DE2207795A1 - Water soluble polymeric compositions and processes for their preparation - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann,

Dipl.-Ing. H. Weickmann, Dipl.-Phys. Dr. K. Fi-ncke
Dipl.-Ing. FAWeickmann, Dipl.-Chem. B. Huber

8 MUNICH 27, DEN

MÖHLSTRASSE 22, CALL NUMBER 43 3921/22

CASE: 71.06571

Jfönufaoture de Produits Chimiques PROTEX
2, Place Joffre, Paris 7th, France

"Water-soluble polymeric compositions and methods too

their manufacture "

The invention relates to new aqueous substances which can be used as flocculants, and in particular
novel terpolymer compositions effective against a wide variety of media.

Many compounds are known which are useful as flocculants or coagulants for solid materials which are in aqueous suspension. Initially, these substances were of natural origin, such as starch or aluminum sulfate. Synthetic substances such as water-soluble polymers were later available. These synthetic
Polymers can be divided into three broad classes:

- Polymers that carry negative charges on the chain in an aqueous medium: these are the anionic ones Flocculants;

- Polymers that are positive on the chain in an aqueous medium Carry charges: these are the cationic ones

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Flocculants and

- finally, materials that do not form ions in an aqueous medium: these are non-ionic flocculants.

The polymers of the first two classes are also polyelectrolytes called.

These three Pdlymerisatklassen are obtained in particular by Acrylamide homopolymerized with suitably selected monomers or copolymerized. Among the anionic flocculants used The copolymers of acrylamide and sodium acrylate or ammonium acrylate are of particular importance. It is also known that. The flocculation of solid materials is only carried out in a suitable manner if the used Polymers are linear polymers, i.e. polymers that have as few branches or bridges as possible and which have a molecular weight of at least 10.

As a result, depending on the type and concentration of the solid materials that are in suspension, the type of aqueous medium, its pH, its temperature, etc., it is often difficult to do the job. Flocculation to achieve maximum efficiency. In other words, it is difficult to obtain flakes of sufficient density and dimensions at the same time to achieve a fast decanting speed and a clear supernatant liquid.

The object of the present invention is to

- to provide new water-soluble terpolymer compositions, which are useful as flocculants in a wide variety of media and which fall into the polyanionic category Funds are to be classified;

- new flocculants and, in particular, means that allow increase the speed of the stain deaching by increasing it to increase the size and density of these flakes; and

- provide new flocculants, which in particular

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to serve, the clarity of the supernatant liquid by decantation of the materials in suspension z \ i improve.

According to the present invention, new water-soluble polymeric substances have become found that can be used as flocculants, and in particular new water-soluble terpolymer substances with high molecular weight which is beneficial as a flocculant can be used for solid materials that are in suspension in aqueous medium.

According to the invention it was surprisingly found that the polymerization of itaconic acid or one of the soluble salts of this acid with

- On the one hand, a water-soluble monomeric oc, ß-unsaturated Monocarboxamide and

- On the other hand, a water-soluble unsaturated one, an oc, ß-dcppel bond containing monomers leads to new terpolymer compositions which have excellent solubility in Have water and correspond to the properties given above.

It is based on the simultaneous copolymerization of these three products in the proportions given below according to the methods given below, the essential feature of the present invention.

The three monomers are simultaneously in a single stage with the formation of a terpolymer, its type and its repeating units depends solely on the amount of the individual monomers used, copolymerized. It is difficult to determine the exact structure of the terpolymer, but it is believed that a statistical Structure according to the relative proportions of the various Receives monomers.

It is possible to use the various free radicals polymerization processes that allow materials with

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To obtain higher molecular weight, apply. The one used to manufacture The methods particularly suitable for the terpolymers according to the invention are, however, those given below:

1) The first essential monomer according to the invention is itaconic acid or its water-soluble sodium or ammonium salts. The formula of itaconic acid is the following:

CH ₂ = C ^ *

C. ^ s / -ITT rr \ ti

UrIp - OUp η

The required amounts of itaconic acid or its water-soluble salts for the preparation of the terpolymers according to the invention extend from 0.2 to 15% based on the total amount of monomers. A preferred composition of the terpolymer comprises 2 to 10% itaconic acid or its water-soluble salts, based on the total amount of the monomers.

2) The second monomer according to the invention is the α, ß-unsaturated one Monocarboxamide from Foriael

R t

CH ₂ «C - CO NH ₂
wherein R is a hydrogen atom or an alkyl group.

A monomer preferred according to the invention is acrylamide:

CH ₂ = CH - CO NH ₂ .

The amount of acrylamide can vary within a wide range from 5 to 95%, depending on whether you want to produce a strong, medium or weakly anionic terpolymer.

3) The third monomer according to the invention is a water-soluble monomer with α, β-ethylenic unsaturation, that with those described above first two monomers is mixed polynierisierbsr and contains polar groups. Examples of such monomers are Acrylic acid and its water-soluble »salts, methacrylic acid and their water-soluble salts, unsaturated polycarboxylic acids and

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their water-soluble salts, such as maleic acid, carboxymethyl acrylate imd their salts, unsaturated hydroxyl-containing and water soluble monomers, / allyl alcohol, ethylene glycol acrylate and vinyl pyrrolidone. A preferred monomer is acrylic acid or its water-soluble sodium and ammonium salts. the Amounts with which the third monomer is used can also be used within wide ranges, i.e. from 5 "to 95% based on the total amount of monomers, vary.

The terpolymers according to the invention can be used with all known polymerisation processes which allow To produce high molecular weight polymers. A particularly preferred method for making the inventive Terpolymers, however, is the "inverse emulsion" process, in which a "water-in-oil" emulsion of an aqueous concentrated one is used Solution of the above monomers in an organic medium that is neither a solvent for the monomers is still for the polymer obtained, with the help of a surface-active Manufactures by means of. The aqueous solution of the monomers is then finely dispersed in the organic medium Droplets distributed, whereupon the polymerization caused by radicals is carried out in the droplets. The procedure persists in that one carries out a large number of polymerizations in aqueous solution in the presence of an organic liquid, as a heat exchanger and at the same time as a fluidizing agent serves, while the direct polymerization of the aqueous solution of the monomers without the presence of an organic Medium would lead to a gel due to the high molecular weight obtained. Another advantage of this procedure consists in that one the terpolymers after the end of the polymerization can be obtained directly in the form of granules or in the form of a powder if the water of polymerization is passed through Distillation removed.

The most important point of this polymerization process is there in that one terpolymer microgels in the course of the polymerization obtained, which are dispersed in the organic medium and which do not agglomerate and which also do not adhere to the

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Glue the walls of the reaction vessel or the stirring device. The stirring causes the aqueous phase to remain dispersed in the organic phase. However, it is necessary to additionally use a surface-active agent in order to prevent the microgels from adhering to the walls of the reaction vessel and to the stirring devices. Many surfactants which allow a "water-in-oil" emulsion to be produced can be used, but it has been found that the best results according to the invention are obtained with sulfonated derivatives of petroleum fractions and their sodium or calcium salses of the general formula Cx Hy SO ^ Na or (0 _χ HySO ^) Ca, where χ is an integer from 20 to *> 0 and y is a <number from JO to 45. The molecular weights of these surface-active agents are between 300 and 1000.

As other surface active agents used according to the invention the sorbitan esters, such as sorbitan tearate, and the oxyethylene derivatives of fatty amines can be mentioned. The amounts of the surface-active agents used according to the invention range from 0.1 to 2%, based on the organic Medium.

The aqueous solutions of the monomers according to the invention contain 30 to 65% by weight of monomers and 35 to 70 % deionized water. * These aqueous solutions are prepared by stirring and using a surfactant in an amount of 20 to 30 % aqueous solution per 80 to 70% % organic medium dispersed in the organic medium. A be \ ^r orzugte composition containing 25% of the aqueous solution and 75% of the organic medium. * (eau bipermutee)

Any product that is neither a solvent can be used as an organic medium for the monomers, nor for the terpolymers obtained, and which has a boiling point which is preferably is above the boiling point of water. It is preferable to use a product that allows to form an azeotropic mixture with water, whereby the

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Facilitates removal of water in the final stage of the polymerization will. Among the many usable products kr_-m the aromatic and aliphatic hydrocarbons ner ™ nen, where "with toluene is a particularly preferred product.

The catalysts that are used to initiate the polymerization of a system of this type are those to radicals dissociating catalysts, which under the action of heat or, at a lower temperature, by the action of a reducing Dissociate connection. Catalysts suitable according to the invention are ammonium persulfate, potassium persulfate, hydrogen peroxide, Azo-bis-isobutyeonitrile \ ind organic peroxides or Hydroperoxides.

Reducing agents that can be used are sodium meta-bilulfite as well as thiosulfates, bisulfites and hydrosulfites.

A catalyst system which is particularly suitable for the production of the terpolymers according to the invention is a redox system which allows the polymerisation at low temperature to produce materials with higher molecular weights. The redox catalyst requires careful removal of traces of oxygen that are dissolved in the medium so that the induction time of the polymerization is shortened. This is achieved by carrying out the polymerization under a stream of nitrogen and in a weak vacuum to avoid the entry of harmful air and to achieve the formation of high molecular weight materials. The quantities of catalyst used range from 0.005 ° / ° to 0.2%, based on the amount of monomer. Preferred amounts range from 0.05 to 0.15 %.

The polymerization temperatures are preferably low. she range between JO and 80 ° C. These polymerization temperatures is achieved through the polymerization of the monomers educated VJarms. It is often necessary to change the reaction medium to cool to avoid too strong a reaction.

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An effective means of regulating the polymerization temperature is to operate at a certain negative pressure in order to keep the organic medium under reflux so that the cooled condensate is able to cool the reaction medium. A suitable polymerization temperature is 65 to 75 ° C at a pressure of 200 to 250 mm Hg.

The following examples are intended to explain the invention further without, however, restricting it.

example 1

First, 4 g of itaconic acid are dissolved in 220 g of deionized water in a beaker. 8 g of acrylic acid to this solution and, while maintaining einsr temperature that is below 30 ⁰ C, the required amount of 50% NaOH solution to bring the pH to 8.5.

250 g of acrylamide, which dissolves ^{at a temperature of ^ 30 °} C., are then added to the mixture obtained.

In a reaction vessel with a capacity of 2000 ecm, which is provided with a stirrer, a thermometer and a reflux condenser, 4 g of the selected one is dissolved in 1500 ecm of toluene Emulsifier (Na sulfonate from a petroleum fraction with a molecular weight of 450 to 500), there is the one obtained above Dissolve the monomers with thorough stirring in order to disperse the aqueous phase well in the toluene and rinse during 15 to 20 minutes violently with nitrogen.

Then 0.4 ml of a 10% ammonium persulfate solution is added and 1 ml of a 10% sodium meta-bisulfite solution, evacuated (250 mm Hg) and heated the reaction medium in a water bath. An exothermic occurs at a temperature of 60 to 65 ° C Response a. The toluene begins to boil and brings the temperature of the reaction mixture to 70 to 75 ° Q, which during Is maintained for 30 minutes. Then the temperature drops to 65 to 67 ° C. After this sequence of reactions has elapsed, a

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second amount of catalyst, which is identical to the first, to complete the polymerization. There is a second exo.therme reaction, which is less violent than the first, whereby the temperature rises to 7O ⁰ C. The reaction mixture is kept at this temperature for a further hour and the water contained in the medium is then distilled off with the aid of a Desii Stark trap. The toluene is decanted off in the upper layer and is continuously returned to the reaction vessel. The distillation is carried out until about 210 g of HpO have been drawn off. In this way, the solid product dispersed in the toluene phase is obtained in the reaction vessel. It is filtered and washed with water or isopropanol to remove the surfactant and the last traces of water. The product was dried in vacuo at 50 to 6O ⁰ C. At the walls of the reaction vessel is liable virtually no deposited product.

Finally, a terpolymer powder is obtained which contains 2.5% sodium itaccnate, 3.5 % sodium acrylate and 94 % acrylamide, which has a viscosity of 2000 cps (determined using the Brookfield RV viscometer, speed 1 in 1% - solution in water).

The polymer obtained is shown in the table below as polymer A denotes.

Example 2

10 g of It, aconic acid and JO g of acrylic acid are dissolved in 220 g of deionized water in a beaker. The mixture is neutralized with Hil fe of a 50% sodium hydroxide solution to a pH value of 8 to 8.5 x Then there was added 160 g of acrylamide, care being taken that the dissolution temperature is below 3O ⁰ C.

The reaction vessel is given 1400 ecm of toluene and 5 g of ci.es selected Emulsifier (Eatrium sulfonate of a petroleum fraction with a molecular weight of 400 to 450), dissolves the emulsification medium while stirring well in toluene and gives the aqueous mixture

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addition of the monomers. Rinse vigorously for 20 minutes with nitrogen.

Subsequently, there was 0.55 ml of a 10% Ammoniunpersulfatlösung and 1 ml of a 10% sodium meta-bisulfite solution added and heated under vacuum to 65 "to 70 ⁰ C. It enters an exothermic reaction. The toluene boils reflux and the temperature is maintained for 45 minutes at 70 to 72 ° C. After this temperature drop is to a second amount of the catalyst to terminate the polymerization, in which one turn holds for one hour at a temperature of 70 ⁰ C.

About 220 g of ILjO are then distilled off by azeotropic distillation in a separator. In the course of this distillation, the gels contained in the medium turn into solid white granules. After the distillation of the water has ended, the mixture is brought to atmospheric pressure and the product is filtered off by filtration. After drying and trituration, a terpolymer is obtained which contains 5 % itaconic acid in the form of the sodium salt, 15% acrylic acid in the form of the sodium salt and 80 % acrylamide. The viscosity of the terpolymer in 1 % strength solution in V / water is 3500 / (Brookfield RV, speed 1). Cps

The product obtained is designated as polymer B in the table.

Example 5

The procedure is the same as in the examples described above, except that the monomer ratios have been modified. In this way a terpolymer is obtained which contains 8% itaconic acid, 22 % acrylic acid and 70% acrylamide.

The polymer obtained is shown in the table below as polymer C designated.

Example 4-

A terpolymer with 5% itaconic acid, 15% meth-

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acrylic acid and 80 % acrylamide. This polymer is referred to as polymer D ″ in the table below.

To evaluate the flocculation properties of the terpolymers produced according to the invention, a suitable device ("HYDEOCURE") is used, which consists of 5 beakers with a capacity of "1 liter, which are provided with stirrers which can be operated at different speeds" operated by a single motor. The medium to be flocculated is dispersed with stirring at a stirring speed of 150 rpm. Solutions of the flocculating products are prepared with a concentration of 1 ° / ₀₀ and increasing amounts of these solutions are added to the beakers. The mixture is stirred for 30 seconds at 150 rpm and then the speed is reduced to 40 rpm. The rate of decantation and the clarity of the supernatant are then observed to determine the amount required to obtain the best flocculation result.

The first medium examined is a suspension of 200 ppm kaolin in water. Those described in the examples above Terpolymers are made with a commercially available sodium acrylate / acrylamide copolymer (Ea-acrylate / acrylamide ratio about 5O / 5O) compared.

The results obtained are summarized in the following table:

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: commercial: polymer

Appearance :

d. flakes: heavy

: heavy: heavy: heavy:: and tight: and tight: and tight:

middle

Decanting: speed of 25 seconds . :

3OSec. 35 sec. 35 sec.

50 sec.

Clarity: good "to: excellent:

:: slightly cloudy, well suspended flok- :: ken

optimal: 5 ppm. : 7 ppm: 7 ppm s 10 ppm: 10 ppm Lot: : : : : :

The second medium examined is a dispersion of 500 ppm titanium oxide. The results obtained are shown in the following Ta Belle summarized:

A. B; C. : commercially available
^D · polymer Appearance
d. flakes heavy
and tight full u.: ex-
difficult to draw Speed
age 35 sec. 4-0 sec .; 40 sec. ^!
• I 45 sec; 1 minute
•

Clarity: excellent

good: good: good until:
: distinguished: excellent:
draws

middle

optimal: 5 ppm amount:

: 10 ppm: 8 ppm:

10 ppm

The third untex-searched medium is a dispersion of 200 ppm Chalk (craie de champagne). The results obtained are given in the following table:

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• ·
A. β; c: D: commercially available
Polymer Appearance
d. flakes : out-:
: draws: out-:
draws: out-:
draws: out-:
draws: middle Speed
age : eye-:
: visible: 10 sec.; 8 sec. I.
• 15 sec.:
• 30 sec. clarity : out-:
: draws: out-:
draws: good and :
excellent : Well :
•
• optimal
lot : 10 ppm:
• ·
• « 15 ppm ί
•
• 10 ppm:
•
• 15 ppm:
•
• 10 ppm

Of the other media investigated, in which the terpolymers according to the invention have been used with success, are dispersions of iron oxide ores, dispersions of copper ores of
These include uranium ores, red clays derived from the treatment of bauxite, industrial wastewater, sewage, coal dispersions, itz solutions and bleaching water from the paper industry.

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Claims (6)

- 14 claims 1. Water-soluble polymeric compositions suitable as flocculants, characterized in that they are obtained by polymerizing 0.2 to 15 % itaconic acid or its water-soluble sodium or ammonium salts, 5 to 95 % of an oc, ß-unsaturated monomeric monocarboxamide, such as acrylamide, or its derivatives, and 5 to 95 % of a water-soluble unsaturated monomer such as acrylic acid and its salts, maleic acid and its salts, or allyl alcohol and its derivatives. 2. Process for the preparation of the water-soluble polymeric compositions according to claim 1, characterized in that that one is an aqueous solution that contains 30 to 65% of the three Contains monomers, in a water-insoluble organic medium in the presence of a surfactant Polymerisationskatelysatorsators and advantageously a reducing agent dispersed. 3. The method according to claim 2, characterized in that the organic medium in which the aqueous solution of the three Monomers is dispersed, is toluene. 4. The method according to claim 2, characterized in that the surfactant is one or more derivatives of sulfonated petroleum fractions, the molecular weights of which are between 300 and 1000. 5. The method according to claim 2, characterized in that the polymerization catalyst in an amount of 0.005 to 0.2% is added and advantageously ammonium sulfate is. 6. The method according to claim 2, characterized in that that the reducing agent is a redox system. 209836/1104