DE10352457A1 - Acrylic acid-based homopolymers with taurine modified for water treatment - Google Patents

Abstract

There are described (meth) acrylic acid copolymers comprising methacrylic acid units, wherein the polymer is functionalized with aminoalkylsulfonic acid. In addition, a process for their preparation and their use for water treatment, scale inhibition in oil recovery and corrosion inhibition in aqueous systems is described.

Description

The The present invention relates to a process for preparing a polymer of (meth) acrylic acid copolymers, those obtainable by this method (Meth) acrylic acid copolymers and their use for water treatment, preferably in cooling or Heating processes, and scaling inhibition in petroleum production.

at oil production it comes during of the funding process by temperature changes and mixing reservoir water with injection water to precipitates of carbonates and sulfates of alkaline earth metals. They clog the pores of the formation and deposit on pipe surfaces, thereby promoting them complicate and sometimes impossible do.

In the water treatment, with cooling or heat processes including seawater desalination, or generally in heat transfer processes the respective cooling or heat medium In general, formulations added to the corrosion and deposits in the circuits prevent or at least delay greatly. For this purpose, formulations depending on the requirements of zinc salts, polyphosphates, phosphonates, Contain polymers, biocides and / or surfactants.

In principle, there are two methods of controlling the corrosion protection and the deposit prevention in open cooling circuits:
On the one hand, it is possible to use phosphorus-containing formulations in the cooling or heating media. Typical examples thereof are polyphosphates and phosphonates such as 1-hydroxyethane-1,1-diphosphonic acid (HEDP), 2-phosphonobutane-1,2,4-tricarboxylic acid (GBTC) and aminotrimethylenephosphonic acid (ATMP), each used in the form of their sodium salts. These phosphorus-containing formulations generally cause hardness stabilization. Polyphosphates also improve corrosion inhibition.

alternative can in cooling and heat media also zinc salts are used, wherein the zinc ions contained therein mainly to protect steel.

In some cases zinc salts are also added in small quantities to the phosphonates, in addition to a hardness stabilization at the same time to protect the steel used.

The Effects of these additives are supported by suitable polymers: Suitable polymers can be used for one supporting the action of phosphonates for hardness stabilization and to others they also stabilize polyphosphates, especially when they are in be added to high concentrations. This will cause calcium phosphate precipitations prevented. Furthermore, can suitable polymers also stabilize zinc compounds, so that it does not lead to deposits on the metal surface and thus to the destruction of the Protective film is coming. The corrosion-inhibiting effect is in the example explained by phosphonates, that a film forms on the metal surface. This will be the Steel from the cooling or heat medium separated. The forming film consists largely of iron (II) - and Calcium ions and the incorporated phosphonate. He is extremely thin, so that ensures stabilization must be, so that it does not collapse and at individual Make corrosion can occur.

to Stabilization of phosphonates and phosphates suitable polymers are basically known from the prior art.

So For example, EP-A 0 244 584 describes N-substituted acrylamides, Wear the sulfoethylamide groups and corrosion inhibition used by industrial refrigeration circuits become. The preparation of these N-substituted acrylamides takes place by transamidation of polymeric acrylamides. The N-substituted Acrylamides according to EP-A 0 244 584 inhibit the phosphate ions but not the phosphonations.

The EP-B 0 330 876 describes, for EP-A 0 244 584, structure-analogous N-substituted Acrylamides. The application according to EP-B 0 However, 330,876 of these N-substituted acrylamides relates on the stabilization of iron in aqueous systems, the exact degree of amidation of the N-substituted acrylamides used is not disclosed.

The US 4,801,388 describes methods for preventing deposits in aqueous systems by adding polymers based on (meth) acrylic acid and sulfoalkyl (meth) acrylamide or (meth) acrylamide.

The US 4,604,431 describes a process for the preparation of acrylamidoalkylsulfonic acid by reacting acrylic or methacrylic acid-containing polymers with alkylsulfonic acids under pressure and at elevated temperature.

US 4,756,881 discloses the use of polymers containing acrylamidoalkanesulfonic acids in combination with organic phosphates for corrosion inhibition in industrial cooling waters.

The Polymers of the above-mentioned prior art have the disadvantage that they are at higher Calcium concentrations fail. Especially with the common In addition, use of phosphonate and zinc ions in cooling or heat cycles are Polymers beneficial to both phosphonations and on Zinc ions have the same stabilizing effect. Further, polymers advantageous when using polyphosphate additives and especially in the presence of calcium ions in high concentration, a precipitate prevent calcium phosphate. Finally, polymers are desirable generally dispersing the solid particles so that their Deposit on the metal surfaces the cooling or heating systems is avoided. These requirements are met by the polymers of State of the art not or only insufficiently fulfilled.

task The present invention thus provides a method for the preparation of polymers in cooling or heating circuits in the respective medium the hardness-stabilizing Support the effect of phosphonates and at the same time stabilize polyphosphates, so for example precipitation does not occur in the presence of calcium ions. Furthermore should obtain the obtainable by the process according to the invention Polymers stabilize zinc compounds so that they do not form deposits on the metal surfaces of cooling or form heat cycles.

• (1) radikalische Polymerisation von (Meth)acrylsäure, wobei ein Polymer I resultiert, und
• (2) Amidierung des aus Verfahrensschritt (1) stammenden Polymers 1 durch Umsetzung mit mindestens einer Aminoalkansulfonsäure.

According to the invention, this object is achieved by a process for the preparation of (meth) acrylic acid copolymers which is characterized by the following process steps:

• (1) radical polymerization of (meth) acrylic acid to give a polymer I, and
• (2) Amidation of the polymer 1 derived from process step (1) by reaction with at least one aminoalkanesulfonic acid.

In Process step (2) of the process according to the invention is the ratio of Carboxylate groups of the polymer derived from process step (1) 1 in proportion to the aminoalkyl sulfonic acid, preferably 2: 1 to 15: 1, more preferably 3 1 to 11: 1, in particular 4: 1 to 8: 1.

Of the Process step (1) is carried out at temperatures of preferably 100 up to 200 ° C, particularly preferably 105 to 135 ° C, in particular 120 to 125 ° C, carried out.

step (1) is preferably in a closed reaction vessel, for example an autoclave. The pressure in process step (1) thus results in general by the vapor pressure (autogenous pressure) of the components used the above temperatures. Regardless, if necessary also under additional Pressure or working under reduced pressure.

The Free-radical polymerization of the monomers is preferably carried out under Use of hydrogen peroxide as initiator. As polymerization initiators can but also all compounds used under the reaction conditions Form radicals, for example peroxides, hydroperoxides, peroxydisulfates, Peroxodicarbonsäuren, Peroxicarbonsäureester and / or azo compounds.

Optionally, in process step (1) of the process according to the invention, it is additionally possible to use further monomers, for example ethylenically unsaturated monomers copolymerizable with (meth) acrylic acid. Suitable copolymers are, for example, monoethylenically unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylenemalonic acid and citraconic acid. Further copolymerizable monomers are C ₁ to C ₄ alkyl esters of monoethylenically unsaturated carboxylic acids, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate. Also suitable as comonomers are alkylpolyethylene glycol (meth) acrylates which are derived from polyalkylene glycols having 2 to 50 ethylene glycol units, monoallyl ethers of polyethylene glycols having 2 to 50 ethylene glycol units and allyl alcohol. Further suitable monomers are acrylamide, methacrylamide, N-vinylformamide, styrene, acrylonitrile, methacrylonitrile and / or monomers carrying sulfonic acid groups and vinyl acetate, vinyl propionate, allyl phosphonate, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-Vi nyl-2-methylimidazoline, diallyldimethylammonium chloride, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. The basic monomers such as dimethylaminoethyl methacrylate can be used for example in the form of the free bases, as salts with strong acids such as hydrochloric acid, sulfuric acid or phosphoric acid or in the form of quaternized compounds as comonomers. Likewise, the above acid group-containing monomers can be used in the form of the free acids or as salts, for example the sodium, potassium or ammonium salts in the polymerization.

The inventive method may preferably be so carried out be that the (meth) acrylic acid copolymer Having sulfonate groups with a counterion selected from the group consisting of protons, alkali ions or Ammoniumio NEN. However, you can generally the sulfonate residues of the (meth) acrylic acid copolymers be saturated with any counterion.

The in process step (1) of the process according to the invention available Polymer I is preferably obtained in a polymer solution which has a solids content of preferably 10 to 70%, particularly preferably 30 to 60%, in particular 45 to 55%.

In a particular embodiment the method according to the invention is before the amidation of the polymer I in process step (2) the polymer solution containing the polymer I to a pH of preferably 2.0 to 9.0, more preferably 4.0 to 7.5, especially 4.5 to 6.5 set. Therefor In principle, all bases are suitable, but preferably aqueous solutions of Alkali hydroxides, for example aqueous sodium hydroxide solution used.

The Amidation (process step (2)) is preferably carried out under a Protective atmosphere carried out, for example, using argon or nitrogen.

Of the Process step (2) of the process according to the invention is preferably at temperatures of 140 to 250 ° C, particularly preferably 165 to 200 ° C, in particular 175 to 185 ° C, carried out. It is the molar ratio from monomer units in polymer I to aminoalkanesulfonic acid, preferably 15 to 1 to 2 to 1, more preferably 11 to 1 to 3 to 1, in particular 8 to 1 to 4 to 1. The pressure in process step (2) is preferably 1 to 25 bar, more preferably 5 to 17 bar, in particular 7 to 13 bar.

In a particular embodiment the method according to the invention is as Aminoalkylsulfonsäure aminoethylsulfonic used so that the polymer resulting from process step (2) Having units based on aminoethylsulfonic acid. However, too Any other aminoalkylsulfonic acids can be used. This will be to the above statements directed.

The sulfoalkylamide structural units produced by process step (2) of the process according to the invention are preferably randomly distributed in the (meth) acrylic acid copolymer:
The reaction type of free-radical polymerization in process step (1) decisively influences the distribution of the sulfoalkylamide units between the individual polymer molecules and along a polymer chain. Thus, in general, a mixture of differently structured polymer chains is obtained than by the radical copolymerization of monomers of corresponding structure. Thus, polymer-analogously prepared polymers can be clearly distinguished from polymers obtained by the radical copolymerization of the monomer acrylamide with acrylic acid and subsequent transamidation of the amide units with aminoalkylsulfonic acid. A radical copolymerization of acrylic acid, terelactic acid and acrylamide with subsequent transamidation generally leads to other structures. In the case of the last-described polymerizations, the distribution of the sulfoalkylamide units is predetermined by the copolymerization parameters of the monomers used in the free-radical copolymerization. As a result, the statistics of the distribution of different functional groups on the polymer backbone in polymer-analogous polymers are generally different from those in the case of introduction of corresponding groups by radical copolymerization.

Another The present invention relates to (meth) acrylic acid copolymers, obtained by the method described above.

• (a) 30 bis 95 Gew.-%, vorzugsweise 40 bis 90 Gew.-%, besonders bevorzugt 60 bis 80 Gew.-%, eines Poly(meth)acrylsäure-Grundgerüsts,
• (b) 5 bis 70 Gew.-%, vorzugsweise 10 bis 60 Gew.-%, besonders bevorzugt 20 bis 40 Gew.-%, Amideinheiten auf Basis von Aminoalkylsulfonsäuren umfassen, wobei das Gesamtgewicht der Einheiten in dem (Meth)acrylsäurecopolymer 100 Gew.% beträgt und alle Gewichtsangaben auf das (Meth)acrylsäurecopolymer bezogen sind.

These (meth) acrylic acid copolymers preferably contain

• (a) from 30 to 95% by weight, preferably from 40 to 90% by weight, particularly preferably from 60 to 80% by weight, of a poly (meth) acrylic acid skeleton,
• (B) 5 to 70 wt .-%, preferably 10 to 60 wt .-%, particularly preferably 20 to 40 wt .-%, Amideinhei based on Aminoalkylsulfonsäuren, wherein the total weight of the units in the (meth) acrylic acid copolymer is 100 wt.% And all weights are based on the (meth) acrylic acid copolymer.

The (Meth) acrylic acid copolymers according to the invention prevent already in the sub-stoichiometric range, that too many calcium ions in the film on the metal surfaces of for example, cooling or heat cycles penetrate.

The weight average molecular weight of the (meth) acrylic acid copolymers according to the invention is preferably 1,000 to 20,000 g / mol, more preferably 1,500 to 10,000 g / mol, in particular 2,000 to 6,000 g / mol. The determination of the weight average Molecular weight is carried out by gel permeation chromatography (= GPC) at room temperature with aqueous Eluents.

The (Meth) acrylic acid copolymers according to the invention have a K value of preferably 5 to 50, more preferably 8 to 35, in particular 11 to 16, on. The K value was calculated according to Fikentscher (ISO 174, DIN 53726).

Optionally, the (meth) acrylic acid copolymers according to the invention may additionally contain units of other ethylenically unsaturated monomers copolymerizable with (meth) acrylic acid. Suitable monomers for this purpose are, for example, monoethylenically unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylenemalonic acid and citraconic acid. Further copolymerizable monomers are C ₁ to C ₄ alkyl esters of monoethylenically unsaturated carboxylic acids, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate. Also suitable as monomers are alkylpolyethylene glycol (meth) acrylates which are derived from polyalkylene glycols having 2 to 50 ethylene glycol units, monoallyl ethers of polyethylene glycols having 2 to 50 ethylene glycol units and allyl alcohol. Further suitable monomers are acrylamide, methacrylamide, N-vinylformamide, styrene, acrylonitrile, methacrylonitrile and / or monomers bearing sulfo groups, and vinyl acetate, vinyl propionate, allyl phosphonate, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinyl-2-methylimidazoline, Diallyldimethylammonium chloride, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. The basic monomers such as dimethylaminoethyl methacrylate can be used for example in the form of the free bases, as salts with strong acids such as hydrochloric acid, sulfuric acid or phosphoric acid or in the form of quaternized compounds as comonomers. Likewise, the above-mentioned acid group-containing monomers can be used in the form of the free acids or as salts, for example the sodium, potassium or ammonium salts in the polymerization.

The Amide units based on aminoalkylsulfonic acids can be derived from any aminoalkylsulfonic acid become. Particularly suitable aminoalkylsulfonic acids are those having 2 to 12, preferably 4 to 10 carbon atoms. The amino groups may be primary, secondary or tertiary. As further substituents can the aminoalkylsulfonic acids For example, hydroxy or alkoxy groups or halogen atoms. The alkyl groups can unsaturated or preferably saturated, straight or branched or closed to the ring. The amino groups can within the chain of aminoalkyl groups or as side or terminal Substituents be arranged. They can also be part of one preferably saturated be heterocyclic ring.

In a preferred embodiment of the present invention, the (meth) acrylic acid copolymer according to the invention contains the structural unit (II) based on aminoethanesulfonic acid (taurine):

In general, the sulfonate moieties of the (meth) acrylic acid copolymers can be reacted with any Ge genion be satisfied. Preferably, the counterion is selected from the group consisting of protons, alkali ions or ammonium ions.

The Sulfoalkylamide structural units are in the (meth) acrylic acid copolymer preferably distributed statistically.

The (Meth) acrylic acid copolymers according to the invention differ in their mode of action in the treatment of water, Scaleinhibierung and in the corrosion protection clearly from the (meth) acrylic acid polymers of the prior art, by transamidation of the corresponding (Meth) acrylsäureamidpolymere with aminoalkylsulfonic acids to be obtained.

These characteristic mode of action is due to the preferred statistical distribution of the sulfoalkylamide structural units. By the direct amidation of the polyacrylic acid is the distribution of the Sulfoethylamide units between the individual polymer molecules and decisively influenced along a polymer chain. So will in characteristically a mixture of differently structured polymer chains obtained as by the radical copolymerization of monomers corresponding structure. Thus, polymer analogues differ Polymer, for example, significantly from polymers produced by the radical copolymerization of the monomer acrylamide with acrylic acid and subsequent transamidation the amide units are obtained with aminoethanesulfonic acid. In the The polymerization described last becomes the distribution of the sulfoethylamide units by the Copolymerisationsparameter of the radical copolymerization predefined monomers used. The result is the distribution different functional groups on the polymer backbone radical copolymerization is significantly different than in the case of polymer analog introduction corresponding groups in already synthesized polymers.

Furthermore The present invention relates to a process for stabilization of phosphates, phosphonates and / or zinc ions, for example Zinc chloride or zinc phosphate, in aqueous systems, wherein the System at least one inventive (meth) acrylic acid copolymer and / or at least one obtainable by the erfindungsge Permitted method (Meth) acrylic acid copolymer is added. It is the Amount of polymer in the aqueous System preferably from 5 to 200 ppm, more preferably 5 to 50 ppm, in particular 10 to 40 ppm, in each case based on the aqueous system.

The polymers of the invention can the aqueous System over one or more dosing be dosed directly or be introduced in mixture with another component.

The The above-described (meth) acrylic acid copolymers according to the invention and / or by the method according to the invention available (Meth) acrylic acid copolymers can for water treatment, scale inhibition in oil production and / or used for corrosion inhibition in aqueous systems become.

• a) Kondensierte lineare und ringförmige Polyphosphate, wie Natriumtriphosphat, Natriumhexametaphosphat;
• b) Phosphonate, wie 2-Phosphonobutan-1,2,4-tricarbonsäure, Aminotri-(methylenphosphonsäure), 1-Hydrozyethylen(1,1-diphosphonsäure), Ethylendiamin-tetramethylen-phosphonsäure, Hexamethylendiamin-tetramethylen-phosphonsäure oder Diethylentriamin-pentamethylen-phosphonsäure,
• c) Aminocarboxylate wie Nitrilotriessigsäure, Ethylendiamintetraessigsäure, Diethylentriaminpentaessigsäure, Hydroxyethylethylendiamintriessigsäure, Methylglycindiessigsäure, Gluconat, Gluconheptonat, Ethylendiamindisuccinat und Imindisuccinat;
• d) wasserlösliche Polymere, wie Homo- und Copolymere von sulfongruppenhaltigen Monomeren, wie 2-Acrylamido-2-methylpropansulfonsäure, Styrolsulfonsäure oder Vinylsulfonsäure mit einem gewichtsmittleren Molekulargewicht von 500 bis 15.000 oder Naphthalinsulfonsäure-Formaldehyd-Polykondensate,

nebst weiteren Formulierungsbestandteilen wie Tensiden, Dispergiermitteln, Entschäumern, Korrosionsinhibitoren, Sauerstoffängern und Bioziden.Optionally, it may be useful to use the (meth) acrylic acid copolymers of the invention in formulations. Another object of the present invention are thus formulations for water treatment, scale inhibition in petroleum production and / or corrosion inhibition containing at least one inventive (meth) acrylic acid copolymer and / or at least one obtainable by the process according to the invention (meth) acrylic acid copolymer. The formulations according to the invention optionally contain further constituents. Such Formierungsbestandteile are for example:

• a) condensed linear and cyclic polyphosphates such as sodium triphosphate, sodium hexametaphosphate;
• b) phosphonates, such as 2-phosphonobutane-1,2,4-tricarboxylic acid, aminotri- (methylenephosphonic acid), 1-hydroxethylene (1,1-diphosphonic acid), ethylenediamine-tetramethylene-phosphonic acid, hexamethylenediamine-tetramethylene-phosphonic acid or diethylenetriaminepentamethylene phosphonic acid,
• c) aminocarboxylates such as nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, methylglycinediacetic acid, gluconate, gluconheptonate, ethylenediamine disuccinate and imindisuccinate;
• d) water-soluble polymers, such as homopolymers and copolymers of sulfone-containing monomers, such as 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid or vinylsulfonic acid having a weight-average molecular weight of 500 to 15,000 or naphthalenesulfonic acid-formaldehyde polycondensates,

together with other formulation ingredients such as surfactants, dispersants, defoamers, corrosion inhibitors, oxygen scavengers and biocides.

The formulation containing the inhibiting or dispersing polymer can be both di rectly added to the aqueous system via one or more metering points.

The The present invention will be clarified by the following examples.

WORKING EXAMPLES

1.) Preparation of polymers according to the invention

• a) In einem Reaktor mit Stickstoffzuführung, Rückflusskühler und Dosiervorrichtung wurde eine Mischung von 394 g destilliertem Wasser und 5,6 g phosphoriger Säure (50%-ig) unter Stickstoffzufuhr und Rühren auf 95°C Innentemperatur erhitzt. Dann wurden parallel (1) 936 g Acrylsäure, (2) 280 g Natriumper-oxidsulfatlösung (10%-ig) und (3) 210 g einer 40 gew.-%igen wässrigen Natriumhydrogensulfitlösung kontinuierlich in 5 h zugegeben. Nach einstündigem Nachrühren bei 95°C wurde das Reaktionsgemisch auf Raumtemperatur abgekühlt und durch Zugabe von 169 g 50 gew.-%iger Natronlauge auf einen pH-Wert von 4,0 eingestellt. Es wurde eine klare Polymerlösung mit einem Feststoffgehalt von 54 Gew.-% und einem K-Wert von 25 (1 gew.-%ige wässrige Lösung, 25°C) erhalten.
• b) In einem druckstabilen Reaktionskessel mit Rührer, Stickstoffzufuhr, Temperaturfühler, Druckanzeige und Entlüftungsmöglichkeit wurde eine Mischung aus 1.000 g der Polymerlösung aus a) (Feststoffgehalt = 50 %) und 130,47 g Taurin (Aminoethansulfonsäure) gefüllt. Zu dieser Mischung wurde 110 g einer 50 %igen wässrigen Natronlauge gegeben. Die Apparatur wurde dreimal mit Stickstoff gespült und geschlossen. Dann wurde das Gemisch unter Rühren auf eine Innentemperatur von 180°C erhitzt. Dabei baute sich ein Druck von ca. 10 bar auf. Bei dieser Temperatur wurde das Gemisch für 5 Stunden gehalten. Dann wurde die Mischung ohne Entspannung abgekühlt. Die Apparatur wurde geöffnet und auf einen pH-Wert von 7,2 eingestellt. Es wurde eine klare gelbe Lösung mit einem Feststoffgehalt von 49,6 % und einem K-Wert von 14,6 (1%ig in 3 % NaCl-Lösung) erhalten.

A polymer of acrylic acid is produced (process step (1)).

• a) In a reactor with nitrogen inlet, reflux condenser and metering device, a mixture of 394 g of distilled water and 5.6 g of phosphorous acid (50% strength) was heated to 95 ° C. internal temperature with the introduction of nitrogen and stirring. Then, in parallel, (1) 936 g of acrylic acid, (2) 280 g of sodium peroxide sulfate solution (10%) and (3) 210 g of a 40% by weight aqueous sodium hydrogen sulfite solution were added continuously in 5 hours. After stirring for one hour at 95 ° C, the reaction mixture was cooled to room temperature and adjusted by the addition of 169 g of 50 wt .-% sodium hydroxide solution to a pH of 4.0. A clear polymer solution having a solids content of 54% by weight and a K value of 25 (1% strength by weight aqueous solution, 25 ° C.) was obtained.
• b) A mixture of 1000 g of the polymer solution from a) (solids content = 50%) and 130.47 g of taurine (aminoethanesulfonic acid) was charged in a pressure-stable reaction vessel with stirrer, nitrogen inlet, temperature sensor, pressure indicator and venting possibility. To this mixture was added 110 g of a 50% aqueous sodium hydroxide solution. The apparatus was purged with nitrogen three times and closed. Then, the mixture was heated with stirring to an internal temperature of 180 ° C. Here, a pressure of about 10 bar built up. At this temperature, the mixture was held for 5 hours. Then the mixture was cooled without relaxation. The apparatus was opened and adjusted to a pH of 7.2. A clear yellow solution with a solids content of 49.6% and a K value of 14.6 (1% in 3% NaCl solution) was obtained.

2.) Preparation of the Reference Polymer by transamidation

• a) In a reactor with nitrogen supply, reflux condenser and Dosing were submitted to 180 g of distilled water and under nitrogen and stirring at reflux temperature heated. The nitrogen flow was turned off and then parallel (1) 180.15 g of acrylic acid, (2) 35.55 g of acrylamide, (3) 143.8 g of a 30 wt .-% aqueous hydrogen peroxide solution and (4) 21.6 g of mercaptoethanol (10% by weight in water) continuously added in 5 h. After two hours stir for at reflux temperature the reaction mixture was cooled to room temperature and by adding 169 g of 50 wt .-% sodium hydroxide solution to a pH set by 4.0. There was a clear solution poly (acrylamide) [16.6 mol%] - acrylic acid with a solids content of 18.2 wt .-% and a K value of 11.5 (1 wt .-% aqueous solution, 25 ° C).
• b) The transamidation is based on the manufacturing specification from the patent EP 0 330 876 B1 Example 1, where the ratio of COOH to SO ₃ H in the product is adjusted to make the polymer comparable to Example 1 (same taurine content in both polymers, raising the pH to pH = 6 to increase the conversion) A mixture of 500 g of the polymer solution from a) (solids content = 18.2%) and 27.7 g of taurine (aminoethanesulfonic acid) was filled in a pressure-stable reaction vessel with stirrer, nitrogen inlet, temperature sensor, pressure indicator and venting possibility. To this mixture was added 76.7 g of a 50% aqueous sodium hydroxide solution. The apparatus was purged with nitrogen three times and closed. Then, the mixture was heated with stirring to an internal temperature of 150 ° C. Here, a pressure of about 10 bar built up. At this temperature, the mixture was held for 4 hours. Then the mixture was cooled without relaxation. The apparatus was opened and adjusted to a pH of 7.2. A clear yellow solution having a solids content of 25.4% and a K value of 13.9 (1% in 3% NaCl solution) was obtained.

3.) Use of polymers for the inhibition of calcium phosphate and calcium phosphonate

a) calcium phosphate inhibition

basis is the exam the inhibiting effect of polymers for use in cooling water circuits.

Equipment:

• Dr. Long photometer, type LP2W
• Filter 435 nm
• Suction device with membrane filter 0.45 μm
• shaking (GFL Model 1083)
• 300 ml Lupolen cup (lockable)
• disposable cuvettes (4 ml, ratiolab)
• Balance Sartorius type LC 4800 - P

• Reagents: Vanadate / Molybdate - Phosphate Determination Reagent (Merck) Test Solution A: 0.42 g of H ₃ PO ₄ solution (5%), to 1 l with dist. Fill up with water Test solution B: 1.64 g / l CaCl ₂ · 6 H ₂ O 0.79 g / l MgSO ₄ · 7 H ₂ O 1.08 g / l NaHCO ₃ Polymer solution: 0.1%, based on active substance

Execution:

100 ml of test solution A are introduced into the Lupolen beakers, 2-4 ml of 0.1% polymer solution are metered in (10-20 ppm) and then 100 ml of test solution B are added. After closing the cups, they are placed for 24 h at 70 ° C in the shaking bath. After cooling (about 1 h), the sample solutions are aspirated through membrane filters (0.45 μm). 50 ml of the aspirated solution is then taken to determine the amount of residual phosphate by adding 10 ml of the vanadate / molybdate reagent. After a reaction time of 10 minutes, it is now possible to determine the phosphate content on the photometer using calibration curves. Concentration of the test solution: GH = 5.4 mmol / l KH = 6.42 mmol / l PO ₄ = 10 ppm polymer = 10-20 ppm active substance Table: Inhibition [%]

b) calcium phosphonate inhibition

basis is the exam the inhibiting effect of polymers for use in refrigeration circuits.

Equipment:

• Dr. Long photometer type LP 2 W, filter 800 nm
• Suction device with membrane filter 0.45 μm
• shaking (GFL Model 1083)
• 300 ml Lupolen cup (lockable)
• Dr. Long production test LCK 350
• Balance Sartorius type LC 4800 - P

reagents:

Test Solution A:

2.2 g / l HEDP 1% w / w (Dequest 2010), or 5.7 g / l PBTC 1% w / v WS (Bayhibit AM) or 2.1 g / l ATMP 1% w / w (Dequest 2000), to 1 l with dist. Fill up with water

Test solution B:

• 1.64 g / l CaCl ₂ .6H ₂ O
• 0.79 g / l MgSO ₄ .7H ₂ O
• 1.08 g / l NaHCO ₃
• 0.1% polymer solution based on active substance

Execution:

100 ml of test solution A are introduced into the Lupolen beakers, 2-4 ml of 0.1% polymer solution are metered in (10-20 ppm) and then 100 ml of test solution B are added. After closing the cups, they are placed for 24 hours at 70 ° C in the shaking bath. After cooling (about 1 hour), the sample solutions are aspirated through a membrane filter (0.45 μm). Now, the inhibited amount of phosphonate by Dr. med. Long production test LCK 350 determined. Concentration of the test solution: GH = 5.4 mmol / l KH = 6.42 mmol / l PO ₄ = 10 ppm polymer = 10-20 ppm active substance

Table: Inhibition [%]

b) organische Formulierung (frei von Phosphat und Schwermetallen)

HEDP

= 1-Hydroxyethan-1,1-diphosphonsäure, Natriumsalz

PBTC

= 2-Phosphonobutan-1,2,4-tricarbonsäure, Natriumsalz

c) Phosphat/Phosphonatformulierung

The transamidated polymer is a terpolymer of AS, acrylamide and acrylamidoethanesulfonic acid. The polymer according to the invention has increased calcium phosphate inhibition in the lower dosing range and increased calcium phosphonate inhibition over the entire dosing range compared to the transamidated polymer. This effect is particularly pronounced when using substoichiometric amounts. 4.) Examples of Formulations for Water Treatment, in Particular for Cooling Water a) Polymer / Zinc Formulation (Free from Phosphate)

b) organic formulation (free of phosphate and heavy metals)

HEDP

= 1-hydroxyethane-1,1-diphosphonic acid, sodium salt

PBTC

= 2-phosphonobutane-1,2,4-tricarboxylic acid, sodium salt

c) Phosphate / phosphonate formulation

5.) Determination of the mean molecular weight

The determination of the weight-average molecular weight was carried out by gel permeation chromatography (= GPC) at room temperature with aqueous eluents (0.08 m TRIS buffer (TRIS = tris (hydroxymethyl) aminomethane) at pH = 7 in distilled water + 0.15 m NaCl + 0.01 M NaN ₃ ). The samples had a concentration of c = 0.1 mass%, the injection _volume was V _inj = 200 μL. The calibration was carried out with a widely distributed sodium polyacrylate calibration mixture. The chromatographic column combination consisted of Waters Ultrahydrogel 1000, 500, 500 and TSK PW-XL 5000 (TosoHaas). For detection, a differential refractometer was used.

Claims (10)

Process for the preparation of (meth) acrylic acid copolymers, characterized by the following process steps: (1) free radical polymerization of (meth) acrylic acid, resulting in a polymer I, and (2) amidation of the process step (1) Polymers I by reaction with at least one aminoalkanesulfonic acid. Method according to claim 1, characterized in that that process step (1) is carried out at temperatures of 100 to 200 ° C. Method according to claim 1 or 2, characterized that process step (2) is carried out at temperatures of 140 to 250 ° C. Method according to one of claims 1 to 3, characterized that the molar ratio of monomers in polymer I to aminoalkanesulfonic 15 to 1 to 2 to 1. (Meth) acrylic acid copolymers, available according to a method according to claims 1 to 4th A (meth) acrylic acid copolymer according to claim 5, comprising (b) 30 to 95% by weight of a poly (meth) acrylic acid skeleton, (c) 5 to 70% by weight of amide units based on aminoalkylsulfonic acids, wherein the total weight of units in the sulfone group-containing polymer is 100% by weight and all weights are based on the sulfone group-containing polymer. (Meth) acrylic acid copolymer according to claim 5 or 6, characterized in that the weight-average Molecular weight of the sulfonic group-containing polymer 1,000 to 20,000 g / mol. Process for the stabilization of phosphates and / or Phosphonates and / or zinc ions in aqueous systems, the System a polymer according to a the claims 5 to 7 is added. Use of (meth) acrylic acid copolymers according to the claims 5 to 7 for water treatment, scale inhibition in oil production and / or corrosion inhibition in aqueous systems. Formulation for water treatment, scale inhibition in oil production and / or corrosion inhibition containing (meth) acrylic acid copolymers according to one the claims 5 to 7.