CA1269486A - Process for preparing improved weak acid resins and porous weak acid resins - Google Patents
Process for preparing improved weak acid resins and porous weak acid resinsInfo
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- CA1269486A CA1269486A CA000505628A CA505628A CA1269486A CA 1269486 A CA1269486 A CA 1269486A CA 000505628 A CA000505628 A CA 000505628A CA 505628 A CA505628 A CA 505628A CA 1269486 A CA1269486 A CA 1269486A
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- hydrolyzable
- acrylate
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- weak acid
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Abstract
ABSTRACT OF THE DISCLOSURE
Weak acid type cation exchange resins are prepared by subjecting to caustic hydrolysis a copoly-mer comprising in polymerized form (1) a major amount of a monoethylenically unsaturated monomer which is hydrolyzable under caustic conditions; (2) a minor amount of a monoethylenically unsaturated monomer which has a less hydrolyzable character than the hydrolyzable monomer, and (3) an effective amount of a crosslinking monomer. For example, copolymers prepared from methyl acrylate, butyl acrylate and divinylbenzene. The resin beads so prepared exhibit increased resistance to osmotic shock.
Weak acid type cation exchange resins are prepared by subjecting to caustic hydrolysis a copoly-mer comprising in polymerized form (1) a major amount of a monoethylenically unsaturated monomer which is hydrolyzable under caustic conditions; (2) a minor amount of a monoethylenically unsaturated monomer which has a less hydrolyzable character than the hydrolyzable monomer, and (3) an effective amount of a crosslinking monomer. For example, copolymers prepared from methyl acrylate, butyl acrylate and divinylbenzene. The resin beads so prepared exhibit increased resistance to osmotic shock.
Description
PROCESS FOR PREPARING IMPROVED WEAK
ACID R13SINS AND POROUS W13AK ACID RESI~7S
The present invention relates to ion exchange resins, and in particular, to ion exchange resins which are acidic in character.
Weak acid resins have been prepared by suspen-sion polymerizing and crosslinking unsatura~ed carboxylicacids such as acrylic acid. Unfortunately, the polymeri-zation of unsaturated carboxylic acids is highly exother-mic making reaction control very difficult. Thus, the physical properties of the ~inal resin product are typically very poor in guali-ty.
Weak acid resins have been prepared by the post-hydrolysis of suspension polymerized, crosslinked acrylic acid esters. Unfoxtunately, such a process provides resin products which have undergone incomplete hydrolysis and exhibit poor physical s~rengths. ThUsr such resins can have low exchange capacities and low resistance to osmotic shock.
32,479A F -1-, ' ~269~
In view of the deficiencies of the prior art, it would be highly desirable to provide a weak acid ion exchange resin with a high operating capacity which can be prepared in a controlled manner and exhibits high resistance to osmotic shock during regeneration.
The present invention is a process for pre-paring weak acid type cation exchange resins by sub-jecting to caustic hydrolysis a copolymer comprising in polymerized form (1) a major amount of a monoethylenic-ally unsaturated monomer which is hydrolyzable undercaustic conditions; (2) a minor amount of a monoethylenic-ally unsaturated monomer which has a less hydrolyzable character than the hydrolyzable monomer; and ~3) an effective amount of a crosslinking monomer; and option-ally a minor amount of a non-hydrolyzable monomer.
As used herein the term "hydrolysis" refers to caustic hydrolysis. The term "caustic" is to be broadly construed to mean a strongly basic species. In another aspect, the present invention is the weak acid type cation exchange resin which is prepared using the process as described hereinbefore.
The process of this invention provides the skilled artisan with a method for preparing weak acid type cation exchange resins exhibiting a high operating ion exchange capa~ity and improved osmotic shock proper-ties. Resin beads of this invention can have a porous character, and in particular, a macroporous character.
Such resin beads can be subjected to an increased number of regeneration cycles without a substantial amount of cracking of said resin beads. Such beads are useful in a wide varie~y of applications which can 32,479A-F -2-~26~L 5t6 include the demineralization of water for enhanced oil recovery, the removal of heavy metal ions from various aqueous streams, and the like.
Polymers useful in the practice of this invention are crosslinked polymers formed by the addi-tion polymerization of at least one polymerizable hydrolyzable monoethylenically unsaturated monomer, at least one polymerizable monoethylenically unsaturated monomer which is less hydrolyzable in character than the hydrolyzable monomer, and at least one polymeriz-able unsaturated monomer capable of providing cross-linking to the polymer.
Hydrolyzable monomers useful herein are monoethylenically unsaturated carboxylic acids such as alkyl acrylates. The choice of alkyl acrylate will depend upon the degree or ease of hydrolysis which is desired. In general, any alkyl ester of acrylic acid, itaconic acid, etc., which is readily hydrolyzable ~mder caustic conditions can be employed. Preferred alkyl acrylates include ethylacrylate, butylacrylate, hexylacrylate, and the like. More prefexred alkyl acrylates are those wherein the alkyl moiety has from 1 to 3 carbon atoms, with methylacrylate being especially preferred.
Non-hydrolyzable monomers which are option-ally useful herein include, or example, acrylonitrile, styrene, e~hylbenzene, vinyl toluene, methylstyrene, vinylbenzyl chloride, and halogenated styrene; hetero-cyclic aromatics such as vinylpyridine and substituted vinylpyridines, vinyl acetate, vinyl chloride, vinyli-dene chloride, N-vinylpyrirolidone, and methacrylates 32,479A-F -3-3.2~9~
which are not highly hydrolyzable under conditions which the hydrolyzable monomers are converted to carboxylic acid moieties.
Monomers which are less hydrolyzable than the aforementioned hydrolyzable monomers include those alkylacrylates which contain an alkyl functionality which provides a less hydrolyzable character to the monomex than said hydrolyzable monomer. In particular, the less hydrolyzable monomer does not undergo hydroly-sis to any subs~antial degree under conditions whichthe hydrolyzable monomer undergoes hydrolysis. Prefer-red less hydrolyzable monomers typically have alkyl functionalities which have higher amounts of carbon atoms than those hydrolyzable monomers. For example, if methylacrylate is the hydrolyzable monomer, then ethylacrylate or butylacrylate can be employed as the monomer which is less hydrolyzable in character.
Similarly, if ethylacrylate is employed as the hydrolyz-able monomer, then butylacrylate or hexylacrylate can be employed as the monomer which is less hydrolyæable in character.
Crosslinking monomers are those monomers which can introduce crosslinking to the resulting polymer. Examples of such monomers are those useful in preparing ion exchange resins and are those polyvinyl crosslinking monomers such as divinylbenzene, divinyl-toluene, divinylxylene, and divinylnapthalene; ethylene glycol dimethacrylate; trimethylol propane triacrylate;
divinylsuccinate; and the like. See, also, those disclosed in U.S. Patent No. 4,~19,245 and U.S. Patent No. 4,444,961.
32,479A-F -4-~z~
The monomer composition which is employed can vary depending upon factors such as the density of the bead desired, the amount of physical stability which is desired, the ion exchange capacity which is desired, and the like. Typically, the amount of hydrolyzable monomer can range from 70 to 90 weight percent; the amount of less hydrolyzable and optional non-hydrolyz-able monomer can range from 1 to 20 weight percent; and the amount of crosslinking monomer can range from 4 to 12 weight percent based on all monomers. If desired, the hydrolyzable monomer portion can be polymerized in conjunction with a monomer such as acrylic acid.
The process of this invention is preferably performed by suspension polymerizing the aforementioned monomers under conditions ~uch that polymerization occurs. Suitable solvents, surfactants, diluents, activators and catalysts are known in the art. See, for example, U.S. Patent No. 4,224,415. The resulting polymer product is isolated and subjected to hydrolysis conditions. Fox example, the polymer can be contacted with a hydroxide solution. The resin can be washed with an acid solution to yield the H-form resln. Beads can be obtained in a gel form or in a porous form.
While beads having a wide range of pore sizes can be employed, beads having pore sizes greater than lOO A (0.01 microns) in diameter are preferred. That is, porous beads of this invention include the macro-porous beads. Macroporous beads are those macrore~icu-lar types of beads as are defined in U.S. Patent No. 4,224,415. For example, macroporous beads are prepared by those techniques described in U.S. Patent No. 4,382,124.
32,479A-F -5-~941~
The resin beads of this invention are prefer-ably spherical beads having particle sizes ranging from 180 to 2,000 microns, preferably from 200 to 1,000 microns. The distribution of the particle size can be narrowed by employing the appropriate s-tabilizer.
Narrow distributions of particle sizes can be obtained by using the method taught in U.S. Patent No. 4,444,961.
The resins of this invention exhibit good osmotic shock resistance as well as high ion exchange capacity. It is believed that the copolymerization of the hydrolyzable monomer with the non-hydrolyzable monomer or less hydrolyzable monomer causes the cross-linking in the bead to be less centralized. The more even spread of crosslinking in the bead is believed to provide a stronger product which exhibits less potential to crack or break during repeated shrinking and swelling.
The following e~amples are presented to ~urther illustrate but not limit the scope of this invention. All parts and percentages are by weight, unless otherwise noted.
Example 1 Into a jacketed stainless steel reactor was charged an aqueous solution comprising 1,500 grams (g) distilled water, 2.4 g carboxymethyl methylcellulose and 2.7 g sodium dichromate. To this solution was charged an organic mixture containing 763 g methyl-acrylate, 105 g n-butylacrylate, 200 g divinylbenzene, 100 g isooctane diluent, 0.5 g tertiary butylperoctoate and 0.9 g tertiary bu~yl perbenæoate. The reactor was 32,479A-F -6-~, purged with nitrogen for 15 minutes. The mixture was then agitated and the polymerization was conducted at 75C for 5 hours, followed by 110C for 3 hours. The reaction mixture was cooled. The spherical polymer product was filtered and washed with distilled water.
The diluent was removed by steam distillation.
The polymer product was mixed with a 20 percent active aqueous sodium hydroxide solution at 100C for 5-6 hours. The polymer product was filtered and washed with 1 normal hydrochloric acid. The final resin exhibits a bulk density in the acid form of 0.83 g/ml. The wet volume of the resin is 4.5 meq/ml. The water retention capacity of the resin is 51.6 percent.
The osmotic shock resistance of the sample is high.
After 500 cycles of treatment of the resin beads with altexnating 5 percent hydrochloric acid and 5 percent sodium hydroxide solutions, 100 percent of the beads are left whole. The operating capacity of the resin is 47 Kg/ft3 of resin~ Other properties of resins which were similarly prepared (designated as Sample No. 13 are presented in Table I.
Table I
Wet Volume Water Osmotic Capacity Retention 1 Shock (%
25 Sample (meq/ml) ~ y~ Expansion whole bead?
1 4.2 48.7 64 100 C-l* 3.32 51.2 90 70 C-2* 4.1 44 71 80 32,479A-F -7-~26~4~6 Table I (Cont.) * Not an example of the invention.
C-1 and C-2 are commercially available macroporous resins. C-1 is a carboxylated macroporous resin comprising substantial amounts of polymerized methacrylate and is sold commercially as AmberliterM DP~1 by Rohm and Haas Company. C-2 is a carboxylated macroporous resin comprising substantial amou~ts of polymerized methyl acrylate and is 1~ sold commercially as DowexrM CCR-2E by The Dow Chemical Company.
1 Expansion is percent expansion based on volume from sodium form o~ resin to acid form.
The data in Table I indicate that the sample of this invention (Sample No. 1) exhibits increased osmotic shock resistance as compared to commercially available macroporous resins. In addition, it is noted that Sample No. 1 has undergone 500 cycles of the treatment as described hereinbefore, while the comparative samples (i.e. Sample Nos. C-1 and C-2) have undergone only 100 cycles of treatment.
Example 2 Into a reactor was charged an aqueous solution comprising 1496 g deionized water, 2.4 g carboxymethyl methylcellulose and 1.5 g sodium dichromate. To this solution was charged an organic mixture containing 150 3~ g ethyl acrylate, 750 g methacrylate, 150 g of a 55 percent active divinylbenzene ~ormulation, 340 g iso-octane, 2.5 g tertiary butylperoctoate and 2.5 g tertiary butyl perbenzoate. The mixture was treated and reacted as in Example 1, hydrolyzed with a 20 percent active aqueous sodium hydroxide solution as described 32,479A-F -8-,. ..
8~
g in Example 1, and filtered and washed with 1 normal hydrochloric acid. The sample was designated as Sample No. 2.
Into a reactor was charged an aqueous solution comprising 1496 g deionized water, 2.4 g carbox~methyl me~hylcellulose and 1.5 g sodium dichromate. To this solution was charged an organic mixture containing 105 g butyl acrylate, 663 g ethyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 100 g isooctane, 0.5 g tertiary butylperoctoate and 0.9 g tertiary butyl perbenzoate. The mixture was treated and reacted, hydrolyzed and washed as described here-inbefore. The sample was designated as Sample No. 3.
For comparison purposes was prepared a cross-linked e~hyl acrylate copolymer which was hydrolyzed and which was designated as Sample No. C-3. Into a reactor was charged 1500 g of an aqueous solution as was described in Example 1. To this solution was charged an organic mixture containing 763 g ethyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 160 g isooctane, 0.5 tertiary butyl per-benzoate and 0.9 g tertiary butyl peroctoate. The mixture was treated and reacted, hydrolyzed and washed as described in Example 1.
For comparison purposes was prepared a cross-linked butylacrylate copolymer which was hydrolyzed and which was designated as Sample No. C-4. Into a reactor was ch~rged 1500 g of an agueous solution as was described in Example 1. To this solution was charged an organic 30 mixture containing 763 g butyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 100 g 32,479A-F -9-,~ .
~;26~
isooctane, 0.5 g tertiary butyl peroctoate and 0.9 g tertiary butyl perbenzoate. The mi~ture was treated and reacted, hydrolyzed and washed as described in Example 1.
For comparison purposes was prepared a cross-linked methyl acrylate copolymer which was hydrolyzed and which was designated as Sample No. C-5. Into a reactor was charged 1,500 g of an agueous solution as described in Example 1. To this was charged an organic mixture containing 763 g methyl acrylate, 126 g of a 55 percent active divinylbenzene formulation, 100 g isooctane and catalyst. The mixture was treated and reacted hydrolyzed and washed as described in Example 1.
Data for the Samples of this Example are presented in Table II.
TABLE II
Water Wet Volume Retention Osmotic Capacity Capacity Shock Percent 20 Sample(meq/ml) (Percent) Whole ~ead
ACID R13SINS AND POROUS W13AK ACID RESI~7S
The present invention relates to ion exchange resins, and in particular, to ion exchange resins which are acidic in character.
Weak acid resins have been prepared by suspen-sion polymerizing and crosslinking unsatura~ed carboxylicacids such as acrylic acid. Unfortunately, the polymeri-zation of unsaturated carboxylic acids is highly exother-mic making reaction control very difficult. Thus, the physical properties of the ~inal resin product are typically very poor in guali-ty.
Weak acid resins have been prepared by the post-hydrolysis of suspension polymerized, crosslinked acrylic acid esters. Unfoxtunately, such a process provides resin products which have undergone incomplete hydrolysis and exhibit poor physical s~rengths. ThUsr such resins can have low exchange capacities and low resistance to osmotic shock.
32,479A F -1-, ' ~269~
In view of the deficiencies of the prior art, it would be highly desirable to provide a weak acid ion exchange resin with a high operating capacity which can be prepared in a controlled manner and exhibits high resistance to osmotic shock during regeneration.
The present invention is a process for pre-paring weak acid type cation exchange resins by sub-jecting to caustic hydrolysis a copolymer comprising in polymerized form (1) a major amount of a monoethylenic-ally unsaturated monomer which is hydrolyzable undercaustic conditions; (2) a minor amount of a monoethylenic-ally unsaturated monomer which has a less hydrolyzable character than the hydrolyzable monomer; and ~3) an effective amount of a crosslinking monomer; and option-ally a minor amount of a non-hydrolyzable monomer.
As used herein the term "hydrolysis" refers to caustic hydrolysis. The term "caustic" is to be broadly construed to mean a strongly basic species. In another aspect, the present invention is the weak acid type cation exchange resin which is prepared using the process as described hereinbefore.
The process of this invention provides the skilled artisan with a method for preparing weak acid type cation exchange resins exhibiting a high operating ion exchange capa~ity and improved osmotic shock proper-ties. Resin beads of this invention can have a porous character, and in particular, a macroporous character.
Such resin beads can be subjected to an increased number of regeneration cycles without a substantial amount of cracking of said resin beads. Such beads are useful in a wide varie~y of applications which can 32,479A-F -2-~26~L 5t6 include the demineralization of water for enhanced oil recovery, the removal of heavy metal ions from various aqueous streams, and the like.
Polymers useful in the practice of this invention are crosslinked polymers formed by the addi-tion polymerization of at least one polymerizable hydrolyzable monoethylenically unsaturated monomer, at least one polymerizable monoethylenically unsaturated monomer which is less hydrolyzable in character than the hydrolyzable monomer, and at least one polymeriz-able unsaturated monomer capable of providing cross-linking to the polymer.
Hydrolyzable monomers useful herein are monoethylenically unsaturated carboxylic acids such as alkyl acrylates. The choice of alkyl acrylate will depend upon the degree or ease of hydrolysis which is desired. In general, any alkyl ester of acrylic acid, itaconic acid, etc., which is readily hydrolyzable ~mder caustic conditions can be employed. Preferred alkyl acrylates include ethylacrylate, butylacrylate, hexylacrylate, and the like. More prefexred alkyl acrylates are those wherein the alkyl moiety has from 1 to 3 carbon atoms, with methylacrylate being especially preferred.
Non-hydrolyzable monomers which are option-ally useful herein include, or example, acrylonitrile, styrene, e~hylbenzene, vinyl toluene, methylstyrene, vinylbenzyl chloride, and halogenated styrene; hetero-cyclic aromatics such as vinylpyridine and substituted vinylpyridines, vinyl acetate, vinyl chloride, vinyli-dene chloride, N-vinylpyrirolidone, and methacrylates 32,479A-F -3-3.2~9~
which are not highly hydrolyzable under conditions which the hydrolyzable monomers are converted to carboxylic acid moieties.
Monomers which are less hydrolyzable than the aforementioned hydrolyzable monomers include those alkylacrylates which contain an alkyl functionality which provides a less hydrolyzable character to the monomex than said hydrolyzable monomer. In particular, the less hydrolyzable monomer does not undergo hydroly-sis to any subs~antial degree under conditions whichthe hydrolyzable monomer undergoes hydrolysis. Prefer-red less hydrolyzable monomers typically have alkyl functionalities which have higher amounts of carbon atoms than those hydrolyzable monomers. For example, if methylacrylate is the hydrolyzable monomer, then ethylacrylate or butylacrylate can be employed as the monomer which is less hydrolyzable in character.
Similarly, if ethylacrylate is employed as the hydrolyz-able monomer, then butylacrylate or hexylacrylate can be employed as the monomer which is less hydrolyæable in character.
Crosslinking monomers are those monomers which can introduce crosslinking to the resulting polymer. Examples of such monomers are those useful in preparing ion exchange resins and are those polyvinyl crosslinking monomers such as divinylbenzene, divinyl-toluene, divinylxylene, and divinylnapthalene; ethylene glycol dimethacrylate; trimethylol propane triacrylate;
divinylsuccinate; and the like. See, also, those disclosed in U.S. Patent No. 4,~19,245 and U.S. Patent No. 4,444,961.
32,479A-F -4-~z~
The monomer composition which is employed can vary depending upon factors such as the density of the bead desired, the amount of physical stability which is desired, the ion exchange capacity which is desired, and the like. Typically, the amount of hydrolyzable monomer can range from 70 to 90 weight percent; the amount of less hydrolyzable and optional non-hydrolyz-able monomer can range from 1 to 20 weight percent; and the amount of crosslinking monomer can range from 4 to 12 weight percent based on all monomers. If desired, the hydrolyzable monomer portion can be polymerized in conjunction with a monomer such as acrylic acid.
The process of this invention is preferably performed by suspension polymerizing the aforementioned monomers under conditions ~uch that polymerization occurs. Suitable solvents, surfactants, diluents, activators and catalysts are known in the art. See, for example, U.S. Patent No. 4,224,415. The resulting polymer product is isolated and subjected to hydrolysis conditions. Fox example, the polymer can be contacted with a hydroxide solution. The resin can be washed with an acid solution to yield the H-form resln. Beads can be obtained in a gel form or in a porous form.
While beads having a wide range of pore sizes can be employed, beads having pore sizes greater than lOO A (0.01 microns) in diameter are preferred. That is, porous beads of this invention include the macro-porous beads. Macroporous beads are those macrore~icu-lar types of beads as are defined in U.S. Patent No. 4,224,415. For example, macroporous beads are prepared by those techniques described in U.S. Patent No. 4,382,124.
32,479A-F -5-~941~
The resin beads of this invention are prefer-ably spherical beads having particle sizes ranging from 180 to 2,000 microns, preferably from 200 to 1,000 microns. The distribution of the particle size can be narrowed by employing the appropriate s-tabilizer.
Narrow distributions of particle sizes can be obtained by using the method taught in U.S. Patent No. 4,444,961.
The resins of this invention exhibit good osmotic shock resistance as well as high ion exchange capacity. It is believed that the copolymerization of the hydrolyzable monomer with the non-hydrolyzable monomer or less hydrolyzable monomer causes the cross-linking in the bead to be less centralized. The more even spread of crosslinking in the bead is believed to provide a stronger product which exhibits less potential to crack or break during repeated shrinking and swelling.
The following e~amples are presented to ~urther illustrate but not limit the scope of this invention. All parts and percentages are by weight, unless otherwise noted.
Example 1 Into a jacketed stainless steel reactor was charged an aqueous solution comprising 1,500 grams (g) distilled water, 2.4 g carboxymethyl methylcellulose and 2.7 g sodium dichromate. To this solution was charged an organic mixture containing 763 g methyl-acrylate, 105 g n-butylacrylate, 200 g divinylbenzene, 100 g isooctane diluent, 0.5 g tertiary butylperoctoate and 0.9 g tertiary bu~yl perbenæoate. The reactor was 32,479A-F -6-~, purged with nitrogen for 15 minutes. The mixture was then agitated and the polymerization was conducted at 75C for 5 hours, followed by 110C for 3 hours. The reaction mixture was cooled. The spherical polymer product was filtered and washed with distilled water.
The diluent was removed by steam distillation.
The polymer product was mixed with a 20 percent active aqueous sodium hydroxide solution at 100C for 5-6 hours. The polymer product was filtered and washed with 1 normal hydrochloric acid. The final resin exhibits a bulk density in the acid form of 0.83 g/ml. The wet volume of the resin is 4.5 meq/ml. The water retention capacity of the resin is 51.6 percent.
The osmotic shock resistance of the sample is high.
After 500 cycles of treatment of the resin beads with altexnating 5 percent hydrochloric acid and 5 percent sodium hydroxide solutions, 100 percent of the beads are left whole. The operating capacity of the resin is 47 Kg/ft3 of resin~ Other properties of resins which were similarly prepared (designated as Sample No. 13 are presented in Table I.
Table I
Wet Volume Water Osmotic Capacity Retention 1 Shock (%
25 Sample (meq/ml) ~ y~ Expansion whole bead?
1 4.2 48.7 64 100 C-l* 3.32 51.2 90 70 C-2* 4.1 44 71 80 32,479A-F -7-~26~4~6 Table I (Cont.) * Not an example of the invention.
C-1 and C-2 are commercially available macroporous resins. C-1 is a carboxylated macroporous resin comprising substantial amounts of polymerized methacrylate and is sold commercially as AmberliterM DP~1 by Rohm and Haas Company. C-2 is a carboxylated macroporous resin comprising substantial amou~ts of polymerized methyl acrylate and is 1~ sold commercially as DowexrM CCR-2E by The Dow Chemical Company.
1 Expansion is percent expansion based on volume from sodium form o~ resin to acid form.
The data in Table I indicate that the sample of this invention (Sample No. 1) exhibits increased osmotic shock resistance as compared to commercially available macroporous resins. In addition, it is noted that Sample No. 1 has undergone 500 cycles of the treatment as described hereinbefore, while the comparative samples (i.e. Sample Nos. C-1 and C-2) have undergone only 100 cycles of treatment.
Example 2 Into a reactor was charged an aqueous solution comprising 1496 g deionized water, 2.4 g carboxymethyl methylcellulose and 1.5 g sodium dichromate. To this solution was charged an organic mixture containing 150 3~ g ethyl acrylate, 750 g methacrylate, 150 g of a 55 percent active divinylbenzene ~ormulation, 340 g iso-octane, 2.5 g tertiary butylperoctoate and 2.5 g tertiary butyl perbenzoate. The mixture was treated and reacted as in Example 1, hydrolyzed with a 20 percent active aqueous sodium hydroxide solution as described 32,479A-F -8-,. ..
8~
g in Example 1, and filtered and washed with 1 normal hydrochloric acid. The sample was designated as Sample No. 2.
Into a reactor was charged an aqueous solution comprising 1496 g deionized water, 2.4 g carbox~methyl me~hylcellulose and 1.5 g sodium dichromate. To this solution was charged an organic mixture containing 105 g butyl acrylate, 663 g ethyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 100 g isooctane, 0.5 g tertiary butylperoctoate and 0.9 g tertiary butyl perbenzoate. The mixture was treated and reacted, hydrolyzed and washed as described here-inbefore. The sample was designated as Sample No. 3.
For comparison purposes was prepared a cross-linked e~hyl acrylate copolymer which was hydrolyzed and which was designated as Sample No. C-3. Into a reactor was charged 1500 g of an aqueous solution as was described in Example 1. To this solution was charged an organic mixture containing 763 g ethyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 160 g isooctane, 0.5 tertiary butyl per-benzoate and 0.9 g tertiary butyl peroctoate. The mixture was treated and reacted, hydrolyzed and washed as described in Example 1.
For comparison purposes was prepared a cross-linked butylacrylate copolymer which was hydrolyzed and which was designated as Sample No. C-4. Into a reactor was ch~rged 1500 g of an agueous solution as was described in Example 1. To this solution was charged an organic 30 mixture containing 763 g butyl acrylate, 200 g of a 55 percent active divinylbenzene formulation, 100 g 32,479A-F -9-,~ .
~;26~
isooctane, 0.5 g tertiary butyl peroctoate and 0.9 g tertiary butyl perbenzoate. The mi~ture was treated and reacted, hydrolyzed and washed as described in Example 1.
For comparison purposes was prepared a cross-linked methyl acrylate copolymer which was hydrolyzed and which was designated as Sample No. C-5. Into a reactor was charged 1,500 g of an agueous solution as described in Example 1. To this was charged an organic mixture containing 763 g methyl acrylate, 126 g of a 55 percent active divinylbenzene formulation, 100 g isooctane and catalyst. The mixture was treated and reacted hydrolyzed and washed as described in Example 1.
Data for the Samples of this Example are presented in Table II.
TABLE II
Water Wet Volume Retention Osmotic Capacity Capacity Shock Percent 20 Sample(meq/ml) (Percent) Whole ~ead
2 3.0 42 97
3 * 3.2 44 98 C-3* 3.5 42 69 C-4* 2.0 26 0 C-5 4.0 50 <20 *
Not an example of the lnventlon.
The data in Table II indicate that the samples of this i~vention (i.e., Sample Nos. 2 and 3) exhibit increased osmotic shock resistance as compared to the comparative samples.
32,479A-F- -10-_.
Not an example of the lnventlon.
The data in Table II indicate that the samples of this i~vention (i.e., Sample Nos. 2 and 3) exhibit increased osmotic shock resistance as compared to the comparative samples.
32,479A-F- -10-_.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A process for preparing weak acid type cation exchange resins by subjecting to caustic hydrolysis a copolymer comprising in polymerized form (1) a major amount, ranging from 70 to 90 weight percent, of an alkyl acrylate which is hydrolyzable under caustic conditions, (2) a minor amount, ranging from 1 to 20 weight percent, of an alkyl acrylate which has a less hydrolyzable character than the hydrolyzable monomer, and (3) an effective amount of a crosslinking monomer wherein said resin exhibits high resistance to osmotic shock.
2. A process of Claim 1 wherein said alkyl acrylate monomer, which is hydrolyzable, is an alkyl ester of acrylic acid.
3. A process of Claim 1 wherein said alkyl acrylate monomer having a less hydrolyzable character is an alkyl ester of acrylic acid.
4. A process of Claim 1 wherein the alkyl acrylate monomer, which is hydrolyzable, is an alkyl ester of acrylic acid which contains an alkyl functionality which contains less carbon atoms than the acrylate monomer having a less hydrolyzable character.
5. A process of Claim 1 wherein said alkyl acrylate monomer, which is hydrolyzable, is an alkyl acrylate, wherein the alkyl moiety less from 1 to 3 carbon atoms.
6. A process of Claim 1 wherein said monoethylenically unsaturated monomer which is the major amount of monomer is methyl acrylate, ethyl acrylate or butyl acrylate and said monoethylenically unsaturated monomer which is the minor amount of monomer is ethyl acrylate or butyl acrylate.
7. A process of Claim 1 wherein said crosslinking monomer is a polyvinyl crosslinking
8. A process of Claim 1 wherein said copolymer is hydrolyzed in the presence of sodium hydroxide solution.
9. A weak acid type cation exchange resin prepared by a process as claimed in Claim 1.
32,479A-F
32,479A-F
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000505628A CA1269486A (en) | 1986-04-02 | 1986-04-02 | Process for preparing improved weak acid resins and porous weak acid resins |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000505628A CA1269486A (en) | 1986-04-02 | 1986-04-02 | Process for preparing improved weak acid resins and porous weak acid resins |
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| Publication Number | Publication Date |
|---|---|
| CA1269486A true CA1269486A (en) | 1990-05-22 |
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| CA000505628A Expired - Fee Related CA1269486A (en) | 1986-04-02 | 1986-04-02 | Process for preparing improved weak acid resins and porous weak acid resins |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044670A (en) * | 2019-12-25 | 2020-04-21 | 西安热工研究院有限公司 | Cation exchange capacity test method for ammonium type and ammonium type mixed powder ion exchange resin |
-
1986
- 1986-04-02 CA CA000505628A patent/CA1269486A/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044670A (en) * | 2019-12-25 | 2020-04-21 | 西安热工研究院有限公司 | Cation exchange capacity test method for ammonium type and ammonium type mixed powder ion exchange resin |
| CN111044670B (en) * | 2019-12-25 | 2022-06-10 | 西安热工研究院有限公司 | Cation exchange capacity test method for ammonium type and ammonium type mixed powder ion exchange resin |
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