Title of Invention

"A PROCESS FOR PREPARING GRAFT COPOLYMER USED FOR ABSORBING HEAVY METAL"

Abstract The nature of invention is related to the process for preparation of graft copolymer used for heavy metal ion uptake. The graft copolymer was synthesized by the grafting of N, N' dimethylacrylamide as monomer onto Na salt of carboxymethylcellulose by applying the potassium peroxymonosulphate and thiourea redox pair through the free radical graft copolymerization process in aqueous medium in inert atmosphere at constant temperature. The product obtained is amphoteric in nature and was applied for the uptake of metals like Cu2+, Pb2+, Ni2+, Zn2+ and Hg2+ and many more metals could be studied in future. Thus it provides the great opportunity of metal ion absorption for the wastage water which is being discharged from chemical industries, steel industries and food industries etc.
Full Text Field of the Invention
The invention relates to preparation of the graft copolymer which provides a process for preparing the graft copolymer of carboxymethylcellulose (Na salt) and N, N' dimethylacrylamide by using peroxymonosulphate and thiourea redox pair, used for absorbing heavy metals.
Background of the Invention
Sodium carboxymetylcellulose is naturally occurring polysaccharide consist of substituted anhydroglucose units and also known as cellulose gum and Na-CMC and by other trade names. The water soluble cellulose ether is manufactured by reacting sodium monochloroacetate with alkali on cellulose. Water is the usual solvent for sodium carboxycellulose and it has good tolerance for dilution by alcohol and acetone. The basic properties that enhance its commercial value are its abilities to thicken water, suspend solids in aqueous media, stabilize emulsions, absorb moisture from the atmosphere and form films. Carboxymethyl group increases the swelliability of polysaccharide. Their unique applications occur in various industries e.g. paper, textile processing, detergents, drilling fluids, pharmaceuticals and cosmetic industry etc and also used as enteric coating for powder and tablets because it is insoluble in stomach acid and soluble in intestinal fluids.
Similarly, N, N' dimethylacrylamide, which is a hydrophilic monomer, has wide applications in various fields such as in biomaterial area: compatible to blood and tissue, in preparation of selective semipermeable amphiphilic membrane. N, N' dimethylacrylamide is also widely used in enhanced oil recovery and in the synthesis of thermoreversible hydrogel, in preparation of commercial contact lenses and its copolymer is used in removal and separation of inorganic ions in aqueous solutions and applied for the metal recovery from a dilute solution such as industrial fluids and waste water but it is so costly and nonbiodegradable. Thus these applications of both prompted us to develop a process for the preparing graft copolymer of carboxymethylcellulose (Na salt) and N, N' dimethylacrylamide by using peroxymonosulphate and thiourea redox pair, used for absorbing heavy metals which would be more environment friendly and low cast.
Prior Art
The graft copolymers of sodium carboxymethyl cellulose with acrylamide (Behari, K.; Kumar R.: (2001) Polym. Mat. Sci. and Eng. (Am. Chem. Soc), 85, 361-362) and di methyl am inoethyl methacrylate (Tan, Y. Z. L.; Li, Z.: (1998) J. Appl.

Polym. Sci., 69, 879-885) have been reported. These graft copolymers have the potential of being used in drilling muds and has the properties of filtrate loss controllability and inhibit clay swelling. Graft copolymer of sodium carbxoymethyl cellulose with acrylamide are used as flooding material in enhanced crude oil recovery (Idehen, K.L.: (2002) Pakistan Journal of Scientific and Industrial Research, 45(6), 363-366). Notable improvement was achieved in specific viscosity of the graft copolymer when compared with unmodified Na carboxymethyl cellulose. For a 1% (wt %) solution at 25°C and a shear rate of 200 s-1, sodium carboxymethyl cellulose has a viscosity of 74.6 cP while the graft copolymer recorded a viscosity of 154 cP. The influence of mono and multivalent cations such as Na, Ca and Al ions on the viscosity of the graft copolymer solution was relatively millimole, suggesting improvement in the so called salt tolerance or cation compatibility. Since sodium carboxymethyl cellulose-g-acrylamide is amphoteric copolymers, which contain both acidic and basic groups along the macromolecular backbone, present great potential for many applications due to their interesting aqueous solution properties (McCormic, C.L.; Johnson, C.B.: (1988) Macromolecules: 21, 686-694). Their uses range from paper manufacture (Reynolds, W.J.; Wasser, R.B: (1981) in "Pulp and Paper Chemistry and Chemical Technology," Vol. 3, Casey, J.P. Ed.; Wiley-Inter Sciences: New York) and water treatment (Flock, H.G., Rausch, E.G.: (1973) In "Water soluble polymers Bikales, N.M.; Ed.: Plenum Press: New York), through oil recovery (Chang, H. L.: (1978)J. Pet. Technol: 30, 1113) to soil modifications (Roth, R.W.: (1957) U.S. Patent 280/985) and medical applications (Hoffman, A.S.; (1987) J. Controlled Release: 4, 213) and out of among applications one of the great advantage, this obtained is the consequent reduced biodegradability of the grafted products because of the drastic change in original structure of the substrate as well as synthetic polymer content in the product that is not a food for bacteria.
Graft copolymerization, among the various methods for modifying polymers appears to be highly attractive, and has made a paramount contribution towards improved industrial and biomedical applications (Hebeish, A.; Guthric, J.T.: (1981) "The Chemistry and Technology of Cellulosic Copolymers" New York, Springer, Green, J.: (1989) Ph.D. Thesis: University of Leeds, Leeds). Trivedi et al. (Trivedi, H.C.; Patel, C.P.; Patel, G.M.: (1999), Eur. Polym. J., 35, 201-208)

has found that carboxymethyl cellulose groups increase the swellability of sodium alginate. This indicates the attractive use of carboxymethylated substrate in many applications. The thermoassociative graft copolymer of sodium carboxymethyl cellulose with poly (N-isopropyl acrylamide) have been reported (Aubry, T.; Bossard, F.; Staikos, G.; Bokias. G.: (2003), Journal of Rheology, 47(2), 577-587). The linear and non-linear rheological data of this graft copolymer clearly show the existence of two temperatures, separated by a transition temp. T1 > T associative. At temperatures below T1, the solutions behave like a soft critical gel corresponding to weak poly (N-isopropylacrylamide) segregation, at temperatures above T1, the solution behave like a stiff critical gel corresponding to strong poly (N-isopropyl acrylamide) segregation. Hydrophobically modified carboxymethyl cellulose are used as thickner (Zhang, J.; Zhang, L.; Xie, X.: (Qinghua Uni, Peop. Rep. China): F. Zhuanli Shenqing Gongkai Shuomingshu CN 1,342,721 (Cl. C08 F22 6106) 3 Apr. 2002, Appl.,2,001, 136, 627; 23 Oct 2001; 7pp) which having good water solubility, salt resistance, heat resistance and antishear viscosity increasing property.
N, N-dimethylacrylamide has been used in the biomaterials area, due to its hydrophilic character, in the abstention of polymeric materials compatible to blood and tissue. The grafting of the N, N-dimethylacrylamide monomer in polymeric substrate like poly (dimethylsiloxane) to be applied as a catheter (Almeida, A.T.; Queiros, A.A.A.; Barrak, E.R.; Higa, O.Z.: (1998) Proceedings of the 13 CBECIMAT, Cu-ritiba PR, 4054) and the abstention of selective semipermeable amphiphilic membranes (Shamlou, S.Y.; Kennedy, J. P.; Levy, R.P.: (1997) J. Biomed Mater Res., 35, 157) used to determine the diffusion characteristics of glucose, insulin and albumin are applications indicating that the N, N-dimethylacrylamide is not harmful to human body.
N, N-dimethylacrylamide has been used as a compatibilizing agent between poly (ethylene terephtalate) films and the disperse dye (Santos, W.L.F.; Porto, M.F.; et al.: (2000) J. Appl. Polym. Sci., 77, 269-282). The polymers and the gels of N, N-dimethylacrylamide (North, A.M.; Scallan, A.M.: (1964) Polymer, 5, 447-455, Saini, G.; Polla-Mattiot, G.; Meirone, M.J.: (1961) Polym. Sci., 5, 512-13, Aopi, T.; Kawashima, M.; Katono, H.; Sanui, K.; Igata, N.; Okano, T.; Sakurai, Y.:

(1994) Macromolecules, 27, 947-952 and poly N, N-diethyl acrylamide (Katayama, S.; Hirokawa, Y.; Tanaka, T.: (1984) Macromolecules, 17, 2641-2643) have been prepared so far and their swelling and transition behaviors in water were investigated. Poly (DMAm) and its copolymers with 2-acrylamido-2-methyl-l-propane sulphonic acid) were applied in various fields, such as in enhanced oil recovery (Sabhapondit, A.; Borthapur, A.; Haque, I.: (2003) Energy and Fuels, 17(3), 683-688) and slow release medical materials (De Queriroz, A.A.A., Gallardo, A.; San Raman J. Higa OZ, (1995) J. Biomatar. Sci. Polym. Edn., 7(6), 523). Copolymers of p-acryloyloxyacetanilide (an acrylic derivative of paracetamol) and N, N-dimethylacrylamide have been shown to have promising anti-thrombogenic behaviour( Anna Bulai, Alvaro-Antonio Alencarde Queiroz, Alberto Gallardo, Julio, Son Roman: (1999) Polymer, 40, 4953-4960) Tetsuoshibanuma et al. reported the graft copolymer of poly (acrylic acid)-g-poly (N, N-dimethylacrylamide) and studied its thermosensitive phase separation behaviour (Tetsuo, Shibanuma, Takashi Aoki, Kohei Sanui, Naoya Ogata, Akihiko Kikuchi, Yasuhisa Sakurai and Teruo Okano: (2000) Macromolecules, 33, 444-450). N, N-dimethylacrylamide has been widely useful in the preparation of thermoreversible hydrogel (Wen-fu Lee, Pao-Li Yeh: (1997) J. Appl. Polym. Sci., 65, 909-916) and its copolymer with acrylic acid has wide application in the removal and separation of inorganic ions in aqueous solution (Rivas, B.L.; Pooley, S.A.; Soto, M.; Maturana, H.A.; Geckeler, K.E.: (1998) J. Appl. Polym. Sci., 67, 93-107) and applied for the metal recovery from a dilute solution, such as industrial fluids and waste water. N, N-dimethyl acrylamide is used in preparation of commercial contact lenses (Menicon Ex) with contact angle 33° (Nakata, Kajuhiko, Kawai, Testsuji, Tanagawa, Sadayasu: Jpn. Kokai Tokkyo Koho JP 2003; 50, 378; 21 Feb. 2003, Appl. 2001 / 238, 672, 7 Aug 2001, 16 pp, Nakamura, Masataka, Yokota, Mitsuru : PCT Int. Appl. WO 03 42, 222 (C1. C07F708) 22 May 2003, Appl. 2001 / JP 8, 680, 2 Oct. 2001, 29 pp). N, N-dimethylacrylamide has been used in the preparation of proton accepting polymers with 39% drag reduction at 100 ppm of hydrocarbon fluids (Shintre, S. N.; Malik, S.; Kulkarni, M.; Gopal K.; Maselkar, R., A.: Council of Scientific and Industrial Research, India; Indian IN


176, 859 (C1. C08 F20/00) 21 Sep, 1 1pp) Thus the sodium carboxymethyl cellulose based graft copolymers were found to multifunctional characteristics as an oil field drilling, mud additive with respect to shale inhibition, viscosity building and filtration control (Zhang, L.M.; Tan, Y.; Li, Z.: (2000) J. Appl. Polym. Sci., 11, 195-201, Zhang, L.M.; Li, Z.; Tan, Y.: (1998) J. Appl. Polym. Sci., 69, 879-885).
Therefore an attempt have been made to graft the N, N dimethylacrylamide onto sodium carboxymethyl cellulose by using an efficient redox pair i.e. peroxymonosulphate/thiourea. Thus the newly synthesized amphoteric graft copolymer (Na-CMC-g-DMAm) could be applied in industries such as petroleum, paper making, textiles, washing and environment protection and in gel formation.
Detail description of the Invention
According to the invention relates to a process for preparing graft copolymer used for absorbing heavy metal comprising the vacuum distillation of N, N' dimethylacrylamide at reduce pressure of 8-20 mm Hg and at reduce temperature of 60°C-120°C, synthesis of sodium carboxymethylcellulose-g-N,N'dimethylacrylamide by the using peroxymonosulphate and thiourea redox pair and estimation of uptake of heavy metal on graft copolymer. Several experiments have been done to find out the better yield of graft copolymer and for each experiment sodium carboxymethylcellulose solution was prepared by the slow addition of calculated amount of sodium carboxymethylcellulose in to reactor containing triple distilled water. The calculated amount of N,N' dimethylacrylamide, sulphuric acid and thiourea were added into the reactor and slow stream of oxygen free nitrogen gas was passed for 30 minutes at constant temperature. A known amount of deoxygenated potassium peroxymonosulphate solution was added to initiate the reaction. The reaction was performed under a continuous flow of oxygen free nitrogen gas. After desired time period the reaction was stopped by letting air into reactor. The grafted material was precipitated by pouring the reaction mixture into water-methanol mixture. The precipitate was filtered, dried and weighed. To the filterate a pinch of hydroquinone was added and concentrated under reduced pressure. The poly N, N' dimethylacrylamide was precipitated by pouring the concentrated filtrate into the pure methanol, dried and weighed. This process involving the peroxymonosulphate and thiourea as a redox pair and it has been found that graft yield is increases upto a certain range of concentration of redox pair and after that it decreases and homopolymer content increases. Similarly it has been also

observed that the graft yield increases upto certain range of concentration of N, N' dimethylacrylamide and homopolymer decreases. The metal ion absorption have been carried out on graft copolymer of different compositions which have been synthesized through this process by varying the concentration of N, N' dimethylacrylamide and taking it in metal ion solution of known concentration and kept undisturbed for 24 hours at constant pH. The strength of unabsorbed metal ions has been determined by standard method. Five metal ions have been chosen for this experiment like Cu, Zn, Ni, Pb and Hg and calculated the percent ion uptake of metal ions on graft copolymer and it has been observed that the percent uptake of metal ions increases on increasing the graft yield and decreases on decreasing the graft yield. Experimental results are also shows that the Hg2+ was least uptakable ion while other metal ions show better result in comparison to Hg2+.
The several experiment have been done by the similar process by varying the concentration of peroxomonosulphate and thiourea and N, N' dimethylacrylamide and it has been found that the yield is increase up to certain range of concentration and homopolymer formation is decreased.
Results and Discussion:
Several experiment have been done by this process by varying the concentration of various constituent of the reaction and it has been found that by this process yield increases and homopolymer formation decreases up to certain range of concentration. On the basis of experimental results the following mechanism is proposed for the process of preparing graft copolymer by peroxymonosulphate and thiourea redox pair, used in absorption of heavy metal ion.

(Formula Removed)
Where R = R1S SO4 ; COH = carboxymethylcellulose; M = monomer
The following examples illustrate the invention. Example 1:
The vacuum distillation of N, N' dimethylacrylamide has been carried out at reduce pressure of 8-14 mm Hg and at reduce temperature of 60°C-120°C. For preparation of graft copolymer 0.3 to 5 gm dm-3 sodium carboxymethyl cellulose solution was taken in reactor having 3 to 35xl0-2mol dm-3of N, N' dimethylacrylamide, 2 to 20x10-3mol dm-3 of acid and 1 to 5x10-3mol dm-3 thiourea solution and slow stream of oxygen free nitrogen gas was passed for 10 to 40 minutes at 15°C to 60°C. After that 1.5 to 18 x10-3 mol dm-3 of deoxygenated peroxymonosulphate solution was added to initiate the reaction. The reaction was carried out under a continuous flow of oxygen free nitrogen gas. After desired time period i.e. from 40 minutes to 5 hours, the reaction was stopped by letting air into reactor. The reaction mixture was poured in water methanol mixture. The grafted material was separated out, which was filtered, dried and weighed. The metal ion absorption have been carried out on graft copolymer of different compositions which have been synthesized
through this process by varying the concentration of N, N' dimethylacrylamide and taking its 0.005 gm to 0.10 gm in 5.0 ml to 50.0 ml of metal ion solution of known concentration and kept undisturbed for 24 hours at constant pH. The strength of unabsorbed metal ions has been determined by standard method. Five metal ions have chosen for this experiment like Cu, Zn, Ni, Pb and Hg and calculated the percent ion uptake of metal ions on graft copolymer
Example 2:
The vacuum distillation of N, N' dimethylacrylamide at reduce pressure of 9-12mm Hg and at reduce temperature of 70°C-100°C has been carried out For preparation of graft copolymer 0.35 to 4 gm dm-3 sodium carboxymethyl cellulose solution was taken in reactor having 5 to 30x10-2 mol dm-3 of N, N' dimethylacrylamide, 3 to 15xl0-3mol dm-3 of acid and 1.5 to 4x10-3 mol dm"3 of thiourea solution and slow stream of oxygen free nitrogen gas was passed for 15 to 30 minutes at 25°C to 50°C. After that 2 to 15 xl(r3 mol dm-3 of deoxygenated peroxymonosulphate solution was added to initiate the reaction. The reaction was carried out under a continuos flow of oxygen free nitrogen gas. After desired time period i.e. from 60 minutes to 4 hours, the reaction was stopped by letting air into reactor. The reaction mixture was poured in water methanol mixture. The grafted material was separated out, which was filtered, dried and weighed. The metal ion absorption have been carried out on graft copolymer of different compositions which have been synthesized through this process by varying the concentration of N, N' dimethylacrylamide and taking its 0.010gm to 0.08 gm in 10 ml to 40 ml of metal ion solution of known concentration and kept undisturbed for 24 hours at constant pH. The strength of unabsorbed metal ions has been determined by standard method. Five metal ions have been chosen for this experiment like Cu, Zn, Ni, Pb and Hg and calculated the percent ion uptake of metal ions on graft copolymer
These examples should not limit the scope of invention.









We claim:
1. Process for preparing graft copolymer of sodium carboxymethyl cellulose and N, N"
dimethylacrylamide using peroxymonosulphate/thiourea redox pair in aqueous
medium comprising the process steps
A) First distilled the N. N' dimethylacrylamide at reduce pressure and at reduced
temperature
B) Then solution of carboxymethyl cellulose had been taken in reactor having N, N'
dimethylacrylamide solution, sulphuric acid and thiourea solution (1.0 to 5.0x10-3
mol dm-3) after that slow stream of oxygen free nitrogen gas was passed in the
reactor for 10 to 40 minutes at 15°C to 60°C. After that deoxygenated
peroxymonosulphate solution (1.5 to 18.0 x10-3' mol dm-3) was added to initiate the
reaction
C) The reaction had been carried out under a continuous flow of oxygen free
nitrogen gas for desired time period i.e. from 40 minutes to 5 hours. The reaction
was stopped by letting air into reactor. Then reaction mixture was poured in water-
methanol mixture. The grafted material had been separated out. which was filtered,
dried and weighed
2. A process as claimed in claim 1. wherein N. N' dimethylacrylamide had been distilled at 8-14 mm Hg pressure.
3. A process as claimed in claim 1 wherein N. N" dimethylacrylamide had been distilled at a temperature from 60-120°C .
4. A process as claimed in claim 1. wherein the concentration of sodium carboxymethyl cellulose is 0.3 to 5.0 gm dm-3 .
5. A process as claimed in claim 1. wherein the concentration of N, N* dimethylacrylamide is 3.0 to 35.0 x 10-2 mol dm-3
6. A process as claimed in claim 1. wherein the concentration of acid is 2.0 to 20.0
x10-3mol dm-3.
7. A process for preparing graft copolymer of sodium carboxymethyl cellulose and N,
N' dimethylacrylamide using peroxymonosulphate/thiourea redox pair in aqueous
medium as claimed in claim 1 is used for absorbing heavy metal ions like Cu++,
Zn++. Ni++, Pb++ and Hg++ ,
8. A process as claimed in claim 1. substantially as here in before describe with reference to any one of the forgoing examples relating to process for preparing graft copolymer by using peroxymonosulphate and thiourea redox pair.

Documents:

1309-DEL-2003-Abstract-(02-02-2011).pdf

1309-del-2003-abstract.pdf

1309-DEL-2003-Claims-(02-02-2011).pdf

1309-DEL-2003-Claims-(18-03-2011).pdf

1309-del-2003-claims.pdf

1309-DEL-2003-Correspondence-others-(02-02-2011).pdf

1309-del-2003-correspondence-others-(09-03-2011).pdf

1309-DEL-2003-Correspondence-Others-(18-03-2011).pdf

1309-del-2003-correspondence-others.pdf

1309-del-2003-correspondence-po.pdf

1309-DEL-2003-Description (Complete)-(02-02-2011).pdf

1309-del-2003-description (complete).pdf

1309-del-2003-Form-1-(09-03-2011).pdf

1309-del-2003-form-1.pdf

1309-del-2003-form-18.pdf

1309-del-2003-form-19.pdf

1309-DEL-2003-Form-2-(02-02-2011).pdf

1309-del-2003-form-2.pdf

1309-del-2003-form-5.pdf

1309-del-2003form-13-(09-03-2011).pdf


Patent Number 247798
Indian Patent Application Number 1309/DEL/2003
PG Journal Number 21/2011
Publication Date 27-May-2011
Grant Date 20-May-2011
Date of Filing 23-Oct-2003
Name of Patentee SRIVASTAVA ARTI
Applicant Address D/O SRI R.C. SRIVASTAVA 2/57 M.I.G. AVAS VIKAS COLONY, JHUNSI, YOJANA NO. 3 ALLAHABAD-221506 U.P. INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 SRIVASTAVA ARTI D/O SRI R.C. SRIVASTAVA 2/57 M.I.G. AVAS VIKAS COLONY, JHUNSI, YOJANA NO. 3 ALLAHABAD-221506 U.P. INDIA.
2 KUMAR RAJESH S/O SRI SAMAR BAHADUR UTTARPATTI(ADAMPUR), HINDI BAGHAILA, JAUNPUR-222001 U.P. INDIA.
3 BEHARI KUNJ 161, B - MEHADAURI COLONY, TELIYARGANJ, ALLAHABAD-211002 U.P. INDIA.
PCT International Classification Number C08D 15/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA