Title of Invention	"A PROCESS FOR THE PREPARATION OF A GRAFT COPOLYMER FOR USE AS A FLOCCULATING AGENTS"
Abstract	This invention relates to a process for the preparation of a graft copolymer for use as a flocculsting/agent comprising preparing a solution of the polysaccharide and adding acrylesmide thereto with stirring, followed by addition of a catalyst solution thereto and allowing the reaction to continue, to obtain the graft copolymer.

Full Text

- 1A - FIELD OF THE INVENTION This invention relates to graft copolymers for use as flocculating agents and drag reduction agents. OBJECTS OF THE INVENTION An object of this invention is to propose graft copolymers of polyacrylamide and polysaccharide and a process for the preparation thereof for flocculstion and drag redution. Another object of this invention is to propose graft copolymrs of polyacrylami.de and polysaccharide and a process for the preparation thereof which have high efficiency, Still another object of th is invention is to propose graft copolymers of polyacrylamide and polyssccharide and a process for the preparation thereof which have controlled biodegradation, A further object of this invention is to propose graft copolymers of polyacrylamide and polysaccharide and a process for the preparation thereof which possess shear stability. Further objects and advantages of this invention will be more apparent from the ensuing description. BRIEF DESCRIPTION OF THE INVENTION According to this invention, there is provided a process for the preparation of a graft copolymer for use as a flocculsting agent Comprising preparing a, solution of the polysaccharide and adding -2- acrylamide thereto with stirring, followed by addition of a catalyst solution thereto and allowing the reaction to continue, to obtain the graft copolymer. In accordance with this invention, the catalyst used may be compounds of inter-transition elements such as Cerium (IV), preferably cerric ammonium nitrate. The potysaccharide is a compound such as carboxymethyl cellulose and the acrylamide may be a substituted or unsubstltuted acrylamide compounds. The reaction is generally carried out at a temperature in the range of 25 to 35°C, preferably 27°C and Is conducted for 24 to 40 hrs. at atmospheric pressure. The polysaccharide is used in a proportion of 2 to 3 gms per 12 to 22 gms of acrylamide. Two grades of polymer (S1 & S2) were synthesised by varying the acrylamide concentratin keeping all other factors constant. Polysaccharide In a proportion of 2 to 3 gms per 12 to 18 gms of the acrylamide is used for forming the copolymer S1. For the formation of graft copolymer S2, a proportion of 2 to 3 gms of polysaccharide is used per 18 to 22 gms of acrylamide. The catalyst is used in a proportion of 1.8 to 2.2 moles x 10 -3 per 2 to 3 gms of the potysaccharide. The intrinsic viscosity of the copolymers S1 & S2 have been found to be 6 to 7 and 7.5 to 8.5 respectively. The number average molecular weight of S1 & S2 have been found to be, for example t - 3 - 1.12*106 GM/M AND 1.4*106 GM/M respectively and the weight average molecular weight is, for example 5.8*106 gm/M and 7.09*106 gm/M respectively. The invention will now be explained in greater detail with the help of the following non-limiting example. EXAMPLE The graft copolymer of CMC was synthesised using Ce(IV) ion 11 induced redox initiator method - The typical experimental details are as follows. 2.5 gms of CMC was dissolved in 100 cm of disti11ed water at room temperature (30o C) wi th constant stirring and bubbling of nitrogen for about 15 mins.. The required amount of acrylamide was dissolved in 75 cm of distilled water and mixed with CMC solution. Then oxygen free nitrogen was purged through the solution for 20 mins,. At this 3 stage, 25 cm of required CAN solution was added to the reaction mixture followed by further purging with nitrogen for 10 mins.a The reaction was a 1 lowed to continue for 24 hrs. after which it-was terminated by adding a saturated solution of hydroquinone, At the end of the reaction, the polymer was precipitated by adding excess quantity of acetone, Following scheme (Scheme-1) was not clear followed for purification of graft copolymer. It was then dried in a vacuum oven, pulverised and sieved. Two grades of graft copolymer were prepared by varying acrylamide concentration , and were abbreviated as S & S . The synthetic details are given in 1 2 Table .1. -5 - _ The graft copolymer based on carboxymethyl cellulose is synthesized by solution polymerisation technique using ceric-ion-induced redox initiation method. The method for graft capolyme-risation is- to generate free radical sites onto the polysaccha-ride backbone (HPG) and allowing these free radicals to act as micro-initiators for acrylamide monomer. The graft copolymers according to the invention are used in flocculation and drag reduction experiments. It is extensively used in various oil field operations utilising its drag reducing properties. The flocculation behaviour of the graft copolymers are studied and Figs-.1-4 of the accompanying drawings show the settling time vs. fall in interface height. Fig.l depicts a comparison of the flocculation studies of S and 1 S in kaolin suspension; 2 Fig.2 depicts a comparison of the flocculation performance of S with Magnafloc 156, Magnsfloc LT22 and Magnafloc 351 in iron ore suspension; Fig.2 shows a comparison in the settling time vs. fall height for S , Magnafloc 351, Magnafloc LT22 and Magnafloc 156 in 1 wt% 2 silica suspension; and Fig.4 shows a comparison of the settling time vs. fall height for S , Magnafloc 351, Magnafloc LT22 and Magnafloc 156, in 5 wt% 2 - 6 -kalin suspension - The graft copolymers of polyacrylamide and polysaccharides show synergistic properties in flocculation and drag reduction. They have high efficiency and shear stabi1ity and control led bio-degradation. The graft copolymer of polyacryl amide and carboxy~-methyl cellulose shows the above properties and shows much better flocculation performance than commercially avai1 able flocculants in various synthetic effluents. (7) We Claim: 1. A process for the preparation of a graft copolymer for use as a flocculating agent comprising preparing a solution of 2 to 3gms of carboxymethyl cellulose and adding 12 to 22gms of thereto with stirring followed by addition olf a solution of a catalyst such as a cerium (IV) compound thereto allowing the reaction to continue, to obtain the graft copolymer. 2. The process as claimed in claim 1 wherein the acrylamide is a substituted or unsubstituted acrylamide. 3. The process as claimed in claim 1 wherein said cerium (IV) compound is cerric ammonium nitrate, 4. The process as claimed in claim 1 wherein the reaction is conducted at a temperature in the range of 25-35°C, preferably at 27°C. 5. The process as claimed in claim 1 wherein the reaction is carried out over a period of 2-40 hrs., preferably 24 hrs. 6. The process as claimed in claim 1 wherein the reaction is conducted at atmospheric pressure. 7. The process as claimed in claim 1 wherein the reaction mixture is purged with a gas such as nitrogen before addition of the catalyst. (8) 8. The process as claimed in claim 1 where in the reaction mixture is purged with a gas such as nitrogen for 1-30 mins., preferably 10 mins, after the addition of the catalyst. 9. The process as claimed in claim 1 wherein the polysaccharide is used in a proportion of 2 to 3gms per 12 to 18gms of acrylamide for graft copolymer S1. 10. The process as claimed in claim 1 wherein the polysaccharide is used in a proportion of 2-3gms per 18 to 22gms of acrylamide for graft copoiymer S2. 11. The process as claimed in claim 1 wherein the catalyst is used in a proportion of 1.8 to 2.2 mole x 103per 2-3gms of the polysaccharide. 12. The process for the preparation of a graft copolymer for use as a flocculating agent substantially as herein described and illustrated. This invention relates to a process for the preparation of a graft copolymer for use as a flocculsting/agent comprising preparing a solution of the polysaccharide and adding acrylesmide thereto with stirring, followed by addition of a catalyst solution thereto and allowing the reaction to continue, to obtain the graft copolymer.

Documents:

00101-cal-2001-abstract.pdf

00101-cal-2001-assignment.pdf

00101-cal-2001-claims.pdf

00101-cal-2001-correspondence.pdf

00101-cal-2001-description(complete).pdf

00101-cal-2001-drawings.pdf

00101-cal-2001-form-1.pdf

00101-cal-2001-form-18.pdf

00101-cal-2001-form-2.pdf

00101-cal-2001-form-3.pdf

00101-cal-2001-form-5.pdf

00101-cal-2001-letters patent.pdf