Patent Application
20080020961
The following examples are intended to exemplify the present invention but are not intended to limit the scope of the invention in any way. The breadth and scope of the invention are to be limited solely by the claims appended hereto.
Molecular weights of all the graft copolymers in the Examples below were determined by aqueous Gel Permeation Chromatography (‘GPC’) using a series of polyacrylic acid standards. The method uses 0.05M sodium phosphate (0.025M NaH2PO4 and 0.025M Na2HPO4) buffered at pH 7/0 with NaN3 as the mobile phase. The columns used in this method are: TSKgel PWx1 Guard column, TSKgel; G6000PWx1, G4000PWx1, G3000PWx1, G2500PWx1 set at a temperature of 32° C. Flow rate is 1 mL per minute, and the injection volume is 450 μL. The instrument is calibrated using five different polyacrylic acids standards injected at five different concentrations: PAA1K (2.0 mg/mL), PAA5K (1.75 mg/mL), PAA85K (1.25 mg/mL), PAA495K (0.75 mg/mL), and PAA1700K (0.2 mg/mL), all from American Polymer Standards Corporation.
Molecular weight of starting polysaccharides in the Examples below was determined by aqueous Gel Permeation Chromatography (GPC) using a series of hydroxyl ethyl starch standards. The method uses 0.05M sodium phosphate (0.025M NaH2PO4 and 0.025M Na2HPO4) buffered at pH 7/0 with NaN3 as the mobile phase. The columns used in this method are: TSKgel PWx1 Guard column, TSKgel; G6000PWx1, G4000PWx1, G3000PWx1, and G2500PWx1 set at a temperature of 32° C. The flow rate is 1 mL/min and injection volume is 450 μL. The instrument is calibrated using five different hydroxyethyl starch standards injected at five different concentrations: HETA10K (2.0 mg/mL), HETA17K (1.75 mg/mL), HETA40K (1.25 mg/mL), HETA95K (0.75 mg/mL), and HETA205K (0.2 mg/mL), all from American Polymer Standards Corporation.
Synthesis of Copolymer Using Grafting Recipe Adapted from Example 1 of U.S. Pat. No. 5,227,446 but Limited to Only Acrylic Acid as the Synthetic Component, with the Molar Ratio of Fe and Peroxide Kept the Same—
A reactor containing 140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01960 dextrin, having a DE of 11 and a number average molecular weight of 14,851 as determined by aqueous GPC described above) and 0.00075 grams of ferrous ammonium sulfate hexahydrate (‘FAS’) (the level of FAS used in the '446 patent when the moles of monomer used in that example are accounted for, or 0.0019 mmoles FAS and 4 ppm as moles of Fe based on moles of acrylic acid monomer) was heated to 98° C. A solution containing 35 grams of acrylic acid (0.486 moles) in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 159,587 as determined by aqueous GPC process noted above.
Synthesis of Copolymer Using Grafting Recipe Adapted from Example 2 of U.S. Pat. No. 5,227,446—
263.1 g of water, 80 g of maltodextrin (Cargill MD™ 01960, soluble component 90%, DE value of 11 to 14), 63.8 g of maleic anhydride and 0.00075 grams (3.5 g of a 0.1% strength) aqueous FAS solution and 94 g of 50% strength aqueous sodium hydroxide solution are heated to a boil in a heated reactor equipped with stirrer, reflux condenser, thermometer, feed devices, and nitrogen inlet and outlet. The degree of neutralization of maleic acid produced from the maleic anhydride in aqueous solution is 90.2%. When the reaction mixture has started boiling, a solution of 178.2 g of acrylic acid in 141.9 g of water is added over the course of 5 hours, and a solution of 16.6 g of 50% strength hydrogen peroxide in 44.4 g of water is added at a constant rate over the course of 6 hours at the boil. When the addition of acrylic acid is complete, the degree of neutralization of the maleic acid and acrylic acid units present in the polymer is 31.1%. When the addition of hydrogen peroxide is complete, the reaction mixture is heated at the boil for a further 1 hour, neutralized to a pH of 7.2 by adding 180 g of 50% strength aqueous sodium hydroxide solution and cooled.
Synthesis of Copolymer Using Grafting Recipe Adapted from Example 11 of U.S. Pat. No. 5,227,446—
192 g of water, 146 g of corn starch, 16 g of maleic anhydride and 0.38 g of phosphorus acid are heated to 98° C. in a heated reactor. The reaction product formed a gel ball after 15 minutes. Heating was continued but the gel did not break. This indicates that the starch needs to be degraded and water soluble before the grafting reaction can occur.
140 grams of water, 75 grams of maltodextrin (Cargill MD™ 01925 dextrin, having a DE of 25 and a number average molecular weight of 10,867 as determined by aqueous GPC described above) and 0.00075 grams of FAS were heated in a reactor to 98° C. A solution containing 25 grams of acrylic acid in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 8 by adding 25 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 56,066 as determined by aqueous GPC process noted above.
140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01960 dextrin, having a DE of 11 and a number average molecular weight of 14,851 as determined by aqueous GPC described above) and 0.00075 grams of FAS were heated in a reactor to 98° C. A solution containing 35 grams of acrylic acid in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 101,340 as determined by aqueous GPC process noted above.
140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01960 dextrin, having a DE of 11 and a number average molecular weight of 14,851 as determined by aqueous GPC described above) were heated in a reactor to 98° C. A solution containing 35 grams of acrylic acid in 30 grams of water and 0.00075 grams of ferrous ammonium sulfate hexahydrate (‘FAS’) was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 101,340 as determined by aqueous GPC process noted above.
140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01918 dextrin, having a DE of 18 and a number average molecular weight of 12,937 as determined by aqueous GPC described above) and 0.00075 grams of FAS were heated in a reactor to 98° C. A solution containing 35 grams of acrylic acid in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 125,980 as determined by aqueous GPC process noted above.
140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01960 dextrin, having a DE of 11 and a number average molecular weight of 14,851 as determined by aqueous GPC described above) and 0.0014 grams of FAS were heated in a reactor to 98° C. A solution containing 35 grams of acrylic acid in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a ph of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 88,450 as determined by aqueous GPC process noted above.
140 grams of water, 65 grams of maltodextrin (Cargill MD™ 01960 dextrin, having a DE of 11 and a number average molecular weight of 14,851 as determined by aqueous GPC described above) and 0.002 grams of FAS were heated in a reactor to 98° C. A solution containing 35 grams of acrylic acid in 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized to a pH of 5 by adding 18 grams of a 50% solution of NaOH. The final product was a clear water white solution having a Gardner color of 1. The number average molecular weight of this polymer was 83,062 as determined by aqueous GPC process noted above.
Low Molecular Weight Copolymer According to the Present Invention Using Increased Level of FAS to Produce the Lower Molecular Weight Polymer.
The copolymer in Comparative Example 2 above was reproduced in the same manner with the exception that instead of 0.00075 grams of FAS, 0.075 grams of FAS was used (100 times the level of FAS used in Comparative Example 1, or 0.19 mmoles of FAS and 400 ppm as moles of Fe based on moles of acrylic acid monomer). The final product was a dark amber solution having a Gardner color of 12. The number average molecular weight of this polymer was 5,265 as determined by aqueous GPC. This example illustrates that higher levels of Fe(II) (400 ppm instead of 4) are required to lower the molecular weight compared to Comparative Example 1. However, this leads to darker colored materials as evidenced by the significant jump in Gardner color from 1 to 12.
Low Molecular Weight Copolymer According to the Present Invention Using Increased Level of FAS to Produce the Lower Molecular Weight Polymer
The copolymer in Comparative Example 1 above was reproduced in the same manner with the exception that instead of 0.00075 grams of FAS, 0.75 grams of FAS was used (1,000 times the level of FAS used in Comparative Example 1, or 1.9 mmoles FAS and 4000 ppm as moles of Fe based on moles of acrylic acid monomer). The final product was a very dark amber solution having a Gardner color of 18. The number average molecular weight of this polymer was 5,380 as determined by aqueous GPC. (This Mn is within experimental error and may indicate a limit of how low a Mn can be reached with increasing levels of Fe.)
Low Molecular Weight Copolymer According to the Present Invention Using Cu (II) Sulfate Pentahydrate Instead of FAS to Produce the Copolymer
The copolymer in Comparative Example 1 above was reproduced in the same manner with the exception that instead of 0.00075 grams of FAS, 0.048 grams of Cu (II) sulfate pentahydrate was used (0.19 mmoles Cu (II) sulfate pentahydrate and 400 ppm as moles of Cu based on moles of acrylic acid monomer, or the same amount of Cu used as Fe used in Example 1). The final product was a clear yellow solution having a Gardner color of 9. The number average molecular weight of this polymer was 3,205 as determined by aqueous GPC. This shows that using Cu instead of Fe produces a lower molecular weight copolymer. Moreover, an acceptable yellow color (Gardner 9 instead of 12), which is much lighter than the dark amber color of Example 1, is obtained by using the Cu salt instead of Fe and neutralizing to a pH of about 5.
Low Molecular Weight Copolymer According to the Present Invention Using Cu (II) Sulfate Pentahydrate Instead of FAS to Produce the Copolymer
The copolymer in Comparative Example 2 above was reproduced in the same manner with the exception that instead of 0.00075 grams of FAS, 0.0022 grams of Cu (II) sulfate pentahydrate was used (0.0088 mmoles Cu (II) sulfate pentahydrate, which is the same molar level as the FAS used in Comparative Example 2). The final product was a dark amber solution having a Gardner color of 11. The number average molecular weight of this polymer was 4,865 as determined by aqueous GPC. This shows that using Cu instead of Fe produces a lower molecular weight copolymer.
Low Molecular Weight and Color Acrylic Acid-Maleic Acid Graft Copolymer Using Cu (II) as a Catalyst and Shorter Feed Times to Produce the Copolymer
A reactor containing 263.1 grams of water 63.8 grams of maleic anhydride (0.65 moles) and 80 grams of maltodextrin (Cargill MD™ 01960, having a DE of 11 and Mn of 14,851) and 0.0022 grams of Copper (II) sulfate pentahydrate (0.0088 mmoles or 2.8 ppm as moles of Cu based on moles of maleic and acrylic acid, or the same molar level as the FAS used in Comparative Example 2) was heated to 98° C. A solution containing 178.2 grams of acrylic acid (2.47 moles) and 141.9 grams of water was added to the reactor over a period of 2.5 hours. An initiator solution comprising 23.7 grams of 35% hydrogen peroxide solution in 37.3 grams of deionized water was simultaneously added to the reactor over a period of 3 hours. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 180 grams of a 50% solution of NaOH. The final product was a clear light amber solution having a Gardner color of 4. The number average molecular weight of this polymer was 5,323 as determined by aqueous GPC.
Low Molecular Weight Acrylic Acid-Maleic Acid Graft Copolymer Using Cu (II) as a Catalyst and Higher Amounts of Natural Material to Synthetic Monomer.
A reactor containing 400 grams of water 100 grams of maleic anhydride (1.02 moles) and 240 grams of maltodextrin (Cargill MD™ 01960, having a DE of 11 and Mn of 14,851) and 0.022 grams of Copper (II) sulfate pentahydrate (0.088 mmoles, or 30 ppm moles of Cu based on moles of maleic and acrylic acid) was heated to 98° C. A solution containing 140 grams of acrylic acid (1.94 moles) and 141.9 grams of water was added to the reactor over a period of 5 hours. The amount of natural component was 50 weight % of total natural component and synthetic monomers. An initiator solution comprising 75 grams of 35% hydrogen peroxide and 25 grams of sodium persulfate dissolved in 80 grams of deionized water was simultaneously added to the reactor over a period of 6 hours. Simultaneously, 75 grams of 50% NaOH dissolved in 100 grams of water was added over 6 hours and 15 minutes so that the maleic acid is partially neutralized during the polymerization process. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 70 grams of a 50% solution of NaOH. The final product was a very dark amber solution with a Gardner color of 17 and a pH of 4.6. The number average molecular weight of this polymer was 1,360 as determined by aqueous GPC. The residual acrylic acid was 546 ppm and the residual maleic acid was 252 ppm.
Low Molecular Weight Acrylic Acid-Maleic Acid Graft Copolymer Using Cu (II) as a Catalyst and Higher Amounts of Natural Material to Synthetic Monomer
A reactor containing 400 grams of water, 100 grams of maleic anhydride (1.02 moles) and 300 grams of 80% solution of Cargill Sweet Satin Maltose and 0.022 grams of Copper (II) sulfate pentahydrate (0.088 mmoles, or 30 ppm as moles of Cu based on moles of maleic and acrylic acid) was heated to 98° C. A solution containing 140 grams of acrylic acid (1.94 moles) and 141.9 grams of water was added to the reactor over a period of 5 hours. The amount of natural component was 50 weight % of total natural component and synthetic monomers. An initiator solution comprising 75 grams of 35% hydrogen peroxide and 25 grams of sodium persulfate dissolved in 80 grams of deionized water was simultaneously added to the reactor over a period of 6 hours. Simultaneously, 75 grams of 50% NaOH dissolved in 100 grams of water was added over 6 hours and 15 minutes partially neutralizing the maleic acid during the polymerization process. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 70 grams of a 50% solution of NaOH. The final product was a very dark amber solution having a Gardner color of 18 and a pH of 4.6. The number average molecular weight of this polymer was 1,340 as determined by aqueous GPC. The residual acrylic acid was 588 ppm and the residual maleic acid was 460 ppm.
Low Molecular Low Color Graft Copolymer Comprising 75 Weight % of the Natural Component
A reactor containing 120 grams of water and 94 grams of Cargill Sweet Satin Maltose (80% solution) and 0.048 grams of Cu(II) sulfate pentahydrate (0.19 mmoles, of 553 ppm as moles of Cu based on moles of acrylic acid monomer) was heated to 98° C. A solution containing 25 grams of acrylic acid (0.347 moles) and 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 18 grams of a 50% solution of NaOH (0.225 moles) for a 65% neutralization of the acrylic acid groups. The final product was a clear golden yellow solution with a Gardner color of 7 and a pH of 5.1. The number average molecular weight of this polymer was 2,024 as determined by aqueous GPC. The polymer solution was stable for months with no signs of phase separation.
Low Molecular Low Color Graft Copolymer Using 85 Weight % of the Natural Component
A reactor containing 120 grams of water and 106 grams of Cargill Sweet Satin Maltose (80% solution) and 0.048 grams of Cu(II) sulfate pentahydrate (0.19 mmoles, or 923 ppm as moles of Cu based on the moles of acrylic acid monomer) was heated to 98° C. A solution containing 15 grams of acrylic acid (0.208 moles) and 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 7.5 grams of a 50% solution of NaOH (0.09 moles) for a 45% neutralization of the acrylic acid groups. The final product was a clear golden yellow solution with a Gardner color of 7 and a pH of 4.9. The number average molecular weight of this polymer was 1,255 as determined by aqueous GPC. The polymer solution was stable for months with no signs of phase separation.
Low Molecular Low Color Graft Copolymer Using 95 Weight % of the Natural Component
A reactor containing 120 grams of water, 119 grams of Cargill Sweet Satin Maltose (80% solution) and 0.048 grams of Cu(II) sulfate pentahydrate (0.19 mmoles Cu(II) sulfate pentahydrate, or 2736 ppm as moles of Cu based on moles of acrylic acid monomer) was heated to 98° C. A solution containing 5 grams of acrylic acid (0.069 moles) and 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 2.5 grams of a 50% solution of NaOH (0.031 moles) for a 45% neutralization of the acrylic acid groups. The final product was a clear golden yellow solution having a Gardner color of 7 and a pH of 4.9. The number average molecular weight of this polymer was below the detectable limit of the GPC. The polymer solution was stable for months with no signs of phase separation.
Low Molecular Weight Acrylic Acid-Maleic Acid Graft Copolymer Using Cu (II) as a Catalyst
A reactor containing 500 grams of water, 100 grams of maleic anhydride (1.02 moles) and 300 grams of 80% solution of Cargill Sweet Satin Maltose and 75 grams of 50% NaOH and 0.022 grams of Cu (II) sulfate pentahydrate (0.088 mrnmoles, or 30 ppm as moles of Cu based on moles of maleic and acrylic acid) was heated to 98° C. A solution containing 140 grams of acrylic acid (1.94 moles) was added to the reactor over a period of 5 hours. The amount of natural component was 50 weight percent of the natural component and the synthetic monomers. An initiator solution comprising 75 grams of 35% hydrogen peroxide and 25 grams of sodium persulfate dissolved in 80 grams of deionized water was simultaneously added to the reactor over a period of 6 hours. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 70 grams of a 50% solution of NaOH. The fmal product was a very dark amber solution with a Gardner color of 15. The number average molecular weight of this polymer was 4,038 as determined by aqueous GPC.
Low Molecular Weight Graft Copolymer
A reactor containing a mixture of 50 grams of maleic anhydride dissolved in 250 grams of water and neutralized with 37.5 grams of a 50% solution of NaOH was heated to 98° C. 150 grams of Cargill Sweet Satin Maltose (65% solution) and 0.011 grams of CuSO4.5H2O was added to the mixture. A monomer solution containing 70 grams of acrylic acid was subsequently added to the reactor over a period of 3 hours and 45 minutes. An initiator solution comprising of 12.5 grams of sodium persulfate and 37.5 grams of a 35% solution of hydrogen peroxide dissolved in 40 grams of water was added to the reactor at the same time as the monomer solution but over a period of 4 hours. The reaction product was held at 98° C. for an additional hour. The final product was a clear light amber solution and had 39% solids.
Low Molecular Weight Graft Copolymer
47 grams of maleic anhydride was dissolved in 172 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95° C. and 39.4 grams of DE 11 (Cargill MD™ 01960 dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.02 grams of ferrous ammonium sulfate hexahydrate were added. A monomer solution containing 70 grams of acrylic acid was subsequently added to the reactor over a period of 4 hours. An initiator solution comprising of 4.7 grams of sodium persulfate and 38.7 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor at the same time and over the same period as the monomer solution. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and 4 grams of a 41% bisulfite solution were simultaneously added to scavenge the residual monomer. The final product was a clear light amber solution and had 44% solids.
Low Molecular Weight Graft Copolymer
47.3 grams of maleic anhydride was dissolved in 172.6 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95 C and 39.4 grams of DE 11(Cargill MD™ 01960) dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.02 grams of ferrous ammonium sulfate hexahydrate was added. A monomer solution containing 70.9 grams of acrylic acid was subsequently added to the reactor over a period of 4 hours. An initiator solution comprising of 4.8 grams of sodium persulfate and 38.7 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor over a period of 5.5 hours. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and simultaneously, 4 grams of a 41% bisulfite solution was added to scavenge the residual monomer. The final product was a clear light amber solution and had 35% solids. The number average molecular weight of this polymer as measured by aqueous GPC was 1755.
Low Molecular Weight Graft Copolymer
22 grams of maleic anhydride was dissolved in 172.6 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95 C and 102.4 grams of DE 11 (Cargill MD™ 01960 dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.01 grams of ferrous ammonium sulfate hexahydrate was added. A monomer solution containing 33 grams of acrylic acid was subsequently added to the reactor over a period of 5 hours. An initiator solution comprising of 2.4 grams of sodium persulfate and 19.4 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor over a period of 5.5 hours. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and simultaneously, 4 grams of a 41% bisulfite solution was added to scavenge the residual monomer. The final product was a clear light amber solution and had 44% solids. The number average molecular weight of this polymer as measured by aqueous GPC was 1280.
Copolymers from the above Examples were tested for anti-redeposition properties in a generic powdered detergent formulation. The powdered detergent formulation was as follows:
The test was conducted in a full scale washing machine using 3 cotton and 3 polyester/cotton swatches. Soil consisting of 17.5 g rose clays 17.5 g bandy black clay and 6.9 g oil blend (75:25 vegetable/mineral) was used. The test was conducted for 3 cycles using 100 g powder detergent per wash load. The polymers were dosed in at 1.0 wt % of the detergent. The wash conditions used were temperature of 33.9° C. (93° F.), 150 ppm hardness and a 10 minute wash cycle.
L (luminance), a (color component) and b (color component) values before the first cycle and after the third cycle was measured as L1, a1, b1 and L2, a2, b2, respectively, using a spectrophotometer. Delta whiteness index is calculated using the L, a, b values above.
1Lower Delta values indicate better anti-redeposition performance.
2Sodium salt of polyacrylic acid, available from Alco Chemical, Chattanooga, Tennessee.
The above data indicates that low molecular weight graft copolymers according to the present invention are far superior to higher molecular weight graft copolymers in anti-redeposition and dispersancy, and are comparable to an industry standard synthetic polymer (here, Alcosperse 602N).
Acid Cleaner
Alkaline Cleaner
Once prepared, water-soluble polymers are incorporated into a water treatment composition that includes the water-soluble polymer and other water treatment chemicals. Other water treatment chemicals include corrosion inhibitors such as orthophosphates, zinc compounds and tolyl triazole. The level of inventive polymer utilized in water treatment compositions is determined by the treatment level desired for the particular aqueous system treated. Water soluble polymers generally comprise from 10 to 25 percent by weight of the water treatment composition. Conventional water treatment compositions are known to those skilled in the art, and exemplary water treatment compositions are set forth in the four formulations below. These compositions containing the polymer of the present invention have application in, for example, the oil field.
where HEDP is 1-hydroxyethylidene-1,1 diphosphonic acid and TKPP is tri-potassium polyphosphate.
The polymers in Example 4 and Comparative Example 2 were tested for anti-redeposition performance. The data below indicates that the polymer of Example 4 was far superior to that of Comparative Example 2 in anti-redeposition properties. Further, the performance of polymer 4 proved superior to a commercial synthetic Na polyacrylate (Alcosperse 602N), which is an industry standard for this application.
One wash anti-redeposition data using commercial Sun liquid detergent. The test protocol is described in Example 4. Lower Delta WI (whiteness index) numbers are better. The data indicate that the low molecular weight graft copolymer of Example 4 produced using the Cu catalyst has superior anti-redeposition properties compared to the graft copolymer of Comparative Example 2 using the same amount of Fe. In fact, Comparative Example 2 polymer performs similar to the control, which does not have any polymer. However, the low molecular weight graft copolymer of this invention performs similar to the industry standard synthetic polyacrylic acid.
Low Molecular Weight Maleic Acid Graft Copolymer Using Cu (II) as a Catalyst and Higher Amounts of Natural Material to Synthetic Monomer
A reactor containing a mixture of 450 grams of water, 100 grams of maleic anhydride (1.02 moles), 300 grams of 80% solution of Cargill Sweet Satin Maltose, 0.0022 grams of Cu(II) sulfate pentahydrate and 75 grams of a 50% solution of NaOH was heated to 98° C. A solution containing 140 grams of acrylic acid (1.94 moles) in 50 grams of water was added to the reactor over a period of 5 hours. The mole percent of maleic in the synthetic part of the copolymer was 34.4. The amount of natural component was 50 weight percent, based on total weight percent of natural component and synthetic monomers. An initiator solution comprising 52 grams of 35% hydrogen peroxide in 80 grams of deionized water was simultaneously added to the reactor over a period of 4 hours. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 70 grams of a 50% solution of NaOH. The final product was a clear yellow solution with a Gardner color of 8. The number average molecular weight of this polymer was 1,429 as determined by aqueous GPC.
Low Molecular Weight Maleic Acid Graft Copolymer with Very High Amounts of Natural Material to Synthetic Monomer.
A reactor containing a mixture of 200 grams of water, 8 grams of maleic anhydride (0.08 moles), 160 grams of Cargill maltodextrin MD 1956 (DE 7.5) and 11.8 grams of a 50% solution of NaOH was heated to 98° C. A shot of 0.0018 grams of ferrous ammonium sulfate hexahydrate was added to the reactor just before monomer and initiator feeds were started. A solution containing 22 grams of acrylic acid (0.31 moles) in 71 grams of water was added to the reactor over a period of 150 minutes. The mole percent of maleic in the synthetic part of the copolymer was 21. The amount of natural component was 84.2 weight percent based on total weight percent of natural component and synthetic monomers. An initiator solution comprising 3 grams of 35% hydrogen peroxide in 22 grams of deionized water was simultaneously added to the reactor over a period of 180 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 10 grams of a 50% solution of NaOH. The number average molecular weight of this polymer was 3,970 as determined by aqueous GPC.
The Calcium Binding/Sequestration Properties of a Series of Polymers Were Measured Using the Test Procedure Below—
Reagent Preparation:
Procedure for Determination of Calcium Binding Capacity:
Titration for Calculating Calcium Binding Capacity (CBC):
Calculation of CBC:
The CBC of various polymers was measured using the procedure described above. Grams of CaCO3 sequestered per mole of COOH in the polymer were calculated using the equations below:
Moles COOH/g polymer=moles of COOH from maleic anhydride portion+moles of COOH from acrylic acid portion
Calcium sequestration is a stoichiometric property and is directly proportional to the moles of acid functionality in the polymer. The data indicates that maleic acid containing graft copolymers have much higher calcium sequestration numbers compared to the synthetic copolymers or the acrylic acid grafts on a molar basis.
Low Molecular Weight Graft Copolymer Using an Oxidized Starch Derivative
A reactor containing 140 grams of water, 65 grams of Flomax 8 (oxidized starch having a Mn of 9,891, available from National Starch and Chemical, Bridgewater, N.J.) and 0.00075 grams of FAS was heated to 98° C. A solution containing 35 grams (0.486 moles) of acrylic acid and 30 grams of water was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 35 grams of a 50% solution of NaOH. The final product was an opaque yellow solution. The number average molecular weight of this polymer was 24,373 as determined by aqueous GPC.
This polymer was tested according to the anti-redeposition test of Example 4. The data indicates that the polymer did not work as well as the synthetic Na polyacrylate. Nevertheless it was far better than the control which did not have any polymer.
The efficacy of various treatments was tested for their ability to prevent the precipitation of calcium carbonate in typical cooling water conditions (a property commonly referred to as the threshold inhibition). This test was developed in correlation with the dynamic testing units, in order to allow for an initially quick screening test of scale threshold inhibitors for cooling water treatment. The ratio of calcium concentration to alkalinity is 1.000:1.448 for the chosen water. This ratio is a fairly accurate average of cooling water conditions found worldwide. One should expect that water wherein the alkalinity is proportionately less will be able to reach higher levels of calcium, and that water containing a proportionally greater amount of alkalinity will reach lower levels of calcium. Since cycle of concentration is a general term, one cycle was chosen, in this case, to be that level at which calcium concentrations equaled 100.0 mg/L Ca as CaCO3 (40.0 mg/L as Ca). The complete water conditions at one cycle of concentration (i.e., make-up water conditions) are as follows:
Simulated Make-Up Water Conditions:
In dynamic testing (where the pH is about 8.80, bulk water temperature is around 104° F., flow is approximately 3.0 m/s, and heat transfer is approximately 17,000 BTU/hr/ft2), above average threshold inhibitors can reach anywhere from four to five cycles of concentration with this water before significant calcium carbonate precipitation begins. Average threshold inhibitors may only be able to reach three to four cycles of concentration before precipitating, while below average inhibitors may only reach two to three cycles of concentration before precipitation occurs. Polymer performance is generally expressed as percent calcium inhibition. This number is calculated by taking the actual soluble calcium concentration at any given cycle, dividing it by the intended soluble calcium concentration for that same given cycle, and then multiplying the result by 100. Resulting percentage amounts that are below 90% calcium inhibition are considered to be indicators of a significant precipitation of calcium carbonate. However, there are two ways in which an inhibitor can react once their threshold limit is reached. Some lose practically all of their calcium carbonate threshold inhibition properties, falling from 90-100% to below 25% threshold inhibition. Others are able to “hold on” better to their inhibition properties, maintaining anywhere from 50% to 80% threshold inhibition.
Testing beyond the threshold limit in order to determine each inhibitor's ability to “hold on” has been found to be a better method of predicting an inhibitors ability to prevent the formation of calcium carbonate in the dynamic testing units. It also allows for greater differentiation in test results. Therefore, a higher cycle (4.0 cycles) was chosen for this test. At this concentration, above average inhibitors should be expected to give better than 60% threshold inhibition. Poor inhibitors should be expected to give less than 20% threshold inhibition, while average inhibitors should fall somewhere in between.
Materials:
Solution Preparations:
All chemicals used are reagent grade and weighed on an analytical balance to ±0.0005 g of the indicated value. All solutions are made within thirty days of testing. Once the solutions are over thirty days old, they are remade.
The hardness, alkalinity, and 12% KCl solutions should be prepared in a one liter volumetric flask using DI water. The following amounts of chemical should be used to prepare these solutions—
250 Cycle Hardness Solution:
10,000 mg/L Ca36.6838 g CaCl2.2H2O
3,000 mg/L Mg25.0836 g MgCl2.6H2O
100 mg/L Li0.6127 g LiCl
250 Cycle Alkalinity Solution:
36,000 mg/L HCO348.9863 g NaHCO3
4,000 mg/L CO37.0659 g Na2CO3
10,000 mg/L Treatment Solutions:
Using percentage of active product in the supplied treatment, a 250 mL of a 10,000 mg/L active treatment solution is made up. This was done for every treatment tested. The pH of the solutions was adjusted to between 8.70 and 8.90 using 50% and 10% NaOH solutions by adding the weighed polymer into a specimen cup or beaker and filling with DI water to approximately 90 mL. The pH of this solution was then adjusted to approximately 8.70 by first adding the 50% NaOH solution until the pH reaches 8.00, and then by using the 10% NaOH until the pH equals 8.70. The solution was then poured into a 250 mL volumetric flask. The specimen cup or beaker was rinsed with DI water and this water added to the flask until the final 250 mL is reached. The formula used to calculate the amount of treatment to be weighed is as follows:
Test Setup Procedure:
The incubator shaker should be turned on and set for a temperature of 50° C. to preheat. 34 screw cap flasks were set out in groups of three to allow for triplicate testing of each treatment, allowing for testing of eleven different treatments. The one remaining flask was used as an untreated blank. Label each flask with the treatment added.
Calibrate the Brinkmann dispensette to deliver 96.6 mL, using DI water, by placing a specimen cup or beaker on an electronic balance and dispensing the water into the container for weighing. Adjust the dispensette accordingly, until a weight of 96.5-96.7 g DI water is delivered. Record this weight and repeat for a total of three measurements and take the average. Once calibrated, dispense the 96.6 mL DI water into each flask.
Using a 2.5 mL electric pipette, add 1.60 mL of hardness solution to each flask. This is the amount that will achieve four cycles of make-up water.
Using a 250 μL electronic pipette, add 200 μL of desired treatment solution to each flask. This amount will result in a 20 mg/L active treatment dosage. Use a new tip on the electric pipette for each treatment solution so cross contamination does not occur.
Using a 2.5 mL electric pipette, add 1.60 mL of alkalinity solution to each flask. This is the amount that will achieve four cycles of make-up water. The addition of alkalinity should be done while swirling the flask, so as not to generate premature scale formation from high alkalinity concentration pooling at the addition site.
Prepare one “blank” solution in the exact same manor the above treated solutions were prepared, except add DI water in place of the treatment solution.
Place all 34 flasks uncapped onto the shaker platform and close the door. Turn the shaker on at 250 rpm and 50° C. Record the time of entry. The flask should be left in the shaker at these conditions for 17 hours.
Prepare a “total” solution in the exact same manor the above treated solutions were prepared, except add DI water in place of both the treatment solution and alkalinity solution. Cap this solution and let sit overnight outside the shaker.
Test Analysis Procedure:
Once 17 hours have passed, remove the 34 flasks from the shaker and let cool for one hour. Filter each flask solution through a 0.2 μm filter membrane. Analyze this filtrate, directly, for lithium, calcium, and magnesium concentrations by either an Inductively Couple Plasma (ICP) Optical Emission System or Flame Atomic Absorption (AA) system. Also analyze these concentrations in the prepared “total” solution.
Calculations of Results:
Once the lithium, calcium, and magnesium concentrations are known in all 34 shaker samples and in the “total” solution, the percent inhibition is calculated for each treatment. The lithium is used as a tracer of evaporation in each flask (typically about ten percent of the original volume). The lithium concentration found in the “total” solution is assumed to be the starting concentration in all 34 flasks. The concentrations of lithium in the 34 shaker samples can then each be divided by the lithium concentration found in the “total” sample. These results will provide the multiplying factor for increases in concentration, due to evaporation. The calcium and magnesium concentrations found in the “total” solution are also assumed to be the starting concentrations in all 34 flasks. By multiplying these concentrations by each calculated evaporation factor for each shaker sample, one can determine the final intended calcium and magnesium concentration for each shaker sample. By subtracting the calcium and magnesium concentrations of the “blank” from both the actual and intended concentrations of calcium and magnesium, then dividing the resulting actual concentration by the resulting intended concentration and multiplying by 100, one can calculate the percent inhibition for each treated sample. The triplicate treatments should be averaged to provide more accurate results. A spreadsheet should be set up to make each individual calculation less time consuming.
Example:
“Total” concentration analysis results:
“Blank” concentration analysis results:
Shaker sample concentration analysis results:
By taking the Li concentration from the shaker sample and dividing by the Li concentration in the “total” sample, one will obtain an evaporation factor of—
1.78 mg/L/1.61 mg/L=1.11
By multiplying the Ca and Mg concentrations in the “total” sample by this factor, one can obtain the final intended concentrations of Ca and Mg in the shaker sample—
Ca1.11×158.0 mg/L=175.4 mg/L Ca
Mg1.11×50.0 mg/L=55.5 mg/L Mg
Finally, by subtracting the calcium and magnesium concentrations of the “blank” from both the actual and intended concentrations of calcium and magnesium, then dividing the resulting actual concentrations of Ca and Mg in the shaker sample by the resulting final intended concentrations and multiplying by 100, one can calculate the percent threshold inhibition of calcium and magnesium—
Ca((150.0 mg/L−4.1 mg/L)/(175.4 mg/L−4.1 mg/L))×100=85.2% Ca inhibition
Mg((54.0 mg/L−49.1 mg/L)/(55.5 mg/L−49.1 mg/L))×100=76.6% Mg inhibition
The polymer of Example 3 was tested in this test at 3 cycles of concentration and compared with a commercial polyacrylate (AQUATREAT 900A from Alco Chemical). The data indicate that the low molecular weight graft copolymer was as good a calcium carbonate inhibitor in this test.
Low molecular weight sulfonated graft copolymers are exemplified in U.S. Pat. No. 5,580,941. These materials are made using mercaptan chain transfer agents. Mercaptan chain transfer agents lower the molecular weight, but in the process generate synthetic polymers. These mercaptans stop a growing chain Equation 1 and start a new polymer chain Equation 2, illustrated in the mechanism below (Odian, P
Performance of materials exemplified in U.S. Pat. No. 5,580,941 (‘the '941 patent’) is mainly due to ungrafted synthetic copolymers generated in this process. This is the reason they exemplify relatively low amounts of saccharide (40 wt % or less). Higher amounts of saccharide will phase separate. Secondly, calcium binding data in Table 4 of the '941 patent is inversely proportional to the amount of saccharide functionality. This indicates that the material is mostly a mixture of synthetic copolymer and saccharide with little to no grafting. The saccharide contribution to Ca binding is negligible.
Finally, Comparative Example 5 of the '941 patent forms a precipitate when higher molecular weight saccharide (maltodextrin with DE 20) is used. This illustrates that there is little grafting and the resulting synthetic polymer is phase separating from the maltodextrin. This does not happen with the other examples because disaccharides like sucrose are used, which are small molecules and are compatible.
In contrast to the polymers of the '941 patent, graft copolymers of the present invention can have greater than 50 wt % maltodextrin and are compatible, indicating high degree of grafting.
Sulfonated Graft Copolymer with Maltodextrin (Without Mercaptan Chain Transfer Agent)
A reactor containing 156 grams of water, 49 grams of maltodextrin (Cargill MD™ 01918 maltodextrin, DE of 18) and 0.0039 grams of FAS was heated to 98° C. A solution containing 81.6 grams of acrylic acid and 129.2 of a 50% solution of sodium 2-acrylamido-2-methyl propane sulfonate (AMPS) was added to the reactor over a period of 45 minutes. An initiator solution comprising 13 grams of 35% hydrogen peroxide solution in 78 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The polymer was then neutralized by adding 27.2 grams of a 50% solution of NaOH. The final product was a clear yellow solution. The number average molecular weight of this polymer was 68,940. This sample remained a clear solution showing no sign of precipitation (phase separation) even after 4 months. In contrast, a blend of Alcosperse 545 (AA-AMPS copolymer) and Cargill MD™ 01918 maltodextrin phase separates within a day. This is similar to the phase separation seen in Comparative Example 5 of the '941 patent where a maltodextrin having a DE of 20 (a lower molecular weight dextrin than that used in our recipe) is used. This clearly indicates that the Example 5 has very little graft copolymer due to the presence of mercaptan, which leads to a lot of synthetic copolymer.
Also, a blend of Alcosperse 545 and saccharose or sucrose is phase stable. This is due to the fact that the latter is a small molecule and is very compatible. This supports our assertion that Examples 1, 2 and 12 of the '941 patent are due to the presence of mercaptans are mostly synthetic copolymers blended with the saccharose. The performance of these polymers in the Table above supports this assertion.
CaCO3 Inhibition Performance
CaCO3 inhibition performance was evaluated according to NACE™ 3076-2001 standardized test with a few modifications. Our modified test used 30 mL total sample size instead of 100 mL indicated in the method. The polymers were tested at 5, 10 and 15 ppm levels. The samples were tested in triplicate rather than duplicate. The samples were heated in heat block rather than oven or water bath and Ca concentration was determined by ICP.
In order to match the sample matrix and dilution for ICP evaluation, the “blank before precipitation” was made by combining 15 mL Ca Brine+15 mL of NaCl Brine plus DI water in place of polymer treatment, and the “blank after precipitation” was made by combining 15 mL Ca Brine+15 mL of Bicarbonate Brine plus DI water instead of polymer.
Samples synthesized above were tested in this modified NACE CaCO3 test. Polymers that give 80% or greater inhibition are generally considered good performers for this application. The data is provided in Table 8 below—
1Low molecular weight polyacrylic acid available from Alco Chemical, Chattanooga, TN.
Synthesis of Graft Copolymer
47 grams of maleic anhydride was dissolved in 172 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95 C and 39.4 grams of DE 11 (Cargill MD™ 01960 dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.02 grams of ferrous ammonium sulfate hexahydrate was added. A monomer solution containing 70 grams of acrylic acid was subsequently added to the reactor over a period of 4 hours. An initiator solution comprising of 4.7 grams of sodium persulfate and 38.7 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor at the same time as the monomer solution i.e. over a period of 4 hours. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and simultaneously, 4 grams of a 41% bisulfite solution was added to scavenge the residual monomer. The final product was a clear light amber solution and had 44% solids.
47.3 grams of maleic anhydride was dissolved in 172.6 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95 C and 39.4 grams of DE 11(Cargill MD™ 01960) dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.02 grams of ferrous ammonium sulfate hexahydrate was added. A monomer solution containing 70.9 grams of acrylic acid was subsequently added to the reactor over a period of 4 hours. An initiator solution comprising of 4.8 grams of sodium persulfate and 38.7 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor over a period of 5.5 hours. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and simultaneously, 4 grams of a 41% bisulfite solution was added to scavenge the residual monomer. The final product was a clear light amber solution and had 35% solids. The number average molecular weight of this polymer as measured by aqueous GPC was 1755.
22 grams of maleic anhydride was dissolved in 172.6 grams of water and neutralized with 22.5 grams of a 50% solution of NaOH. The mixture was heated to 95 C and 102.4 grams of DE 11(Cargill MD™ 01960 dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.01 grams of ferrous ammonium sulfate hexahydrate was added. A monomer solution containing 33 grams of acrylic acid was subsequently added to the reactor over a period of 5 hours. An initiator solution comprising of 2.4 grams of sodium persulfate and 19.4 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water was added to the reactor over a period of 5.5 hours. The reaction product was held at 95° C. for 30 minutes. 0.3 grams of erythorbic acid dissolved in 0.6 grams of water and simultaneously, 4 grams of a 41% bisulfite solution was added to scavenge the residual monomer. The final product was a clear light amber solution and had 44% solids. The number average molecular weight of this polymer as measured by aqueous GPC was 1280.
The samples above were evaluated for barium sulfate inhibition using the procedure below:
NOTE: Biological growth occurs in this solution due to sulfate content. Use within 1 week of making.
g=(V×C)/S
g=(100×1)/35=2.857 g of polymer in 100 mL of seawater
g=(3000×1)/44.4=67.57 g of polymer in 3000 mL
μl=[(V1×C1)/C2]×1000
μl=[(30×50)/10,000]×1000=150 μl
% inhibition=((S*d)−B/(T−B), where
The polymer of Example 38 was tested in all 3 of the brines detailed in Table 1. The data indicate that the polymer is very compatible in these brines.
Graft Copolymer with 10 Weight Percent Maltodextrin.
A reactor containing 150 grams of water, 90 grams of a 50% solution of NaOH, 10 grams of maltodextrin (Cargill MD™ 01960 dextrin) and 0.00075 grams of ferrous ammonium sulfate hexahydrate (‘FAS’) was heated to 98° C. A solution containing 90 grams of acrylic acid was added to the reactor over a period of 45 minutes. An initiator solution comprising 3.6 grams of 35% hydrogen peroxide solution in 30 grams of deionized water was simultaneously added to the reactor over a period of 60 minutes. The reaction product was held at 98° C. for an additional hour. The pH of the polymer solution was 7.
The graft copolymer of this Example with low levels of saccharide functionality (10 weight percent) was tested for brine compatibility in Brine 3. This polymer was found to be insoluble in Brine 3 when dosed at 250, 1,000, 5,000, 25,000 and 100,000 ppm levels.
Graft Copolymer with 10 Weight Percent Maltodextrin.
15 grams of maleic anhydride is dissolved in 250 grams of water and 135 grams of a 50% solution of NaOH is heated to 95 C and 10 grams of DE 11(Cargill MD™ 01960) dextrin, spray-dried maltodextrin obtained by enzymatic conversion of common corn starch, available from Cargill Inc., Cedar Rapids, Iowa) and 0.00113 grams of ferrous ammonium sulfate hexahydrate is added. A monomer solution containing 125 grams of acrylic acid is subsequently added to the reactor over a period of 5 hours. An initiator solution comprising of 5.4 grams of sodium persulfate and 45 grams of a 35% solution of hydrogen peroxide dissolved in 12.7 grams of water is added to the reactor over a period of 5.5 hours. The reaction product is held at 95° C. for 60 minutes.
The graft copolymer of this Example with low levels of saccharide functionality (10 weight percent) is tested for brine compatibility in Brine 3. The polymer is found to be insoluble in Brine 3 when dosed at 250, 1,000, 5,000, 25,000 and 100,000 ppm levels.
The Polymers Synthesized in Examples 36 and 38 Were Tested for Compatibility in Ethylene Glycol—
Although the present invention has been described and illustrated in detail, it is to be understood that the same is by way of illustration and example only, and is not to be taken as a limitation. The spirit and scope of the present invention are to be limited only by the terms of any claims presented hereafter.
The present application is a continuation-in-part of U.S. application Ser. No. 11/459,233, filed 21 Jul. 2006.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11459233 | Jul 2006 | US |
| Child | 11780494 | US |
