Title of Invention	"AN IMPROVED PROCESS FOR THE PREPARATION OF STEREOREGULAR POLYMER USING CLATHRATES"
Abstract	The present invention provides an improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 80°C for minimum 4 hours under stirring and recovering the polymer by conventional methods. The polystyrene is extensively used for disposable tumbler, television cabinets, meat and food trays.

Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF STEREOREGULAR POLYMER USING CLATHRATES"

Abstract

The present invention provides an improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 80°C for minimum 4 hours under stirring and recovering the polymer by conventional methods. The polystyrene is extensively used for disposable tumbler, television cabinets, meat and food trays.

Full Text	This invention relates to an improved process for the preparation of stereoregular polymer using clathrates. The invention particularly relates to the preparation of stereoregular vinyl polymers such as syndiotactic rich polystyrene or isotactic rich poly aery lonitrile polymers through inclusion polymerisation using clathrate such as ß-cyclodextrin with styrene and acrylonitrile as the monomers. At present Polystyrene (PS) is extensively used for disposable tumblers, television cabinets, meat and food trays. Rigid form insulation in various forms is being used increasingly in construction industry and modified styrene plastics are replacing steel or aluminium parts in automobiles. Light weight concrete is made from prefoamed expanded polystyrene beads and portland cements (Kirk-Orthmer in Encyclopaedia of Chemical Technology, vol.21, pp836, 1983). Stereoregular PS are prepared by the polymerisation of the monomer with stereospecific catalysts of the Zieglar-Natta type. PS polymers are being prepared by emulsion polymerisation (Polymer Science by V.R.Gowariker, N.V.Viswanathan and J. Sreedhar; published by Wiley Eastern Limited, New Delhi; pp366, 1990). Although polyacrylonitrile(PAN) polymers do not find extensive application industrially, they are produced in reasonable quantities to suit uses which do not involve intricate moulding(Kirk-Orthmer in Encyclopedia of Chemical Tecnology vol.1, pp427, 1978).] Stereoregular PAN polymer is prepared by the polymerisation of the monomer with stereospecific catalysts of the Zieglar-Natta type. PAN polymer is being prepared by suspension polymerisation method (Polymer Synthesis by S.R.Sandler and W.Karo, vol.1. Academic press New York; pp318,1974). Polymerisation under various conditions result in polymers of divergent stereoregularities. Thus the proportion of syndiotactic, isotactic and atactic polymers formed vary drastically depending on the method of preparation, temperature, catalyst and irradiation. Isotactic rich polystyrene are prepared by using stereospecific catalyst system like LiC4H9/H2O [R..J.Kern, Nature 187,410, 1960] and also it can be prepared by using TiCl4 supported on MgCl2/Al(i-C4H9)3 catalyst system. Polymerisation of styrene in the presence of homogeneous catalytic systems consisting of tetrabenzyltitaniummethyl alumoxane in toluene resulted in syndiotactic rich polystyrene [A. Grassi, P.Long, A.Proto and A.Zambelli. Macromolecules 1989, 22, 104- 108]. The properties of the PS polymer prepared have been shown to depend on the stereoregularities of the same. Polymerisation of PAN yielded 75% syndiotactic and 25% isotactic polymers. Anionic polymerisation resulted in 55-60% syndiotactic and 35-40% isotactic PAN polymers. Irradiation of urea canal gave 50% syndiotactic and 50% isotactic polymers (R.Yamadera and M.M.Murano, J.Polym.Sci., A5, 1059 (1967). The properties of the above mentioned polymer prepared have been shown to depend on the stereoregularities of the same. Methods of preparation of polystyrene and polyacrylonitrile polymers known so far result in polymers of certain molecular weights and stereoregularities. It is also difficult by these procedures employed to uniformly control the molecular weights and stereoregularity of desired nature. While decrease in molecular weights lead to polymers with better blowing, increase in adhesiveness, decrease in crystallinity and decrease in barrier properties, increase in syndiotacticity and isotacticity results in increase in crystallinity. Since the polymer with lesser molecular weights and better stereoregularities are difficult to prepare in a controlled manner by the existing methods better methods to achieve them could be arrived at by employing inclusion polymerisation. Clathrates are cage complexes formed by inclusion of guest (any molecule of appropriate dimension) into a host (cyclophanes, calixaranes and cyclodextrins) molecule i /" which possess a cavity that can accommodate the former. Sometimes several molecules of the same kind may assemble to form cages which accommodate one or several molecules of guest molecules inside them. Although clathrate is a general name for such •^ cage complexes, several other names like cryptands, cavitands are also used to describe them. Crown ethers, calixaranes, cyclophanes, cyclodextrins, urea and deoxycholic acid are few such molecules which function as excellent host molecules in forming clathrates. These clathrates are unique because of their multifaceted characteristics. They possess cavities of dimensions that can accommodate a wide variety of guest molecules. Their hydrophobic exterior and hydrophilic interior (calixaranes) or hydrophilic exterior and hydrophobic interior (cyclodextrins) enable complexatioh with hydrophobic or partially hydrophobic guest molecules. Their ability to distinguish antipodes and their potentiality to effect regioselective and stereoselective reactions on included guest molecules along with their ability to function as phase-transfer catalysts makes them excellent enzyme mimics. Among these clathrates, cyclodextrins are unique in that they exhibit all the above mentioned characteristics in a much more profound manner than the other clathrate hosts mentioned above. Numerous reviews have been dedicated to the subject of inclusion polymerisation (M.Farina, in Inclusion Compounds, J.T.Atwood, J.E.D.Davies, and D.D.Macnicol, Eds., Academic Press, London, 1984, pp297) using clathrates and various hosts and different monomer guest molecules such as 2,3-dimethylbutadiene, vinylchloride, trans-1,3-pentadiene and 4-bromostyrene. Such inclusion polymerisation changes the physical and chemical nature of the included monomers leading to polymers with controlled stereoregularity (D.M.White, J. Am. Chem. Soc., 82, 5678, 1960; I.Sakurder and K. Manbu, Kogyo Kagaku Zasshi, 80, 304, 1959; H.R.Allcock, W.T.Ferrar, and M.L.Livin, J. Macromol., 15, 597,1982). Very little work has been done in the field of inclusion polymerisation involving clathrates for the synthesis of stereoregular polymers. However no work on preparation of stereoregular polystyrene and polyacrylonitrile polymers employing clathrates such as cyclodextrin has been reported so far. The main objectives of the invention is to produce a process for the preparation of stereoregular vinyl polymers such as sydiotactic rich polystyrene and isotactic rich polyacrylonitrile polymers using clathrate. Another objective of the present invention is to prepare vinyl polymers particularly polystyrene and polyacrylonitrile polymers using clathrate such as ß-cyclodextrin, calixaranes, cyclophanes, urea, thiourea. Still another objective of this present invention is to effect inclusion polymerisation using clathrates preferably ß-cyclodextrin. Inclusion of monomers such as styrene and acrylonitrile inside ß-cyclodextrin cavity prior to polymerisation has resulted in preparation of polystyrene and acrylonitrile respectively of different molecular weights and different tacticity proportions at various concentrations of ß-cyclodextrin employed. Hence, use of ß-cyclodextrin in polymerisation has resulted in polystyrene and polyacrylonitrile whose molecular weights and tacticity proportions can be controlled to yield polystyrene and polyacrylonitrile which can be used for some specific purposes such as light weight concrete, disposable tumblers, meat and in food packaging industries. Other new findings are: 1. Stoichiometries and binding constant values of the inclusion complexes of styrene and acrylonitrile monomers with ß-cyclodextrin were determined from UV-Visible spectrophotometric measurements. Binding constant values for the 1:1 styrene:p-CD and acrylonitrile:ß-CD complexes obtained were 31,395 ± 3500 and 7242 ± 360 M-1 respectively. 2. Molecular weights of the polystyrene and polyacrylonitrile polymers prepared were determined. They range from 3.19440 x 104 to 4.69728 x 105 for polystyrene and 9.1547 x 104 to 4.6973 x 103 for polyacrylonitrile. 3. Stereoregularity of polystyrene polymers prepared were determined by 13C-NMR spectroscopic measurements. 4. Stereoregularity of polyacrylonitrile polymers prepared were determined by 1H-NMR spectroscopic measurements The Stereoregularity distribution of the polystyrene polymers prepared in the presence of various ß-CD concentrations as determined by 13C-NMR are shown in Table 1. Table-1. ß-CD mediated stereoregularity in PS polymers. (Table Removed) Styrene monomer was used after purification The stereoregularity distribution of the polyacrylonitrile polymers prepared in the presence of various ß-CD concentrations as determined by 1H-NMR are shown in Table 2. Table.2 ß-CD-mediated stereoregularity in polyacrylonitrile polymers. (Table Removed) Acrylonitrile monomer was used after purification. This methodology offers preparation of polymers which differ in molecular weights and stereoregularities that can find specific end use. Hence, it projects a larger implication on polymer synthesis in general. Accordingly, the present invention provides an improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 80°C for minimum 4 hours under stirring and recovering the polymer by conventional methods. In another embodiment of the present invention the polymerization is effected by methods selected from suspension polymerization, emulsion polymerization, free radical polymerization and inclusion polymerization. In yet another embodiment of the present invention the monomers used in the polymerization and compounds selected from styrene, acrylonitrile, methacrylate, methyl methacrylate, vinyl chloride and vinyl alcohol. In still another embodiment of the present invention clathrate employed is compound selected from ß-cyclodextrin, ß-cyclodextrin-polymer, calixaranes, cyclophanes, urea and thiourea, preferably ß-cyclodextrin and its polymer. In yet another embodiment of the invention the initiator employed in catalytic amounts may be compounds such as potassium persulphate and ammonium persulphate. In still another embodiment of the invention the anionic emulsifying agent employed may be compounds such as sodium lauryl sulphate in the range of 0.5% -1.0%. In still another embodiment of the invention the polymers used may be vinyl polymers such as polystyrene, polyvinyl alcohol, polyvinyl chloride and polyacrylates particularly polystyrene and poly aery lonitrile. In yet another embodiment of the invention the recovery of some vinyl polymers may be carried out using precipitating agent selected from aluminium sulphate in the range 2-5%. The process of this invention is provided by the following examples, which are illustrative only and should not be construed to limit the scope of the invention. Example 1 A mixture of styrene (0.1746 mole), potassium persulphate 20 mg, sodium laurylsulphate 200 mg and sodium hydrogen phosphate 20 mg in 40 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum. In a typical reaction such as the one in control gave an yield of 14.5 gm (80%). The results of tacticity studies are given in Table. 1. Polymerisation carried out in the absence of ß-CD gave 18% atactic, 17% isotactic and 65% syndiotactic. Example 2 A mixture of styrene (0.1047 mole), ß-CD (0.0105 mole), potassium persulphate 12 mg, sodium laurylsulphate 120 mg and sodium hydrogen phosphate 12 mg in 25 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum. When the molar ratio of styrene to ß-CD was 5:1, the proportion of atactic, isotactic and syndiotactic polymers formed was found to be 15, 15 and 70% respectively. Example 3 A mixture of styrene (0.1047 mole), ß-CD (0.00524 mole), potassium persulphate 12 mg, sodium laurylsulphate 120 and sodium hydrogen phosphate 12 mg in 25 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum. However the molar ratio was increased to 10:1 and 20:1, the ratio of atactic, isotactic and syndiotactic was found to be 14:13:73 and 13:10:77 respectively. Example 4 A mixture of styrene (0.0524 mole),ß-CD-epichlorohydrin polymer (0.00524 mole), potassium persulphate 6 mg, sodium laurylsulphate 60 mg and sodium hydrogen phosphate 6 mg in 15 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuun. When the molar ratio of styrene to ß-CD-polymer was 10:1, the proportion of atactic, isotactic and syndiotactic polymers formed was found to be 5, 8 and 87 respectively. Thus a increase in styrene: ß-CD ratio caused an increase in the percentage of syndiotacticity. In otherwords, an increase in the styrene: ß-CD ratio caused an decrease in the proportion of both atactic and isotactic polymer formed (Table-1). Syndiotactic polymer is more favoured at lower ß-CD concentrations than isotactic and atactic polymer because the orientation of the ß-CD complex in the opposite direction will be more favoured from a steric point of view. At higher ß-CD concentrations syndiotactic polymer is less favoured because of increase in bulky ß-CD groups in the vicinity of the oppositively oriented styrene phenyl rings. Example 5 A mixture of acrylonitrile (0.106 mole), sodium metabisulfite (0.007 gm), ammonium persulfate (0.171 gm) and a drop of acid in water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried. In a typical reaction such as the one in control gave an yield of 5 gm (89.0%). The results of tacticity studies are given in Table.2. Polymerisation carried out in the absence of ß-CD gave 54% isotactic and 46% syndiotactic polymers. Example 6 A mixture of acrylonitrile (0.024 mole), ß-CD (0.0047 moles), sodium metabisulfite (0.0016 gm), ammonium persulfate (0.038 gm) and a drop of acid water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried. When the molar ratio of acrylonitrile to ß-CD was 5:1, the proportion of isotactic and syndiotactic polymers formed was found to be 59 and 41% respectively. Example 7 A mixture of acrylonitrile (0.0475 moles),ß-CD (0.0047 moles), sodium metabisulfite (0.0031 gm), ammonium persulfate (0.0076 gm) and a drop of acid in water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried. However, when the molar ratio was increased to 10:1 and 20:1, the isotactic to syndiotactic ratio was found to be 64:36 and 68:32 respectively. Thus a decrease in AN: ß-CD ratio caused an increase in the percentage of syndiotacticity. In otherwords, an increase in the AN: ß-CD ratio caused an increase in the proportion of isotactic polymer formed (Table-2). Syndiotactic polymer is more favoured at higher ß-CD concentrations than isotactic polymer because the orientation of the ß-CD complex in the opposite direction will be more favored from a steric point of view than the presence of two ß-CD units in adjacent position which will lead to an isotactic polymer. Steric hinderence between adjacent ß-CD units is reduced at lower ß-CD concentrations, thereby favoring more isotactic than syndiotactic polymer. Interestingly, the proportion of isotactic polymer formed at lower ß-CD concentrations was found to be more than that obtained in the total absence of ß-CD. The reason for this is not known. Similarly monomers other than styrene and acrylonitrile monomers such as methyl methacrylate, vinyl chloride and vinyl alcohol can be employed for preparing syndiotactic and isotactic rich polymers. Similarly other clathrates such as calixaranes, cyclophanes, urea and thiourea can be used for preparing syndiotactic and isotactic rich polymers. Determination of molecular weight: The molecular weight of the polymers prepared were determined by Oswalt viscometer (Polymer Science by V.R.Gowariker, N.V.Viswanathan and Jayadev Sridar published by Wiley Eastern Limited, New Delhi; pp406, 1990). Different known concentrations of the polystyrene polymer in benzene and polyacrylonitrile polymer in dimethyl formamide were prepared. The solvents flow time (to) and the solution flow time (t) for different concentrations were measured using the same viscometer. The difference between the flow rates gives the relative viscosity (ηr =Η/Η0 = t/to). Specific viscosities were calculated by subtracting unity from relative viscosity (ΗSP = ηr -1, where ηsp is the specific viscosity). At each concentration corresponding reduced viscosity (ηred = ηsp /C, where C is the concentration) and the inherent viscosity (ηinh = 1nηr / C) were evaluated. Extrapolation of reduced viscosity against concentration and inherent viscosity against concentration (both extrapolated to zero concentration) gave a common ordinate intercept namely the intrinsic viscosity (Η). The viscosity average molecular weights of the prepared polystyrene and polyacrylonitrile polymers are calculated based on Mark-Houwkin equation [Ti] = K.M'v Where K and a are constants for a given polymer, solvent and temperature system. The molecular weights of the above prepared polymers are given in table 3 and Table 4. Table - 3. Molecular weights of prepared PS Polymers (Table Removed) Table - 4. Molecular weights of prepared PAN Polymers (Table Removed) Determination of tacticity distribution of polystyrene: The streoregularity distribution in PS polymers were determined by I3C-NMR spectra. 13C-NMR spectra of PS polymers were recorded on the 270 MHz instrument at room temperature. The I3C NMR spectra of PS polymers were analysed by using aromatic C-1 signal according to method described by Matsuzaki (K.Matsuzaki, T.Uryu, K.Osada, T.Kawamura. Macromolecules, 5, 816, 1972). The aromatic C-1 signal at 145.1 to 146.1 ppm consist of three main peaks corresponding to isotactic, atactic and syndiotactic triads of the polymer irrespective of whether ß-CD is employed or not. The peak at lower magnetic field (146.1 ppm) corresponds to isotactic, the peak at 145.5 ppm corresponds to atactic and peak obtained in higher magnetic field (145.1 ppm) corresponds to syndiotactic triads. The triads obtained from this spectra in all the polymers do not obey the Bernoullian statistics as such , but nearly obey the Bernoullian statistics, when the assumption is based on pentad sequences. Determination of tacticity of polyacrylonitrile: The streoregularegularity distribution in PAN polymers were determined by 1H NMR spectra. An 1H NMR spectra of PAN polymers were recorded on the 270 MHz nstrument at 100°C. The quintet at 3.17 ppm corresponds to α -CH and the multiple! between 2.06 and 2.17 ppm correspond to ß-CH2 protons present in the polymer irrespective of whether ß-CD was employed or not in the polymerisation. The multiple! obtained is interpreted as the AB part of an ABX2 system due to overlapping of the syndiotactic (higher field) and isotactic (lower field) triplets. The tacticity of the polymer prepared was calculated from this NMR spectrum according to the method described by Yamadera [Yamadera and Murano, J.Poly.Sci., A5, 1059 (1967)] by using the relation (Formula Removed) Where D(Τ) is the intensity at chemical shift τ, 2b the half-width value, τi is the chemical shift of each peak, and DMi is the intensity of the peak at chemical shift τi. Determination of binding constant value for the 1:1 complex of styrene with ß-CD. The orientation of styrene inside ß-CD cavity was investigated by UV-Visible spectroscopy. Styrene exhibits λmu at 248 nm (e = 3547) in ethanol. Addition of ß-CD (9.948 x lO-4M) to Styrene (4.37 x lO-4M) resulted in absorption at 243 nm. A plot of ΔA versus [ß-CD]/[Styrene] indicated formation of 1:1 complex between Styrene and ß-CD. Binding constant value was determined both by double reciprocal plot method and Scatchard analysis method (C.Farmoso, Biochem. Biophys. Res.Commun., 50, 95,1973). (M.M.Maheswaran and S.Divakar, Indian. J. Chem., 30A, 30- 34, 1991). A plot of 1/ΔA against l/[ß-CD] gave straight line with slope equal to 1/(Δ AAB K), where ΔAAB is the difference in absorbance between free styrene and its ß-CD complex and K is the binding constant value for the 1:1 complex. An average binding constant value of 31,395 ± 3500 M'1 was obtained for the 1:1 complex. Determination of binding constant value for the 1:1 complex of acrylonitrile with ß-CD: The variation in stereoregularity due to complexation of acrylonitrile by ß-CD was investigated by uv-vis spectroscopy. Acrylonitrile exhibits a strong absorption at 203 nm in water (Ε =8342). With the addition of increasing amounts of ß-CD, the absorption at 203 nm decreased with an isobestic point at 210nm. A titration plot of A (difference in absorption between acrylonitrile and that at a certain concentration of ß-CD) versus [ß-CD] / [AN] exhibited an asymptotic curve with 1:1 stoichiometry, indicating formation of a 1:1 complex. The binding constant value was determined by the method of Farmoso (C.Farmoso, Biochem. Biophys. Res.Commun., 50, 95(1973). A plot of I/ A against 1/[ß-CD] gave a straight line with slope equal to ( AAB K ), where A is the difference in absorbance between free acrylonitrile and its P-CD complex and K is the binding constant value for the 1:1 complex. A value of 7242+360 M'1 was obtained for the acrylonitrile ß-CD complex. The formation of an inclusion complex was further conformed by 1H-NMR spectrum. It showed a change in the acrylonitrile (monomer) multiplets in the 5.72 - 6.42 ppm egion in the presence of ß-CD. (table-3) - Acrylonitrile monomer shows two group of signals centered at 5.81 and 6.32 ppm in D20. On adding an equivalent amount of ß- CD, the signals showed slight changes in chemical shift values of the multiplets centered at 5.92 and 6.3 ppm, indicating formation of an inclusion complex. (Formula Removed) Main advantages of the invention are: a) In PS polymers the tacticity proportion of the polymer prepared was found to be altered with decrease in ß-CD concentration. Decrease in ß-CD concentration resulted in increase in syndiotacticity. b) In case of PAN, tacticity proportion of the polymer prepared was found to be altered with increase in ß-CD concentration. Increase in ß-CD concentration resulted in decrease in isotacticity c) The molecular weights of polystyrene and poly aery lonitrile polymers decreased on increase in concentration of ß-CD and its derivatives. d) ß-CD used can be recovered and reused. e) The use of ß-CD during polymerisation provides a method for preparing polystyrene and polyacrylonitrile polymers whose molecular weights and tacticities could be controlled. f) Polymerisation of PAN was achieved under mild reaction conditions. We Claim: 1. An improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 800C for minimum 4 hours under stirring and recovering the polymer by conventional methods. 2. An improved process as claimed in claim 1, wherein the polymerization is effected by methods selected from suspension polymerization, emulsion polymerization, free radical polymerization and inclusion polymerization. 3. An improved process as claimed in claims 1- 2, wherein the monomers used in the polymerization and compounds selected from styrene, acrylonitrile, methacrylate, methyl methacrylate, vinyl chloride and vinyl alcohol. 4. An improved process as claimed claim 1 to 3, wherein clathrate employed is compound selected from f3-cyclodextrin, f3-cyclodextrin-polymer, calixaranes, cyclophanes, urea and thiourea, preferably f3-cyclodextrin and its polymer. 5. An improved process as claimed in claim 1 to 4, wherein the emulsifying agent employed may be compounds such as sodium lauryl sulphate in the range of 0.5% 6. An improved process for the preparation of stereoregular polymer using clathrates substantially as herein described with reference to the examples.

Full Text

This invention relates to an improved process for the preparation of stereoregular polymer using clathrates. The invention particularly relates to the preparation of stereoregular vinyl polymers such as syndiotactic rich polystyrene or isotactic rich poly aery lonitrile polymers through inclusion polymerisation using clathrate such as ß-cyclodextrin with styrene and acrylonitrile as the monomers.
At present Polystyrene (PS) is extensively used for disposable tumblers, television cabinets, meat and food trays. Rigid form insulation in various forms is being used increasingly in construction industry and modified styrene plastics are replacing steel or aluminium parts in automobiles. Light weight concrete is made from prefoamed expanded polystyrene beads and portland cements (Kirk-Orthmer in Encyclopaedia of Chemical Technology, vol.21, pp836, 1983). Stereoregular PS are prepared by the polymerisation of the monomer with stereospecific catalysts of the Zieglar-Natta type. PS polymers are being prepared by emulsion polymerisation (Polymer Science by V.R.Gowariker, N.V.Viswanathan and J. Sreedhar; published by Wiley Eastern Limited, New Delhi; pp366, 1990).
Although polyacrylonitrile(PAN) polymers do not find extensive application industrially, they are produced in reasonable quantities to suit uses which do not involve intricate moulding(Kirk-Orthmer in Encyclopedia of Chemical Tecnology vol.1, pp427, 1978).]

Stereoregular PAN polymer is prepared by the polymerisation of the monomer with stereospecific catalysts of the Zieglar-Natta type. PAN polymer is being prepared by suspension polymerisation method (Polymer Synthesis by S.R.Sandler and W.Karo, vol.1. Academic press New York; pp318,1974).
Polymerisation under various conditions result in polymers of divergent stereoregularities. Thus the proportion of syndiotactic, isotactic and atactic polymers formed vary drastically depending on the method of preparation, temperature, catalyst and irradiation.
Isotactic rich polystyrene are prepared by using stereospecific catalyst system like LiC4H9/H2O [R..J.Kern, Nature 187,410, 1960] and also it can be prepared by using TiCl4 supported on MgCl2/Al(i-C4H9)3 catalyst system. Polymerisation of styrene in the presence of homogeneous catalytic systems consisting of tetrabenzyltitaniummethyl alumoxane in toluene resulted in syndiotactic rich polystyrene [A. Grassi, P.Long, A.Proto and A.Zambelli. Macromolecules 1989, 22, 104- 108]. The properties of the PS polymer prepared have been shown to depend on the stereoregularities of the same.
Polymerisation of PAN yielded 75% syndiotactic and 25% isotactic polymers. Anionic polymerisation resulted in 55-60% syndiotactic and 35-40% isotactic PAN polymers. Irradiation of urea canal gave 50% syndiotactic and 50% isotactic polymers (R.Yamadera and M.M.Murano, J.Polym.Sci., A5, 1059 (1967). The properties of the

above mentioned polymer prepared have been shown to depend on the stereoregularities of the same.
Methods of preparation of polystyrene and polyacrylonitrile polymers known so far result in polymers of certain molecular weights and stereoregularities. It is also difficult by these procedures employed to uniformly control the molecular weights and stereoregularity of desired nature. While decrease in molecular weights lead to polymers with better blowing, increase in adhesiveness, decrease in crystallinity and decrease in barrier properties, increase in syndiotacticity and isotacticity results in increase in crystallinity. Since the polymer with lesser molecular weights and better stereoregularities are difficult to prepare in a controlled manner by the existing methods better methods to achieve them could be arrived at by employing inclusion polymerisation.
Clathrates are cage complexes formed by inclusion of guest (any molecule of appropriate dimension) into a host (cyclophanes, calixaranes and cyclodextrins) molecule
i /"
which possess a cavity that can accommodate the former. Sometimes several molecules of the same kind may assemble to form cages which accommodate one or several molecules of guest molecules inside them. Although clathrate is a general name for such
•^
cage complexes, several other names like cryptands, cavitands are also used to describe them. Crown ethers, calixaranes, cyclophanes, cyclodextrins, urea and deoxycholic acid are few such molecules which function as excellent host molecules in forming

clathrates. These clathrates are unique because of their multifaceted characteristics. They possess cavities of dimensions that can accommodate a wide variety of guest molecules. Their hydrophobic exterior and hydrophilic interior (calixaranes) or hydrophilic exterior and hydrophobic interior (cyclodextrins) enable complexatioh with hydrophobic or partially hydrophobic guest molecules. Their ability to distinguish antipodes and their potentiality to effect regioselective and stereoselective reactions on included guest molecules along with their ability to function as phase-transfer catalysts makes them excellent enzyme mimics. Among these clathrates, cyclodextrins are unique in that they exhibit all the above mentioned characteristics in a much more profound manner than the other clathrate hosts mentioned above.
Numerous reviews have been dedicated to the subject of inclusion polymerisation (M.Farina, in Inclusion Compounds, J.T.Atwood, J.E.D.Davies, and D.D.Macnicol, Eds., Academic Press, London, 1984, pp297) using clathrates and various hosts and different monomer guest molecules such as 2,3-dimethylbutadiene, vinylchloride, trans-1,3-pentadiene and 4-bromostyrene. Such inclusion polymerisation changes the physical and chemical nature of the included monomers leading to polymers with controlled stereoregularity (D.M.White, J. Am. Chem. Soc., 82, 5678, 1960; I.Sakurder and K. Manbu, Kogyo Kagaku Zasshi, 80, 304, 1959; H.R.Allcock, W.T.Ferrar, and M.L.Livin, J. Macromol., 15, 597,1982).

Very little work has been done in the field of inclusion polymerisation involving clathrates for the synthesis of stereoregular polymers. However no work on preparation of stereoregular polystyrene and polyacrylonitrile polymers employing clathrates such as cyclodextrin has been reported so far.
The main objectives of the invention is to produce a process for the preparation of stereoregular vinyl polymers such as sydiotactic rich polystyrene and isotactic rich polyacrylonitrile polymers using clathrate.
Another objective of the present invention is to prepare vinyl polymers particularly polystyrene and polyacrylonitrile polymers using clathrate such as ß-cyclodextrin, calixaranes, cyclophanes, urea, thiourea.
Still another objective of this present invention is to effect inclusion polymerisation using clathrates preferably ß-cyclodextrin.
Inclusion of monomers such as styrene and acrylonitrile inside ß-cyclodextrin cavity prior to polymerisation has resulted in preparation of polystyrene and acrylonitrile respectively of different molecular weights and different tacticity proportions at various concentrations of ß-cyclodextrin employed. Hence, use of ß-cyclodextrin in polymerisation has resulted in polystyrene and polyacrylonitrile whose molecular weights and tacticity proportions can be controlled to yield polystyrene and polyacrylonitrile

which can be used for some specific purposes such as light weight concrete, disposable tumblers, meat and in food packaging industries.
Other new findings are:
1. Stoichiometries and binding constant values of the inclusion complexes of styrene
and acrylonitrile monomers with ß-cyclodextrin were determined from UV-Visible
spectrophotometric measurements. Binding constant values for the 1:1 styrene:p-CD
and acrylonitrile:ß-CD complexes obtained were 31,395 ± 3500 and 7242 ± 360 M-1
respectively.
2. Molecular weights of the polystyrene and polyacrylonitrile polymers prepared were
determined. They range from 3.19440 x 104 to 4.69728 x 105 for polystyrene and
9.1547 x 104 to 4.6973 x 103 for polyacrylonitrile.
3. Stereoregularity of polystyrene polymers prepared were determined by 13C-NMR
spectroscopic measurements.
4. Stereoregularity of polyacrylonitrile polymers prepared were determined by 1H-NMR
spectroscopic measurements
The Stereoregularity distribution of the polystyrene polymers prepared in the presence of various ß-CD concentrations as determined by 13C-NMR are shown in Table 1.

Table-1. ß-CD mediated stereoregularity in PS polymers.

(Table Removed)
Styrene monomer was used after purification
The stereoregularity distribution of the polyacrylonitrile polymers prepared in the presence of various ß-CD concentrations as determined by 1H-NMR are shown in Table 2. Table.2 ß-CD-mediated stereoregularity in polyacrylonitrile polymers.

(Table Removed)
Acrylonitrile monomer was used after purification.

This methodology offers preparation of polymers which differ in molecular weights and stereoregularities that can find specific end use. Hence, it projects a larger implication on polymer synthesis in general.
Accordingly, the present invention provides an improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 80°C for minimum 4 hours under stirring and recovering the polymer by conventional methods.
In another embodiment of the present invention the polymerization is effected by methods selected from suspension polymerization, emulsion polymerization, free radical polymerization and inclusion polymerization.
In yet another embodiment of the present invention the monomers used in the polymerization and compounds selected from styrene, acrylonitrile, methacrylate, methyl methacrylate, vinyl chloride and vinyl alcohol.
In still another embodiment of the present invention clathrate employed is compound selected from ß-cyclodextrin, ß-cyclodextrin-polymer, calixaranes, cyclophanes, urea and thiourea, preferably ß-cyclodextrin and its polymer.

In yet another embodiment of the invention the initiator employed in catalytic amounts may be compounds such as potassium persulphate and ammonium persulphate.
In still another embodiment of the invention the anionic emulsifying agent employed may be compounds such as sodium lauryl sulphate in the range of 0.5% -1.0%.
In still another embodiment of the invention the polymers used may be vinyl polymers such as polystyrene, polyvinyl alcohol, polyvinyl chloride and polyacrylates particularly polystyrene and poly aery lonitrile.
In yet another embodiment of the invention the recovery of some vinyl polymers may be carried out using precipitating agent selected from aluminium sulphate in the range 2-5%.
The process of this invention is provided by the following examples, which are illustrative only and should not be construed to limit the scope of the invention.
Example 1
A mixture of styrene (0.1746 mole), potassium persulphate 20 mg, sodium laurylsulphate 200 mg and sodium hydrogen phosphate 20 mg in 40 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum. In a typical

reaction such as the one in control gave an yield of 14.5 gm (80%). The results of tacticity studies are given in Table. 1. Polymerisation carried out in the absence of ß-CD gave 18% atactic, 17% isotactic and 65% syndiotactic.
Example 2
A mixture of styrene (0.1047 mole), ß-CD (0.0105 mole), potassium persulphate
12 mg, sodium laurylsulphate 120 mg and sodium hydrogen phosphate 12 mg in 25 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum.
When the molar ratio of styrene to ß-CD was 5:1, the proportion of atactic, isotactic and syndiotactic polymers formed was found to be 15, 15 and 70% respectively.
Example 3
A mixture of styrene (0.1047 mole), ß-CD (0.00524 mole), potassium persulphate
12 mg, sodium laurylsulphate 120 and sodium hydrogen phosphate 12 mg in 25 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuum.
However the molar ratio was increased to 10:1 and 20:1, the ratio of atactic, isotactic and syndiotactic was found to be 14:13:73 and 13:10:77 respectively.

Example 4
A mixture of styrene (0.0524 mole),ß-CD-epichlorohydrin polymer (0.00524
mole), potassium persulphate 6 mg, sodium laurylsulphate 60 mg and sodium hydrogen phosphate 6 mg in 15 mL of water were taken in a three necked round bottom flask. The mixture was stirred at a 70°C for 6 hours. The polymer was isolated by adding 3% aluminium sulfate solution. The precipitate formed was filtered, washed with hot water and dried in vacuun.
When the molar ratio of styrene to ß-CD-polymer was 10:1, the proportion of
atactic, isotactic and syndiotactic polymers formed was found to be 5, 8 and 87 respectively.
Thus a increase in styrene: ß-CD ratio caused an increase in the percentage of syndiotacticity. In otherwords, an increase in the styrene: ß-CD ratio caused an decrease in the proportion of both atactic and isotactic polymer formed (Table-1).
Syndiotactic polymer is more favoured at lower ß-CD concentrations than isotactic and atactic polymer because the orientation of the ß-CD complex in the opposite direction will be more favoured from a steric point of view. At higher ß-CD concentrations syndiotactic polymer is less favoured because of increase in bulky ß-CD groups in the vicinity of the oppositively oriented styrene phenyl rings.

Example 5
A mixture of acrylonitrile (0.106 mole), sodium metabisulfite (0.007 gm), ammonium persulfate (0.171 gm) and a drop of acid in water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried.
In a typical reaction such as the one in control gave an yield of 5 gm (89.0%). The results of tacticity studies are given in Table.2. Polymerisation carried out in the absence of ß-CD gave 54% isotactic and 46% syndiotactic polymers.
Example 6
A mixture of acrylonitrile (0.024 mole), ß-CD (0.0047 moles), sodium metabisulfite (0.0016 gm), ammonium persulfate (0.038 gm) and a drop of acid water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried.
When the molar ratio of acrylonitrile to ß-CD was 5:1, the proportion of isotactic and syndiotactic polymers formed was found to be 59 and 41% respectively.

Example 7
A mixture of acrylonitrile (0.0475 moles),ß-CD (0.0047 moles), sodium metabisulfite (0.0031 gm), ammonium persulfate (0.0076 gm) and a drop of acid in water between 40°C were taken in a 3 necked round bottom flask and stirred. Rapid steam of N2 was passed. After 4 hours stirring was stopped. It was then treated with hot water and filtered. After washing with hot water and methanol, the residue was dried. However, when the molar ratio was increased to 10:1 and 20:1, the isotactic to syndiotactic ratio was found to be 64:36 and 68:32 respectively.
Thus a decrease in AN: ß-CD ratio caused an increase in the percentage of syndiotacticity. In otherwords, an increase in the AN: ß-CD ratio caused an increase in the proportion of isotactic polymer formed (Table-2).
Syndiotactic polymer is more favoured at higher ß-CD concentrations than isotactic polymer because the orientation of the ß-CD complex in the opposite direction will be more favored from a steric point of view than the presence of two ß-CD units in adjacent position which will lead to an isotactic polymer. Steric hinderence between adjacent ß-CD units is reduced at lower ß-CD concentrations, thereby favoring more isotactic than syndiotactic polymer. Interestingly, the proportion of isotactic polymer formed at lower ß-CD concentrations was found to be more than that obtained in the total absence of ß-CD. The reason for this is not known.

Similarly monomers other than styrene and acrylonitrile monomers such as methyl methacrylate, vinyl chloride and vinyl alcohol can be employed for preparing syndiotactic and isotactic rich polymers.
Similarly other clathrates such as calixaranes, cyclophanes, urea and thiourea can be used for preparing syndiotactic and isotactic rich polymers.
Determination of molecular weight:
The molecular weight of the polymers prepared were determined by Oswalt viscometer (Polymer Science by V.R.Gowariker, N.V.Viswanathan and Jayadev Sridar published by Wiley Eastern Limited, New Delhi; pp406, 1990). Different known concentrations of the polystyrene polymer in benzene and polyacrylonitrile polymer in dimethyl formamide were prepared. The solvents flow time (to) and the solution flow time (t) for different concentrations were measured using the same viscometer. The difference between the flow rates gives the relative viscosity (ηr =Η/Η0 = t/to). Specific viscosities were calculated by subtracting unity from relative viscosity (ΗSP = ηr -1, where ηsp is the specific viscosity). At each concentration corresponding reduced viscosity (ηred = ηsp /C, where C is the concentration) and the inherent viscosity (ηinh = 1nηr / C) were evaluated. Extrapolation of reduced viscosity against concentration and inherent viscosity against concentration (both extrapolated to zero concentration) gave a common ordinate intercept namely the intrinsic viscosity (Η).

The viscosity average molecular weights of the prepared polystyrene and polyacrylonitrile polymers are calculated based on Mark-Houwkin equation [Ti] = K.M'v
Where K and a are constants for a given polymer, solvent and temperature system. The molecular weights of the above prepared polymers are given in table 3 and Table 4.
Table - 3. Molecular weights of prepared PS Polymers

(Table Removed)
Table - 4. Molecular weights of prepared PAN Polymers

(Table Removed)
Determination of tacticity distribution of polystyrene:
The streoregularity distribution in PS polymers were determined by I3C-NMR spectra. 13C-NMR spectra of PS polymers were recorded on the 270 MHz instrument at room temperature. The I3C NMR spectra of PS polymers were analysed by using aromatic C-1 signal according to method described by Matsuzaki (K.Matsuzaki, T.Uryu, K.Osada, T.Kawamura. Macromolecules, 5, 816, 1972). The aromatic C-1 signal at 145.1 to 146.1 ppm consist of three main peaks corresponding to isotactic, atactic and syndiotactic triads of the polymer irrespective of whether ß-CD is employed or not. The peak at lower magnetic field (146.1 ppm) corresponds to isotactic, the peak at 145.5 ppm corresponds to atactic and peak obtained in higher magnetic field (145.1 ppm) corresponds to syndiotactic triads. The triads obtained from this spectra in all the polymers do not obey the Bernoullian statistics as such , but nearly obey the Bernoullian statistics, when the assumption is based on pentad sequences.
Determination of tacticity of polyacrylonitrile:
The streoregularegularity distribution in PAN polymers were determined by 1H NMR spectra. An 1H NMR spectra of PAN polymers were recorded on the 270 MHz nstrument at 100°C. The quintet at 3.17 ppm corresponds to α -CH and the multiple! between 2.06 and 2.17 ppm correspond to ß-CH2 protons present in the polymer irrespective of whether ß-CD was employed or not in the polymerisation. The multiple! obtained is interpreted as the AB part of an ABX2 system due to overlapping of the
syndiotactic (higher field) and isotactic (lower field) triplets. The tacticity of the polymer prepared was calculated from this NMR spectrum according to the method described by Yamadera [Yamadera and Murano, J.Poly.Sci., A5, 1059 (1967)] by using the relation
(Formula Removed)
Where D(Τ) is the intensity at chemical shift τ, 2b the half-width value, τi is the chemical shift of each peak, and DMi is the intensity of the peak at chemical shift τi.
Determination of binding constant value for the 1:1 complex of styrene with ß-CD.
The orientation of styrene inside ß-CD cavity was investigated by UV-Visible spectroscopy. Styrene exhibits λmu at 248 nm (e = 3547) in ethanol. Addition of ß-CD (9.948 x lO-4M) to Styrene (4.37 x lO-4M) resulted in absorption at 243 nm. A plot of ΔA versus [ß-CD]/[Styrene] indicated formation of 1:1 complex between Styrene and ß-CD.
Binding constant value was determined both by double reciprocal plot method and Scatchard analysis method (C.Farmoso, Biochem. Biophys. Res.Commun., 50, 95,1973). (M.M.Maheswaran and S.Divakar, Indian. J. Chem., 30A, 30- 34, 1991). A plot of 1/ΔA
against l/[ß-CD] gave straight line with slope equal to 1/(Δ AAB K), where ΔAAB is the difference in absorbance between free styrene and its ß-CD complex and K is the binding

constant value for the 1:1 complex. An average binding constant value of 31,395 ± 3500
M'1 was obtained for the 1:1 complex.
Determination of binding constant value for the 1:1 complex of acrylonitrile with ß-CD:
The variation in stereoregularity due to complexation of acrylonitrile by ß-CD was investigated by uv-vis spectroscopy. Acrylonitrile exhibits a strong absorption at 203 nm in water (Ε =8342). With the addition of increasing amounts of ß-CD, the absorption at 203 nm decreased with an isobestic point at 210nm. A titration plot of A (difference in absorption between acrylonitrile and that at a certain concentration of ß-CD) versus [ß-CD] / [AN] exhibited an asymptotic curve with 1:1 stoichiometry, indicating formation of a 1:1 complex. The binding constant value was determined by the method of Farmoso (C.Farmoso, Biochem. Biophys. Res.Commun., 50, 95(1973). A plot of I/ A against 1/[ß-CD] gave a straight line with slope equal to ( AAB K ), where A is the difference in absorbance between free acrylonitrile and its P-CD complex and K is the binding constant value for the 1:1 complex. A value of 7242+360 M'1 was obtained for the acrylonitrile ß-CD complex.
The formation of an inclusion complex was further conformed by 1H-NMR spectrum. It showed a change in the acrylonitrile (monomer) multiplets in the 5.72 - 6.42 ppm egion in the presence of ß-CD. (table-3) - Acrylonitrile monomer shows two group of signals centered at 5.81 and 6.32 ppm in D20. On adding an equivalent amount of ß-

CD, the signals showed slight changes in chemical shift values of the multiplets centered at 5.92 and 6.3 ppm, indicating formation of an inclusion complex.

(Formula Removed)
Main advantages of the invention are:
a) In PS polymers the tacticity proportion of the polymer prepared was found to be
altered with decrease in ß-CD concentration. Decrease in ß-CD concentration
resulted in increase in syndiotacticity.
b) In case of PAN, tacticity proportion of the polymer prepared was found to be altered
with increase in ß-CD concentration. Increase in ß-CD concentration resulted in
decrease in isotacticity
c) The molecular weights of polystyrene and poly aery lonitrile polymers decreased on
increase in concentration of ß-CD and its derivatives.
d) ß-CD used can be recovered and reused.
e) The use of ß-CD during polymerisation provides a method for preparing polystyrene
and polyacrylonitrile polymers whose molecular weights and tacticities could be
controlled.
f) Polymerisation of PAN was achieved under mild reaction conditions.

We Claim:

1. An improved process for the preparation of stereoregular polymer using clathrates which comprises polymerizing vinyl monomers by conventional methods in presence of clathrates or their polymers such as herein described, wherein the ratio of monomers and clathrates or their polymers ranges from 5:1 to 20:1 in presence of conventional initiators ranging from 0.000044 mole to 0.000074 mole/mole of mixture of styrene and in presence of emulsifying agents at a temperature in the range of 35 to 800C for minimum 4 hours under stirring and recovering the polymer by conventional methods.

2. An improved process as claimed in claim 1, wherein the polymerization is effected by methods selected from suspension polymerization, emulsion polymerization, free radical polymerization and inclusion polymerization.

3. An improved process as claimed in claims 1- 2, wherein the monomers used in the polymerization and compounds selected from styrene, acrylonitrile, methacrylate, methyl methacrylate, vinyl chloride and vinyl alcohol.

4. An improved process as claimed claim 1 to 3, wherein clathrate employed is compound selected from f3-cyclodextrin, f3-cyclodextrin-polymer, calixaranes, cyclophanes, urea and thiourea, preferably f3-cyclodextrin and its polymer.

5. An improved process as claimed in claim 1 to 4, wherein the emulsifying agent employed may be compounds such as sodium lauryl sulphate in the range of 0.5%

6. An improved process for the preparation of stereoregular polymer using clathrates substantially as herein described with reference to the examples.

Documents:

2149-del-1998-abstract.pdf

2149-DEL-1998-Claims.pdf

2149-del-1998-correspondence-others.pdf

2149-del-1998-correspondence-po.pdf

2149-del-1998-description (complete).pdf

2149-del-1998-form-1.pdf

2149-del-1998-form-19.pdf

2149-del-1998-form-2.pdf

« Previous Patent

Next Patent »

Patent Number

215745

Indian Patent Application Number

2149/DEL/1998

PG Journal Number

12/2008

Publication Date

21-Mar-2008

Grant Date

03-Mar-2008

Date of Filing

24-Jul-1998

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SOUNDAR DIVAKAR	CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSURE, INDIA.
2	PALANI SWAMY RAVI	TECHNOLOGICAL RESEARCH INSTITUTE, MYSURE, INDIA.

PCT International Classification Number

A61K 31/80

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA