CA2111402A1 - Suspension polymerization process for water-soluble monomers - Google Patents
Suspension polymerization process for water-soluble monomersInfo
- Publication number
- CA2111402A1 CA2111402A1 CA002111402A CA2111402A CA2111402A1 CA 2111402 A1 CA2111402 A1 CA 2111402A1 CA 002111402 A CA002111402 A CA 002111402A CA 2111402 A CA2111402 A CA 2111402A CA 2111402 A1 CA2111402 A1 CA 2111402A1
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- Canada
- Prior art keywords
- water
- monomers
- monomer
- dimethylaminopropyl
- amino
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/20—Aqueous medium with the aid of macromolecular dispersing agents
Abstract
ABSTRACT OF THE DISCLOSURE
A process is provided for suspension polymerization of water-soluble monomers in aqueous suspension to form spherical, unagglomerated polymer beads. The polymerization is conducted in the presence of a nonionic, substituted hydroxyalkylcellulose dispersant which is especially effective in protecting themonomer droplets from coalescence prior to their forming stable polymer particles.
A process is provided for suspension polymerization of water-soluble monomers in aqueous suspension to form spherical, unagglomerated polymer beads. The polymerization is conducted in the presence of a nonionic, substituted hydroxyalkylcellulose dispersant which is especially effective in protecting themonomer droplets from coalescence prior to their forming stable polymer particles.
Description
A SUSPENSION POLYMERIZATION PROCESS FOR WATER-SOLUBLE
MONOMERS
This invention relates to suspension polymerization processes, and more particularly to suspension polymerization processes for water-soluble monomers.
BACKGROUND OF THE ~VENTION
Suspension polymerization is commonly conducted in an aqueous suspending medium, by suspending discrete droplets of monomer in the aqueous medium, initiating a free radical polymerization, and continuing the polymerization until the suspended droplets have formed solid, spherical partides. Such particles, especially when forrned by copolymerization of a monoethylenically unsaturated monomer and a -~
polyethylenically unsaturated, crosslinking monomer, are particularly useful as intermediate materials in the production of ion exchange resins. Many common - monomers, such as styrene, a-methylstyrene, methyl methacrylate, ethyl acrylate and the like, are not soluble in water, and thus are well suited to suspension polymerization.
However, some monomers, as for example acrylic acid, methacrylic acid, hydroxyethyl methacrylate, acrylonitrile, acr,vlamide, methacrylamide, vinyl pyridine, dimethylaminoethyl methacrylate and the like, are soluble in water to a significant extent.
tj 2 When suspension polymerization is attempted with a monomer which is partially or fully water soluble, monomer partitions into the aqueous phase. In the case of fully water-soluble monomers, the suspended droplets may never even form, andeven where the droplets form, several undesired phenomena occur during 5 polymerization, sudh as the occurrence of emulsion, "popcorn" or precipitationpolymers in the aqueous phase, caused by dissolved monomer forrning insoluble polymer which precipitates from solution, or the formation of p~rticle agglomerates caused by the presence of soluble polymers in the aqueous phase. The agglomerates lead to a polymer product with poor hydraulic characteristics, and the presence of 10 pol,vmer in the aqueous phase also leads to fouling of process equipment.
Techniques known to those skilled in the art for suspension polymerization of water-soluble monomers indude saturating the aqueous suspending medium with a salt, e.g. an inorganic salt such as sodium chloride or sodium sulfate, to reduce the solubility of the monomer in the aqueous medium. This helps reduce, but not 15 eliminate, some of the undesired phenomena. Most suspension stabilizers are insoluble or unstable in a high-salt, aqueous phase, and thus do not adequately protect the monomer droplets, allowing them to agglomerate.
SUMMARY OF THE lNVEN~ON
I have discovered a suspension polymerization process which comprises forming 20 a suspension of a mixture of monomers, which mixture includes a major amount of at least one water-soluble monomer and from about 0.1 to about 50 weight percent, based on the total monomer weight, of a crosslinking monomer, in an aqueous medium containing from about 5 weight percent to saturation of a water-soluble, non-reactive inorganic salt in the presence of a free-radical initiator and from about 0.01 to about 4 25 weight percent of a nonionic surhctant-type dispersant having a hydroxyalkylcellulose backbone, a molecular weight of from about 30,000 to 2,000,000, hydrophobic alkyl side chains containing from 1 to about 24 carbon atoms, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl side chains per 100 repeating units of the polymer backbone, and an average of from about 1 to about 8 ethylene oxide groups 30 substituting each repeating unit of the polymer backbone, wherein the alkyl group in the hydroxyalkylcellulose backbone is from C1 to C24, establishing polymerization conditions in the suspension, and allowing the monomers to polymerize until they have formed water-insoluble particles.
r~
DETAILED DESCRIPTION OF THE ~VENTION
The water-soluble monomers useful in the present invention include, but are not limited to, acid monomers such as acrylic, methacrylic, itaconic, maleic, fumaric and crotonic acids and the like, water-soluble anhydrides such as acrylic anhydride and 5 methacrylic anhydride, amino-substituted acrylamides and methacrylamides such as dimethylaminopropyl methacrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropyl acrylamide, dimethylaminoethyl acrylamide, N, N-bis-(dimethylaminoethyl) methacr,vlamide, N, N-bis-(dimethylaminopropyl) acrylamide, N, N-bis-(dimethylaminoethyl) acrylamide, and N, N-bis-(dimethylaminopropyl) 10 methacrylamide; amino-substituted acrylates and methacrylates such as dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate and dimethylaminopropyl acrylate; hydroxyalkyl acrylates and methacrylates such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate; other nitrogen-substituted, 15 water-soluble monomers such as acrylonitrile, vinyl pyridines, vinylbenzyl pyrro!idone, N-vinyl-2-pyrrolidone and the like; or mixtures thereof. The water-soluble monomer is present in the monomer mixture as the major component; that is, the water-soluble monomer or monomers are present at a level of at least 50 weight percent of the total monomers. As used herein, the term "water-soluble", as applied to monomers, indicates 20 that the monomer has a water solubility of about on~ weight percent or greater; that is, at least about one gram of the monomer will dissolve in 100 g of water. In another embodiment of the present invention, the water solubilit,v of the monomer is at least about 10 grams in 100 grams of water, and in yet another embodiment the water solubility is at least about 50 grams in 100 grams of water.
CrosslinWng monomers useful in the present invention indude both water-soluble and water insoluble crosslinkers, including aromatic aosslinkers such asdivinylbenzene, trivinylbenzene, divinylnaphthalene, divinyltoluene, divinylchlorobenzene, diallyl phthalate, divinylxylene, divinylethylbenzene.
trivinylnaphthalene, polyvinylanthracenes and the like, and aliphatic crosslinkers such as diethyleneglycol divinyl ether, trimethylolpropane trimethacrylate, diethylene glycol divinyl ether, diethylene glycol dimethacrylate, ethylene glycol diacrylate, neopentyl glyc~l dimethacrylate, pentaerythritol tetra- and trimethacrylates, allyl acrylate, divinyl ketone, N,N'-methylenediacrylimide, N,N'-methylene-dimethacrylimide, N,N'-ethylenediacrylimide, diallyl maleate, diallyl fumarate, diallyl succinate, diallyl 2 ::
:
carbonate, diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, diallyl tartrate, diallyl tricarballylate, triallyl aconitate, triallyl citrate; and the polyallyl and polyvinyl ethers of glycol, glycerol and pentaerythritol, bisphenol-A dimethacrylate, the polyallyl and polyvinyl ethers of resorcinol, and the like, and mixtures thereof.
5 Preferred crosslinking monomers are divinylbenzene, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, hexamethylene-bis-methacrylamide and diethylene glycol divinyl ether and mixtures thereof. The crosslinking monomer are present at a level from about 0.1 to about 50 percent, preferably from about 0.1 to about 20 percent" by weight, of the total monomer mixture.
Other, non-water-soluble monomers may be present in a minor amount in the monomer mixture; that is, they may be present at less than 50% by weight of the total monomer mixture. Such non-water-soluble monomers are preferably present at less than about 25% by weight of the total monomer mixture. The non-water-soluble monomers useful in the present invention indude those which are copolymerizable 15 with the combination of the water-soluble monomer and the crosslinWng monomer.
These include both aromatic and aliphatic monomers having monoethylenic unsaturation, induding those whidh are substituted with functional groups other than the ethylenic groups.
Polymerization initiators useful in the present invention include monomer-20 soluble initiators such as peroxides, hydroperoxides and related initiators, as forexample benzoyl peroxide, tert-butyl hydroperoxide, cumene peroxide, tetralin peroxide, acetyl peroxide, caproyl peroxide, tert-butyl perbenzoate, tert-butyl diperphthalate, methyl ethyl ketone peroxide and the like. Also useful are azo initiators such as azodusobutyronitrile, azodiisobutyramide, 2,2'-azo-bis-(2,4-25 dimethylvaleronitrile), azo-bis-(a-methylbutyronitrile) and dimethyl, diethyl or dibutyl azo-bis-(methylvalerate). The initiators are used at a level of from about 0.01 to about 5% by weight, based on the total weight of the monomers; preferably the peroxideinitiators are used at a level of from about 0.01% to 3% by weight, based on the total weight of the monomers, and preferably the azo initiators are used at a level from about 30 0.01% to about 2% by weight, based on the total weight of the monomers. Preferred initiators are the azo initiators, and particularly preferred is 2,2'-azo-bis-(2,4-dimethylvaleronitrile).
Salts useful for reducing solubility of the water-soluble monomer in the aqueousphæ are water-soluble, non-reactive inorganic salts of a monovalent, divalent or aluminum cation and a monovalent or divalent anion, including, but not limited to, water-soluble, non-reactive inorganic salts of a monovalent, divalent or aluminum cation and a monovalent or divalent anion, as for example sodium, potassium, lithium and ammonium salts of chloride, bromide, iodide, sulfate, carbonate and nitrate and 5 the magnesium and calcium salts of chloride, bromide, iodide and nitrate. Preferred salts are sodium chloride, sodium sulfate and sodium nitrate. The salt is dissolved in the aqueous medium at levels from about S weight percent, based upon the total weight of the aqueous phase, to saturation of the salt in the aqueous phase. The term, "non-reactive", as applied to the salts herein, means that the salt does not react chemically 10 with water, the monomers or the polymers formed from the monomers.
The dispersants useful in the present invention are nonionic surfactants having a hydroxyalkylcellulose backbone, hydrophobic alkyl side chains containing from 1 to about 24 carbon atoms, and an average of from about 1 to about 8 ethylene oxide groups, preferably from about 1 to about S ethylene oxide groups, substituting each 15 repeating unit of the hydroxyalkylcellulose backbone, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl groups per 100 repeating units in the hydroxyalkylcellulose backbone. The alkyl group in the hydroxyalkylcellulose may contain from 1 to about 24 carbons, and may be linear, branched or cyclic. Preferred is a hydroxyethylcellulose containing from about 0.1 to about 10 C16 alkyl side chains per 20 100 anhydroglucose units and from about 2.5 to about 4 ethylene oxide groups substituting each anhydroglucose unit.
The process of the present invention comprises forming a suspension of the monomer mixture, including a major amount of at least one water-soluble monomer and from about 0.1 to about 50 weight percent, based on the total monomer weight, of a 25 crosslinking monomer, and optionally a minor amount of an additional, copolymerizable monomer, in an aqueous medium containing from about S weight percent to saturation of a water-soluble, non-reactive inorganic salt in the presence of from about 0.1 to about 5 weight percent of a monomer-soluble, free-radical initiator and from about 0.01 to about 4 weight percent of a nonionic surfactant-type dispersant 30 having a hydroxyalkylcellulose backbone, a molecular weight of from about 30,000 to 2,000,000, and a hydrophobic, Cl to about C24 alkyl side chain, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl side chains per 100 repeating units of the polymer backbone, wherein the alkyl group in the hydroxyalkylcellulose backbone is from Cl to C24, establishing polymerization conditions in the suspension, allowing the monomers to polymerize until they have formed water-insoluble particles, and separating the particles from the aqueous phase.
The monomer phase forms spherical droplets within the aqueous phase; these are preferably kept suspended by agitation, but other techniques for maintaining5 suspension which will be readily apparent to those sk~led in the art may be employed, as for example using a static mixer, or suspending the droplets in a liquid stream moving opposite to the direction in which the droplets tend to move by their density.
The polymerization reaction occurs within the suspended monomer droplets, and isinitiated by establishing a temperature in the droplet which is at~least as great as the 10 decomposition temperature of the polymerization initiator. A reasonable lowertemperature for polymerization is about 50C, which is above the decomposition temperature of many common initiators; one skilled in the art will realize that if an initiator is selected having a higher decomposition temperature than this, the minimum temperature will be chosen according to the decomposition temperature of the actual 15 initiator used. The upper limit for the polymerization reaction is the boiling temperature of the suspending medium; the medium employed herein is aqueous, so at atmospheric pressure the maximum temperature will be 100C, and higher temperatures may be used at higher pressures. A lower temperature may be advantageous to prevent decomposition of one or more of the monomers or the 20 dispersant, or for other reasons which will be apparent to one skilled in the art.
The process of the present invention may be used for preparing both gel and macroporous resins. For the preparation of macroporous resins a porogen is commonly used. Porogens useful for making macroporous resins are well known to those skilled in the art; their nature and selection is discussed in, for example, US Patent No.
25 3,991,017. Porogens are substances in which the monomers are soluble but the resulting polymer is insoluble, and which will dissolve the monomers within the suspended droplet, without reacting with the other components of the polymerization mixture.
Thus for the present process, sufficient porogen must remain within the suspended droplet to dissolve the monomer mixture at least partially, and to create the pores 30 within the particle as the polymer forms. The preferred porogens are xylene and toluene.
The following examples are intended to illustrate the invention and not to limit it except as it is limited in the daims. All ratios and percentages given herein are by weight unless otherwise specified, and all reagents used in the exarnples are of good commercial quality unless otherwise specified.
This example is intended to illustrate the process of the present invention as used 5 for preparing a crosslinked copolymer from water-soluble dimethylaminopropyl methacrylamide (DMAPMA) monomer, The dispersant used was a modified hydroxyethylcellulose substituted with about 4.0 moles of ethylene oxide per anhydroglucose unit and approximately 0.7--1.0 cetyl groups per 100 anhydroglucose units, and having a molecular weight of 10 approximately 300,000 and a viscosity in 1% aqueous solution of approxirnately 400 megaPascals.
An aqueous solution was prepared by weighing 246.5 g sodium chloride, grinding approximately 15 g of this sodium chloride in a mortar with 3.72 g dispersant to a ~omogeneous mixture. The unground sodium chloride was added, with stirring, to 1 5 683.5 g deionized water at 50C. The ground sodium chloride-dispersant rnixture was added slowly to the water, which was then stirred at 50C until all the solids had dissolved.
A monomer mixture was made by mixing 159 g DMAPMA, 8.36 g high-purity divinylbenzene (80% purity) and 0.836 g diethyleneglycol divinyl ether. To 148 g20 xylene was added, with stirring, 1.68 g 2,2'-azo-bis-(2,4-dimethylvaleronitrile) initiator.
The aqueous phase was placed in a reactor vessel and stirred at 52C. The monomer mixture was mixed with the xylene-initiator solution and was transferred to the reactor vessel. Stirring at 52C was continued for 20 hours, after which the solids were drained and washed with water to remove the salt and most of the xylene.
The resulting anion exchange resin beads were porous, spherical, and free from agglomerated or misshapen particles. A 300-ml sample of these resin beads was conditioned by passing through it in the following sequence, at a flow rate of approximately 2 liters per hour, 1 liter of 4% aqueous sodium hydroxide solution, 1 liter of deionized water, 1 liter of 10~o aqueous hydrochloric acid and 1 liter of deionized water. The resin was then backwashed with deionized water, allowed to settle, and i~
then drained. One liter of 4% aqueous sodium hydroxide was then passed through the settled bed, followed by a final rinse of deionized water.
The conditioned resin bed was loaded with chloride by passing through it, at a rate of 17 ml/minute, 500 ml of 10% aqueous hydrochloric acid, followed by one bed volurne (BV) of deionized water at the same flow rate. The deionized water flow was continued at approximately 70 ml/minute until the eMuent conductivity measured less 5 than 50 ~mho. The resin bed was then backwashed with deionized water to removetrapped air and voids, and regenerated by passing through it, at a flow rate of 17 ml/minute, 500 ml of 4% aqueous sodium hydroxide. One BV of deionized water was then passed through the bed at 17 ml/minute, after which the flow of deionized water was increased to 70 ml/minute and continued until the conductivity of the rinse water 10 fell below 50 ~lmho. The total volume of deionized water required to reduce the conductivity of the rinse water to this level was recorded as the rinse requirement, in bed volumes of water. The rinse requirement for this sample was 2.2 BV.
As a comparison, a sample of porous, spherical beads prepared by copolymerizing methyl acrylate with approximately 4% DVB and functionalized by 15 aminolysis with dimethylaminoprowlamine produced a resin of the prior art having the sarne anion-exchange functionality as the resin beads of this example. It should be noted that the molecular weight of a repeating monomer unit of the methyl acrylate copolymer is approximately 86, while after aminolysis, the molecular weight of arepeating unit is 156; thus the molecular weight of each monomer unit has 20 approxirnately doubled, and the crosslinker content of the aminolyzed copolymer is therefore approximately 2%, compared to the 4% crosslinker of the copolyrner of the present invention. This aminolyzed copolymer was subjected to the same procedure for determining the rinse requirement, and this was determined to be 11.7 BV. It is well known to those skilled in the art that lower osslinking tends to produce materials that 25 rinse more readily, because the rinse water can penetrate the copolymer more readily.
Despite this, the resins of the present invention had a significantly lower rinse requirement than this prior-art resin.
From the above, it is seen that the method of the present invention is capable of producing spherical anion exchange resins free from agglomerated or misshapen 30 particles, and having the particularly advantageous property of low rinse requirement.
This exarnple illustrates the process of the present invention using DMAPMA
- and a different crosslinking monomer, trimethylolpropane triacrylate (T~TA).
. `
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 1, except that 161.97 g DMAPMA, 8.525 g TMPTA and 139.5 g ~xylene were used, and the initiator weight was 1.705 g.
This example illustrates the process of the present invention using DMAPMA
and additional l~MPTA.
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 2, except that the TMPTA content of the monomer mixture was increased from 5 to 10 weight percent, based on the total weight of the 1 0 monomers.
This exarnple illustrates the process of the present invention using DMAPMA
and adding hexamethylene-bis-methacrylamide (HMBMA) to the TMPTA of Example 2 the crosslinking monomer. In this example the ~xylene was omitted to produce a gel resinbead.
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 1, except that the crossl:nking monomer used was 3%HMBMA and 3% TMPTA, based on the total weight of the monomers, and the ~xylene was omitted. The suspension mixture was heated to 55C for 14 hours. -~`"`'.
MONOMERS
This invention relates to suspension polymerization processes, and more particularly to suspension polymerization processes for water-soluble monomers.
BACKGROUND OF THE ~VENTION
Suspension polymerization is commonly conducted in an aqueous suspending medium, by suspending discrete droplets of monomer in the aqueous medium, initiating a free radical polymerization, and continuing the polymerization until the suspended droplets have formed solid, spherical partides. Such particles, especially when forrned by copolymerization of a monoethylenically unsaturated monomer and a -~
polyethylenically unsaturated, crosslinking monomer, are particularly useful as intermediate materials in the production of ion exchange resins. Many common - monomers, such as styrene, a-methylstyrene, methyl methacrylate, ethyl acrylate and the like, are not soluble in water, and thus are well suited to suspension polymerization.
However, some monomers, as for example acrylic acid, methacrylic acid, hydroxyethyl methacrylate, acrylonitrile, acr,vlamide, methacrylamide, vinyl pyridine, dimethylaminoethyl methacrylate and the like, are soluble in water to a significant extent.
tj 2 When suspension polymerization is attempted with a monomer which is partially or fully water soluble, monomer partitions into the aqueous phase. In the case of fully water-soluble monomers, the suspended droplets may never even form, andeven where the droplets form, several undesired phenomena occur during 5 polymerization, sudh as the occurrence of emulsion, "popcorn" or precipitationpolymers in the aqueous phase, caused by dissolved monomer forrning insoluble polymer which precipitates from solution, or the formation of p~rticle agglomerates caused by the presence of soluble polymers in the aqueous phase. The agglomerates lead to a polymer product with poor hydraulic characteristics, and the presence of 10 pol,vmer in the aqueous phase also leads to fouling of process equipment.
Techniques known to those skilled in the art for suspension polymerization of water-soluble monomers indude saturating the aqueous suspending medium with a salt, e.g. an inorganic salt such as sodium chloride or sodium sulfate, to reduce the solubility of the monomer in the aqueous medium. This helps reduce, but not 15 eliminate, some of the undesired phenomena. Most suspension stabilizers are insoluble or unstable in a high-salt, aqueous phase, and thus do not adequately protect the monomer droplets, allowing them to agglomerate.
SUMMARY OF THE lNVEN~ON
I have discovered a suspension polymerization process which comprises forming 20 a suspension of a mixture of monomers, which mixture includes a major amount of at least one water-soluble monomer and from about 0.1 to about 50 weight percent, based on the total monomer weight, of a crosslinking monomer, in an aqueous medium containing from about 5 weight percent to saturation of a water-soluble, non-reactive inorganic salt in the presence of a free-radical initiator and from about 0.01 to about 4 25 weight percent of a nonionic surhctant-type dispersant having a hydroxyalkylcellulose backbone, a molecular weight of from about 30,000 to 2,000,000, hydrophobic alkyl side chains containing from 1 to about 24 carbon atoms, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl side chains per 100 repeating units of the polymer backbone, and an average of from about 1 to about 8 ethylene oxide groups 30 substituting each repeating unit of the polymer backbone, wherein the alkyl group in the hydroxyalkylcellulose backbone is from C1 to C24, establishing polymerization conditions in the suspension, and allowing the monomers to polymerize until they have formed water-insoluble particles.
r~
DETAILED DESCRIPTION OF THE ~VENTION
The water-soluble monomers useful in the present invention include, but are not limited to, acid monomers such as acrylic, methacrylic, itaconic, maleic, fumaric and crotonic acids and the like, water-soluble anhydrides such as acrylic anhydride and 5 methacrylic anhydride, amino-substituted acrylamides and methacrylamides such as dimethylaminopropyl methacrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropyl acrylamide, dimethylaminoethyl acrylamide, N, N-bis-(dimethylaminoethyl) methacr,vlamide, N, N-bis-(dimethylaminopropyl) acrylamide, N, N-bis-(dimethylaminoethyl) acrylamide, and N, N-bis-(dimethylaminopropyl) 10 methacrylamide; amino-substituted acrylates and methacrylates such as dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate and dimethylaminopropyl acrylate; hydroxyalkyl acrylates and methacrylates such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate; other nitrogen-substituted, 15 water-soluble monomers such as acrylonitrile, vinyl pyridines, vinylbenzyl pyrro!idone, N-vinyl-2-pyrrolidone and the like; or mixtures thereof. The water-soluble monomer is present in the monomer mixture as the major component; that is, the water-soluble monomer or monomers are present at a level of at least 50 weight percent of the total monomers. As used herein, the term "water-soluble", as applied to monomers, indicates 20 that the monomer has a water solubility of about on~ weight percent or greater; that is, at least about one gram of the monomer will dissolve in 100 g of water. In another embodiment of the present invention, the water solubilit,v of the monomer is at least about 10 grams in 100 grams of water, and in yet another embodiment the water solubility is at least about 50 grams in 100 grams of water.
CrosslinWng monomers useful in the present invention indude both water-soluble and water insoluble crosslinkers, including aromatic aosslinkers such asdivinylbenzene, trivinylbenzene, divinylnaphthalene, divinyltoluene, divinylchlorobenzene, diallyl phthalate, divinylxylene, divinylethylbenzene.
trivinylnaphthalene, polyvinylanthracenes and the like, and aliphatic crosslinkers such as diethyleneglycol divinyl ether, trimethylolpropane trimethacrylate, diethylene glycol divinyl ether, diethylene glycol dimethacrylate, ethylene glycol diacrylate, neopentyl glyc~l dimethacrylate, pentaerythritol tetra- and trimethacrylates, allyl acrylate, divinyl ketone, N,N'-methylenediacrylimide, N,N'-methylene-dimethacrylimide, N,N'-ethylenediacrylimide, diallyl maleate, diallyl fumarate, diallyl succinate, diallyl 2 ::
:
carbonate, diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, diallyl tartrate, diallyl tricarballylate, triallyl aconitate, triallyl citrate; and the polyallyl and polyvinyl ethers of glycol, glycerol and pentaerythritol, bisphenol-A dimethacrylate, the polyallyl and polyvinyl ethers of resorcinol, and the like, and mixtures thereof.
5 Preferred crosslinking monomers are divinylbenzene, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, hexamethylene-bis-methacrylamide and diethylene glycol divinyl ether and mixtures thereof. The crosslinking monomer are present at a level from about 0.1 to about 50 percent, preferably from about 0.1 to about 20 percent" by weight, of the total monomer mixture.
Other, non-water-soluble monomers may be present in a minor amount in the monomer mixture; that is, they may be present at less than 50% by weight of the total monomer mixture. Such non-water-soluble monomers are preferably present at less than about 25% by weight of the total monomer mixture. The non-water-soluble monomers useful in the present invention indude those which are copolymerizable 15 with the combination of the water-soluble monomer and the crosslinWng monomer.
These include both aromatic and aliphatic monomers having monoethylenic unsaturation, induding those whidh are substituted with functional groups other than the ethylenic groups.
Polymerization initiators useful in the present invention include monomer-20 soluble initiators such as peroxides, hydroperoxides and related initiators, as forexample benzoyl peroxide, tert-butyl hydroperoxide, cumene peroxide, tetralin peroxide, acetyl peroxide, caproyl peroxide, tert-butyl perbenzoate, tert-butyl diperphthalate, methyl ethyl ketone peroxide and the like. Also useful are azo initiators such as azodusobutyronitrile, azodiisobutyramide, 2,2'-azo-bis-(2,4-25 dimethylvaleronitrile), azo-bis-(a-methylbutyronitrile) and dimethyl, diethyl or dibutyl azo-bis-(methylvalerate). The initiators are used at a level of from about 0.01 to about 5% by weight, based on the total weight of the monomers; preferably the peroxideinitiators are used at a level of from about 0.01% to 3% by weight, based on the total weight of the monomers, and preferably the azo initiators are used at a level from about 30 0.01% to about 2% by weight, based on the total weight of the monomers. Preferred initiators are the azo initiators, and particularly preferred is 2,2'-azo-bis-(2,4-dimethylvaleronitrile).
Salts useful for reducing solubility of the water-soluble monomer in the aqueousphæ are water-soluble, non-reactive inorganic salts of a monovalent, divalent or aluminum cation and a monovalent or divalent anion, including, but not limited to, water-soluble, non-reactive inorganic salts of a monovalent, divalent or aluminum cation and a monovalent or divalent anion, as for example sodium, potassium, lithium and ammonium salts of chloride, bromide, iodide, sulfate, carbonate and nitrate and 5 the magnesium and calcium salts of chloride, bromide, iodide and nitrate. Preferred salts are sodium chloride, sodium sulfate and sodium nitrate. The salt is dissolved in the aqueous medium at levels from about S weight percent, based upon the total weight of the aqueous phase, to saturation of the salt in the aqueous phase. The term, "non-reactive", as applied to the salts herein, means that the salt does not react chemically 10 with water, the monomers or the polymers formed from the monomers.
The dispersants useful in the present invention are nonionic surfactants having a hydroxyalkylcellulose backbone, hydrophobic alkyl side chains containing from 1 to about 24 carbon atoms, and an average of from about 1 to about 8 ethylene oxide groups, preferably from about 1 to about S ethylene oxide groups, substituting each 15 repeating unit of the hydroxyalkylcellulose backbone, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl groups per 100 repeating units in the hydroxyalkylcellulose backbone. The alkyl group in the hydroxyalkylcellulose may contain from 1 to about 24 carbons, and may be linear, branched or cyclic. Preferred is a hydroxyethylcellulose containing from about 0.1 to about 10 C16 alkyl side chains per 20 100 anhydroglucose units and from about 2.5 to about 4 ethylene oxide groups substituting each anhydroglucose unit.
The process of the present invention comprises forming a suspension of the monomer mixture, including a major amount of at least one water-soluble monomer and from about 0.1 to about 50 weight percent, based on the total monomer weight, of a 25 crosslinking monomer, and optionally a minor amount of an additional, copolymerizable monomer, in an aqueous medium containing from about S weight percent to saturation of a water-soluble, non-reactive inorganic salt in the presence of from about 0.1 to about 5 weight percent of a monomer-soluble, free-radical initiator and from about 0.01 to about 4 weight percent of a nonionic surfactant-type dispersant 30 having a hydroxyalkylcellulose backbone, a molecular weight of from about 30,000 to 2,000,000, and a hydrophobic, Cl to about C24 alkyl side chain, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl side chains per 100 repeating units of the polymer backbone, wherein the alkyl group in the hydroxyalkylcellulose backbone is from Cl to C24, establishing polymerization conditions in the suspension, allowing the monomers to polymerize until they have formed water-insoluble particles, and separating the particles from the aqueous phase.
The monomer phase forms spherical droplets within the aqueous phase; these are preferably kept suspended by agitation, but other techniques for maintaining5 suspension which will be readily apparent to those sk~led in the art may be employed, as for example using a static mixer, or suspending the droplets in a liquid stream moving opposite to the direction in which the droplets tend to move by their density.
The polymerization reaction occurs within the suspended monomer droplets, and isinitiated by establishing a temperature in the droplet which is at~least as great as the 10 decomposition temperature of the polymerization initiator. A reasonable lowertemperature for polymerization is about 50C, which is above the decomposition temperature of many common initiators; one skilled in the art will realize that if an initiator is selected having a higher decomposition temperature than this, the minimum temperature will be chosen according to the decomposition temperature of the actual 15 initiator used. The upper limit for the polymerization reaction is the boiling temperature of the suspending medium; the medium employed herein is aqueous, so at atmospheric pressure the maximum temperature will be 100C, and higher temperatures may be used at higher pressures. A lower temperature may be advantageous to prevent decomposition of one or more of the monomers or the 20 dispersant, or for other reasons which will be apparent to one skilled in the art.
The process of the present invention may be used for preparing both gel and macroporous resins. For the preparation of macroporous resins a porogen is commonly used. Porogens useful for making macroporous resins are well known to those skilled in the art; their nature and selection is discussed in, for example, US Patent No.
25 3,991,017. Porogens are substances in which the monomers are soluble but the resulting polymer is insoluble, and which will dissolve the monomers within the suspended droplet, without reacting with the other components of the polymerization mixture.
Thus for the present process, sufficient porogen must remain within the suspended droplet to dissolve the monomer mixture at least partially, and to create the pores 30 within the particle as the polymer forms. The preferred porogens are xylene and toluene.
The following examples are intended to illustrate the invention and not to limit it except as it is limited in the daims. All ratios and percentages given herein are by weight unless otherwise specified, and all reagents used in the exarnples are of good commercial quality unless otherwise specified.
This example is intended to illustrate the process of the present invention as used 5 for preparing a crosslinked copolymer from water-soluble dimethylaminopropyl methacrylamide (DMAPMA) monomer, The dispersant used was a modified hydroxyethylcellulose substituted with about 4.0 moles of ethylene oxide per anhydroglucose unit and approximately 0.7--1.0 cetyl groups per 100 anhydroglucose units, and having a molecular weight of 10 approximately 300,000 and a viscosity in 1% aqueous solution of approxirnately 400 megaPascals.
An aqueous solution was prepared by weighing 246.5 g sodium chloride, grinding approximately 15 g of this sodium chloride in a mortar with 3.72 g dispersant to a ~omogeneous mixture. The unground sodium chloride was added, with stirring, to 1 5 683.5 g deionized water at 50C. The ground sodium chloride-dispersant rnixture was added slowly to the water, which was then stirred at 50C until all the solids had dissolved.
A monomer mixture was made by mixing 159 g DMAPMA, 8.36 g high-purity divinylbenzene (80% purity) and 0.836 g diethyleneglycol divinyl ether. To 148 g20 xylene was added, with stirring, 1.68 g 2,2'-azo-bis-(2,4-dimethylvaleronitrile) initiator.
The aqueous phase was placed in a reactor vessel and stirred at 52C. The monomer mixture was mixed with the xylene-initiator solution and was transferred to the reactor vessel. Stirring at 52C was continued for 20 hours, after which the solids were drained and washed with water to remove the salt and most of the xylene.
The resulting anion exchange resin beads were porous, spherical, and free from agglomerated or misshapen particles. A 300-ml sample of these resin beads was conditioned by passing through it in the following sequence, at a flow rate of approximately 2 liters per hour, 1 liter of 4% aqueous sodium hydroxide solution, 1 liter of deionized water, 1 liter of 10~o aqueous hydrochloric acid and 1 liter of deionized water. The resin was then backwashed with deionized water, allowed to settle, and i~
then drained. One liter of 4% aqueous sodium hydroxide was then passed through the settled bed, followed by a final rinse of deionized water.
The conditioned resin bed was loaded with chloride by passing through it, at a rate of 17 ml/minute, 500 ml of 10% aqueous hydrochloric acid, followed by one bed volurne (BV) of deionized water at the same flow rate. The deionized water flow was continued at approximately 70 ml/minute until the eMuent conductivity measured less 5 than 50 ~mho. The resin bed was then backwashed with deionized water to removetrapped air and voids, and regenerated by passing through it, at a flow rate of 17 ml/minute, 500 ml of 4% aqueous sodium hydroxide. One BV of deionized water was then passed through the bed at 17 ml/minute, after which the flow of deionized water was increased to 70 ml/minute and continued until the conductivity of the rinse water 10 fell below 50 ~lmho. The total volume of deionized water required to reduce the conductivity of the rinse water to this level was recorded as the rinse requirement, in bed volumes of water. The rinse requirement for this sample was 2.2 BV.
As a comparison, a sample of porous, spherical beads prepared by copolymerizing methyl acrylate with approximately 4% DVB and functionalized by 15 aminolysis with dimethylaminoprowlamine produced a resin of the prior art having the sarne anion-exchange functionality as the resin beads of this example. It should be noted that the molecular weight of a repeating monomer unit of the methyl acrylate copolymer is approximately 86, while after aminolysis, the molecular weight of arepeating unit is 156; thus the molecular weight of each monomer unit has 20 approxirnately doubled, and the crosslinker content of the aminolyzed copolymer is therefore approximately 2%, compared to the 4% crosslinker of the copolyrner of the present invention. This aminolyzed copolymer was subjected to the same procedure for determining the rinse requirement, and this was determined to be 11.7 BV. It is well known to those skilled in the art that lower osslinking tends to produce materials that 25 rinse more readily, because the rinse water can penetrate the copolymer more readily.
Despite this, the resins of the present invention had a significantly lower rinse requirement than this prior-art resin.
From the above, it is seen that the method of the present invention is capable of producing spherical anion exchange resins free from agglomerated or misshapen 30 particles, and having the particularly advantageous property of low rinse requirement.
This exarnple illustrates the process of the present invention using DMAPMA
- and a different crosslinking monomer, trimethylolpropane triacrylate (T~TA).
. `
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 1, except that 161.97 g DMAPMA, 8.525 g TMPTA and 139.5 g ~xylene were used, and the initiator weight was 1.705 g.
This example illustrates the process of the present invention using DMAPMA
and additional l~MPTA.
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 2, except that the TMPTA content of the monomer mixture was increased from 5 to 10 weight percent, based on the total weight of the 1 0 monomers.
This exarnple illustrates the process of the present invention using DMAPMA
and adding hexamethylene-bis-methacrylamide (HMBMA) to the TMPTA of Example 2 the crosslinking monomer. In this example the ~xylene was omitted to produce a gel resinbead.
The spherical copolymer beads of this example were prepared using the same procedure as that of Example 1, except that the crossl:nking monomer used was 3%HMBMA and 3% TMPTA, based on the total weight of the monomers, and the ~xylene was omitted. The suspension mixture was heated to 55C for 14 hours. -~`"`'.
Claims (30)
1. A process for preparing spherical, crosslinked copolymer beads from water-soluble monomers which comprises forming a suspension of a mixture of monomers, which mixture includes a major amount of at least one water-soluble monomer and from about 0.1 to about 50 weight percent, based on the total monomer weight, of a crosslinking monomer, in an aqueous medium containing from about 5 weight percent to saturation of a water-soluble, non-reactive inorganic salt in the presence of a free-radical initiator and from about 0.01 to about 4 weight percent of a nonionic surfactant-type dispersant having a hydroxyalkylcellulose backbone, a molecular weight of from about 30,000 to 2,000,000, a hydrophobic alkyl side chain containing from 1 to about 24 carbon atoms, the alkyl side chains being present at a level of from about 0.1 to about 10 alkyl side chains per 100 repeating units of the polymer backbone, and an average of from about 1 to about 8 ethylene oxide groups substituting each repeating unit of the polymer backbone, wherein the alkyl group in the hydroxyalkylcellulose backbone is from C1 to C24, establishing polymerization conditions in the suspension, and allowing the monomers to polymerize until they have formed water-insoluble particles.
2. The process of Claim 1 wherein the water-soluble monomer or monomers has a water solubility of at least 1 gram per 100 grams of water.
3. The process of claim 1 wherein the water-soluble monomer or monomers has a water solubility of at least 10 gram per 100 grams of water.
4. The process of Claim 1 wherein the water-soluble monomer or monomers has a water solubility of at least 50 gram per 100 grams of water.
5. The process of Claim 1 wherein the water-soluble monomer or monomers is one or more acid monomers.
6. The process of Claim 5 wherein the acid monomer or monomers is selected from the group consisting of acrylic, methacrylic, itaconic, maleic, fumaric and crotonic acids.
7. The process of Claim 1 wherein the water-soluble monomer is one or more anhydride monomer or a mixture of one or more anhydride monomers with one or more acid monomers,
8. The process of Claim 7 wherein the anhydride monomer or monomers is selected from the group consisting of acrylic anhydride and methacrylic anhydride.
9. The process of Claim 1 wherein the water-soluble monomer or monomers is one or more amino-substituted acrylamides or methacrylamides or mixtures thereof.
10. The process of Claim 9 wherein the amino-substituted acrylamides or methacrylamides are selected from the group consisting of dimethylaminopropyl methacrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropyl acrylamide, dimethylaminoethyl acrylamide, N,N-bis-(dimethylaminoethyl) methacrylamide, N,N-bis-(dimethylaminopropyl) acrylamide, N,N-bis-(dimethylaminoethyl) acrylamide, and N,N-bis-(dimethylaminopropyl) methacrylamide.
11. The process of Claim 10 wherein the amino-substituted acrylamide is dimethylaminopropyl acrylamide.
12. The process of Claim 10 wherein the amino-substituted methacrylamide is dimethylaminopropyl methacrylamide.
13. The process of Claim 1 wherein the water-soluble monomer or monomers is one or more amino-substituted acrylates or methacrylates.
14. The process of Claim 13 wherein the amino-substituted acrylates or methacrylates are selected from the group consisting of dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate and dimethylaminopropyl acrylate.
15. The process of Claim 14 wherein the amino-substituted acrylate is dimethylaminoethyl acrylate.
16. The process of Claim 14 wherein the amino-substituted acrylate is dimethylaminopropyl acrylate.
17. The process of Claim 14 wherein the amino-substituted methacrylate is dimethylaminoethyl methacrylate.
18. The process of Claim 14 wherein the amino-substituted methacrylate is dimethylaminopropyl methacrylate.
19. The process of Claim 1 wherein the water-soluble monomer or monomers is one or more hydroxyalkyl acrylates or methacrylates.
20. The process of Claim 19 wherein the hydroxyalkyl acrylates or methacrylates are selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate.
21. The process of Claim 19 wherein the hydroxyalkyl acrylate is hydroxyethyl acrylate.
22. The process of Claim 19 wherein the hydroxyalkyl methacrylate is hydroxyethyl methacrylate.
23. The process of Claim 1 wherein the amount of crosslinking monomer is from about 0.1 to about 20 weight percent.
24. The process of Claim 1 wherein the free-radical initiator is present at fromabout 0.01 to about 5 percent, based on the total weight of the monomers.
25. The process of Claim 1 wherein the free-radical initiator is a peroxide or hydroperoxide initiator and is present at a level of from about 0.01 to about 3% by weight, based on the total weight of the monomers.
26. The process of Claim 1 wherein the free-radical initiator is an azo initiator and is present at a level of from about 0.01 to about 2% by weight, based on the total weight of the monomers.
27. The process of Claim 26 wherein the free-radical initiator is 2,2'-azo-bis-(2,4-dimethylvaleronitrile).
28. The process of Claim 1 wherein the dispersant has an average of from about 1 to about 5 ethylene oxide groups substituting each repeating unit of the polymer backbone.
29. The process of Claim 1 wherein the dispersant has an average of from about 2.5 to about 4 ethylene oxide groups substituting each repeating unit of the polymer backbone.
30. The process of Claim 1 wherein the alkyl side chains of the dispersant are C16 alkyl side chains.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/994,246 US5498678A (en) | 1992-12-21 | 1992-12-21 | Suspension polymerization process for water-soluble monomers |
| US07/994,246 | 1992-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2111402A1 true CA2111402A1 (en) | 1994-06-22 |
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ID=25540459
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002111402A Abandoned CA2111402A1 (en) | 1992-12-21 | 1993-12-14 | Suspension polymerization process for water-soluble monomers |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US5498678A (en) |
| EP (1) | EP0604109B1 (en) |
| JP (1) | JPH06220111A (en) |
| KR (1) | KR940014442A (en) |
| CN (1) | CN1105031A (en) |
| AU (1) | AU5220093A (en) |
| BR (1) | BR9305103A (en) |
| CA (1) | CA2111402A1 (en) |
| DE (1) | DE69305149T2 (en) |
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| US5830967A (en) * | 1994-10-24 | 1998-11-03 | Amcol International Corporation | Process for producing an oil and water adsorbent polymer capable of entrapping solid particles and liquids and the product thereof |
| US5837790A (en) * | 1994-10-24 | 1998-11-17 | Amcol International Corporation | Precipitation polymerization process for producing an oil adsorbent polymer capable of entrapping solid particles and liquids and the product thereof |
| US6107429A (en) * | 1994-10-24 | 2000-08-22 | Amcol International Corporation | Process for producing an oil and water adsorbent polymer capable of entrapping solid particles and liquids and the product thereof |
| US5712358A (en) * | 1995-06-07 | 1998-01-27 | Amcol International Corporation | Process for producing an oil sorbent copolymer and the product thereof |
| EP0831366A1 (en) * | 1996-09-24 | 1998-03-25 | Eastman Kodak Company | Synthesis of matte beads containing a carboxylic acid monomer and their use in photographic elements |
| US5919854A (en) * | 1996-10-03 | 1999-07-06 | Cytec Technology Corp. | Process for preparing aqueous dispersions |
| US5843320A (en) * | 1996-10-03 | 1998-12-01 | Cytec Technology Corp. | Aqueous dispersions |
| US6664326B1 (en) | 1996-10-03 | 2003-12-16 | Cytec Technology Corp. | Aqueous dispersions |
| US6608124B1 (en) | 1996-10-03 | 2003-08-19 | Cytec Technology Corp. | Aqueous dispersions |
| US5792366A (en) * | 1996-10-03 | 1998-08-11 | Cytec Technology Corp. | Aqueous dispersions |
| US5696228A (en) * | 1996-10-03 | 1997-12-09 | Cytec Technology Corp. | Process for producing substantially dry polymer particles from aqueous dispersions |
| US6702946B1 (en) | 1996-10-03 | 2004-03-09 | Cytec Technology Corp. | Aqueous dispersions |
| CA2277143C (en) * | 1996-12-23 | 2008-02-19 | Ciba Specialty Chemicals Water Treatments Limited | Particles having surface properties and methods of making them |
| US5985992A (en) * | 1997-12-10 | 1999-11-16 | Cytec Technology Corp. | Anionic polymer products and processes |
| US6262168B1 (en) | 1998-03-11 | 2001-07-17 | Cytec Technology Corp. | Aqueous dispersions |
| US6686035B2 (en) | 1999-02-05 | 2004-02-03 | Waters Investments Limited | Porous inorganic/organic hybrid particles for chromatographic separations and process for their preparation |
| US6410672B1 (en) * | 1999-07-28 | 2002-06-25 | Ionics, Incorporated | Ion exchange and electrochemical methods and devices employing one-step quaternized and polymerized anion selective polymers |
| US6528167B2 (en) * | 2001-01-31 | 2003-03-04 | Waters Investments Limited | Porous hybrid particles with organic groups removed from the surface |
| US7250214B2 (en) * | 2001-08-09 | 2007-07-31 | Waters Investments Limited | Porous inorganic/organic hybrid monolith materials for chromatographic separations and process for their preparation |
| AU2003285121A1 (en) | 2002-10-30 | 2004-06-07 | Waters Investments Limited | Porous inorganic/organic hybrid materials and preparation thereof |
| US20040215139A1 (en) * | 2002-12-20 | 2004-10-28 | Todd Cohen | Apparatus and method for implanting left ventricular pacing leads within the coronary sinus |
| GB2427611A (en) * | 2004-02-17 | 2007-01-03 | Waters Investments Ltd | Porous hybrid monolith materials with organic groups removed from the surface |
| JP5308665B2 (en) * | 2004-07-30 | 2013-10-09 | ウオーターズ・テクノロジーズ・コーポレイシヨン | Porous inorganic / organic hybrid materials with ordered domains for chromatographic separation and methods for their preparation |
| US10773186B2 (en) | 2004-07-30 | 2020-09-15 | Waters Technologies Corporation | Porous inorganic/organic hybrid materials with ordered domains for chromatographic separations and processes for their preparation |
| JP2010515804A (en) | 2007-01-12 | 2010-05-13 | ウオーターズ・テクノロジーズ・コーポレイシヨン | Porous carbon-heteroatom-silicon hybrid inorganic / organic material for chromatographic separation and method for its preparation |
| DE102009003560B4 (en) * | 2009-03-03 | 2015-01-22 | Hydro Aluminium Deutschland Gmbh | Process for producing a sorbent coated aluminum strip, sorbent coated aluminum strip and its use |
| US11439977B2 (en) | 2009-06-01 | 2022-09-13 | Waters Technologies Corporation | Hybrid material for chromatographic separations comprising a superficially porous core and a surrounding material |
| JP6151021B2 (en) | 2009-06-01 | 2017-06-21 | ウオーターズ・テクノロジーズ・コーポレイシヨン | Hybrid material for chromatographic separation |
| US20130112605A1 (en) | 2010-07-26 | 2013-05-09 | Waters Technologies Corporation | Superficially porous materials comprising a substantially nonporous core having narrow particle size distribution; process for the preparation thereof; and use thereof for chromatographic separations |
| US11642653B2 (en) | 2016-03-06 | 2023-05-09 | Waters Technologies Corporation | Hybrid material for chromatographic separations comprising a superficially porous core and a surrounding material |
| CN115260399B (en) * | 2022-08-26 | 2023-10-03 | 核工业北京化工冶金研究院 | Acrylonitrile skeleton macroporous resin and preparation method and application thereof |
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-
1992
- 1992-12-21 US US07/994,246 patent/US5498678A/en not_active Expired - Fee Related
-
1993
- 1993-06-23 JP JP5152439A patent/JPH06220111A/en not_active Withdrawn
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- 1993-12-07 AU AU52200/93A patent/AU5220093A/en not_active Abandoned
- 1993-12-14 DE DE69305149T patent/DE69305149T2/en not_active Expired - Fee Related
- 1993-12-14 CA CA002111402A patent/CA2111402A1/en not_active Abandoned
- 1993-12-14 EP EP93310094A patent/EP0604109B1/en not_active Expired - Lifetime
- 1993-12-17 BR BR9305103A patent/BR9305103A/en not_active Application Discontinuation
- 1993-12-21 CN CN93112999A patent/CN1105031A/en active Pending
Also Published As
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|---|---|
| AU5220093A (en) | 1994-06-30 |
| DE69305149D1 (en) | 1996-11-07 |
| JPH06220111A (en) | 1994-08-09 |
| EP0604109A3 (en) | 1994-07-13 |
| DE69305149T2 (en) | 1997-03-06 |
| CN1105031A (en) | 1995-07-12 |
| EP0604109B1 (en) | 1996-10-02 |
| US5498678A (en) | 1996-03-12 |
| EP0604109A2 (en) | 1994-06-29 |
| KR940014442A (en) | 1994-07-18 |
| BR9305103A (en) | 1994-06-28 |
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