical and has in In contrast to conventional bead polymerization, there is no influence on the particles size. Low stirring speeds are used, which are sufficient to keep suspended monomer droplets in suspension and to remove the To support heat of polymerization. Various agitators can be used for this types are used. Lattice stirrers with an axial wire are particularly suitable kung.

The volume ratio of encapsulated monomer droplets to aqueous phase is 1: 0.75 to 1:20, preferably 1: 1 to 1: 6.

The polymerization temperature depends on the decomposition temperature of the put initiator. It is generally between 50 to 180 ° C, preferably between 55 and 130 ° C. The polymerization takes 0.5 to a few hours. It has proven to apply a temperature program in which the polymerization at low temperature, for example 60 ° C is started and the reaction temperature rature is increased with increasing polymerization conversion. In this way For example, the demand for a safe course of reaction and high Fulfill polymerization conversion very well. After the polymerization, the polymer Risat with usual methods, for example by filtering or decanting, iso and washed if necessary.  

In process step b), the amidomethylation reagent is first prepared. For this purpose, for example, phthalimide or a phthalimide derivative in one Solvent dissolved and mixed with formalin. Then it is submerged cleavage a bis (phthalimido) ether is formed from this. The phthalimido ether can optionally converted to the phthalimido ester. Preferred phthalimide Derivatives in the sense of the present invention are phthalimide itself or sub substituted phthalimides, for example methylphthalimide.

In step b), inert solvents are used as solvents Set that are suitable for swelling the polymer, preferably chlorinated hydrocarbons substances, particularly preferably dichloroethane or methylene chloride.

In process step b), the bead polymer is condensed with phthalimide derivatives siert. The catalyst used here is oleum, sulfuric acid or sulfur trioxide set.

The cleavage of the phthalic acid residue and thus the exposure of the aminomethyl Group takes place in process step c) by treating the phthalimidomethylated cross-linked polymer beads with aqueous or alcoholic solutions of an Alka lihydroxids, such as sodium hydroxide or potassium hydroxide at temperatures between 100 and 250 ° C, preferably 120-190 ° C. The concentration of the sodium hydroxide solution is in the range of 10 to 50% by weight, preferably 20 to 40% by weight. This procedure ren enables the production of crosslinked bead polymers containing aminoalkyl groups sate with a substitution of aromatic nuclei greater than 1.

The resulting aminomethylated bead polymer eventually becomes full desalinated water washed free of alkali.

In process step d), the polymers according to the invention are produced by reacting the aminomethyl group-containing, cross-linked,  vinyl aromatic base polymers in suspension with thiourea or sub substituted thiourea or salts of thiocyanic acid.

Thiourea or salts of thiocyanic acid are particularly preferably used.

Mineral acids are used as the suspension medium, preferably aqueous salts acid in concentrations between 10 and 40% by weight, preferably 20 to 35% by weight.

The present invention furthermore relates to those according to the invention Monodisperse bead polymers prepared with thiourea according to the process groups of substances.

The process according to the invention preferably gives rise to monodisperse bead polymers with the functional groups which form during process step d):

wherein
R _{1 represents} hydrogen or an alkyl group,
R _{2 represents} hydrogen or an alkyl group,
R _{3 represents} hydrogen or an alkyl group and
n represents an integer from 1 to 5, particularly preferably 1.

In the radicals R ₁ , R ₂ and R ₃ , each alkyl preferably represents C ₁ -C ₆ alkyl.

In the monodisperse bead polymers according to the invention with thiourea group Each aromatic nucleus preferably carries 0.1 to 2 of the above-mentioned functions bright groups (1), (2), (3) or (4).

The proportion of the individual functional groups in the sum of the functional groups as a whole is preferably
30 to 80% (1)
5 to 30% (2)
1 to 95% (3)
1 to 5% (4).

The crosslinked pearls prepared according to the invention and containing thiourea groups polymers are suitable for the adsorption of metals, especially heavy metals and precious metals and their compounds from aqueous solutions and organic Liquids. The thiourea group-containing ver wetted bead polymers are particularly suitable for removing heavy metals or precious metals from aqueous solutions, especially from aqueous solutions of Alkaline earths or alkalis, from brines of alkali chloride electrolysis, from aqueous Hydrochloric acids, from waste water or flue gas washes, but also from liquid or gaseous hydrocarbons, natural gases, natural gas condensates, petroleum or  Halogenated hydrocarbons, such as chlorinated or fluorocarbons or Fluorine / chlorine hydrocarbons.

The thiourea groups produced according to the invention are very particularly suitable Pen-containing, cross-linked pearl polymers for the removal of mercury, elements the platinum group as well as gold or silver from the solutions listed above, rivers liquids or gases.

The bead polymers according to the invention are particularly suitable for removal of rhodium or platinum group elements as well as gold, silver or rhodium or catalyst metal residues containing noble metal from organic solutions or solvents average.

Examples example 1 a) Preparation of the monodisperse, macroporous polymer beads on the Base of styrene, divinylbenzene and ethylstyrene

3000 g of deionized water are placed in a 10 l glass reactor and one Solution of 10 g gelatin, 16 g di-sodium hydrogen phosphate dodecahydrate and 0.73 g of resorcinol was added to 320 g of deionized water and mixed. The The mixture is heated to 25 ° C. A mixture is then stirred from 3200 g of microencapsulated monomer droplets with narrow particle size ver division of 3.6 wt .-% divinylbenzene and 0.9 wt .-% ethyl styrene (used as commercial isomer mixture of divinylbenzene and ethylstyrene with 80% Divinylbenzene), 0.5% by weight dibenzoyl peroxide, 56.2% by weight styrene and 38.8% by weight of isododecane (technical isomer mixture with a high proportion of pentams thylheptan), the microcapsule being made of a formaldehyde-cured Complex coacervate made of gelatin and a copolymer of acrylamide and acrylic acid exists, and 3200 g of aqueous phase with a pH of 12 added. The average particle size of the monomer droplets is 460 μm.

The batch is stirred by increasing the temperature after a temperature Program at 25 ° C and polymerized at 95 ° C. The approach is cooled, washed over a 32 micron sieve and then in a vacuum 80 ° C dried. 1893 g of a spherical polymer with a average particle size of 440 µm, narrow particle size distribution and smoother Surface.

The polymer is chalky white when viewed from above and has a bulk density of approx. 370 g / l.  

b) Preparation of the amidomethylated bead polymer

2373 g of dichloroethane, 705 g of phthalimide and 505 g of 29.2% by weight formalin are initially introduced at room temperature. The pH of the suspension is adjusted to 5.5 to 6 with sodium hydroxide solution. The water is then removed by distillation. Then 51.7 g of sulfuric acid are added. The resulting water is removed by distillation. The batch is cooled. 189 g of 65% oleum and then 371.4 g of monodisperse bead polymer, prepared by process step a) from Example 1, are metered in at 30 ° C. The suspension is heated to 70 ° C. and stirred at this temperature for a further 6 hours. The reaction broth is drawn off, fully demineralized water is metered in and residual amounts of dichloroethane are removed by distillation.
Yield of amidomethylated bead polymer: 2140 ml
Elemental analysis composition:
Carbon: 75.3% by weight;
Hydrogen: 4.9% by weight;
Nitrogen: 5.8% by weight;
Rest: oxygen

c) Preparation of the aminomethylated bead polymer

1019 g of 45% by weight are added to 2100 ml of amidomethylated bead polymer Sodium hydroxide solution and 406 ml of fully demineralized water are metered in at room temperature. The Suspension is heated to 180 ° C and stirred at this temperature for 6 hours.

The bead polymer obtained is washed with deionized water.
Yield of aminomethylated bead polymer: 1770 ml
The total yield - extrapolated - is 1804 ml
Elemental analysis composition: nitrogen: 11.75% by weight From the elemental analysis composition of the aminomethylated bead polymer, it can be calculated that, on a statistical average per aromatic nucleus - originating from the styrene and divinylbenzene units - 1.17 hydrogen atoms were substituted by aminomethyl groups.

d) Preparation of the monodisperse resin with thiourea groups Feedstocks

In a 4 liter autoclave, 1132 ml of noble water are pre-heated at room temperature sets. 1700 ml of aminomethylated bead polymer from step c) are metered in, 470 g of 30% by weight hydrochloric acid and 485 g of thiourea.

The suspension is stirred for 30 minutes at room temperature. Then will the autoclave heated to 145 ° C in 2 hours. At 145 ° C is another 15 hours touched.

Working up the approach

The mixture is cooled and relaxed. The supernatant liquid is drawn off. The bead polymer obtained is washed successively with 4% by weight sodium hydroxide solution and finally with deionized water.
Yield: 1652 ml
Elemental analyzes:
10.4% by weight nitrogen
10.2% by weight sulfur

Example 2

The removal of mercury from aqueous solutions containing sodium chloride with thiourea-containing, macroporous, monodisperse polymer beads

• 1. 100 ml of the macroporous, monodisperse bead polymer containing thiourea prepared according to Example 1 are filled into a glass column. The glass columns are heated to an internal temperature of 60 ° C. 1000 ml of an aqueous sodium chloride brine of the following composition is filtered through the resin per hour: 300 g sodium chloride per liter brine, 20 mg mercury per liter brine. The brine is adjusted to a pH of 9.2 with sodium hydroxide solution and heated to 60 ° C.
  The amount of mercury is determined in the process. After filtering 785 liters of brine through the resin, 2 mg of mercury per liter of drain are analyzed in the drain. The resin has absorbed a total of 154 g of mercury.
• 2. In a comparative experiment, 100 ml of thiourea are placed in a glass column Group-containing, macroporous, heterodisperse bead polymer filled in according to DE-A 24 29 944 and under the same conditions as in Example 2a) described with brine. After filtration of 625 Liters of brine over the resin become 2 mg of mercury per liter Process analyzed. The resin has taken up a total of 124 g of mercury.

Example 2 shows a clear superiority in the intake of mercury for macroporous, monodisperse pearl containing thiourea groups according to the invention polymers compared to a heterodisperse bead polymer, from an aq Rigen sodium chloride solution, as is known from DE-A 24 29 944.  

Example 3

The removal of mercury from aqueous hydrochloric acid with thiourea-containing, macroporous, monodisperse bead polymers

• 1. 50 ml of the thiourine prepared according to Example 1 are placed in a glass column macroporous, monodisperse bead polymer containing material groups fills. At room temperature, 500 ml of 10 wt .-% aqueous per hour Filtered hydrochloric acid, which contains 20 mg mercury per liter. In the process the remaining amount of mercury is analyzed. After 180 liters of filtered hydrochloric acid there is an amount of 2 mg of mercury per liter of drain in the drain certainly. The resin has taken up a total of 95 g of mercury.
• 2. In a comparative experiment, 50 ml of thiourea group is in a glass column Pen-containing, macroporous, heterodisperse bead polymer, manufactured according to DE-A 24 29 944, filled in and under the same conditions as in Example 3a described with 10 wt .-% hydrochloric acid. After filtration Of 134 liters of 10% by weight hydrochloric acid, a quantity of 2 mg mercury per liter of drain analyzed. The resin has a total of 77 g Mercury added.

A clear superiority of the invention is also evident for acidic solutions according to monodisperse bead polymers containing thiourea groups in the Adsorption of mercury compared to a heterodisperse bead polymer, known from DE-A 24 29 944.

Both Example 2 and Example 3 show that the pearl poly merisate not only higher throughput in liters, but also higher absorption Have mercury until 2 mg mercury per liter of effluent is measured in the eluate become. These values can be obtained with heterodisperse thiourea groups Bead polymers according to the prior art DE-A 24 29 944 and EP-A 0 422 480 cannot be achieved.

Claims (24)

1. A process for the preparation of monodisperse, crosslinked bead polymers with thiourea groups, characterized in that

• a) converting monomer droplets from at least one monovinylaromatic compound and at least one polyvinylaromatic compound into a monodisperse, crosslinked bead polymer,
• b) this monodisperse, crosslinked polymer beads amidomethylated with phthalimide derivatives,
• c) the amidomethylated bead polymer is converted to aminomethylated bead polymer and
• d) the aminomethylated bead polymer can react with thiourea, substituted thiourea or salts of thiocyanic acid.

2. The method according to claim 1, characterized in that the monomer droplets are microencapsulated with a complex coacervate. 3. The method according to claim 2, characterized in that process step a) is carried out in the presence of a protective colloid. 4. The method according to claims 1 to 3, characterized in that Ver step a) is carried out in the presence of at least one initiator. 5. The method according to claims 1 to 3, characterized in that the Monomer droplets contain porogens and macro after polymerization form porous, crosslinked bead polymers.   6. The method according to claims 1 to 5, characterized in that in Ver step a) a polymerization inhibitor is used. 7. The method according to claim 3, characterized in that as protection colloidal gelatin, starch, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, polymethacrylic acid or copolymers of (meth) acrylic acid or (Meth) acrylic acid esters can be used. 8. The method according to claim 1, characterized in that as monovinyl aromatic compounds include monoethylenically unsaturated compounds be set. 9. The method according to claim 1, characterized in that as polyvinyl aromatic compounds divinylbenzene, divinyltoluene, trivinylbenzene, Divinylnaphthalene, trivinylnaphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate or allyl methacrylate be used. 10. The method according to claim 4, characterized in that as the initiator Per oxy compounds such as dibenzoyl peroxide, dilauryl peroxide, bis (p-chlorobene zoyl peroxide), dicyclohexyl peroxydicarbonate, tert.-butyl peroctoate, tert.- Butylperoxy-2-ethylhexanoate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dime thylhexane or tert-amylperoxy-2-ethylhexane, as well as azo compounds such as 2,2'-azobis (isobutyronitrile) or 2,2'-azobis (2-methylisobutyronitrile) be set. 11. The method according to claim 1, characterized in that in process step b) a phthalimido ether is first formed.   12. The method according to claim 11, characterized in that the phthalimi doether is produced from phthalimide or its derivatives and formalin. 13. The method according to claims 11 and 12, characterized in that the Reaction of the phthalimido ether with the bead polymer in the presence of Oleum, sulfuric acid or sulfur trioxide takes place. 14. Monodisperse polymer beads, characterized in that these with Thiourea groups are functionalized. 15. Monodisperse bead polymers prepared with thiourea groups a method according to claim 1. 16. Monodisperse polymer beads according to claims 14 or 15, characterized characterized in that they have a macroporous structure. 17. Monodisperse bead polymers according to claims 14 to 16, characterized in that these contain the functional groups
or
(CH ₂ ) _n -N = C = N- (CH ₂ ) _n (4)
wherein
R _{1 represents} hydrogen or an alkyl group,
R _{2 represents} hydrogen or an alkyl group,
R _{3 represents} hydrogen or an alkyl group and
n represents an integer from 1 to 5,
exhibit. 18. Use of the monodisperse, crosslinked thiourea groups Bead polymers according to claims 14 to 17 for the removal of Heavy metals or precious metals from aqueous solutions of alkaline earths or alkalis or their vapors, from sols of alkali chloride electrolysis, from aqueous hydrochloric acids, from waste water or flue gas washes, groundwater or waste water from landfill, from liquid or gaseous hydrocarbons substances, natural gases, natural gas condensates, petroleum, as well as from liquid or gaseous halogenated hydrocarbons. 19. Use of the bead polymers according to claims 14 to 17, characterized characterized in that as heavy metals or noble metals mercury, el elements of the platinum group, gold or silver are removed. 20. Use of bead polymers according to claims 14 to 17 for Ent Removal of rhodium or platinum group elements as well as gold, silver or rhodium or precious metal-containing catalyst residues from organic Solutions or solvents.   21. Process for removing heavy metals or precious metals from aq solutions or vapors, aqueous solutions of alkaline earths or Alkalis, brines of alkali chloride electrolysis, aqueous hydrochloric acids, waste water or flue gas washes, groundwater or landfill waste water, liquid gen or gaseous hydrocarbons or liquid or gaseous Halogenated hydrocarbons, characterized in that pearl polymers risks according to claims 14 to 17. 22. The method according to claim 21, characterized in that as heavy talle or precious metals mercury, elements of the platinum group, gold or Silver to be removed. 23. Process for removing rhodium or platinum group elements as well as gold, silver, rhodium or precious metal-containing catalyst residues from organic solutions or solvents, characterized in that to use bead polymers according to claims 14 to 17. 24. Use of the bead polymers according to claims 14 to 17 in the chemical industry, electronics industry, electroplating and upper surface industry or the waste disposal or recycling industry.