Title of Invention	"A PROCESS FOR THE PREPARATION OF POLYMERIC ADSORBENTS BY PRECIPITATION POLYMERIZATION"
Abstract	A process for the preparation of adsorbents selective for phenolic compound has been developed. The process includes the steps of mixing template monomer with a porogen and polymerization initiator and initiating polymerization by conventional method, crushing and sieving the obtained polymer and washing with solvent followed by hydrolyzing by acid or alkali treatment to get the desired polymeric adsorbent.

Title of Invention

"A PROCESS FOR THE PREPARATION OF POLYMERIC ADSORBENTS BY PRECIPITATION POLYMERIZATION"

Abstract

A process for the preparation of adsorbents selective for phenolic compound has been developed. The process includes the steps of mixing template monomer with a porogen and polymerization initiator and initiating polymerization by conventional method, crushing and sieving the obtained polymer and washing with solvent followed by hydrolyzing by acid or alkali treatment to get the desired polymeric adsorbent.

Full Text	This invention relates to a process for preparation of polymeric adsorberris, by precipitation polymerization, more particularly it relates to the process for the preparation of adsorbents selective for phenolic compounds. Phenolic compounds such as phenol, p- nitrophenol, 2,4 and 2,6-dinitrophenol, isomers of bisphenol A etc. are many a time present in aromatic compounds as trace impurities (e.g. phenol in anisole or nitrophenols in nitrober.zene, o,p- bisphenol in bisphenol-A). These impurities lead to problems in down stream processing of these chemicals. Aromatics containing phenolic impurities when undergo catalytic oxidation / reduction reactions, phenols if present can form tarry products, which poison / deactivate the catalyst. Hence for enhancing the catalyst life as well as for better economics of the process it is necessary to remove phenolic impurities from aromatics. Another necessity for removal of phenol arises from the improvement in quality that is desirable for any product. Phenolic impurities can be removed from aqueous streams using a variety of methods such as adsorption, distillation, and solvent extraction. These methods are commonly used on industrial scale as well and have been discussed in the literature. Various kinds of adsorbents are used to achieve the same goal. The adsorbents used for removal of phenolic compounds can be either inorganic or organic in nature. The inorganic adsorbents used for such applications are silicas and zeolites where as commonly used organic adsorbents are polymeric in nature. There are two kinds of polymeric adsorbents in common use for removal of phenolic compounds. These are crosslinked styrene - divinylbenzene resins (Amberlite XAD - 2, 4) marketed by Rohm and Haas or their equivalents and crosslinked aery late / methacrylate resins (Amberlite XAD - 7, 8) or their equivalents. These are suitable for removal of phenols from aqueous phase. Though these adsorbents are suitable for removal of phenolic compounds from aqueous phase, they do not have any structural feature that can distinguish between various phenols and hence they are not selective for a particular phenol. These adsorbents are able to remove phenols from aqueous streams as well as non-polar organic streams mainly based on the polarity difference between the solute and the solvent. In literature there are references for preparation of polymers, which are selective to a particular substrate such as drugs (theophyllin, phenobarbital, creatanine), steroids (cholesterol, corticosteroids), nucleic acid bases, carbohydrates. The technique of preparation of such polymers is known as molecular imprinting ( Wulff, G., Angew. Chem. Int. Ed Eng., 34 (1995), 1812 -1832, Mosbach, K. and Ramstrom, O., Biotechnolog)>, 14 (1996), 163 - 173, Steinke, J., Sherrington, D. C. and Dunkin, I. R., Advances in polymer science Vol. 123 (1995), 81 -125). The polymers prepared by this technique are known as molecularly imprinted polymers or more commonly and herein after referred as MIPs. (MIPs) The MIPs are prepared by polymerization of monomers around a template molecule in the presence of a large excess of crosslinker. During' synthesis, the template is either covalently or non-covalently linked to the monomers. After polymerization, the template is removed from the polymer leaving behind a cavity on the surface. These cavities have shape and size similar to the template molecule used during polymerization and hence are selective to those particular substrates. There are no reports in the literature for the preparation of polymeric adsorbents selective for phenolic compounds using molecular imprinting technique by precipitation polymerization. The object of the present invention is therefore to provide a process for the preparation of polymeric adsorbents by precipitation polymerization. Accordingly the present invention provides a process for preparation of polymeric adsorbents by precipitation polymerization which comprises (a) mixing requisite amount of a template monomer such as herein described, with a crosslinker as described herein, along with a porogen selected from cyclo hexanol or aromatic solvent such as defined herein and a polymerization initiator, typically a radical initiator as defined herein , degassing the obtained mixture by evacuator or by passage of inert gas, (b) polymerizing the monomer solution obtained in step (a) by conventional method as herein described, at a temperature ranging 60° - 90°C, for a period of 24 h, (c) crushing and sieving the polymer formed to get particle having size 250u - 100u and washing it with a solvent as defined herein, to remove the unreacted monomers as well as the porogen, (d) hydrolyzing the polymer by acid or alkali treatment such as herein described, for a period ranging from 6-10 hours followed by washing with solvent and drying at a temperature ranging 50° to 60°C, to get the desired polymeric adsorbent. In an embodiment the template monomer may be either a carbonate ester or carboxylate ester having one or more vinylic / allylic / styrenic unsaturations as exemplified by phenyl methacrylate, 2 - (methacryloyl), ethyl, phenyl carbonate, phenyl, 4 - vinyl benzoate, phenyl, 4 - vinyl phenyl carbonate, allyl phenyl carbonaze, phenyl acrylate, 2 -(acryloyl), ethyl, phenyl carbonate, 2,4- DHB (2.4- dihydrcxy benzophenone) methacrylate, allyl, 2,4- DHB carbonate, p- nitrophenyl methacrylare, p- nitrophenyl acrylate, allyl, p- nitrophenyl carbonate, allyl bisphenyl carbonare, bisphenyl methacrylate, p- cumyl phenyl methacrylate, 2,4- dinitrophenyl acrylate, 2,4- dinitrophenyl methacrylate, p- methoxy phenyl methacrylate, aJlyl, o- methoxy phenyl carbonate, o- methoxy phenyl methacrylate, allyl, p- methoxy phenyl carbonate, o- methoxy phenyl acrylate, p- methoxy phenyl acrylate. In another embodiment the crosslinker used for polymerization may be acrylic or methacrylic or styrenic in nature with two or more unsaturations as exemplified by methylene bis acrylamide, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, divinyl benzene, ethylene glycol diacrylate, trimethylol propane triacrylate. In another embodiment the porogen used during the polymerization process may be either alcoholic in nature such as cyclohexanol or an aromatic solvent such as benzene, toluene, xylene. In yet another embodiment the initiator used for the thermal polymerization may be chosen from a class of compounds such as azo, peroxides, hydroperoxices, persulphates, more preferably from azo initiators. In yet another embodiment the degassing of the monomer solution may be carried out by evacuation of the solution or by passage of an inert gas such as nitrogen, argon, helium. In yet another embodiment the polymerization of the template monomer may be carried out thermally between 60° - 90° C and more preferably between 70° - 80° C. In yet another embodiment, after polymerization, the imprinted polymer may be crushed to a particle size In yet another embodiment the hydrolysis of the template monomer may be carried out using preferably alkali solution viz. NaOH or KOH of a strength between 0.1 to 2.0 N and more preferably between 0.5 to 1.5 N for a period ranging frcm 6 to 10 hours. In yet another embodiment the solvent used for washing of the polymer may be selected from ethanol, methanol, acetone, chloroform. In a feature of the present invention is provided a process for preparation of polymeric adsorbents, by the process of precipitation polymerization in presence of a porogen (Wulff, G. and Vesper, W. J. Chromatogr., 167 (1978), 171-186; Selkrgren, B., Ekherg, B. and Mosbach, K., J. Chromatogr., 347 (1985), 1-10; Shea, K. J. and Sasaki, D. Y., J. Am. Chem. Soc., Ill (1989), 3442-3444; Whitcomhe, M., Rodriguez, M. E., Villar, P. andVulfson, £, J. Am. Chem. Soc., 117(1995), 7105-7111; Cheong, S., Mcniven, S., Rachkov, A., Levi, K., Yano, K. and Kanibe, I., Macromolecuks, 30 (1997), 1317-1322). The porogen used in the process is such that it is a good solvent for the monomers but a poor solvent for the polymer. Due to this the polymer phase separates as it is formed entrapping the solvent in it. This leads to a highly porous structure with a large surface area. These polymers can also be prepared by any other conventional methods of polymerization such as suspension polymerization (Mayes, A. and Mosbach, K., Anal. Chem. 68, (1996), 3769-3774), emulsion polymerization, bi continuous emulsion polymerization etc. Because of their shape and size selectivity, MIPs have found applications in areas such as racemic resolution, as sensor materials or as shape selective catalysts. The process of the present invention is described hereinbelow with reference to the examples that are illustrative only and should not be construed to limit the scope of the present invention in any manner. Example 1 0.8 g of phenyl methacrylate and 3.2 g of divinyl benzene (50%) were weighed in glass test tube (15ml capacity). To this 4.0 g toluene (porogen) and lOOmg of azobis isobutyronitrile, AJBN (free radical initiator) was added. The contents were thoroughly mixed on a cyclo mixer and the solution was degassed by bubbling nitrogen gas through it for 10-15 min. The tube was then sealed and polymerization was carried out in a water bath maintained at 75° C for 24 hours. After the polymerization the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ sieve and particles below 75 u were used as adsorbent. The polymer was then washed for 10-15 hours with methanol and dried in air. The hydrolysis of the template, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally' methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. Example 2 1.83 g of 2-(methacryloyI), ethyl, phenyl carbonate and 1.0 ml ethylene glycol dimethacrylate, EGDMA were taken in a glass tube (15ml capacity). To this 2.8 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The solution was mixed vigorously on cyclo mixer and then degassed by bubbling N2 gas through it for 10-15min. The tube was then sealed and polymerization was carried out at 75° C for a period of 24 hours. After the polymerization, the polymer rod was taken out of the rube and crushed in a mortar. The polymer was sieved through a 75 u. sieve. The polymer particles below 75 u. size were chosen for the adsorption experiments. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, 2-(methacryloyl), ethyl, phenyl carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. Example 3 2.0 g of phenyl, 4-viny phenyl carbonate and 1.0 ml ethylene glycol dimethacrylate, EGDMA were taken in a glass tube. To this 3.0 g cyclohexanol and 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of Nj gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours. After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ sieve. The particles below 75 u, were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, phenyl, 4-vinyl phenyl carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. EXAMPLE 4 0.6 g of 2,4- DHB (2,4- dihydroxy benzophenone) methacrylate and 2.4 g trimethylol propane trimethacrylate (TRIM) were taken in a glass tube. To this 3.0 g toluene and 50 mg AJBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours. After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 u, sieve. The particles below 75 u, were used in further studies. The polymer was then washed for' 10-15 hours with methanol and dried. The hydrolysis of the template, 2,4- DHB methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. EXAMPLE 5 0.6 g of allyl, 2,4- DHB carbonate and 2.4 g TRIM were taken in a glass tube. To this 3.0 g toluene and 50 mg AIBN were added. The contents were mixed thoroughly on cycle mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours. After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ, sieve. The particles below 75 (i were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, allyl, 2,4- DHB carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum'at 50°-60° C in an oven. EXAMPLE 6 1.0 g of phenyl methacrylate and 1.0 ml EGDMA were taken in a glass tube. To this 2.0 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours. After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ. sieve. The particles below 75 u, were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. EXAMPLE 7 3.2 g of p- cumyl, phenyl methacrylate and 1.0 ml EGDMA were taken in a glass tube. To this 4.2 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours. After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75µ, sieve. The particles below 75µ were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, p- cumyl, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven. The process of the above invention has following advantages 1. The process provides means for preparation'of polymeric adsorbents that are selective for phenolic compounds. 2. The process being generic in nature can be extended to synthesis of MIPs selective for various other substrates of importance. 3. This process can directly be carried out in a HPLC column, wherein a porous, monolithic polymeric packing material is obtained in a single step. We Claim: 1. A process for preparation of polymeric adsorbents by precipitation polymerization which comprises (a) mixing requisite amount of a template monomer such as herein described, with a crosslinker as described herein, along with a porogen selected from cyclo hexanol or aromatic solvent such as defined herein and a polymerization initiator, typically a radical initiator as defined herein , degassing the obtained mixture by evacuator or by passage of inert gas, (b) polymerizing the monomer solution obtained in step (a) by conventional method as herein described, at a temperature ranging 60° - 90°C, for a period of 24 h, (c) crushing and sieving the polymer formed to get particle having size 250u - 100[J and washing it with a solvent as defined herein, to remove the unreacted monomers as well as the porogen, (d) hydrolyzing the polymer by acid or alkali treatment such as herein described, for a period ranging from 6-10 hours followed by washing with solvent and drying at a temperature ranging 50° to 60°C, to get the desired polymeric adsorbent. 2. A process as claimed in claim 1, the template monomer is either a carbonate ester or carboxylate ester having one or more vinylic /allylic/ styrenic unsaturations as exemplified by phenyl methacrylate, 2- (methacryloyl), ethyl, phenyl carbonate, phenyl, 4 -vinyl benzoate, phenyl, 4- vinyl phenyl carbonate, allyl phenyl carbonate, phenyl acrylate, 2 - (acryloyl), ethyl, phenyl carbonate, 2,4- DHB (2,4 -dihydroxy benzophenone ) methacrylate, allyl, 2,4 - DHB carbonate, p - nitrophenyl methacrylate, p - nitrophenyl acrylate, allyl, p -nitrophenyl carbonate, allyl bisphenyl carbonate, bisphenyl methacrylate, p - cumyl phenyl methacrylate, 2,4 - dinitrophenyl acrylate, 2,4 - dinitrophenyl methacrylate, p - methoxy phenyl methacrylate, allyl, o - methoxy phenyl carbonate, o - methoxy phenyl methacrylate, allyl, p - methoxy phenyl carbonate, o -methoxy phenyl methacrylate, allyl, p - methoxy phenyl carbonate, o - methoxy phenyl acrylate, p - methoxy phenyl acrylate. 3. A process as claimed in claims 1 and 2, the crosslinker used for polymerization is acrylic or methacrylic or styrenic in nature with two or more unsaturations as exemplified by methylene bis acrlamide, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, divinyl benzene, ethylene glycol diacrylate, trimethylol propane triacrylate. 4. A process as claimed in claims 1 to 3 wherein aromatic solvent used is selected from benzene, toluene, xylene. 5. A process as claimed in claims 1 to 4 the initiator used for the thermal polymerization is chosen from a class of compounds such as azo, peroxides, hydroperoxides, persulphates, more preferably from azo initiators. 6. A process as claimed in claims 1 to 5 the polymerization of the template monomer is carried out thermally preferably at temperature ranging 70° - 80°C. 7. A process as claimed in claims 1 to 6 wherein crushed polymer is ≤ 250µ particle size , preferably ≤150 µ particle size and most preferably ≤ 100 µ particle size . 8. A process as claimed in claims 1 to 7 wherein hydrolysis of the template monomer is carried out using preferably alkali solution selected from NaOH or KOH of a strength ranging 0.1 to 2.0 N and more preferably ranging 0.5 to 1.5 N 9. A process as claimed in claims 1 to 8 wherein the solvent used for washing of the polymer is selected from ethanol, methanol.acetone , chloroform. 10. A process for preparation of polymeric adsorbents by precipitation polymerization substantially as described herein with reference to the examples.

Full Text

This invention relates to a process for preparation of polymeric adsorberris, by precipitation polymerization, more particularly it relates to the process for the preparation of adsorbents selective for phenolic compounds.
Phenolic compounds such as phenol, p- nitrophenol, 2,4 and 2,6-dinitrophenol, isomers of bisphenol A etc. are many a time present in aromatic compounds as trace impurities (e.g. phenol in anisole or nitrophenols in nitrober.zene, o,p- bisphenol in bisphenol-A). These impurities lead to problems in down stream processing of these chemicals. Aromatics containing phenolic impurities when undergo catalytic oxidation / reduction reactions, phenols if present can form tarry products, which poison / deactivate the catalyst. Hence for enhancing the catalyst life as well as for better economics of the process it is necessary to remove phenolic impurities from aromatics. Another necessity for removal of phenol arises from the improvement in quality that is desirable for any product.
Phenolic impurities can be removed from aqueous streams using a variety of methods such as adsorption, distillation, and solvent extraction. These methods are commonly used on industrial scale as well and have been discussed in the literature.
Various kinds of adsorbents are used to achieve the same goal. The adsorbents used for removal of phenolic compounds can be either inorganic or organic in nature. The inorganic adsorbents used for such applications are silicas and zeolites where as commonly used organic adsorbents are polymeric in nature.
There are two kinds of polymeric adsorbents in common use for removal of phenolic compounds. These are crosslinked styrene - divinylbenzene resins (Amberlite XAD - 2, 4) marketed by Rohm and Haas or their equivalents and

crosslinked aery late / methacrylate resins (Amberlite XAD - 7, 8) or their equivalents. These are suitable for removal of phenols from aqueous phase.
Though these adsorbents are suitable for removal of phenolic compounds from aqueous phase, they do not have any structural feature that can distinguish between various phenols and hence they are not selective for a particular phenol. These adsorbents are able to remove phenols from aqueous streams as well as non-polar organic streams mainly based on the polarity difference between the solute and the solvent.
In literature there are references for preparation of polymers, which are selective to a particular substrate such as drugs (theophyllin, phenobarbital, creatanine), steroids (cholesterol, corticosteroids), nucleic acid bases, carbohydrates. The technique of preparation of such polymers is known as molecular imprinting ( Wulff, G., Angew. Chem. Int. Ed Eng., 34 (1995), 1812 -1832, Mosbach, K. and Ramstrom, O., Biotechnolog)>, 14 (1996), 163 - 173, Steinke, J., Sherrington, D. C. and Dunkin, I. R., Advances in polymer science Vol. 123 (1995), 81 -125). The polymers prepared by this technique are known as molecularly imprinted polymers or more commonly and herein after referred as MIPs. (MIPs)
The MIPs are prepared by polymerization of monomers around a template molecule in the presence of a large excess of crosslinker. During' synthesis, the template is either covalently or non-covalently linked to the monomers. After polymerization, the template is removed from the polymer leaving behind a cavity on the surface. These cavities have shape and size similar to the template molecule used during polymerization and hence are selective to those particular substrates.

There are no reports in the literature for the preparation of polymeric adsorbents selective for phenolic compounds using molecular imprinting technique by precipitation polymerization.
The object of the present invention is therefore to provide a process for the preparation of polymeric adsorbents by precipitation polymerization.
Accordingly the present invention provides a process for preparation of polymeric adsorbents by precipitation polymerization which comprises
(a) mixing requisite amount of a template monomer such as herein described, with
a crosslinker as described herein, along with a porogen selected from cyclo
hexanol or aromatic solvent such as defined herein and a polymerization
initiator, typically a radical initiator as defined herein , degassing the obtained
mixture by evacuator or by passage of inert gas,
(b) polymerizing the monomer solution obtained in step (a) by conventional
method as herein described, at a temperature ranging 60° - 90°C, for a period
of 24 h,
(c) crushing and sieving the polymer formed to get particle having size 250u -
100u and washing it with a solvent as defined herein, to remove the unreacted
monomers as well as the porogen,
(d) hydrolyzing the polymer by acid or alkali treatment such as herein described,
for a period ranging from 6-10 hours followed by washing with solvent and
drying at a temperature ranging 50° to 60°C, to get the desired polymeric
adsorbent.
In an embodiment the template monomer may be either a carbonate ester or carboxylate ester having one or more vinylic / allylic / styrenic unsaturations as exemplified by phenyl methacrylate, 2 - (methacryloyl), ethyl, phenyl carbonate,

phenyl, 4 - vinyl benzoate, phenyl, 4 - vinyl phenyl carbonate, allyl phenyl carbonaze, phenyl acrylate, 2 -(acryloyl), ethyl, phenyl carbonate, 2,4- DHB (2.4- dihydrcxy benzophenone) methacrylate, allyl, 2,4- DHB carbonate, p- nitrophenyl methacrylare, p- nitrophenyl acrylate, allyl, p- nitrophenyl carbonate, allyl bisphenyl carbonare, bisphenyl methacrylate, p- cumyl phenyl methacrylate, 2,4- dinitrophenyl acrylate, 2,4- dinitrophenyl methacrylate, p- methoxy phenyl methacrylate, aJlyl, o- methoxy phenyl carbonate, o- methoxy phenyl methacrylate, allyl, p- methoxy phenyl carbonate, o- methoxy phenyl acrylate, p- methoxy phenyl acrylate.
In another embodiment the crosslinker used for polymerization may be acrylic or methacrylic or styrenic in nature with two or more unsaturations as exemplified by methylene bis acrylamide, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, divinyl benzene, ethylene glycol diacrylate, trimethylol propane triacrylate.
In another embodiment the porogen used during the polymerization process may be either alcoholic in nature such as cyclohexanol or an aromatic solvent such as benzene, toluene, xylene.
In yet another embodiment the initiator used for the thermal polymerization may be chosen from a class of compounds such as azo, peroxides, hydroperoxices, persulphates, more preferably from azo initiators.
In yet another embodiment the degassing of the monomer solution may be carried out by evacuation of the solution or by passage of an inert gas such as nitrogen, argon, helium.

In yet another embodiment the polymerization of the template monomer may be carried out thermally between 60° - 90° C and more preferably between 70° - 80° C.
In yet another embodiment, after polymerization, the imprinted polymer may be crushed to a particle size In yet another embodiment the hydrolysis of the template monomer may be carried out using preferably alkali solution viz. NaOH or KOH of a strength between 0.1 to 2.0 N and more preferably between 0.5 to 1.5 N for a period ranging frcm 6 to 10 hours.
In yet another embodiment the solvent used for washing of the polymer may be selected from ethanol, methanol, acetone, chloroform.
In a feature of the present invention is provided a process for preparation of polymeric adsorbents, by the process of precipitation polymerization in presence of a porogen (Wulff, G. and Vesper, W. J. Chromatogr., 167 (1978), 171-186; Selkrgren, B., Ekherg, B. and Mosbach, K., J. Chromatogr., 347 (1985), 1-10; Shea, K. J. and Sasaki, D. Y., J. Am. Chem. Soc., Ill (1989), 3442-3444; Whitcomhe, M., Rodriguez, M. E., Villar, P. andVulfson, £, J. Am. Chem. Soc., 117(1995), 7105-7111; Cheong, S., Mcniven, S., Rachkov, A., Levi, K., Yano, K. and Kanibe, I., Macromolecuks, 30 (1997), 1317-1322). The porogen used in the process is such that it is a good solvent for the monomers but a poor solvent for the polymer. Due to this the polymer phase separates as it is formed entrapping the solvent in it. This leads to a highly porous structure with a large surface area.
These polymers can also be prepared by any other conventional methods of polymerization such as suspension polymerization (Mayes, A. and Mosbach, K.,

Anal. Chem. 68, (1996), 3769-3774), emulsion polymerization, bi continuous emulsion polymerization etc.
Because of their shape and size selectivity, MIPs have found applications in areas such as racemic resolution, as sensor materials or as shape selective catalysts.
The process of the present invention is described hereinbelow with reference to the examples that are illustrative only and should not be construed to limit the scope of the present invention in any manner.
Example 1
0.8 g of phenyl methacrylate and 3.2 g of divinyl benzene (50%) were weighed in glass test tube (15ml capacity). To this 4.0 g toluene (porogen) and lOOmg of azobis isobutyronitrile, AJBN (free radical initiator) was added. The contents were thoroughly mixed on a cyclo mixer and the solution was degassed by bubbling nitrogen gas through it for 10-15 min. The tube was then sealed and polymerization was carried out in a water bath maintained at 75° C for 24 hours.
After the polymerization the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ sieve and particles below 75 u were used as adsorbent. The polymer was then washed for 10-15 hours with methanol and dried in air. The hydrolysis of the template, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally' methanol. The polymer was then dried under vacuum at 50°-60° C in an oven.

Example 2
1.83 g of 2-(methacryloyI), ethyl, phenyl carbonate and 1.0 ml ethylene glycol dimethacrylate, EGDMA were taken in a glass tube (15ml capacity). To this 2.8 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The solution was mixed vigorously on cyclo mixer and then degassed by bubbling N2 gas through it for 10-15min. The tube was then sealed and polymerization was carried out at 75° C for a period of 24 hours.
After the polymerization, the polymer rod was taken out of the rube and crushed in a mortar. The polymer was sieved through a 75 u. sieve. The polymer particles below 75 u. size were chosen for the adsorption experiments. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, 2-(methacryloyl), ethyl, phenyl carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven.
Example 3
2.0 g of phenyl, 4-viny phenyl carbonate and 1.0 ml ethylene glycol dimethacrylate, EGDMA were taken in a glass tube. To this 3.0 g cyclohexanol and 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of Nj gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours.

After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ sieve. The particles below 75 u, were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, phenyl, 4-vinyl phenyl carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven.
EXAMPLE 4
0.6 g of 2,4- DHB (2,4- dihydroxy benzophenone) methacrylate and 2.4 g trimethylol propane trimethacrylate (TRIM) were taken in a glass tube. To this 3.0 g toluene and 50 mg AJBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours.
After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 u, sieve. The particles below 75 u, were used in further studies. The polymer was then washed for' 10-15 hours with methanol and dried. The hydrolysis of the template, 2,4- DHB methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven.

EXAMPLE 5
0.6 g of allyl, 2,4- DHB carbonate and 2.4 g TRIM were taken in a glass tube. To this 3.0 g toluene and 50 mg AIBN were added. The contents were mixed thoroughly on cycle mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours.
After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ, sieve. The particles below 75 (i were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, allyl, 2,4- DHB carbonate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum'at 50°-60° C in an oven.
EXAMPLE 6
1.0 g of phenyl methacrylate and 1.0 ml EGDMA were taken in a glass tube. To this 2.0 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours.

After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75 µ. sieve. The particles below 75 u, were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in an oven.
EXAMPLE 7
3.2 g of p- cumyl, phenyl methacrylate and 1.0 ml EGDMA were taken in a glass tube. To this 4.2 g cyclohexanol, 0.5 g dodecanol and 50 mg AIBN were added. The contents were mixed thoroughly on cyclo mixer and degassed by passage of nitrogen gas through the solution for 10-15 min. The tube was sealed and the polymerization was carried out at 75° C for 24 hours.
After polymerization, the polymer rod was taken out of the tube and crushed in a mortar. The polymer was sieved through a 75µ, sieve. The particles below 75µ were used in further studies. The polymer was then washed for 10-15 hours with methanol and dried. The hydrolysis of the template, p- cumyl, phenyl methacrylate was carried out by refluxing the polymer with 100 ml aqueous solution of 1 N NaOH for 6 hours. After hydrolysis the polymer was washed with dilute HC1 followed by water and finally methanol. The polymer was then dried under vacuum at 50°-60° C in
an oven.
The process of the above invention has following advantages

1. The process provides means for preparation'of polymeric adsorbents that
are selective for phenolic compounds.
2. The process being generic in nature can be extended to synthesis of MIPs
selective for various other substrates of importance.
3. This process can directly be carried out in a HPLC column, wherein a
porous, monolithic polymeric packing material is obtained in a single step.

We Claim:
1. A process for preparation of polymeric adsorbents by precipitation
polymerization which comprises
(a) mixing requisite amount of a template monomer such as herein
described, with a crosslinker as described herein, along with a
porogen selected from cyclo hexanol or aromatic solvent such as
defined herein and a polymerization initiator, typically a radical
initiator as defined herein , degassing the obtained mixture by
evacuator or by passage of inert gas,
(b) polymerizing the monomer solution obtained in step (a) by
conventional method as herein described, at a temperature ranging
60° - 90°C, for a period of 24 h,
(c) crushing and sieving the polymer formed to get particle having size
250u - 100[J and washing it with a solvent as defined herein, to
remove the unreacted monomers as well as the porogen,
(d) hydrolyzing the polymer by acid or alkali treatment such as herein
described, for a period ranging from 6-10 hours followed by
washing with solvent and drying at a temperature ranging 50° to
60°C, to get the desired polymeric adsorbent.
2. A process as claimed in claim 1, the template monomer is either a
carbonate ester or carboxylate ester having one or more vinylic
/allylic/ styrenic unsaturations as exemplified by phenyl methacrylate,
2- (methacryloyl), ethyl, phenyl carbonate, phenyl, 4 -vinyl benzoate,

phenyl, 4- vinyl phenyl carbonate, allyl phenyl carbonate, phenyl acrylate, 2 - (acryloyl), ethyl, phenyl carbonate, 2,4- DHB (2,4 -dihydroxy benzophenone ) methacrylate, allyl, 2,4 - DHB carbonate, p - nitrophenyl methacrylate, p - nitrophenyl acrylate, allyl, p -nitrophenyl carbonate, allyl bisphenyl carbonate, bisphenyl methacrylate, p - cumyl phenyl methacrylate, 2,4 - dinitrophenyl acrylate, 2,4 - dinitrophenyl methacrylate, p - methoxy phenyl methacrylate, allyl, o - methoxy phenyl carbonate, o - methoxy phenyl methacrylate, allyl, p - methoxy phenyl carbonate, o -methoxy phenyl methacrylate, allyl, p - methoxy phenyl carbonate, o - methoxy phenyl acrylate, p - methoxy phenyl acrylate.
3. A process as claimed in claims 1 and 2, the crosslinker used for
polymerization is acrylic or methacrylic or styrenic in nature with two
or more unsaturations as exemplified by methylene bis acrlamide,
trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate,
divinyl benzene, ethylene glycol diacrylate, trimethylol propane
triacrylate.
4. A process as claimed in claims 1 to 3 wherein aromatic solvent used
is selected from benzene, toluene, xylene.
5. A process as claimed in claims 1 to 4 the initiator used for the
thermal polymerization is chosen from a class of compounds such as
azo, peroxides, hydroperoxides, persulphates, more preferably from
azo initiators.

6. A process as claimed in claims 1 to 5 the polymerization of the
template monomer is carried out thermally preferably at temperature
ranging 70° - 80°C.
7. A process as claimed in claims 1 to 6 wherein crushed polymer is ≤
250µ particle size , preferably ≤150 µ particle size and most
preferably ≤ 100 µ particle size .
8. A process as claimed in claims 1 to 7 wherein hydrolysis of the
template monomer is carried out using preferably alkali solution
selected from NaOH or KOH of a strength ranging 0.1 to 2.0 N and
more preferably ranging 0.5 to 1.5 N

9. A process as claimed in claims 1 to 8 wherein the solvent used for
washing of the polymer is selected from ethanol, methanol.acetone ,
chloroform.
10. A process for preparation of polymeric adsorbents by precipitation
polymerization substantially as described herein with reference to the
examples.

Documents:

3319-del-1998-abstract.pdf

3319-del-1998-claims.pdf

3319-del-1998-correspondence-others.pdf

3319-del-1998-correspondence-po.pdf

3319-del-1998-description (complete).pdf

3319-del-1998-form-1.pdf

3319-del-1998-form-19.pdf

3319-del-1998-form-2.pdf

3319-del-1998-form-3.pdf

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Patent Number

215140

Indian Patent Application Number

3319/DEL/1998

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

21-Feb-2008

Date of Filing

09-Nov-1998

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001 INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	RAGHUNATH ANANT MASHELKAR	NATIONAL CHEMICAL LABORATORY, PUNE 411008, INDIA.
2	VIVEK PRABHAKAR JOSHI	NATIONAL CHEMICAL LABORATORY, PUNE 411008, INDIA.
3	MOHAN GOPALKRISHNA KULKARNI	NATIONAL CHEMICAL LABORATORY, PUNE 411008, INDIA.

PCT International Classification Number

C08F 112/34

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA