Title of Invention	A PROCESS FOR THE PREPARATION OF MACROPOROUS BIS(PICOLYL) AMINE POLYMERS
Abstract	A process for the preparation of macroporous bis(picolyl) amine polymers. The invention describes a process for preparation of a class of new chelating polymers from bis(picolyl) amine. The macroporous bis(picolyl) amine polymers prepared by the process of this invention are useful in selective removal of metal ions in mixed stream of other metal ions.

Full Text

This invention relates to a process for the preparation of macroporous bis(picolyl) amine polymers useful for the selective removal of metal ion application. The bis (picolyl) amines having general formula 1 in the drawing accompanying this specification wherein R = (2-picolyl) , ( 3- picolyl). The macroporous bis(picolyl) amine polymers prepared by the process of this invention are useful in selective removal of metal ions in mixed stream of other metal ions. These type of polymers are also referred to as chelating polymers. The macroporous bis(picolyl) amine polymers prepared by the process of this invention are new chelating polymers useful in the selective removal of copper ions in mixed streams of other metal ions such as nickel, iron and the like. The new chelating polymers are prepared by covalently attaching the chelating ligand such as the bis(picolyl) amine described by the process of this invention. Selective removal of metal ions are useful in mining and easing environmental problems such as pollution due to metal ion contamination in a mixed stream of metal ions. In the hydrometallurgical applications to remove copper from ores, use of chelating resins with specific copper ion selectivity is desired. The selectivity is desired in mixed stream of other metal ions to be economically viable. Although chelating polymers for the selective removal of copper ions in mixed stream are known, the disadvantages are in terms of higher selectivity, choice of pH in these operations and the overall process economics. Chelating polymers can be defined as those polymers wherein, the chelating group has been incorporated. Thus a chelating polymer essentially has two components - the polymer matrix of choice and the chelating ligand which is incorporated in the polymer matrix. The incorporation of the chelating group is conventionally done by the chemical modification of the polymer or by polymerization of functionalised monomers that contains the desired chelating group. Chemical modification of the polymers is the preferred route to prepare chelating polymers. The advantages are that the polymers are available in diverse forms such as macroporous beads of different pore size, pore volume and pore size distribution, membranes or as fibers. The stability offered by the hydrocarbon backbone is the other attractive feature. The chelating polymers extensively studied and commercially available are those based on styrene or its derivatives crosslinked with divinyl benzene. The disadvantages of these systems are : 1. The polymers are highly hydrophobic and thus have non specific characteristics. 2. The polymers have high cross-link density which limits the porosity. Low porosity restricts the concentration of active chelating ligand in the polymer matrix. 3. The process of chemical modification is through reactive etherification that entails multiple steps thus affecting the overall efficiency of the chelating polymer. The object of the present invention is to provide a process for the preparation of macroporous bis(picolyl) amine polymers that offers advantages over the available chelating polymers such as the ones described above. The novel macroporous bis(picolyl) amine polymers prepared by the process of this invention has bis(2-picolyl) amine and bis(3-picolyl) amine as the chelating ligands and the modified polymers are useful in selective removal of copper ions in mixed stream containing other metal ions. Another object of the present invention is to provide a process for the preparation of macroporous bis(picolyl) amine polymers that are stable during the conditions adopted for the selective removal of copper ions from mixed metal ion streams. Yet another object of the present invention is to provide a process for the preparation of macroporous bis(picolyl) amine polymers that offer high surface area for the ligands to be bound on the surface thus offering better process economics. Yet another object of the present invention is to provide a single step process for the preparation of macroporous bis(picolyl) amine polymers thus offering better selectivity and control. Accordingly , the present invention provides a process for the preparation of macroporous bis (picolyl) amine polymers useful for the selective removal of metal ion applications, which comprises reacting macroporous glycidyl polymers preferably glycidal methacrylate-ethylene glycol dimethacrylate with the bis(picolyl) amine ligands of general formula 1 & tho drawing aocompanying this apecificatiofP wherein R = 2 -picolyl, 3 - picolyl, in a polar solvent, at a temperature in the range of 65 to 90°C , for a period ranging from 24 to 36 hours, cooling the reaction mixture to ambient temperature, separating the solids from the said reaction mixture by conventional methods such as filtration, washing the obtained solids with the said reaction medium, drying the solids to get macroporous bis(picolyl) amine polymers, followed by treating the obtained macroporous bis(picolyl) amine polymers with 2N sulphuric acid and 2N alkali metal hydroxide solution to get ready to use macroporous bis(picolyl) amine polymers. In an embodiment of the present invention, the bis(picolyl) amine used may be such as bis(2-picolyl) amine, bis (3-picolyl) amine of general formula 1 as shown in accompanying drawing. In yet another embodiment of the invention, the macroporous glycidyl polymers used may be prepared as per the process described in the example no. 1 and 2. In another embodiment of this invention, the polar solvent used may be such as alcohol selected from methanol, ethanol, isopropanol or water. In yet another embodiment of the invention , the alkali metal hydroxide used for conditioning the macroporous polymer is selected from sodium hydroxide, potassium hydroxide or the like. The invention is described herein below with reference to the examples which are illustrative in nature and should not be construed to limit the scope of this invention, in any manner. Example 1 Preparation of Macroporous polymer 1 In an inert atmosphere of nitrogen, 7.4 ml of glycidyl methacrylate, 22.1 ml ethylene glycol dimethacrylate, 3.8 ml cyclohexanol were stirred in 225.0 ml distilled water and polymerized using 2.25 grams of poly(vinyl pyrrolidone) in the presence of 0.6 gram of azobis(isobutyronitrile) for 3 hours. The beads generated were washed thoroughly with water, o methanol and dried at 40 C under vacuum. The yield obtained was 29.0 grams. Example 2 Preparation of Macroporous polymer 2 In an inert atmosphere of argon, 13.7 ml of glycidyl methacrylate, 19.0 ml ethylene glycol dimethacrylate, 4.7 ml cyclohexanol were stirred in 250.0 ml distilled water and polymerised using 2.5 grams of poly(vinyl pyrrolidone) in the presence of 0.6 gram of azobis(isobutyronitrile) for 3 hours. The beads generated were washed thoroughly with water, methanol and dried o at 40 C under vacuum. The yield obtained was 31.4 grams. Exaaple 3 5.0 grams glycidyl methacrylate-ethylene glycol dimethacrylate copolymer beads prepared as per example 1 were stirred with 5.88 grams of bis(2-picolyl) amine in 7 5.0 ml ethanol for 24 hours at o 70 C. The solution was cooled to ambient temperature and filtered. The solids were washed with ethanol and dried. The yield obtained was 5.6 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. Exaaple 4 5.o grams of glycidyl methacrylate-ethylene glycol dimethacrylate copolymer beads prepared as example 2 were stirred with 2.94 grams of bis(2-picolyl) amine in 85.0 ml of methanol o for 30 hours at 65 C. The solution was cooled to ambient temperature and the contents filtered. The solids were washed with methanol and dried. The yield obtained was 5.18 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. Example 5 5.0 grams glycidyl methacrylate-ethylene glycol dimethacrylate copolymer beads prepared as per example 1 were stirred with 11.76 grams of bis(2-picolyl) amine for 24 hours in 75.0 ml o water at 75 C. The solution was cooled to ambient temperature and filtered, washed with distilled water and dried. The yield obtained was 5.42 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. Example 6 5.0 grams of glycidyl methacrylate-ethylene glycol dimethacrylate copolymer beads prepared example 1 were stirred with 5.88 grams of bis(3-picolyl) amine in 100 ml ethanol for 24 o hours at 70 C. The solution was cooled to ambient temperature and filtered. The solids were washed with ethanol and dried. The yield obtained was 5.71 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. Example 7 5.0 grams of glycidyl methacrylate-ethylene glycol dimethacrylate copolymer beads prepared as per example 1 were stirred with 2.95 grams of bis(3-picolyl) amine in 120 ml o methanol for 30 hours at 60 C. The solution was cooled to ambient temperature and filtered. The solids were washed with methanol and dried. The yield obtained was 5.36 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. Example 8 5.0 grams of glycidyl methacrylate-ethylene glycol dimethacry-late copolymer beads prepared as per example 2 were stirred with 5.88 grams of bis(3-picolyl) amine in 100 ml distilled water o for 24 hours at 90 C. The solution was cooled to ambient temperature and the solids were washed with distilled water and dried. The yield obtained was 5.80 grams. The modified chelating polymer beads were conditioned with 2N sulphuric acid and then with 0.2N sodium hydroxide solution before use. The advantages of the invention are as follows : 1. The polymer matrix used for the preparation of novel chelating polymers in the process of this invention are neither hydrophobic or hydrophilic. This prevents nonspecific binding of chelating ligands as encountered in conventional polymer matrix hitherto used. 2. The polymer matrixrix used is macroporous. This facilitates in higher loading of the chelating ligand since the surface area available is large as compared to conventional polymer matrices previously used which high crosslink density reducing the porosity leading to lower concentration of chelating ligands that could be incorporated.3. In the conventional polymer matrices, the chemical modification is made through less reactive etherification, while in the process of this invention, the covalent attachment of the chelating ligand is through facile reaction of the ring opening of the epoxy group. The number of steps in chemical modification is thus reduced and the effective chelating capacity is thus not lost. We Claim: 1. A process for the preparation of macroporous bis (picolyl) amine polymers useful for the selective removal of metal ion applications, which comprises reacting macroporous glycidyl polymers, preferably glycidal methacrylate-ethylene glycol dimethacrylate , with the bis(picolyl) amine ligands of general formula 1 ffi the drawing accompanying this specification* wherein R = 2 -picolyl, 3 - picolyl, in a polar solvent, at a temperature in the range of 65 to 90°C , for a period ranging from 24 to 36 hours, cooling the reaction mixture to ambient temperature, separating the solids from the said reaction mixture by conventional methods such as filtration, washing the obtained solids with the said reaction medium, drying the solids to get macroporous bis(picolyl) amine polymers, followed by treating the obtained macroporous bis(picolyl) amine polymers with 2N sulphuric acid and 2N alkali metal hydroxide solution to get ready to use macroporous bis(picolyl) amine polymers. 2. A process as claimed in claims 1 wherein, the polar solvent used may be such as alcohol selected from methanol, ethanol, isopropanol or water. 3. A process as claimed in claims 1-2 wherein, the alkali metal hydroxide used for conditioning the macroporous bis(picolyl) amine polymer is such as sodium hydroxide, potassium hydroxide. 4. A process for the preparation of macroporous bis(picolyl) amine polymers useful for the selective removal of metal ion applications substantially as herein described with reference to the examples.

Documents:

790-del-1997-abstract.pdf

790-del-1997-claims.pdf

790-del-1997-complete spcecifiction (granted).pdf

790-del-1997-correspondence-others.pdf

790-del-1997-correspondence-po.pdf

790-del-1997-description (complete).pdf

790-del-1997-drawings.pdf

790-del-1997-form-1.pdf

790-del-1997-form-19.pdf

790-del-1997-form-2.pdf

790-del-1997-form-3.pdf