Process for preparing monodisperse, crosslinked bead polymers having thiourea groups and their use for adsorbing metal compounds

Abstract

The present invention relates to a process for preparing novel, monodisperse crosslinked bead polymers having thiourea groups and their use for adsorbing metal compounds, in particular heavy metal compounds or noble metal compounds.

What is claimed is:  
     
         1 . A process for preparing monodisperse, crosslinked bead polymers having thiourea groups comprising 
 (a) reacting monomer droplets made from at least one monovinylaromatic compound and at least one polyvinylaromatic compound to give a monodisperse, crosslinked bead polymer,    (b) amidomethylating the monodisperse, crosslinked bead polymer from step (a) with phthalimide derivatives,    (c) converting the amidomethylated bead polymer from step (b) to an aminomethylated bead polymer, and    (d) reacting the aminomethylated bead polymer from step (c) with thiourea, with substituted thiourea, or with salts of thiocyanic acid.    
     
     
         2 . A process according to  claim 1  wherein the monomer droplets are microencapsulated using a complex coacervate.  
     
     
         3 . A process according to  claim 1  wherein step (a) is carried out in the presence of a protective colloid.  
     
     
         4 . A process according to  claim 1  wherein step (a) is carried out in the presence of at least one initiator.  
     
     
         5 . A process according to  claim 1  wherein the monomer droplets comprise porogens that, after the polymerization, form macroporous, crosslinked bead polymers.  
     
     
         6 . A process according to  claim 1  wherein a polymerization inhibitor is used in step (a).  
     
     
         7 . A process according to  claim 3  wherein the protective colloids are gelatin, starch, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, copolymers made from (meth)acrylic acid or (meth)acrylate, or mixtures thereof.  
     
     
         8 . A process according to  claim 1  wherein the monovinylaromatic compounds are monoethylenically unsaturated compounds.  
     
     
         9 . A process according to  claim 1  wherein the polyvinylaromatic compounds are divinylbenzene, divinyltoluene, trivinylbenzene, divinyinaphthalene, trivinylnaphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, or mixtures thereof.  
     
     
         10 . A process according to  claim 1  wherein the initiator is a peroxy compound or an azo compound.  
     
     
         11 . A process according to  claim 10  wherein the initiator is dibenzoyl peroxide, dilauroyl peroxide, bis-(p-chlorobenzoyl) peroxide, dicyclohexyl peroxydicarbonate, tert-butyl peroctoate, tert-butyl peroxy-2-ethyl-hexanoate, 2,5-bis-(2-ethylhexanoylperoxy)-2,5-dimethylhexane, or tert-amylperoxy-2-ethylhexane,  
     
     
         12 . A process according to  claim 10  wherein the initiator is 2,2′-azobis(isobutyronitrile) or 2,2′-azobis-(2-methylisobutyronitrile).  
     
     
         13 . A process according to  claim 1  wherein a phthalimido ether is formed in step (b).  
     
     
         14 . A process according to  claim 13  wherein the phthalimido ether is prepared from phthalimide or from a derivative thereof and formalin.  
     
     
         15 . A process according to  claim 13  wherein the reaction of the phthalimido ether with the bead polymer takes place in the presence of oleum, sulfuric acid, or sulfur trioxide.  
     
     
         16 . A monodisperse bead polymer functionalized with thiourea groups.  
     
     
         17 . A monodisperse bead polymer having thiourea groups prepared by a process according to  claim 1 .  
     
     
         18 . A monodisperse bead polymer according to  claim 17  having a macroporous structure.  
     
     
         19 . A monodisperse bead polymer having the functional groups  
                         (CH 2 ) n —NR 1 H]  (2)                    or (CH 2 ) n —N═C═N—(CH 2 ) n   (4)        wherein    R 1  is hydrogen or an alkyl group,    R 2  ishydrogenoranalkylgroup,    R 3  is hydrogen or an alkyl group, and    n is an integer from 1 to 5.    
     
     
         20 . A process comprising removing heavy metals or noble metals from aqueous solutions, from saline solutions from alkali metal chloride electrolysis, from aqueous hydrochloric acids, from waste water or flue gas scrubber effluent, from ground water or landfill runoff water, from liquid or gaseous hydrocarbons, or from halogenated hydrocarbons with a monodisperse bead polymer according to  claim 16 .  
     
     
         21 . A process comprising removing heavy metals or noble metals from aqueous solutions, from saline solutions from alkali metal chloride electrolysis, from aqueous hydrochloric acids, from waste water or flue gas scrubber effluent, from ground water or landfill runoff water, from liquid or gaseous hydrocarbons, or from halogenated hydrocarbons with a monodisperse bead polymer prepared by a process according to  claim 1 .  
     
     
         22 . A process according to  claim 20  wherein the metal is mercury, elements of the platinum group, gold, silver, or a combination thereof.  
     
     
         23 . A process according to  claim 20  wherein rhodium, elements of the platinum group, gold, silver, rhodium- or noble-metal-containing catalyst residues are removed from organic solutions or solvents.  
     
     
         24 . A process according to  claim 20  wherein heavy metals or noble metals are removed from recycle wastes.