CA1223700A - Process for producing acrylamide-type cationic polymeric flocculant - Google Patents
Process for producing acrylamide-type cationic polymeric flocculantInfo
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- CA1223700A CA1223700A CA000384593A CA384593A CA1223700A CA 1223700 A CA1223700 A CA 1223700A CA 000384593 A CA000384593 A CA 000384593A CA 384593 A CA384593 A CA 384593A CA 1223700 A CA1223700 A CA 1223700A
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- Prior art keywords
- acrylamide
- exchange resin
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- acidic cation
- cation exchange
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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
- C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
- C08F20/52—Amides or imides
- C08F20/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
- C08F20/56—Acrylamide; Methacrylamide
-
- 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
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Polymerisation Methods In General (AREA)
Abstract
TITLE OF THE INVENTION
PROCESS FOR PRODUCING ACRYLAMIDE-TYPE CATIONIC
POLYMERIC FLOCCULANT
ABSTRACT OF THE DISCLOSURE
Polyacrylamide useful as a high-molecular-weight, well water-soluble flocculant, especially cationic polymeric flocculant, is produced by rendering crude acrylamide substantially free from N-acryloyl acrylamide, said crude acrylamide being obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH in the range of from 4 to 10, and then polymerizing the acrylamide.
PROCESS FOR PRODUCING ACRYLAMIDE-TYPE CATIONIC
POLYMERIC FLOCCULANT
ABSTRACT OF THE DISCLOSURE
Polyacrylamide useful as a high-molecular-weight, well water-soluble flocculant, especially cationic polymeric flocculant, is produced by rendering crude acrylamide substantially free from N-acryloyl acrylamide, said crude acrylamide being obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH in the range of from 4 to 10, and then polymerizing the acrylamide.
Description
:~2~37~1~
This invention relates to an improved process for producing an acrylamide-type cationic polymeric flocculant.
Acrylamide polymers find many applications, for example as paper processing resins, fiber treating agents, polymeric flocculants and oil recovery additives, because of their good water-solubility and high molecular weights.
Particularly in Jap n, these polymers are extensively used as paper processing resins and polymeric flocculants. For use as paper processing resins, polymers which have a relatively low molecular weight of, for example, several hundred thousand can be used, but polymers used as polymeric flocculants are usually required to have a molecular weight of as high as several million or more. Recently, acrylamide polymers having a super high molecular weight of more than ten million have come into production.
Acrylamide-type polymeric flocculants are Toughly classified into nonionic polymeric flocculants obtained by using acrylamide alone as a monomer, anionic polymeric flocculants obtained by partial hydrolysis of the amide l33~
~,~
3 ~2237~
group of nonionic acrylamide polymers or by copolymerizing acrylamide with an anionic monomer such as acrylic acid, and cationic polymeric flocculants obtained by copolymeri-zation of acrylamide with a cationic monomer such as methacryloyloxyethyl trimethyl ammonium chloride.
The nonionic and anionic polymeric flocculants are used mainly as sedimentation promoters in treating general waste water, pulp spent liquors, mine waste water, etc , whereas the principal use of the cationic polymeric flocculants are as dehydrating aids in dehydrating organic active sludge generate~ by sewage treatment, treatmellt oE
excre~cnt, treatment o waste water from disposal o~ :Eood wastes, etc.
With the widespread practice of a high level of waste water treatment and the widespread establishment of sewerage, the amount of organic active sludge discharged has increased year by year, and the amounts of acrylamlde-type polymeric -floccula~nts, particularly cationic polymeric -flocculants, used for the above purpose have greatly increased. Since an increase in the ratio of dehydration of organic active sludge permits a decrease in the amount of heavy oil used in incinerating.the sludge and makes it easy to handle the sludge in reclamation thereof, it has been desired to develop cationic polymeric flocculants having higher perormance.
Acrylamide a main raw material ~or acrylamide-type polymer.ic flocculants has recently become producible ` ' ' , 4 ~ ~37~
relatively easily by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst in a neutral region of pH 4 to 10, more generally 6 to 9 instead of the conventional sulfuric acid method which involves hydration of acrylonitrile under strong acidity with a pH of 1 or less.
The present inventors found that acrylamide obtained by the catalytic hydrating method can be used with good results as a raw material for nonionic or anionic acrylamide polymers not only for production of relatively low-molecular-weight polymers useful as paper processing resins but also for production of nonionic or anionic polymeric flocculants having super high molecular weights, and that as a raw material for cationic polymers, the above acrylamide may be-used satisfactorily for production of polymers having such low molecular weights às to be suitable for use~as paper processing resins, but when the above acrylamide used to produce cationic polymeric floccuiants having high molecular weights, the products have very poor solubility in water and in an extreme case, they only become swollen with water and dissolve hardly at all. Consequently, the present inventors keenly recognized that this problem sets a great restriction on the production of cationic polymeric flocculants of high performance.
The present inventors assiduously investigated the cause of the adverse effects of the above acrylamide on the production of catiollic polymeric flocculants without any 5 ~ ~37~
deleterious effect on the production of nonionic and anionic polymeric flocculants, and unexpectedly found that N-acryloyl acrylamide present in acrylamide is a substance which causes such adverse effects.
In U.S. Patent No. 3,130,~29~ formation o~ N-acryloyl acrylamide during the hydration reaction of acrylonitrile by the sulfuric acid method is presumed. In this patent, however, the formation of N-acryloyl acrylamide is merely presumed and not confirmed. The presence of an acid and heat is considered to be essential for ~he formation of N-acryloyl acrylamide. The N-acryloyl acrylamide in acrylamide produced by this method, when considered from its structure, is a difunctional crosslinkable impurity like methylenebisacrylamide, and the present inventors lS presume it to be one of the impurities which reduce the water-solubility of nonionic polymeric flocculants having a molecular weight of several million or more.
On the other hand, the formation of N-acryloyl acrylamide in a neutral region of a pH 4-10, more generally 6 to 9, as in the catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst contemplated in the present invention, has not been known.
The process of the invention is able to produce acrylamide-type cationic polymeric flocculants which have high molecular weights and excellent solubility in water and are useful as dehydrating agents.
In accordance with the present invention, there is provided a process for producing an acrylamide-type cationic polymeric flocculant comprising polymerizing acrylamide obtained by the catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH of from 4 to 10, a temperature of from 50 to 150C and a pressure of from atmospheric pressure to an elevated pressure of up to about 10 kg/cm2, charac-terized in that, a crude aqueous acrylamide solution obtained by the catalytic hydration is purified by treating with either a single or combined method selected from physical adsorption, reactive adsorption, decomposition by a chemical reaction and solvent extraction, so that the concentration of N-acryloyl acrylamide contained in the acrylamide solution is not more than 3 ppm based on the acrylamide contained therein, and then the acrylamide solution is subjected to copolymerization of acrylamide and a cationic monomer selected from the group consisting of amino alcohol esters of methacrylic or acrylic acid, N-aminoalkyl substitution products of methacrylamide or acrylamide and the salts or quaternary ammonium salts thereof in a mole ratio of from 90:10 to 50:50.
In the following disclosure, reference is made to the accompanying drawings, in which:
Figure 1 is a graph showing the effect o-E the dissolving temperature on the water-solubility of a cationic polymeric flocculant prepared by using9 as a starting material, acrylamide purified by recrystallization to which N-acryloyl acrylamide has been added; and - ~;237~Q
Figure 2 is a graph showing the effect of the dissolving temperature on the water-solubility of a cationic polymeric flocculant prepared by using, as a starting ma~erial, acrylamide purified by crystallization to which methylenebisacrylamide , a typical crosslinkable compound, has been added.
In these graphs, the ordinate shows the weight percent of a water-insoluble portion of the flocculant, and the abscissa, the content in ppm of N-acryloyl acrylamide based on the weight of acrylamide. The numerals 1, 2, 3 and 4 refer respectively to a dissolving temperature of 20C, 50C~ 60C, and 70C.
lhe present inventors ascertained that N-acryloyl acrylamide is present as an impurity in the aqueous acrylamide solution obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst, and conducted an experiment in which N-acryloyl acrylamide was added to acrylamide fully purified by a recrystallization method and being free from N-acryloyl acrylamide, and a comparative experiment in which methylenebisacrylamide was added to the purified acrylamide. The results are shown in Reference examples 1 an
This invention relates to an improved process for producing an acrylamide-type cationic polymeric flocculant.
Acrylamide polymers find many applications, for example as paper processing resins, fiber treating agents, polymeric flocculants and oil recovery additives, because of their good water-solubility and high molecular weights.
Particularly in Jap n, these polymers are extensively used as paper processing resins and polymeric flocculants. For use as paper processing resins, polymers which have a relatively low molecular weight of, for example, several hundred thousand can be used, but polymers used as polymeric flocculants are usually required to have a molecular weight of as high as several million or more. Recently, acrylamide polymers having a super high molecular weight of more than ten million have come into production.
Acrylamide-type polymeric flocculants are Toughly classified into nonionic polymeric flocculants obtained by using acrylamide alone as a monomer, anionic polymeric flocculants obtained by partial hydrolysis of the amide l33~
~,~
3 ~2237~
group of nonionic acrylamide polymers or by copolymerizing acrylamide with an anionic monomer such as acrylic acid, and cationic polymeric flocculants obtained by copolymeri-zation of acrylamide with a cationic monomer such as methacryloyloxyethyl trimethyl ammonium chloride.
The nonionic and anionic polymeric flocculants are used mainly as sedimentation promoters in treating general waste water, pulp spent liquors, mine waste water, etc , whereas the principal use of the cationic polymeric flocculants are as dehydrating aids in dehydrating organic active sludge generate~ by sewage treatment, treatmellt oE
excre~cnt, treatment o waste water from disposal o~ :Eood wastes, etc.
With the widespread practice of a high level of waste water treatment and the widespread establishment of sewerage, the amount of organic active sludge discharged has increased year by year, and the amounts of acrylamlde-type polymeric -floccula~nts, particularly cationic polymeric -flocculants, used for the above purpose have greatly increased. Since an increase in the ratio of dehydration of organic active sludge permits a decrease in the amount of heavy oil used in incinerating.the sludge and makes it easy to handle the sludge in reclamation thereof, it has been desired to develop cationic polymeric flocculants having higher perormance.
Acrylamide a main raw material ~or acrylamide-type polymer.ic flocculants has recently become producible ` ' ' , 4 ~ ~37~
relatively easily by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst in a neutral region of pH 4 to 10, more generally 6 to 9 instead of the conventional sulfuric acid method which involves hydration of acrylonitrile under strong acidity with a pH of 1 or less.
The present inventors found that acrylamide obtained by the catalytic hydrating method can be used with good results as a raw material for nonionic or anionic acrylamide polymers not only for production of relatively low-molecular-weight polymers useful as paper processing resins but also for production of nonionic or anionic polymeric flocculants having super high molecular weights, and that as a raw material for cationic polymers, the above acrylamide may be-used satisfactorily for production of polymers having such low molecular weights às to be suitable for use~as paper processing resins, but when the above acrylamide used to produce cationic polymeric floccuiants having high molecular weights, the products have very poor solubility in water and in an extreme case, they only become swollen with water and dissolve hardly at all. Consequently, the present inventors keenly recognized that this problem sets a great restriction on the production of cationic polymeric flocculants of high performance.
The present inventors assiduously investigated the cause of the adverse effects of the above acrylamide on the production of catiollic polymeric flocculants without any 5 ~ ~37~
deleterious effect on the production of nonionic and anionic polymeric flocculants, and unexpectedly found that N-acryloyl acrylamide present in acrylamide is a substance which causes such adverse effects.
In U.S. Patent No. 3,130,~29~ formation o~ N-acryloyl acrylamide during the hydration reaction of acrylonitrile by the sulfuric acid method is presumed. In this patent, however, the formation of N-acryloyl acrylamide is merely presumed and not confirmed. The presence of an acid and heat is considered to be essential for ~he formation of N-acryloyl acrylamide. The N-acryloyl acrylamide in acrylamide produced by this method, when considered from its structure, is a difunctional crosslinkable impurity like methylenebisacrylamide, and the present inventors lS presume it to be one of the impurities which reduce the water-solubility of nonionic polymeric flocculants having a molecular weight of several million or more.
On the other hand, the formation of N-acryloyl acrylamide in a neutral region of a pH 4-10, more generally 6 to 9, as in the catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst contemplated in the present invention, has not been known.
The process of the invention is able to produce acrylamide-type cationic polymeric flocculants which have high molecular weights and excellent solubility in water and are useful as dehydrating agents.
In accordance with the present invention, there is provided a process for producing an acrylamide-type cationic polymeric flocculant comprising polymerizing acrylamide obtained by the catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH of from 4 to 10, a temperature of from 50 to 150C and a pressure of from atmospheric pressure to an elevated pressure of up to about 10 kg/cm2, charac-terized in that, a crude aqueous acrylamide solution obtained by the catalytic hydration is purified by treating with either a single or combined method selected from physical adsorption, reactive adsorption, decomposition by a chemical reaction and solvent extraction, so that the concentration of N-acryloyl acrylamide contained in the acrylamide solution is not more than 3 ppm based on the acrylamide contained therein, and then the acrylamide solution is subjected to copolymerization of acrylamide and a cationic monomer selected from the group consisting of amino alcohol esters of methacrylic or acrylic acid, N-aminoalkyl substitution products of methacrylamide or acrylamide and the salts or quaternary ammonium salts thereof in a mole ratio of from 90:10 to 50:50.
In the following disclosure, reference is made to the accompanying drawings, in which:
Figure 1 is a graph showing the effect o-E the dissolving temperature on the water-solubility of a cationic polymeric flocculant prepared by using9 as a starting material, acrylamide purified by recrystallization to which N-acryloyl acrylamide has been added; and - ~;237~Q
Figure 2 is a graph showing the effect of the dissolving temperature on the water-solubility of a cationic polymeric flocculant prepared by using, as a starting ma~erial, acrylamide purified by crystallization to which methylenebisacrylamide , a typical crosslinkable compound, has been added.
In these graphs, the ordinate shows the weight percent of a water-insoluble portion of the flocculant, and the abscissa, the content in ppm of N-acryloyl acrylamide based on the weight of acrylamide. The numerals 1, 2, 3 and 4 refer respectively to a dissolving temperature of 20C, 50C~ 60C, and 70C.
lhe present inventors ascertained that N-acryloyl acrylamide is present as an impurity in the aqueous acrylamide solution obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst, and conducted an experiment in which N-acryloyl acrylamide was added to acrylamide fully purified by a recrystallization method and being free from N-acryloyl acrylamide, and a comparative experiment in which methylenebisacrylamide was added to the purified acrylamide. The results are shown in Reference examples 1 an
2 below. ~hese results demonstrate that N-acryloyl acrylamide, quite different from a typical crosslinkable compound such as methylenebisacrylamide~ exerts no adverse effects on the water-solubility of nonionic and anionic polymeric flocculants, but that it exerts the same degree of deleterious effects on the water-solubility of cationic polymeric flocculants as does methylenebisacrylamide even when its content is extremely small. It has also been ~Z~ 7~C~
ascertained that as shown in Examples given hereinbelow, there is a very strong correlation between the degree of poorness of the water-solubility of an acrylamide polymer and the content of N-acryloyl acrylamide.
A comparison between Figu~,res 1 and 2 shows that N-acryloyl acrylamide and methylenebisacrylamide behave ~uite differently toward the dissolving temperature. This fact suggests that the mechanism of reduction of water solubility by N-acryloyl acrylamide differs from that by methylenebisacrylamide, a typical crosslinkable compound.
The present inventors ,selected acrylamides which can be used without any problem in the production of nonionic and anionic polymeric flocculants from those acrylamides which were produced by the catalytic hydrating method and had verious manufacturing histories, and produced cationic polymeric flocculants from the selected acrylamides. From the dissolving temperatures and water solubility, they determined a correlation between thè
presumed content and analytical content of N-acryloyl acrylamide using Figure 1. The results show that these content values show a very good agreement, and the content of N-acryloyl acrylamide greatly affects the water-solubility o'f cationic polymeric flocculants.
It is presumed from the foregoing facts that N-acryloyl acrylamide does not adversely affect the water solubility of nonionic and anionic polymeric flocculants, but causes a reduction in the water solubility of cationic :3~2~23~
g polymeric flocculants.
The present invention is described below in more detail.
The aqueous crude acrylamide solution used in this invention is obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH in the range of from 4 to 10, more generally from 6 to 9. Various metallic copper catalysts have been proposed for use in the production of acrylamide, and any of these can be used in the present invention.
They may, for example, be metallic copper or catalysts containing metallic copper. Specific examples are given below.
(1) A combination of a copper ion and copper in the form of wire, powder, etc.
(2) Reduced copper obtained by reducing a copper compound such as copper oxide, copper hydroxide or copper salts with hydrogen, carbon monoxide, etc. at a high tem-perature of, for example, 100 to 400C.
ascertained that as shown in Examples given hereinbelow, there is a very strong correlation between the degree of poorness of the water-solubility of an acrylamide polymer and the content of N-acryloyl acrylamide.
A comparison between Figu~,res 1 and 2 shows that N-acryloyl acrylamide and methylenebisacrylamide behave ~uite differently toward the dissolving temperature. This fact suggests that the mechanism of reduction of water solubility by N-acryloyl acrylamide differs from that by methylenebisacrylamide, a typical crosslinkable compound.
The present inventors ,selected acrylamides which can be used without any problem in the production of nonionic and anionic polymeric flocculants from those acrylamides which were produced by the catalytic hydrating method and had verious manufacturing histories, and produced cationic polymeric flocculants from the selected acrylamides. From the dissolving temperatures and water solubility, they determined a correlation between thè
presumed content and analytical content of N-acryloyl acrylamide using Figure 1. The results show that these content values show a very good agreement, and the content of N-acryloyl acrylamide greatly affects the water-solubility o'f cationic polymeric flocculants.
It is presumed from the foregoing facts that N-acryloyl acrylamide does not adversely affect the water solubility of nonionic and anionic polymeric flocculants, but causes a reduction in the water solubility of cationic :3~2~23~
g polymeric flocculants.
The present invention is described below in more detail.
The aqueous crude acrylamide solution used in this invention is obtained by catalytic hydration of acrylonitrile with water in the presence of a metallic copper catalyst at a pH in the range of from 4 to 10, more generally from 6 to 9. Various metallic copper catalysts have been proposed for use in the production of acrylamide, and any of these can be used in the present invention.
They may, for example, be metallic copper or catalysts containing metallic copper. Specific examples are given below.
(1) A combination of a copper ion and copper in the form of wire, powder, etc.
(2) Reduced copper obtained by reducing a copper compound such as copper oxide, copper hydroxide or copper salts with hydrogen, carbon monoxide, etc. at a high tem-perature of, for example, 100 to 400C.
(3) Reduced copper obtained by reducing a copper compound such as copper oxide, copper hydroxide or copper salts in the liquid phase with a reducing agent such as hydrazine, an alkali or alkaline earth metal borohydride compound, or formaldehyde.
(4) Reduced copper obtained by treating a copper compound such as copper oxide, copper hydroxide or copper salts in the liquid phase with a metal having a greater 237~
ionizing tendency than copper, such as zinc, aluminum, iron or tin.
ionizing tendency than copper, such as zinc, aluminum, iron or tin.
(5) Raney copper obtained by leaching a Raney alloy composed of copper and aluminum, zinc or magnesium.
(6) Metallic copper obtained by thermally decompos-ing an organic copper compound such as copper formate or copper oxalate at a temperature of~ for example, 100 to 400C.
(7) A thermal decomposition product of copper hydride.
These copper-containing catalysts may contain metals other than copper, such as chromiwn or molybdenum, which are normally used, as well as usually employed carriers.
The reaction between acrylonitrile and water in the presence of the aforesaid copper-containing catalyst is usually carried out in the liquid phase by using water in an almost arbitrary amount, preferably at least 4 moles, based on acrylonitrile at a temperature o:E 50 to 150C, preferably 80 to 140C, under atmospheric pressure or an elevated pressure which does not cause boiling of water and acrylonitrile, for example up to about 10 kg/cm in a suspended or fixed catalyst bed in accordance with a continuous or batchwise reaction mode. The reaction is carried out while avoiding contact of the reactants and the copper-containing catalyst with oxygen or an oxygen-containing gas.
:~Z~23~
The reaction is per-formed at a pH in the range of from 4 to 10, more generally from 6 to 9. If the pH
is below 4, the rate of the reaction is slow~ and if the pH is above 10, side-reactions such as hydrolysis of the resulting acrylamide or the formation of nitrilo compounds take place noticeably and the yield of the desired product decreases. Hence, pH values outside the specified range are undesirable.
The resul-ting aqueous solution of crude acrylamide is then usually subjected to a distillation operation in order to remove unreacted acrylonitrile from the solution or concentrate the solution so as to obtain an aqueous acrylamide solution having a concentration of, for example, about 30 to 50% by weight. The aqueous solution of crude acrylamide, optionally concentrated as above, is then tTeated on an ion-exchange resin in order to remove impurities normally present, such as copper ions, or acrylic acid which is the hydrolysis product.
In the process of this invention, the amount of N-acryloyl acrylamide contained in the aqueous solution of acrylamide can always be controlled with good accuracy depending upon the desired acrylamide polymer to be produced.
Methods avai]able for removing N-acryloyl acrylamide from the aqueous solution of acrylamide include, for example, physical adsorption by activated caTbon, activated clay, etc.; reactive adsorption by a compound containing primary and secondary amines such as polyamines, a weakly basic ~L~2~7~
anion exchange resin containing primary and secondary amino groups, or a compound having a peptide linkage such as a protein (e.g., silk) or its disintegration product;
decomposition by a chemical reaction such as alkaline hydrolysis, or oxidation; extraction with a solvent such as chloroform or carbon tetrachloride; and sublimation which is normally employed in the art. Alternatively, it is possible to add a compound capable of forming an adduct with N-acryloyl acrylamide, thereby rendering the latter non-deleterious.
These methods can be used either singly or in a combination of two or more. Although some of these methods are known as a method for purifying an aqueous solution of acrylamide obtained by the catalytic hydrating method, the content of N-acryloyl acrylamide cannot be reduced, under the purifying conditions in the prior art, to below the - - permissible amount specified in the process of this invention.
-Since the amount of N-acryloyl acrylamide contained in the aqueous solution of crude acrylamide differs depending upon the reaction conditions, the purifying conditions should always be analy~ed, quantified and controlled in order to adjust the content of N-acryloyl acrylamide in the purified acrylamide to below ~he permissible value specified in the process of the invention.
The present inventors have found that the amount of N-acryloyl acrylamide in the aqueous solution of crude acrylamide increases as the concentration of acrylonitrile - 13 ~ 37~
in the reaction system and the reaction temperature increase, and the use of such conditions can easily lead to the formation of an aqueous solution of acrylamide unsuitable for use as a raw material for cationic polymeric flocculants.
The amount of N-acryloyl acrylamide in the acrylamide which is permissible in the production of cationic polymeric flocculants is not more than 10 ppm, preferably not more than 5 ppm, more preferably not more than 1 ppm. Accord-ingly, in the present application, the "acrylamide sub-stantially free from N-acryloyl acry~amide", denotes acrylamide containing not more than 10 ppm of N-acryloyl acrylamide.
The aqueous acrylamide solution so purified is then polymerized in a customary manner to give acrylamide-type cationic polymeric flocculants.
In the production of acrylamide polymers in accordance with this invention, various known conventional polymerization initiators can be used. Examples inciude azo compounds such as azobisdimethylvaleronitrile, azobis (sodium cyanovalerate), azobisisobutyronitrile and azobis-aminopropane hydrochloride; organic peroxides such as benzoyl peroxide, lauroyl peroxide and tertiary butyl -hydroperoxide, and inorganic peroxides such as potassium persulfate, sodium perbromate, ammonium persulfate and hydrogen peroxide~
~ xamples of suitable reducing agents are inorganic compounds such as ferrous sulfate, ferrous chloride, sodium ~2~3~
bisulfite, sodium metasulfite, sodium thiosulfate and nitrite salts, and organic compounds such as dimethyl-aniline, 3-dimethylaminopropionitrile and phenylhydrazine.
For production of a high-molecular-weight polymer by the process of this invention, a mixture of acrylamide and a cationic monomer copolymerizable with acrylamide is used in a mole ratio of from 90:10 to 50:50. Examples o~ the cationic comonomer are amino alcohol esters of methacrylic or acrylic acid ~such as dimethyl-aminoethyl methacrylate or diethylaminoethyl acrylate) and the salts or quaternary ammonium salts thereof; and N-aminoalkyl substitution products of methacrylamide or acrylamide (such as N-methacryloyl-N', N'-dimethyl-1,3-diaminopropane or N-acryloyl-N',N'-dimethyl-l,l-dimethyl-l, lS 3-diaminopropane) and the salts or quaternary ammonium salts thereof.
The following Referential Examples and Examples illustrate the present invention further.
Referential Example 1 A 70~ aqueous solution of acrylamide was prepared under heating from commercially available acrylamide crystals and distilled water. The solution was cooled at 5C to precipitate acrylamide crystals. This recrylstal-?5 lization procedure was repeated to obtain purified acrylamide.
To the purified acrylamide was added N-acryloyl acrylamide in an amount of 1, 3, 6, 10, 20, 30, and 50 ppm respectively based on the weight of the acrylamide. In accordance with l~
~iL2~37a:~
the polymerization recipes shown below, high-molecular-weight nonionic, anionic and cationic polymeric flocculants were respectively produced, and tested for water solubility.
The results are shown in Table 1.
Non-ionic polymeric flocculants:
(A) Acrylamide was dissolved in distilled water to a concentration of 20% by weight. Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present. At 30C, ~.8 mg of ammonium persulfate and 2.2 mg of sodiunl bisulfite were added thereto, and the reaction was carried out while allowing the temperature to rise by the heat of polymerization and the polymerization to proceed by the effect of the tem-perature rise. After arise in temperature was no longer noted, the reaction mixture was allowed to stand further for 1 hour to terminate the polymerization. Thus~ an agar-like mass consisting of an acrylamide polymer and water was obtained.
The agar-like mass was then coarsely crushed by a mincer, dried in hot air at 1~0C for 1 hour, and pulver-ized to form a powdery nonionic polymeric flocculant which was found to have a molecular weight, calculated from its intrinsic viscosity, of about 7 million.
(~) A nonionic polymeric flocculant having a molecular weight of about 10 million was prepared by operating in the same way as in (A) above except that the ~2~3'7~
amounts of ammonium persulfate and sodium bisulfite were changed to 6.0 mg and 1.5 mg, respectively.
(C) A nonionic polymeric flocculant having a molecular weight of about 13 million was prepared by operating in the same way as in (A) above except that the amounts of ammonium persulfate and sodium bisulfite were changed to 3.5 mg and l.0 mg, respectively.
Anionic polymeric flocculant:
An aqueous solution of a mixkure of acrylamide and sodium acrylate in a mole ratio of 80:20 in a monomer concentration of 20% by weight was prepared by using acrylamide, sodium acrylate and distilled water. Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present.
At 30C, 60 mg of sodium 4,4'-azobis-4-cyanovalerate, 4.0 mg of ammonium persulfate and 2 mg of sodium bisulfite were added. The mixture was then worked up in the same way as in the preparation of the nonionic polymeric flocculants to give an anionic polymeric flocculant having a molecular weight of about 12 million.
Cationic polymeric flocculants:
(A) An aqueous solution of a mixture of acrylamide and N-methacryloyl-N',N',N'-trimethyl-1,3-diaminopropane chloride in a mole ratio of 90:10 in distilled water in a monomer concentration of 20% by weight was prepared. The pH of the solution was adju~ted to 5 0. Then, 500 g of the ~L~23~
aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present. At 30C, 100 mg of sodium 4,4'-azobis-4-cyanovalerate, 7.2 mg o-f ammonium persulfate and 3.6 mg of sodium bisulfite were added. The mixture was worked up in the same way as in the preparation of the nonionic polymeric flocculants to give a cationic polymeric flocculant A containing 0.11 cation equivalent/100 g.
(B) A solution of a mixture of acrylamide and methacryloyloxyethyl trimethyl ammonium chloride in a mole ratio o-f 50:50 or 85:15 in distilled water in a monomer concentration of 20% by weight was prepared. The pH of the solution was àdjusted to 5Ø Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown into it to remove any dissolved oxygen present. At 30C, 100 mg of sodium 4,4'-azobis-4-cyanovalerate, 7.2 mg o-f ammonium persulfate and 3.6 mg of sodium bisulfate were added. The mixture was worked up in the same way as in the preparation of the nonionic polymeric flocculants. Thus, cationic polymeric flocculants B ~ B' containing 0.36 cation equivalent/100 g and 0.16 cation equivalent/lOOg, respectively, were obtained.
Water solubility test:
One gram of the powdery polymer sample was added to 1,000 g of distilled water, and the mixture was stirred for 1 hour by a magnetic stirrer. The solution was then ~23~
filtered through a 200-mesh wire screen to separate and collect a water-insoluble portion from the solution. The water-insoluble portion was dried at 120C, and its amount was measured.
Table 1 Amount of N-acryloyl acrylamide _ added ~ppm based on acrylamide) l l 1 1 3 l6 10 20 l30 50 Type of acrylamide polymeric ~ I ~
flocculant \ I l _ _ Nonionic polymeric flocculant l l l l l l~molecular weight about IO~O IO O O i O O
,7 million) , I I ~ !
Ditto (molecular weight about O O O ~ O O O _ .itto (molecular weight about ~O ¦O ¦ O ¦
Anionic polymeric flocculant r i ~molecular weight about O O O O O I O O
12 million) Cationic polymeric flocculant A _ (cation equivalent: O O! O Q X I X X
0.11 eq./100 g) ~ 1, , `
iDitto B ~cation equivalent: i l _ 0.36 eq./100 g) ,O I O, a I x I x x I x ~Ditto B' ~cation equivalent: io I a I x x x x I x 1 0.16 eq./100 g) ~
.
In the above table, the evaluation of water solubility is as follows:
o : the amount of the water-insoluble portion is less than 0.2%
a the amount of the water-insoluble portion is 0.2-2.0%.
X : the amount of the water-insoluble portion is more than 2.0%.
- 1 9 ~ 37 Referential ~xample _ Methylenebisacrylamide was added in a weight of 1, 1.5, 3, 6, and 10 ppm respectively based on acrylamide to pure acrylamide obtained in the same way as in Referential Example 1. Using the resulting polymeric flocculant, the same water-solubility test as in Referential Example 1 was conducted. The results are shown in Table 2.
Table 2 Amount of methylenebis acrylamide added (ppm based on acrylamide) ~ 0.6 1.5 3 6 10 Type of acrylamide polymeric \
flocculant \ !
Nonionic polymeric flocculant (molecular weight aboutO O ~ IX X
7 million) . _ _ j .
Ditto ~molecular weight about O O I a x I x 10 million) l Ditto ~molecular weight about O I ~ X IX X
13 million) _ Anionic polymeric flocculant . I
~molecular weight about . O O X 'IX X .
12 million) .
Cationic polymeric flocculant A l ~cation equivalent: O O X X X
0.11 eq./100 g) l . Ditto B ~cation equivalent: ¦I o l~ X i X
¦ 0.36 eq./100 g) ¦ O l ~ I
0.16 eq./100 g) ¦ O O ~ X ¦ X
-The evaluation of the water-solubility was done in accordance with the same standards as given in the footnote to Table 1.
- 20 - ~2 Example 1 Production of an aqueous solution of crude acrylamide:
A reactor was charged with 70 parts by weight of Raney copper and 1,000 parts of an aqueous solution of acrylonitrile in a concentration of 25% by weight, and the reaction was carried out at 135C for 4 hours at a pH
of 7 to 9. The catalyst was removed from the resulting reaction solution by filtration, and the residue was passed through a vacuum-distillation device to remove the unreacted acrylonitrile and a part of water to give a 50% by weight aqueous solution of acrylamide. The crude aqueous acrylamide solution contained less than 300 ppm of acrylo-nitrile and less than 80 ppm of copper.
Purification of the aqueous acrylamide solution:
Glass columns A, B and C each having an inside diameter of 20 mm and a lèn~th of 50 cm were provided, and the aqueous acrylamide solution was purified by ~he following method.
~ 1~ One hundred milliliters of a strongly acidic cation exchange resin (Amberlite IR-120B, a tradename for a product of Rohm ~ Haas Co.) was filled in the column A
and maintained in H form. The column B was filled with 100 ml of a strongly basic anion exchange resin ~Diaion PA316, a tradename for a~product of Mitsubishi Chemical Industries, Ltd.), and the resin was maintained in carbonate salt form. The two columns were connected in series in the - 21 - ~ ~Z37~0 order A-B. The aqueous crude acrylamide solution was passed through the columns ~t room temperature and an SV
of 2 (200 ml/hr), and f~actions formed during 3 to 7 hours ~l-a), 12 to 16 hours (l-b) and 26 to 30 hours ~l-c) after the starting of passing the solution were collected and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
~ 2) One hundred milliliters of a strongly acidic cation exchange resin (Amberlite IR-120B) was filled in the column A and maintained in H form. One hundred milliliters of a weakly basic anion exchange resin (Lewatit MP-62, a tradename for a product of Bayer AG) was filled in the column B and maintained in free form. The two columns were connected in series in the order A-B. The above aqueous solution of crude acrylamide was aerated by blowing air into it at room temperature, and then the acrylamide solution was passed through the columns A and B. Fractions formed during 3 to 7 hours ~2-a), 21 to 25 hours (2-b) and 31 to 35 hours ~2-c) after the starting of passing the .
solution were collected and used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(3) The column C was fil~ed with 100 ml of -activated carbon (Filtrasoap F~00, a tradename for a product of Calgon, Inc.), and fully washed with water. The columns A and B were filled with the same ion exchange resins as in (2) above. The three columns A, B and C were connected 37~13 in series in the order A-B-C. The aforesaid aqueous solution of acrylamide was passed through the columns A, B, and C
at room temperature and an SV of 2 (200 ml/hr), and fractions formed during 4 to 8 hours (3-a), 15 to 19 hours (3-b) and 24 to 28 hours (3-c~ after the starting of passing the solution were collected and used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(4) An aqueous solution of acrylamide obtained by the same treatment as in (2) above was heated to 40C, and an aqueous solution of sodium hydroxide was added while blowing air into it to adjust the pH of the solution to 12.8.
Subsequently, the solution was allowed to stand at 40C
while blowing air therein for 10 minutes (4-a). Then, dilute sulfuric acid was added to adjust the pH of the solution to 7Ø The resulting acrylamide solution was used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(5) One hundred milliliters of a weakly basic .
anion exchange resin having secondary amino groups ~Diaion WA-20, a tradename for a product of Mitsubishi Chemical Industries, Ltd.) was charged in column C and the anion exchange resin was formed in free form. An aqueous solution of acrylamide obtained by the same treatment as in (2) was passed through the column C at room temperature and an S~
of 2 (200 ml/hour). Fractions formed during 1 to 5 hours (5-a), 11 to 15 hours (5-b) and 26 to 30 hours (5-c) after ~223~
the starting of passing the solution were collected and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
(6) Five hundred parts by weight of an aqueous solution of acrylamide obtained by the same treatment as in (2) above was washed with 100 parts of chloroform (6-a) or 100 parts of carbon tetrachloride (6-b), and then offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
(7) One hundred milliliters of a strongly acidic cation exchange resin, Amberlite IR-120B, maintained in H form, and 100 ml of a strongly basic anion exchange resin Diaion PA316 maintained in a carbonate salt form were well mixed, and the mixture was equally divided and filled in the columns A and B. The columns were connected in series in the order A-B. The aforesaid aqueous solution of crude acrylamide was passed through the columns A and B at room temperature and an SV of 2 (200 ml/hr). Fractions formed during 3 to 7 hours (7-a), 12 to 16 hours (7-b) and 26 to 30 hours (7-c) after the starting of passing the solution were collected, and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
24 ~Z;~3~
Process for producing polymers and method for testing water-solubility:
By the method described in Referential Example 1, a polymer was prepared and the water-solubility of the resulting polymer was tested.
Method for analysis of N-acryloyl acrylamide:
The acrylamide prepared in Referential Example 1 which contained a known amount of N-acryloyl acrylamide was extracted with chloroform containing a predetermined amount of dimethyl phthalate used as an internal standard. The chloroform layer was separated and concentrated and a calibration curve of N-acryloyl acrylamide was made using gas chromatography. Using the calibration curve, the content of N-acryloyl acrylamide in the above aqueous solution of purified acrylamide was determined.
Table 3 summarizes the relation between the content of N-acryloyl acrylamide in a polymer-and the water solubility of the polymer.
- 2 5 - ~ 2~7~
, ~ O O C--,` .~ X__ Y o. O O O ~ X ~ ~ .
~ _ ~ _ _ . _. _ _ _ _ _ ._ ~ ~ O O O ~ X X X
~ _ __ .. ~ , O O O O X ~ X
I . _ _ ._ _ __ . I
l U~ O O Cj O X X
. .. . _. ... . _ I _ _ _ . . . _. _ _ ~ o O O CJ O ~ X
___ -. 1 -- _ l o O O C) O X X
. _ . _ _ ,~ __ . .__ __ ~--~ ~ O O O O X X X
. -----1-- I _ __ _ ~ ~ O O O O X X X
_ _ __~_ i ~ -- --- --- --.Q I~ O O O O O X ~C
. __ _ _. _ __ I____ ~ ~ O O O O O P~ PC
~ ... . ---------- ~ 1--------~ ------------------------------- ------a) l ~ O O O O G a x ~ _ _ __ . . I_ _ _ E~ l ~ O O O O O a ~c _ __._.___.... ____ _ __ _ _ . _ Ln o O O O O O O a _ __ _ _ .n ~ O O O C ) O O a _._ __ ~ _ ~1 ~o _ O O O_ O O O O
Uo, O O O O O O` O
_ I _ l Uo) O O O O O O O
_ ~ 1 ---~ ' _ _ / ~ ~ ~ V ~ ~o ~ o~
. . ~ ~: ~ ~ ~ ~ ~1 0 O O
a~ I ~ ~ ~ ~ ~ ~ ~l ~ ~ ~ '~
.,1 ~ ~ ~ ~ ~ ~ JJ ~ ~ ~ O ~
4~ ~ ~ t~ O ~J ~ .~ ~ ~J o . Q~ Ql -'S~ aJ ~ ~ ~ O ,1 0 .~ ~ ~ O
~ ~ ~ ~d ~ ~ ~ ~ ..
P~ 5~ ~ ~ c~ 3 3 c) ~ , ~ ~ ~ G ~ ~ ~ ~ ~ ~ ~ ,~ ~ ~ ~ ~1 .C ~ 1 ~4 ~ ~ ~ ~ ~0 ~ ~ S~ ~D ~ ~ O ~ O ~ O
~ ~ Z -' ~ ~1 E ~rl ~1 ~1 a) rl a 40~ ¢ 40 ~ ~ ~ ~ h ~ ~ ~ ~ 3 ,~ ~ a ,_ ~ â ~1 a o ~ d ~ CJ' JJ
~ ~ ~ P' ~o o~ ~ rl ~ O ~ r~ ~ O ~rl a E~ ~ ~ ~ a~ c~ a c~ ~1 ~ ~ ." ~ ~ a o ~ g ~ ~ 3 ~o ~ v ~ vv ~ g~ ~ ~ ~ ~ vv ~v O ~ ~ ~rl o ~rl ~ d E ~`1 ~d u ,1 "
__. __ . 1.. _ C ~ ~ 1 ¢ __ _C~_ ~ ~1 - 26 - ~2~3~
Referential Example 3 An attempt was made to produce nonionic, anionic and cationic polymers using an aqueous solution of acrylamide which was treated in the same way as in Example 1, (4) except that the time during which the solution was allowed to stand while blowing air at 40C was changed to 1 hour (4-b) and 4 hours (4-c), respectively. But the rate of the polymerization was so slow that the polymerization was not completed.
Example 2 The same glass columns A, B and C as in Bxample 1 were pTovided. Column A was filled with 100 ml of a strongly acidic cation exchange resin, Amberlite IR-120B, in an H
-form; column B, with 100 ml of a s~rongly basic anion exchange resin, Diaion PA316, in an OH form, and column C, with 100 ml of a weakly acidic cation exchange resin (~ewatic CNP-80, a tradename for a product of Bayer AG) in an H form. The three columns were connected in series in the order A-B-C. The same aqueous solution of crude acrylamide as used in Example 1 was passed through the columns A, B and C at 18C and an SV of 2 (200 ml/hr).
Fractions formed during 3 to 7 hours (8-a), 21 to 25 hours (8-b) and 41 to 45 hours (8-c) after starting the passing of the solution were collected and analyzed for their content of N-acryloyl acrylamide. The content of ~-acryloyl acryl-amide was less than 0.5 ppm in all of these fractions.
- 27 ~237~
Seven types of polymers were produced from these fractions in the same way as in Referential Example 1 and were tested for water solubility. All of these polymers were found to contain less than 0.2% of a water-insoluble portion.
Example 3 The same glass columns A, B and C as used in Example 1 and a glass column D having an inside diameter of 23 mm and a length of 2 m were provided. The columns A and B were each filled with 100 ml of a strongly acidic cation exchange resin IR-120 B in an H form, and the column C was filled with 100 ml o-f a weakly basic anion exchange resin, Lewatit MP-62, in a -free form. The column D was packed with strainless steel Raschig- rings. The four columns were connected in series in the order A-D-B-C.
The same aqueous solution of crude acrylamide as used in Example 1 was passed through the columns A, D, B and C at 20C and a~l SV of 200 ml/hr-. A small amount of sodium hydroxide was continuously introduced from the inlet of column D to maintain the aqueous acrylamide solution at the inlet of column D at a pH of 12.5 to 12.8. Fractions formed during 8 to 12 hours (9-a), 28 to 32 hours (9-b) and 48 to 52 hours (9-c) after the starting of the passing of the solution were collected and analyzed for their content of N-acryloyl acrylamide. In all of these frac-tions, the content of N-acryloyl acrylamide was less than 0.5 ppm.
- 28 ~ 370~
Seven types of polymers were produced from the fractions in the same way as in Referential Example 1, and tested for water solubility. All of these polymers were found to contain less than 0.2~ of a water-insoluble portion.
These copper-containing catalysts may contain metals other than copper, such as chromiwn or molybdenum, which are normally used, as well as usually employed carriers.
The reaction between acrylonitrile and water in the presence of the aforesaid copper-containing catalyst is usually carried out in the liquid phase by using water in an almost arbitrary amount, preferably at least 4 moles, based on acrylonitrile at a temperature o:E 50 to 150C, preferably 80 to 140C, under atmospheric pressure or an elevated pressure which does not cause boiling of water and acrylonitrile, for example up to about 10 kg/cm in a suspended or fixed catalyst bed in accordance with a continuous or batchwise reaction mode. The reaction is carried out while avoiding contact of the reactants and the copper-containing catalyst with oxygen or an oxygen-containing gas.
:~Z~23~
The reaction is per-formed at a pH in the range of from 4 to 10, more generally from 6 to 9. If the pH
is below 4, the rate of the reaction is slow~ and if the pH is above 10, side-reactions such as hydrolysis of the resulting acrylamide or the formation of nitrilo compounds take place noticeably and the yield of the desired product decreases. Hence, pH values outside the specified range are undesirable.
The resul-ting aqueous solution of crude acrylamide is then usually subjected to a distillation operation in order to remove unreacted acrylonitrile from the solution or concentrate the solution so as to obtain an aqueous acrylamide solution having a concentration of, for example, about 30 to 50% by weight. The aqueous solution of crude acrylamide, optionally concentrated as above, is then tTeated on an ion-exchange resin in order to remove impurities normally present, such as copper ions, or acrylic acid which is the hydrolysis product.
In the process of this invention, the amount of N-acryloyl acrylamide contained in the aqueous solution of acrylamide can always be controlled with good accuracy depending upon the desired acrylamide polymer to be produced.
Methods avai]able for removing N-acryloyl acrylamide from the aqueous solution of acrylamide include, for example, physical adsorption by activated caTbon, activated clay, etc.; reactive adsorption by a compound containing primary and secondary amines such as polyamines, a weakly basic ~L~2~7~
anion exchange resin containing primary and secondary amino groups, or a compound having a peptide linkage such as a protein (e.g., silk) or its disintegration product;
decomposition by a chemical reaction such as alkaline hydrolysis, or oxidation; extraction with a solvent such as chloroform or carbon tetrachloride; and sublimation which is normally employed in the art. Alternatively, it is possible to add a compound capable of forming an adduct with N-acryloyl acrylamide, thereby rendering the latter non-deleterious.
These methods can be used either singly or in a combination of two or more. Although some of these methods are known as a method for purifying an aqueous solution of acrylamide obtained by the catalytic hydrating method, the content of N-acryloyl acrylamide cannot be reduced, under the purifying conditions in the prior art, to below the - - permissible amount specified in the process of this invention.
-Since the amount of N-acryloyl acrylamide contained in the aqueous solution of crude acrylamide differs depending upon the reaction conditions, the purifying conditions should always be analy~ed, quantified and controlled in order to adjust the content of N-acryloyl acrylamide in the purified acrylamide to below ~he permissible value specified in the process of the invention.
The present inventors have found that the amount of N-acryloyl acrylamide in the aqueous solution of crude acrylamide increases as the concentration of acrylonitrile - 13 ~ 37~
in the reaction system and the reaction temperature increase, and the use of such conditions can easily lead to the formation of an aqueous solution of acrylamide unsuitable for use as a raw material for cationic polymeric flocculants.
The amount of N-acryloyl acrylamide in the acrylamide which is permissible in the production of cationic polymeric flocculants is not more than 10 ppm, preferably not more than 5 ppm, more preferably not more than 1 ppm. Accord-ingly, in the present application, the "acrylamide sub-stantially free from N-acryloyl acry~amide", denotes acrylamide containing not more than 10 ppm of N-acryloyl acrylamide.
The aqueous acrylamide solution so purified is then polymerized in a customary manner to give acrylamide-type cationic polymeric flocculants.
In the production of acrylamide polymers in accordance with this invention, various known conventional polymerization initiators can be used. Examples inciude azo compounds such as azobisdimethylvaleronitrile, azobis (sodium cyanovalerate), azobisisobutyronitrile and azobis-aminopropane hydrochloride; organic peroxides such as benzoyl peroxide, lauroyl peroxide and tertiary butyl -hydroperoxide, and inorganic peroxides such as potassium persulfate, sodium perbromate, ammonium persulfate and hydrogen peroxide~
~ xamples of suitable reducing agents are inorganic compounds such as ferrous sulfate, ferrous chloride, sodium ~2~3~
bisulfite, sodium metasulfite, sodium thiosulfate and nitrite salts, and organic compounds such as dimethyl-aniline, 3-dimethylaminopropionitrile and phenylhydrazine.
For production of a high-molecular-weight polymer by the process of this invention, a mixture of acrylamide and a cationic monomer copolymerizable with acrylamide is used in a mole ratio of from 90:10 to 50:50. Examples o~ the cationic comonomer are amino alcohol esters of methacrylic or acrylic acid ~such as dimethyl-aminoethyl methacrylate or diethylaminoethyl acrylate) and the salts or quaternary ammonium salts thereof; and N-aminoalkyl substitution products of methacrylamide or acrylamide (such as N-methacryloyl-N', N'-dimethyl-1,3-diaminopropane or N-acryloyl-N',N'-dimethyl-l,l-dimethyl-l, lS 3-diaminopropane) and the salts or quaternary ammonium salts thereof.
The following Referential Examples and Examples illustrate the present invention further.
Referential Example 1 A 70~ aqueous solution of acrylamide was prepared under heating from commercially available acrylamide crystals and distilled water. The solution was cooled at 5C to precipitate acrylamide crystals. This recrylstal-?5 lization procedure was repeated to obtain purified acrylamide.
To the purified acrylamide was added N-acryloyl acrylamide in an amount of 1, 3, 6, 10, 20, 30, and 50 ppm respectively based on the weight of the acrylamide. In accordance with l~
~iL2~37a:~
the polymerization recipes shown below, high-molecular-weight nonionic, anionic and cationic polymeric flocculants were respectively produced, and tested for water solubility.
The results are shown in Table 1.
Non-ionic polymeric flocculants:
(A) Acrylamide was dissolved in distilled water to a concentration of 20% by weight. Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present. At 30C, ~.8 mg of ammonium persulfate and 2.2 mg of sodiunl bisulfite were added thereto, and the reaction was carried out while allowing the temperature to rise by the heat of polymerization and the polymerization to proceed by the effect of the tem-perature rise. After arise in temperature was no longer noted, the reaction mixture was allowed to stand further for 1 hour to terminate the polymerization. Thus~ an agar-like mass consisting of an acrylamide polymer and water was obtained.
The agar-like mass was then coarsely crushed by a mincer, dried in hot air at 1~0C for 1 hour, and pulver-ized to form a powdery nonionic polymeric flocculant which was found to have a molecular weight, calculated from its intrinsic viscosity, of about 7 million.
(~) A nonionic polymeric flocculant having a molecular weight of about 10 million was prepared by operating in the same way as in (A) above except that the ~2~3'7~
amounts of ammonium persulfate and sodium bisulfite were changed to 6.0 mg and 1.5 mg, respectively.
(C) A nonionic polymeric flocculant having a molecular weight of about 13 million was prepared by operating in the same way as in (A) above except that the amounts of ammonium persulfate and sodium bisulfite were changed to 3.5 mg and l.0 mg, respectively.
Anionic polymeric flocculant:
An aqueous solution of a mixkure of acrylamide and sodium acrylate in a mole ratio of 80:20 in a monomer concentration of 20% by weight was prepared by using acrylamide, sodium acrylate and distilled water. Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present.
At 30C, 60 mg of sodium 4,4'-azobis-4-cyanovalerate, 4.0 mg of ammonium persulfate and 2 mg of sodium bisulfite were added. The mixture was then worked up in the same way as in the preparation of the nonionic polymeric flocculants to give an anionic polymeric flocculant having a molecular weight of about 12 million.
Cationic polymeric flocculants:
(A) An aqueous solution of a mixture of acrylamide and N-methacryloyl-N',N',N'-trimethyl-1,3-diaminopropane chloride in a mole ratio of 90:10 in distilled water in a monomer concentration of 20% by weight was prepared. The pH of the solution was adju~ted to 5 0. Then, 500 g of the ~L~23~
aqueous solution was taken, and nitrogen gas was blown therein to remove any dissolved oxygen present. At 30C, 100 mg of sodium 4,4'-azobis-4-cyanovalerate, 7.2 mg o-f ammonium persulfate and 3.6 mg of sodium bisulfite were added. The mixture was worked up in the same way as in the preparation of the nonionic polymeric flocculants to give a cationic polymeric flocculant A containing 0.11 cation equivalent/100 g.
(B) A solution of a mixture of acrylamide and methacryloyloxyethyl trimethyl ammonium chloride in a mole ratio o-f 50:50 or 85:15 in distilled water in a monomer concentration of 20% by weight was prepared. The pH of the solution was àdjusted to 5Ø Then, 500 g of the aqueous solution was taken, and nitrogen gas was blown into it to remove any dissolved oxygen present. At 30C, 100 mg of sodium 4,4'-azobis-4-cyanovalerate, 7.2 mg o-f ammonium persulfate and 3.6 mg of sodium bisulfate were added. The mixture was worked up in the same way as in the preparation of the nonionic polymeric flocculants. Thus, cationic polymeric flocculants B ~ B' containing 0.36 cation equivalent/100 g and 0.16 cation equivalent/lOOg, respectively, were obtained.
Water solubility test:
One gram of the powdery polymer sample was added to 1,000 g of distilled water, and the mixture was stirred for 1 hour by a magnetic stirrer. The solution was then ~23~
filtered through a 200-mesh wire screen to separate and collect a water-insoluble portion from the solution. The water-insoluble portion was dried at 120C, and its amount was measured.
Table 1 Amount of N-acryloyl acrylamide _ added ~ppm based on acrylamide) l l 1 1 3 l6 10 20 l30 50 Type of acrylamide polymeric ~ I ~
flocculant \ I l _ _ Nonionic polymeric flocculant l l l l l l~molecular weight about IO~O IO O O i O O
,7 million) , I I ~ !
Ditto (molecular weight about O O O ~ O O O _ .itto (molecular weight about ~O ¦O ¦ O ¦
Anionic polymeric flocculant r i ~molecular weight about O O O O O I O O
12 million) Cationic polymeric flocculant A _ (cation equivalent: O O! O Q X I X X
0.11 eq./100 g) ~ 1, , `
iDitto B ~cation equivalent: i l _ 0.36 eq./100 g) ,O I O, a I x I x x I x ~Ditto B' ~cation equivalent: io I a I x x x x I x 1 0.16 eq./100 g) ~
.
In the above table, the evaluation of water solubility is as follows:
o : the amount of the water-insoluble portion is less than 0.2%
a the amount of the water-insoluble portion is 0.2-2.0%.
X : the amount of the water-insoluble portion is more than 2.0%.
- 1 9 ~ 37 Referential ~xample _ Methylenebisacrylamide was added in a weight of 1, 1.5, 3, 6, and 10 ppm respectively based on acrylamide to pure acrylamide obtained in the same way as in Referential Example 1. Using the resulting polymeric flocculant, the same water-solubility test as in Referential Example 1 was conducted. The results are shown in Table 2.
Table 2 Amount of methylenebis acrylamide added (ppm based on acrylamide) ~ 0.6 1.5 3 6 10 Type of acrylamide polymeric \
flocculant \ !
Nonionic polymeric flocculant (molecular weight aboutO O ~ IX X
7 million) . _ _ j .
Ditto ~molecular weight about O O I a x I x 10 million) l Ditto ~molecular weight about O I ~ X IX X
13 million) _ Anionic polymeric flocculant . I
~molecular weight about . O O X 'IX X .
12 million) .
Cationic polymeric flocculant A l ~cation equivalent: O O X X X
0.11 eq./100 g) l . Ditto B ~cation equivalent: ¦I o l~ X i X
¦ 0.36 eq./100 g) ¦ O l ~ I
0.16 eq./100 g) ¦ O O ~ X ¦ X
-The evaluation of the water-solubility was done in accordance with the same standards as given in the footnote to Table 1.
- 20 - ~2 Example 1 Production of an aqueous solution of crude acrylamide:
A reactor was charged with 70 parts by weight of Raney copper and 1,000 parts of an aqueous solution of acrylonitrile in a concentration of 25% by weight, and the reaction was carried out at 135C for 4 hours at a pH
of 7 to 9. The catalyst was removed from the resulting reaction solution by filtration, and the residue was passed through a vacuum-distillation device to remove the unreacted acrylonitrile and a part of water to give a 50% by weight aqueous solution of acrylamide. The crude aqueous acrylamide solution contained less than 300 ppm of acrylo-nitrile and less than 80 ppm of copper.
Purification of the aqueous acrylamide solution:
Glass columns A, B and C each having an inside diameter of 20 mm and a lèn~th of 50 cm were provided, and the aqueous acrylamide solution was purified by ~he following method.
~ 1~ One hundred milliliters of a strongly acidic cation exchange resin (Amberlite IR-120B, a tradename for a product of Rohm ~ Haas Co.) was filled in the column A
and maintained in H form. The column B was filled with 100 ml of a strongly basic anion exchange resin ~Diaion PA316, a tradename for a~product of Mitsubishi Chemical Industries, Ltd.), and the resin was maintained in carbonate salt form. The two columns were connected in series in the - 21 - ~ ~Z37~0 order A-B. The aqueous crude acrylamide solution was passed through the columns ~t room temperature and an SV
of 2 (200 ml/hr), and f~actions formed during 3 to 7 hours ~l-a), 12 to 16 hours (l-b) and 26 to 30 hours ~l-c) after the starting of passing the solution were collected and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
~ 2) One hundred milliliters of a strongly acidic cation exchange resin (Amberlite IR-120B) was filled in the column A and maintained in H form. One hundred milliliters of a weakly basic anion exchange resin (Lewatit MP-62, a tradename for a product of Bayer AG) was filled in the column B and maintained in free form. The two columns were connected in series in the order A-B. The above aqueous solution of crude acrylamide was aerated by blowing air into it at room temperature, and then the acrylamide solution was passed through the columns A and B. Fractions formed during 3 to 7 hours ~2-a), 21 to 25 hours (2-b) and 31 to 35 hours ~2-c) after the starting of passing the .
solution were collected and used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(3) The column C was fil~ed with 100 ml of -activated carbon (Filtrasoap F~00, a tradename for a product of Calgon, Inc.), and fully washed with water. The columns A and B were filled with the same ion exchange resins as in (2) above. The three columns A, B and C were connected 37~13 in series in the order A-B-C. The aforesaid aqueous solution of acrylamide was passed through the columns A, B, and C
at room temperature and an SV of 2 (200 ml/hr), and fractions formed during 4 to 8 hours (3-a), 15 to 19 hours (3-b) and 24 to 28 hours (3-c~ after the starting of passing the solution were collected and used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(4) An aqueous solution of acrylamide obtained by the same treatment as in (2) above was heated to 40C, and an aqueous solution of sodium hydroxide was added while blowing air into it to adjust the pH of the solution to 12.8.
Subsequently, the solution was allowed to stand at 40C
while blowing air therein for 10 minutes (4-a). Then, dilute sulfuric acid was added to adjust the pH of the solution to 7Ø The resulting acrylamide solution was used for the production of polymers and the analysis of the N-acryloyl acrylamide content.
(5) One hundred milliliters of a weakly basic .
anion exchange resin having secondary amino groups ~Diaion WA-20, a tradename for a product of Mitsubishi Chemical Industries, Ltd.) was charged in column C and the anion exchange resin was formed in free form. An aqueous solution of acrylamide obtained by the same treatment as in (2) was passed through the column C at room temperature and an S~
of 2 (200 ml/hour). Fractions formed during 1 to 5 hours (5-a), 11 to 15 hours (5-b) and 26 to 30 hours (5-c) after ~223~
the starting of passing the solution were collected and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
(6) Five hundred parts by weight of an aqueous solution of acrylamide obtained by the same treatment as in (2) above was washed with 100 parts of chloroform (6-a) or 100 parts of carbon tetrachloride (6-b), and then offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
(7) One hundred milliliters of a strongly acidic cation exchange resin, Amberlite IR-120B, maintained in H form, and 100 ml of a strongly basic anion exchange resin Diaion PA316 maintained in a carbonate salt form were well mixed, and the mixture was equally divided and filled in the columns A and B. The columns were connected in series in the order A-B. The aforesaid aqueous solution of crude acrylamide was passed through the columns A and B at room temperature and an SV of 2 (200 ml/hr). Fractions formed during 3 to 7 hours (7-a), 12 to 16 hours (7-b) and 26 to 30 hours (7-c) after the starting of passing the solution were collected, and offered for use in the production of polymers and the analysis of the N-acryloyl acrylamide content.
24 ~Z;~3~
Process for producing polymers and method for testing water-solubility:
By the method described in Referential Example 1, a polymer was prepared and the water-solubility of the resulting polymer was tested.
Method for analysis of N-acryloyl acrylamide:
The acrylamide prepared in Referential Example 1 which contained a known amount of N-acryloyl acrylamide was extracted with chloroform containing a predetermined amount of dimethyl phthalate used as an internal standard. The chloroform layer was separated and concentrated and a calibration curve of N-acryloyl acrylamide was made using gas chromatography. Using the calibration curve, the content of N-acryloyl acrylamide in the above aqueous solution of purified acrylamide was determined.
Table 3 summarizes the relation between the content of N-acryloyl acrylamide in a polymer-and the water solubility of the polymer.
- 2 5 - ~ 2~7~
, ~ O O C--,` .~ X__ Y o. O O O ~ X ~ ~ .
~ _ ~ _ _ . _. _ _ _ _ _ ._ ~ ~ O O O ~ X X X
~ _ __ .. ~ , O O O O X ~ X
I . _ _ ._ _ __ . I
l U~ O O Cj O X X
. .. . _. ... . _ I _ _ _ . . . _. _ _ ~ o O O CJ O ~ X
___ -. 1 -- _ l o O O C) O X X
. _ . _ _ ,~ __ . .__ __ ~--~ ~ O O O O X X X
. -----1-- I _ __ _ ~ ~ O O O O X X X
_ _ __~_ i ~ -- --- --- --.Q I~ O O O O O X ~C
. __ _ _. _ __ I____ ~ ~ O O O O O P~ PC
~ ... . ---------- ~ 1--------~ ------------------------------- ------a) l ~ O O O O G a x ~ _ _ __ . . I_ _ _ E~ l ~ O O O O O a ~c _ __._.___.... ____ _ __ _ _ . _ Ln o O O O O O O a _ __ _ _ .n ~ O O O C ) O O a _._ __ ~ _ ~1 ~o _ O O O_ O O O O
Uo, O O O O O O` O
_ I _ l Uo) O O O O O O O
_ ~ 1 ---~ ' _ _ / ~ ~ ~ V ~ ~o ~ o~
. . ~ ~: ~ ~ ~ ~ ~1 0 O O
a~ I ~ ~ ~ ~ ~ ~ ~l ~ ~ ~ '~
.,1 ~ ~ ~ ~ ~ ~ JJ ~ ~ ~ O ~
4~ ~ ~ t~ O ~J ~ .~ ~ ~J o . Q~ Ql -'S~ aJ ~ ~ ~ O ,1 0 .~ ~ ~ O
~ ~ ~ ~d ~ ~ ~ ~ ..
P~ 5~ ~ ~ c~ 3 3 c) ~ , ~ ~ ~ G ~ ~ ~ ~ ~ ~ ~ ,~ ~ ~ ~ ~1 .C ~ 1 ~4 ~ ~ ~ ~ ~0 ~ ~ S~ ~D ~ ~ O ~ O ~ O
~ ~ Z -' ~ ~1 E ~rl ~1 ~1 a) rl a 40~ ¢ 40 ~ ~ ~ ~ h ~ ~ ~ ~ 3 ,~ ~ a ,_ ~ â ~1 a o ~ d ~ CJ' JJ
~ ~ ~ P' ~o o~ ~ rl ~ O ~ r~ ~ O ~rl a E~ ~ ~ ~ a~ c~ a c~ ~1 ~ ~ ." ~ ~ a o ~ g ~ ~ 3 ~o ~ v ~ vv ~ g~ ~ ~ ~ ~ vv ~v O ~ ~ ~rl o ~rl ~ d E ~`1 ~d u ,1 "
__. __ . 1.. _ C ~ ~ 1 ¢ __ _C~_ ~ ~1 - 26 - ~2~3~
Referential Example 3 An attempt was made to produce nonionic, anionic and cationic polymers using an aqueous solution of acrylamide which was treated in the same way as in Example 1, (4) except that the time during which the solution was allowed to stand while blowing air at 40C was changed to 1 hour (4-b) and 4 hours (4-c), respectively. But the rate of the polymerization was so slow that the polymerization was not completed.
Example 2 The same glass columns A, B and C as in Bxample 1 were pTovided. Column A was filled with 100 ml of a strongly acidic cation exchange resin, Amberlite IR-120B, in an H
-form; column B, with 100 ml of a s~rongly basic anion exchange resin, Diaion PA316, in an OH form, and column C, with 100 ml of a weakly acidic cation exchange resin (~ewatic CNP-80, a tradename for a product of Bayer AG) in an H form. The three columns were connected in series in the order A-B-C. The same aqueous solution of crude acrylamide as used in Example 1 was passed through the columns A, B and C at 18C and an SV of 2 (200 ml/hr).
Fractions formed during 3 to 7 hours (8-a), 21 to 25 hours (8-b) and 41 to 45 hours (8-c) after starting the passing of the solution were collected and analyzed for their content of N-acryloyl acrylamide. The content of ~-acryloyl acryl-amide was less than 0.5 ppm in all of these fractions.
- 27 ~237~
Seven types of polymers were produced from these fractions in the same way as in Referential Example 1 and were tested for water solubility. All of these polymers were found to contain less than 0.2% of a water-insoluble portion.
Example 3 The same glass columns A, B and C as used in Example 1 and a glass column D having an inside diameter of 23 mm and a length of 2 m were provided. The columns A and B were each filled with 100 ml of a strongly acidic cation exchange resin IR-120 B in an H form, and the column C was filled with 100 ml o-f a weakly basic anion exchange resin, Lewatit MP-62, in a -free form. The column D was packed with strainless steel Raschig- rings. The four columns were connected in series in the order A-D-B-C.
The same aqueous solution of crude acrylamide as used in Example 1 was passed through the columns A, D, B and C at 20C and a~l SV of 200 ml/hr-. A small amount of sodium hydroxide was continuously introduced from the inlet of column D to maintain the aqueous acrylamide solution at the inlet of column D at a pH of 12.5 to 12.8. Fractions formed during 8 to 12 hours (9-a), 28 to 32 hours (9-b) and 48 to 52 hours (9-c) after the starting of the passing of the solution were collected and analyzed for their content of N-acryloyl acrylamide. In all of these frac-tions, the content of N-acryloyl acrylamide was less than 0.5 ppm.
- 28 ~ 370~
Seven types of polymers were produced from the fractions in the same way as in Referential Example 1, and tested for water solubility. All of these polymers were found to contain less than 0.2~ of a water-insoluble portion.
Claims (13)
1. A process for producing an acrylamide-type cationic polymeric flocculant comprising polymerizing acrylamide obtained by the catalytic hydration of acryloni-trile with water in the presence of a metallic copper catalyst at a pH of from 4 to 10, a temperature of from 50 to 150°C and a pressure of from atmospheric pressure to an elevated pressure of up to about 10 kg/cm2, charac-terized in that, a crude aqueous acrylamide solution obtained by the catalytic hydration is purified by treating with either a single or combined method selected from physical adsorption, reactive adsorption, decomposition by a chemical reaction and solvent extraction, so that the concentration of N-acryloyl acrylamide contained in the acrylamide solution is not more than 3 ppm based on the acrylamide contained therein, and then the acrylamide solution is subjected to copolymerization of acrylamide and a cationic monomer selected from the group consisting of amino alcohol esters of methacrylic or acrylic acid, N-aminoalkyl substitution products of methacrylamide or acrylamide and the salts or ammonium salts thereof in a mole ratio of from 90:10 to 50:50.
2. The process of claim 1 wherein the concentra-tion of N-acryloyl acrylamide in the acrylamide to be polymerized is not more than 1 ppm based on acrylamide.
3. The process of claim 1 wherein the reactive adsorption is carried out by using a strongly acidic cation exchange resin, a weakly basic anion exchange resin and then a weakly basic anion exchange resin having primary and/or secondary amino groups.
4. The process of claim 1 wherein the aqueous acrylamide solution is subjected to reactive adsorption and then to solvent extraction.
5. The process of claim 4 wherein the reactive adsorption is carried out by using a strongly acidic cation exchange resin and then a weakly basic anion exchange resin.
6. The process of claim 5 wherein the solvent extraction is carried out using chloroform or carbon tetrachloride.
7. The process of claim 1 wherein first the reactive adsorption is carried out by using a strongly acidic cation exchange resin and then a weakly basic anion exchange resin and then the physical adsorption is carried out.
8. The process of claim 7 wherein the physical adsorption is carried out using activated carbon.
9. The process of claim 1 wherein the aqueous acrylamide solution is treated first on a strongly acidic cation exchange resin and then on a weakly basic anion exchange resin.
10. The process of claim 1 wherein the aqueous solution of acrylamide is treated with a strongly acidic cation exchange resin and then a weakly basic anion exchange resin and then subjected to decomposition by a chemical reaction.
11. The process of claim 10 wherein the decompo-sition by a chemical reaction is carried out by using an alkali.
12. The process of claim 1 wherein the reactive adsorption is carried out by using a strongly acidic cation exchange resin, a strongly basic anion exchange resin and then a weakly acidic cation exchange resin.
13. The process of claim 1 wherein first the reactive adsorption is carried out by using a strongly acidic cation exchange resin, then the decomposition by a chemical reaction is carried out by using an alkali, and finally the reactive adsorption is carried out by using a strongly acidic cation exchange resin and then a weakly basic anion exchange resin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55121743A JPS5747309A (en) | 1980-09-04 | 1980-09-04 | Preparation of acrylamide cationic high polymeric coagulant |
| JP121743/1980 | 1980-09-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1223700A true CA1223700A (en) | 1987-06-30 |
Family
ID=14818774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384593A Expired CA1223700A (en) | 1980-09-04 | 1981-08-25 | Process for producing acrylamide-type cationic polymeric flocculant |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS5747309A (en) |
| KR (1) | KR860001550B1 (en) |
| AT (1) | AT370747B (en) |
| AU (1) | AU543111B2 (en) |
| CA (1) | CA1223700A (en) |
| DD (1) | DD202036A5 (en) |
| DE (1) | DE3135149A1 (en) |
| ES (1) | ES504916A0 (en) |
| FI (1) | FI70032C (en) |
| FR (1) | FR2489338B1 (en) |
| GB (1) | GB2083053B (en) |
| IT (1) | IT1139422B (en) |
| NL (1) | NL186165C (en) |
| RO (1) | RO83586B (en) |
| ZA (1) | ZA815194B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3801736A1 (en) * | 1988-01-21 | 1989-07-27 | Nitrokemia Ipartelepek | METHOD FOR PRODUCING ACRYLIC ACID AMID / ACRYLIC ACID COPOLYMERS OF HIGH MOLECULAR WEIGHT |
| MX18620A (en) * | 1988-12-19 | 1993-10-01 | American Cyanamid Co | HIGH PERFORMANCE POLYMERIC FLOCULANT, PROCESS FOR ITS PREPARATION, METHOD FOR THE RELEASE OF WATER FROM A DISPERSION OF SUSPENDED SOLIDS AND FLOCULATION METHOD OF A DISPERSION OF SUSPENDED SOLIDS |
| JPH03119011A (en) * | 1989-10-03 | 1991-05-21 | Mitsui Toatsu Chem Inc | Production of cationic high molecular-weight polymer |
| KR100318327B1 (en) * | 1995-12-16 | 2002-04-22 | 구광시 | Manufacturing method of emulsion type polymer coagulant |
| DE10041392A1 (en) * | 2000-08-23 | 2002-03-07 | Stockhausen Chem Fab Gmbh | Water-soluble homopolymers and copolymers with improved environmental compatibility |
| JP3996535B2 (en) * | 2003-03-20 | 2007-10-24 | Ｎｅｃ液晶テクノロジー株式会社 | Liquid crystal display |
| DE102004032766A1 (en) * | 2004-07-06 | 2006-02-09 | Röhm GmbH & Co. KG | Concentrated aqueous methacrylamide solution with the addition of methacrylic acid |
| CN116023587B (en) * | 2022-10-31 | 2024-05-07 | 中国矿业大学(北京) | Iron-based hybrid flocculant and preparation method and application thereof |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3130229A (en) * | 1961-02-06 | 1964-04-21 | Dow Chemical Co | Method for the manufacture of acrylamide |
| AU407356B2 (en) * | 1965-12-31 | 1970-10-22 | Process for the preparation of aqueous solutions of flocculating agents of the poly-acrylic amide type having high molecular weight | |
| DE2255391C3 (en) * | 1972-11-11 | 1982-05-13 | Bayer Ag, 5090 Leverkusen | Process for the production of high molecular weight cationic copolymers |
| JPS5082011A (en) * | 1973-11-22 | 1975-07-03 | ||
| JPS5083323A (en) * | 1973-11-29 | 1975-07-05 | ||
| JPS5291819A (en) * | 1976-01-28 | 1977-08-02 | Mitsui Toatsu Chem Inc | Purification of aqueous solutions of acrylamide |
| GB2059952B (en) * | 1979-09-13 | 1983-07-20 | Mitsui Toatsu Chemicals | Purifying aqueous acrylamide solutions |
-
1980
- 1980-09-04 JP JP55121743A patent/JPS5747309A/en active Granted
-
1981
- 1981-07-28 ZA ZA815194A patent/ZA815194B/en unknown
- 1981-07-28 AU AU73501/81A patent/AU543111B2/en not_active Ceased
- 1981-08-12 FI FI812485A patent/FI70032C/en not_active IP Right Cessation
- 1981-08-24 ES ES504916A patent/ES504916A0/en active Granted
- 1981-08-24 NL NLAANVRAGE8103925,A patent/NL186165C/en not_active IP Right Cessation
- 1981-08-25 CA CA000384593A patent/CA1223700A/en not_active Expired
- 1981-09-02 DD DD81232976A patent/DD202036A5/en not_active IP Right Cessation
- 1981-09-03 AT AT0381681A patent/AT370747B/en not_active IP Right Cessation
- 1981-09-03 GB GB8126731A patent/GB2083053B/en not_active Expired
- 1981-09-03 IT IT23767/81A patent/IT1139422B/en active
- 1981-09-04 FR FR8116859A patent/FR2489338B1/en not_active Expired
- 1981-09-04 RO RO105236A patent/RO83586B/en unknown
- 1981-09-04 KR KR1019810003294A patent/KR860001550B1/en not_active IP Right Cessation
- 1981-09-04 DE DE19813135149 patent/DE3135149A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| IT8123767A0 (en) | 1981-09-03 |
| FI70032C (en) | 1986-09-12 |
| DD202036A5 (en) | 1983-08-24 |
| NL186165C (en) | 1990-10-01 |
| KR860001550B1 (en) | 1986-10-04 |
| FR2489338A1 (en) | 1982-03-05 |
| JPS5747309A (en) | 1982-03-18 |
| FI70032B (en) | 1986-01-31 |
| FI812485L (en) | 1982-03-05 |
| AU7350181A (en) | 1982-09-23 |
| ZA815194B (en) | 1982-07-28 |
| IT1139422B (en) | 1986-09-24 |
| ATA381681A (en) | 1982-09-15 |
| RO83586B (en) | 1984-04-30 |
| RO83586A (en) | 1984-04-02 |
| DE3135149C2 (en) | 1991-05-08 |
| NL186165B (en) | 1990-05-01 |
| KR830007738A (en) | 1983-11-07 |
| DE3135149A1 (en) | 1982-04-08 |
| AU543111B2 (en) | 1985-04-04 |
| ES8300344A1 (en) | 1982-11-01 |
| GB2083053A (en) | 1982-03-17 |
| ES504916A0 (en) | 1982-11-01 |
| NL8103925A (en) | 1982-04-01 |
| AT370747B (en) | 1983-04-25 |
| FR2489338B1 (en) | 1987-04-30 |
| GB2083053B (en) | 1984-09-12 |
| JPH0260682B2 (en) | 1990-12-18 |
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