Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Ion-exchange polymer or process of preparing
Reexamination Certificate
2000-08-21
2003-11-18
Zitomer, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Ion-exchange polymer or process of preparing
C521S030000, C521S033000, C525S375000, C526S218100, C526S219600, C526S228000, C526S230500, C526S232100
Reexamination Certificate
active
06649663
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for preparing novel, monodisperse ion exchangers having chelating functional groups, and to the use of these.
U.S. Pat. No. 4,444,961 discloses a process for preparing monodisperse, macroporous chelating resins. In this process, haloalkylated polymers are aminated and the aminated polymer is reacted with chloroacetic acid to give chelating resins of iminodiacetic acid type.
A disadvantage of this process is post-crosslinking at the haloalkylated bead polymers stage of the process and also at the subsequent aminomethylated bead polymers stage of the process. EP-A 481,603 describes the disadvantages of post-crosslinking arising at these two stages and a method for the minimization thereof.
The present invention provides hitherto unknown monodisperse chelating resins whose preparation avoids the haloalkylated intermediate stage, and also the use of these.
The novel process does away with post-crosslinking.
The novel products have a uniform structure. Surprisingly, it has been found that the absence of post-crosslinking allows a relatively high degree of substitution of the aromatic rings with functional groups to be achieved and thus a relatively high exchange capacity in the final product. The yield of final product, based on the monomers used, is moreover markedly higher than is the case with final products prepared according to the prior art.
SUMMARY OF THE INVENTION
The present invention, therefore, provides a process for preparing monodisperse ion exchangers having chelating functional groups comprising
(a) reacting monomer droplets made from at least one monovinylaromatic compound and at least one polyvinylaromatic compound, and, if desired, a porogen and/or, if desired, an initiator or an initiator combination 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) converting the aminomethylated bead polymer from step (c) to ion exchangers having chelating groups.
DETAILED DESCRIPTION OF THE INVENTION
The novel ion exchangers with the properties described above are obtained without post-crosslinking. Furthermore, the monodisperse ion exchangers prepared according to the present invention and having chelating groups
give markedly better removal of heavy metals and noble metals from aqueous solutions or organic liquids or vapors thereof, particularly of mercury from aqueous solutions of alkaline-earth metals or alkali metals, in particular removal of mercury from saline solutions from alkali metal chloride electrolysis,
give markedly better removal of heavy metals, particularly mercury or arsenic, from aqueous hydrochloric acid, particularly from waste water from flue gas scrubber effluent but also from landfill eluate or groundwater,
give markedly better removal of heavy metals, particularly mercury or arsenic, or noble metals, from liquid or gaseous hydrocarbons, such as natural gases, natural gas condensates, or mineral oils, or halogenated hydrocarbons, such as chloro- or fluorohydrocarbons,
give markedly better removal of elements of the platinum group or gold or silver from aqueous or organic solutions, and
give markedly better removal of rhodium or elements of the platinum group or gold or silver or of rhodium- or noble-metal-containing catalyst residues from organic solutions or solvents, and give markedly better removal of alkaline-earth metals, such as magnesium, calcium, barium or strontium, from aqueous saline solutions, as usually produced in alkali metal chloride electrolysis,
than do the chelating resins known from the prior art.
The novel ion exchangers are, therefore, highly suitable for a very wide variety of application sectors in the chemical industry, the electronics industry, or industries that dispose of or recycle waste, or in electroplating or surface-finishing.
The monodisperse, crosslinked vinylaromatic base polymer according to process step (a) may be prepared by the processes known from the literature. Processes of this type are described, for example, in U.S. Pat. No. 4,444,961, EP-A 46,535, U.S. Pat. No. 4,419,245, or WO 93/12167, the contents of which are incorporated into the present application in relation to process step (a).
In process step (a), at least one monovinylaromatic compound and at least one polyvinylaromatic compound are used. However, it is also possible to use mixtures of two or more monovinylaromatic compounds and mixtures of two or more polyvinylaromatic compounds.
Preferred monovinylaromatic compounds for the purposes of the present invention in process step (a) are monoethylenically unsaturated compounds, such as, styrene, vinyltoluene, ethylstyrene, &agr;-methylstyrene, chlorostyrene, chloromethylstyrene, alkyl acrylates, and alkyl methacrylates. Particular preference is given to the use of styrene or mixtures of styrene with the above-mentioned monomers.
Preferred polyvinylaromatic compounds for the purposes of the present invention for process step (a) are multifunctional ethylenically unsaturated compounds, such as, divinylbenzene, divinyltoluene, trivinylbenzene, divinyinaphthalene, trivinylnaphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, or allyl methacrylate.
The amounts used of the polyvinylaromatic compounds are generally from 1 to 20% by weight (preferably from 2 to 12% by weight, particularly preferably from 4 to 10% by weight), based on the monomer or its mixture with other monomers. The nature of the polyvinylaromatic compounds (crosslinking agents) is selected with the subsequent use of the spherical polymer in mind. In many cases divinylbenzene is suitable. For most uses, commercial qualities of divinylbenzene are sufficient, and comprise ethylvinylbenzene, besides the divinylbenzene isomers.
In one preferred embodiment of the present invention, microencapsulated monomer droplets are used in process step (a).
Possible materials for the microencapsulation of the monomer droplets are those known for use as complex coacervates, in particular, polyesters, natural or synthetic polyamides, polyurethanes, and polyureas.
An example of a particularly suitable natural polyamide is gelatin, which is used, in particular, as coacervate and complex coacervate. For the purposes of the present invention, gelatin-containing complex coacervates are primarily combinations of gelatin with synthetic polyelectrolytes. Suitable synthetic polyelectrolytes are copolymers incorporating units of, for example, maleic acid, acrylic acid, methacrylic acid, acrylamide, or methacrylamide. Particular preference is given to the use of acrylic acid and acrylamide. Gelatin-containing capsules may be hardened using conventional hardeners, such as formaldehyde or glutaric dialdehyde. The encapsulation of monomer droplets with gelatin, with gelatin-containing coacervates and with gelatin-containing complex coacervates is described in detail in EP-A 46,535. The methods for encapsulation using synthetic polymers are known. An example of a highly suitable process is interfacial condensation, in which a reactive component dissolved in the monomer droplet (for example, an isocyanate or an acid chloride) is reacted with a second reactive component dissolved in the aqueous phase (for example, an amine).
The monomer droplets, which may be microencapsulated if desired, may, if desired, contain an initiator or mixtures of initiators to initiate the polymerization. Examples of initiators suitable for the novel process are peroxy compounds, such as dibenzoyl peroxide, dilauroyl peroxide, bis(p-chlorobenzoyl) peroxide, dicyclohexyl peroxydicarbonate, tert-butyl peroctoate, tert-butyl peroxy-2-ethylhexanoate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, and tert-amylperoxy-2-ethylhexane, and azo compounds, such as 2,2′-azobis(isobutyronitrile) and 2,2′-azobis(2-methylisobutyronitrile).
The amounts used of t
Hees Bruno
Klipper Reinhold
Lehmann Bernhard
Lütjens Holger
Schnegg Ulrich
Akorli Godfried R.
Bayer Aktiengesellschaft
Eyl Diderico van
Zitomer Fred
LandOfFree
Process for preparing monodisperse ion exchangers having... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing monodisperse ion exchangers having..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing monodisperse ion exchangers having... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3129212