MXPA99007725A - Method for carrying out polycondensation reactions - Google Patents

Abstract

The invention relates to a method for carrying out polycondensation reactions, according to which the polycondensation of a monomeric educt is carried out with an external supply of heat in an at least two-stage reactor combination comprising a pre-reactor and a high-viscosity reactor, the resulting low-molecular cleavage products being removed by evaporation. In the pre-reactor the reaction product is concentrated into a viscous starting product, and said viscous starting product then fully reacted into a polycondensation product in the high-viscosity reactor under addition of thermal and mechanical energy over a period of between 20 seconds and 60 minutes.

Description

PROCEDURE FOR THE REALIZATION OF REACTIONS OF POLICON-DENSA ION. Field of the invention. - A polycondensation reaction is a chemical reaction in which a macromolecule is formed in stages (Emons, HH, Fedtke, M., Hellmond, P., Landschulz, G., Pdschl, R., Pritzkow, W., Ratzsch, M., Zimmermann, G., Lehrbuch der Technischen Chemie, VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig, 1984). At each stage of the condensation a reaction product is formed, which is in equilibrium with the other participants in the reaction. The reaction is therefore an equilibrium reaction. The reaction is carried out respectively between two different functional groups of the starting products (monomers), a low molecular weight product (for example water, hydrogen halide, alcohols, etc.) being dissociated at each stage of the reaction and at the same time In time, a polymer chain is prolonged in a monomer unit. Thus, the products of the reaction are the macromolecule and the corresponding low molecular weight cleavage products, which are in equilibrium with the starting materials. If it is desired to achieve a high conversion in the polycondensation reaction, low weight dosing products should be removed from equilibrium *} g O? ? molecular to move the balance of the reaction towards the products. If at the beginning of the reaction the monomers are dissolved in a solvent, the task to be solved may further consist in also removing the solvent from the reaction mixture. The low molecular weight cleavage products can be used in this case as solvents. In the removal of the low molecular weight cleavage products or, if appropriate, the solvent, the viscosity of the reaction mixture can be changed from a solution of low viscosity (for example similar to that of water) at the start of the reaction to a polymer melt or high viscosity polymer solution at the end of the reaction. Frequently it is even necessary to remove the low molecular weight cleavage products and, if necessary, the solvent to a dry solid product in order to achieve the conversion of the desired reaction. Description of the prior art. The traditional methods for the removal of the low molecular weight cleavage products or, where appropriate, the solvent, consist of distillation. In other words, the low molecular weight cleavage products or, if appropriate, the solvent are removed simultaneously or stepwise (alternatively reaction and distillation) while evaporating the polycondensation reaction. The chemical reactors for carrying out the polycondensation reactions therefore have two tasks. These have to be able to efficiently mix and transport the reaction mixture at low and high viscosities (if necessary to dry solids) and at the same time have to provide the possibility of evaporating the mixture. of the reaction the low molecular weight cleavage products or else the solvent. In the process for the poly condensation reactions according to the state of the art, the following reactors are used. Spindle reactors. High volume screw reactors of the ZDS-R type from OCKER, Fa. Werner and Pfleiderer, Stuttgart, already in 1962 for the polycondensation of polyesters. The machines are used with a low number of revolutions and with long residence times (1 to 2.5). The procedure is described in Herrmann: Schnecken- aschinen in der Verfahrenstechnik, Springer Verlag 1972. The disadvantage in these machines is the reduced, mixing effect due to the reduced number of revolutions. Plate Reactors (Zimmer Fa, Frankfurt / Main) This type of reactors represents an economic alternative to screw reactors and is currently used worldwide in the production of polyester. The principle of the reactor is based on ring disks that rotate slowly, which generate cast films and veils, which form a large surface for the transition of the products. In the normal embodiment, the disk reactors are not self-cleaning. A variant of the reactor, which has been equipped with scrapers to improve self-cleaning, is still being tested on a pilot scale. The reactor can be used, in the same way as the screw reactor, through a wide range of viscosities. However, the presence of a fusion that forms a liquid is a precondition for operation. A transition to a non-flowable phase or to a solid product is not possible. Extruder of two trees. Recently two-shaft extruders have been used, which rotate in the same direction, with a small volume and with a high number of revolutions for the polycondensation. Examples: ZSK type of Fa Werner and Pfleiderer, Stuttgart or type ZE of the Fa. Berstorff, Hanno-ver. GREVENSTEIN, A: Reaktive Extrusion und Aufbereitung, Cari Hanser Verlag 1996 cites as particular cases polyethylene terephthalate (PET), polybutethylene terephthalate (PBT), copolyesters, polyimide (Pl) and polyetheri ida (PEI). The mixing effect is good due to the high number of revolutions. At the same time, high shear and energy dissipation are present, which can have a negative effect in the case of sensitive polymers on the quality of the product. Due to the small volume of the reactor, however, this type is interesting only for processes that require a small type of residence (as a rule < 1 minute). Therefore, most of the time, only a final conden sation is carried out in the industry. Reactors with wire mesh baskets, (for example Werner and Pfleiderer). This type of reactor offers a large volume of reaction and therefore long residence times and is used on an industrial scale for the polycondensation reactions. However, it is limited to the other types due to the maximum processable viscosity of the polymer. Large-volume kneading reactors (for example Fa. List). This type is equivalent to the extruders of two trees in what refers to the efficiency of mixing and kneading. However, due to the large volume, high residence times can also be realized. In contrast to the types of reactors 3, these reactors have, however, an axial refixing and a conveyor effect that depends to a large extent on the viscosity, that is to say that at low to medium viscosities the premix is high and the conveyor effect is bad . So this type of reactor is less interesting, industrially, for loading with a medium of low viscosity. Detailed description of the invention. It has been found that in the polycondensation reactions an essential improvement of the quality of the product can be achieved if the polycondensation of a monomer feed is carried out under external heat input in a reactor combination, constituted in at least two stages, constituted by a pre-reactor and a high-viscosity reactor, evaporating the low molecular weight dissociation products that are formed and carrying out in the previous reactor a concentration of the product of the reaction to a viscous pre-product. The viscosity of the viscous prior product should be greater than 200 mPas, preferably greater than 500 mPas. The viscous precursor is then fed to the high viscosity reactor in which it reacts completely to give the polycondensation product, with a simultaneous supply of thermal and mechanical energy and with a residence time of 20 seconds to 60 minutes. The preliminary reactor is constituted by an apparatus in which an efficient and intense thermal exchange is guaranteed. For this purpose, all types of apparatus suitable for heat exchange can be used, which have a sufficient working volume for carrying out the chemical reaction (for example heat exchangers of tubular bundles, falling film evaporators, plate heat exchangers). , temperature-controlled static mixer-reactor (TSM), vessels with agitator with a special agitation geometry for viscous products, etc.). Other combinations of heat exchangers can also be imagined as preliminary reactors. The high viscosity reactor is characterized by a sufficient thermal input and a supply of mechanical energy for mixing and transport as well as for the surface renewal of the reaction mixture. A sufficient reactor volume to guarantee the residence time as well as the ability to process the highly viscous masses, if necessary, to dryness. Especially preferred in this process is the comminution of the solid product formed into many small particles. By this comminuting the evaporation or separation of the dissociation product formed during the condensation is considerably improved and the diffusion pathways for the dissociation products are considerably reduced. In addition to the more efficient separation of the dissociation products, the heat transfer due to the large surfaces of the particles of the solid product is clearly improved, which leads to completely reacted products. The product prepared in this way clearly has a lower amount of residual monomers and has indices corresponding to the industrial application as well as chemical-analytical clearly better. Preferably, a coil evaporator or other heat exchanger in combination with a coil reactor will be used as a precursor reactor and a high-volume kneader reactor as a high-viscosity reactor., in which the product of the polycondensation is circulated and shredded by means of the kneading elements and / or the rotary shearing elements. The starting liquid is pumped, for example, firstly through one or more heat exchangers which are operated with a plurality of phases and enters a helical tube through a decompression valve with partial evaporation. As already indicated by CASPER in CIT 42 (1970), n0-6, page 349 et seq., A turbulent annular liquid flow is formed in the helical tube, which guarantees a good thermal and material transport, even at the increasing viscosity as a consequence of the reaction. The pre-condensed and partially evaporated product in the coil is sent to the high-volume rotisserie reactor. In the large-volume kneader reactor, the polycondensation is continued under permanent mixing. In this case the viscosity keeps increasing. In special cases a transition takes place to a solid product that is no longer flowable. For the process according to the invention, any commercially available kneader reactor can be used, insofar as it is capable of achieving the aforementioned objectives. In our example, a reactor of the CRP type of the Fa is used. List AG, Arisdorf, CH. A device with reinforced rotors is especially preferred. The low molecular weight cleavage products, evaporated, and, if necessary, the solvent, can be removed both in the pre-reactor, after the pre-reactor, in the high-viscosity reactor or can be discharged with the product from the reactor combination. according to the invention. The advantages of the combination of reactors according to the invention will be explained below by means of obtaining the sodium salt of polyaspartic acid (PAA-Na), of the intermediate product polysuccinimide (PSI). For the production of the polysuccinimide, anhydride of maleic acid (MSA) and ammonia (NH3) are initially prepared, batchwise or continuously, by an aqueous solution of ammonium salt of maleic acid or by an aqueous solution of the ammonium salt of maleic acid with low molecular weight adducts of ammonium salt of maleic acid, and then continuously polymerized in the reactor combination according to the invention to give polysuccinimide. In this case, polycondensation reactions and intramolecular cyclocondensation reactions are also verified together with others. In these condensation reactions, the reaction mixture must be removed as widely as possible, both the solvent consisting of water and also the water of the reaction dissociated during condensation, in order to achieve a high degree of conversion (or a high molecular weight). The monomer starting material can be obtained preferably by reacting 1,4-butanedicarboxylic acid or 1,4-butenedicarboxylic acid or a derivative thereof with ammonia or with a compound supplying ammonia. For example urea, ammonium salts of carbonic acid, ammonium salts of phosphoric acid or formamide. As other educts, in the process according to the invention, maleic acid, fumaric acid, malic acid, asparaginic acid and asparagine as mixtures of these can be used instead of maleic acid anhydride. In addition, other co-condensable monomers can be added to the reaction mixture in the reactor combination according to the invention. Examples of suitable co-condensing compounds are fatty acids, polybasic carboxylic acids, their anhydrides and amides, polybasic hydroxycarboxylic acids, their anhydrides and amides, polyhydroxycarboxylic acids, aminocarboxylic acids, sugar acids, alcohols, polyols, amines, polyamines, amino alcohols. , to inoazúcares, carbohydrates, mono and polycarboxylic acids ethylenically unsaturated, protein hydrolysates, for example corn pro-tein hydrolysates, soy protein hydrolysates and aminosulphonic acids. In order to promote condensation, auxiliary condensation agents can also be added to the reaction mixtures. In this case, mention may be made, for example, of phosphoric acid, polyphosphoric acid, phosphorous acids, phosphonic acids and acid salts such as sodium bisulfate, potassium bisulfate and ammonium bisulfate. In a preferred embodiment, these condensation aids will be added to the reaction mixture in the last reaction stage in the high viscosity reactor. A high conversion is directly related to a good quality of the product, that is to say with good industrial application properties, which are accepted by the customers (for example: ZnO dispersion test, NACE test).

According to another development of the invention, the polymers obtained in the second reaction step in the high-viscosity reactor can be subjected to a solvolysis. The polymer prepared in this way preferably has, in a fundamental way, recurring asparaginic acid units. These polymers advantageously serve in aqueous or non-aqueous systems for the dispersion of inorganic or organic particles and especially for the inhibition and dispersion of precipitates during the treatment of waters. Exemplary embodiments As a basis of comparison, tests according to the state of the art with a single reactor were carried out in the first place. a) Coil reactor. The reaction mixture must be fluid for processing in the coil reactor. In this case, a concentration by evaporation can be carried out to a viscous melt. The quality of the product, when a coil reactor or a pre-reactor is used, is clearly worse than in the case of the combination of the reactors according to the invention (see, for example, 1 ^, ZnO test, NACE test, for the description of the trial see below). The previous reactors, such as for example the coil reactor, are simple and inexpensive devices with high flow rates. b) High viscosity reactor. The only reactor used was a high viscosity reactor from the Firma List. The reaction mixture can not be concentrated by evaporation to dryness at the necessary flow rates. A List reactor is not suitable for processing at low viscosities. The low viscosity educt "flows quickly through the reactor". The device has high specific mechanical costs. The whole process of concentration by evaporation of the aqueous solution of low viscosity through the fusion / high viscosity solution to the solid product is carried out in a special apparatus for the production of highly viscous products. The quality of the product is clearly worse than in the case of the combination of the reactors according to the invention (see, for example, M ^, ZnO test, NACE test, for the description of the tests see below). c) Method according to the invention using a combination of reactors. The previous reactor was constituted by a coil reactor and by a high viscosity reactor constituted by a List reactor. The process according to the invention with the combination of the reactors formed by the coil for the List reactor represents the best of the processes compared to the processes with only one reactor. In the coil reactor, the solution of the low viscosity educt is condensed to a high viscosity melt / solution. The List reactor, connected downstream, is then fed with the high viscosity melt / solution, which must have a viscosity greater than 200 mPas, preferably greater than 500 mPas, so that the advantages of the reactor can be fully exploited. Due to the substantially larger reactor volume, a longer residence time and, therefore, a lower reaction temperature can be realized. In this way an efficient, less aggressive manufacturing method is produced, which translates into the quality of the maximum product achieved (see, for example, M ", ZnO test, NACE test, for the description of the tests see below). The reaction and concentration by evaporation in the precursor reactor is carried out at a residence time of 0.5 to 300 minutes, preferably 1 to 20 minutes, and more preferably 2 to 10 minutes, at temperatures above 100 ° C, preferably from 100 to 250 ° C, and particularly preferably from 110 to 220 ° C, and at pressures from 0.01 to 100 bar, preferably from 0.1 to 25 bar and especially preferably from 1 to 100 bar. up to 10 bars. In the high-viscosity reactor are established, with residence times preferably from 20 seconds to 60 minutes, and particularly preferably from 1 minute to 30 minutes, temperatures from 100 to 350 ° C, preferably from 120 to 250 ° C, and particularly preferably from 140 to 220 ° C, and pressures from 0.01 to 10 bar, preferably from 0.1 to 3 bar and more preferably from 0.5 to 2 bar. The solution of ammonium salt of maleic acid can be prepared batchwise or also continuously from water, maleic acid and ammonia and fed to the reactor combination. In this case, the molar ratio between the nitrogen in the ammonia and in the maleic acid is from 0.1 to 25, preferably from 0.5 to 8, and particularly preferably from 0.9 to 4. The proportion in water in the solution is from 20 to 90% by weight, preferably from 20 to 60% by weight, and particularly preferably from 25 to 40% by weight. When the educt solution is prepared in a discontinuous manner, a prior condensation can be produced in the storage tank, in which up to 2 molecules are combined on average. The following industrial application tests and evaluation procedures were used for the comparison of the formed polycondensation products: Determination of the Threshold effect (inhibition of calcium carbonate precipitation by addition of sub-stoichiometric inhibitor) according to a modified method NACE1): 1) NACE: National Association of Corrosion engineers. Solutions evaluated: 1. 12.15 g of calcium chloride dihydrate p.a. 68 g of magnesium chloride hexahydrate p.a. completed with distilled water, free of C02, up to 1,000 ml of solution. 2. 7.36 g of sodium bicarbonate p.a. Completed with distilled water, free of C02, up to 1,000 ml of solution. 3. 1,000 mg of the inhibitory substance to be tested, supplemented with distilled water, free of CO2, up to 1,000 ml of solution. Solutions 1 and 2 should be filtered through a 0.45 μm membrane filter, before use, and should be saturated with carbon dioxide. The inhibitor solutions corresponding to the desired measurement concentration are available in narrow neck, glass bottles of 250 ml: ppm of inhibitor μl of inhibitor solution 1 200 2 400 3 600 5 1,000 10 2,000. On the previously arranged solutions, 100 ml of solutions 1 and 2 are respectively pumped with a 100 ml pipette. Immediately afterwards the bottles are closed perfectly, shaken once by hand and placed in a water bath heated to 70 ° C. At this temperature the samples are stored for 16 hours. As a comparison, a sample without addition of inhibitor is carried out concomitantly. (For the determination of the starting value, the calcium content is determined, by titration, immediately after the mixing of solution 1 and 2). At the end of this time, the samples are removed simultaneously from the water bath and cooled slowly to a temperature of 30 ° C. A 5 mm sample is then filtered through a 0.45 μm membrane filter in an amount of distilled water of about 100 ml and acidified with 0.5 ml of concentrated hydrochloric acid for stabilization. The necessary determination now of the calcium content is carried out by titration against an indicator. The percentage inhibition is calculated as follows: a - b. 100 =% inhibition c - b a: Amount of calcium found in the sample b: Amount of calcium in the blank sample (after tempered) c; Amount of calcium in the blank sample (before tempering). Determination of the dispersion capacity of the solid product in the zinc oxide model. Dissolve 1 g of the dispersing agent to be tested in 50 ml of distilled water. The pH of the sample should be 10. The sample prepared in this way refers to a 100 ml volumetric flask and is completed with distilled water (stock solution). Mixers of 250 ml, 10.0 g of ZnO p.A. (Merck) and suspended with 140 to 170 ml of water. The following amounts of dispersing agents are added to this suspension. 50 ppm 1 ml stock 100 ppm 2 ml stock 250 ppm 5 ml stock 500 ppm 10 ml stock 1,000 ppm 20 ml stock 1,500 ppm 30 ml stock. The mixture is pre-dispersed with a disperser (for example Ultraturrax stirrer) and then completed to 200 ml. The suspension of the finished sample is shaken three times by hand and stored for 3 hours at room temperature. An aliquot of 5 ml is then taken with a pipette with a single label at 150 ml and transferred to a 50 ml graduated flask, in which 10 ml of 1N hydrochloric acid and approximately 20 ml of precursor were placed. Water. After completion of the volumetric flask, an aliquot of 10 ml was added and it was titrated at pH 11 with EDTA solution against indicator. Evaluation: V * t * 81.37 * 5 =% ZnO 0.025100 V = Volume of EDTA solution t = Title of the EDTA solution 81.37 = Molecular weight of ZnO 5 = 50/10 of the volumetric flask of HCl 0.025 = 5/200 of the test tube 100 =% . Example 1. The example described below was carried out according to the general description of process c) using a combination of reactors.

Obtaining NH4 salt solution of maleic acid. 51.7 kg of H20 with a temperature of 60 ° C were placed in a 250 liter tank and 75 kg of solid maleic acid anhydride were added, so that a solution of maleic acid was formed. Then 16.9 kg of ammonia is metered in gaseous state (under refrigeration at 90 to 100 ° C. The solution formed of the maleic acid NH4 salt is tempered at 100 to 105 ° C and pumped at a flow rate of 41 kg. per hour in a polycondensation installation Obtaining the polysuccinimide The condensation installation consists of a pre-heater with a length of 8.4 meters (internal diameter 10 mm), in which the solution is heated up to 192 ° C at a pressure of 10 bar The solution arrives, from the pre-heater, through a diaphragm to a coil evaporator with a length of 15 meters (internal diameter 15 mm), in which the solution of the reaction reaches a temperature of 193 ° C and a pressure of 2.9 bar behind the diaphragm, the reaction mixture is conducted through a pipe, with a length of 6 meters, at 195 ° C, to an apparatus of the Firm List (CRP 12 Konti). The List reactor is concentrated by evaporation to dryness the reaction mixture at temperatures of 190 to 195 ° C and with a number of revolutions of 31 / minute and, in this case, polymerizes completely. The granular polysuccinimide formed is obtained in an amount of about 21 kg per hour. It has a saponification index of 10.61 mmoles NaOH / g PSI. Obtaining the Na salt solution of poliaspara-gínico acid. To an amount, prepared in advance, of 2,100 g of water and 360 g = 9 mol of NaOH, at 20 ° C, under stirring, 1,000 g of polysuccinimide are added in portions. In this case the temperature increases, due to the exotherm, up to 60 ° C and the PSI dissolves. Another 64.4 g = 1.61 moles of NaOH are added, the temperature is raised to 100 to 110 ° C and 3 x 700 g of ammonia-water are removed by distillation with the addition of 2 x 700 g of water. After the addition of 175.6 g of water, 3,000 g of a 43.7% by weight solution of the Na salt of polyaspartic acid are obtained.

Distribution of the NACE assay assays molecular weights ZnO concentration 3 ppm / 10 ppm with GPCl1 ^, 10 - 300 mg [% of the teo- [g / mol] [% of theory] ria] 2.350 80 78/100. Example 2. The example described below was carried out using a single reactor according to the general description of process a) (prior art). Obtaining the solution of the NH4 salt of maleic acid. A solution of the maleic acid NH 4 salt, tempered at 100 to 105 ° C, prepared as in Example 1, is pumped in an amount of 40 kg / hour to a polycondensation facility. Obtaining the Na / NH 4 salt solution of polyaspartic acid. The condensation installation consists of a pre-heater, with a length of 8.4 meters (internal diameter 10 mm), in which the solution is heated to 230 ° C at a pressure of 45 bars. The solution arrives, from the pre-heater, through a diaphragm, to a coil evaporator, with a length of 15 meters (internal diameter 15 mm), in which the solution of the reaction reaches a temperature of 205 ° C and has a pressure of 7.8 bar behind the diaphragm. The reaction mixture is conducted to a tank through a pipe with a length of 6 meters. Simultaneously, 40 kg / hour of aqueous hydroxide solution of 15% sodium hydroxide are dosed in this tank. The aqueous solution formed of polyaspartic acid has a saponification number of 2.09 mmole of NaOH / g of solution. Obtaining the Na salt solution of polyaspartic acid. They are added to a quantity, prepared in advance, of 3,000 g of Na / NH 4 salt solution of polyaspartic acid, 501.6 g = 6.27 mole of 50% NaOH solution. The temperature is raised to 100 to 110. ° C and 3x600 g of water-ammonia are distilled off by the addition of 2x600 g of water. Remaining remain 2,901, 6 g of a 42.8% solution of the Na salt of the PAS. Distribution of the NACE test assays of molecular weights of ZnO 3 ppm / 10 ppm according to GPCM ,,, 10 - 300 mg [% of the teo- [g / mol] [% of theory] ria] 1,450 64 60/79. Example 3. The example described below was carried out according to the general description of process b) (state of the art).

Obtaining the solution of the NH4 salt of maleic acid. A solution of the NH 4 salt of maleic acid, tempered at 100 to 105 ° C, prepared as in example 1, is pumped with an amount of 40 kg / hour to a kneading apparatus for polycondensation. Obtaining the fusion of polycondensate. The tank is connected to the kneading apparatus through a pipe with a length of 29.4 meters (internal diameter 10 to 15 mm), which is heated to 100 to 10 ° C. In the kneading device of the Firma List (CRP 12 Konti), the reaction mixture is polymerized at temperatures of 190 to 195 ° C and at a speed of 31 / minute. The polycondensate formed, a high viscosity melt, is obtained with an amount of approximately 22 kg per hour. This presents a saponification index of 10.51 mmoles NaOH / g of the fusion. Obtaining the Na salt solution of poliaspara-gínico acid. They are added in portions to a quantity, prepared in advance, of 2,100 g of water and 360 g = 9 moles of NaOH, at 20 ° C, with stirring, 1,000 g of polycondensate melt. In this case the temperature increases, due to the exo-termia, up to 60 ° C and the polycondensate dissolves. Another 60.4 g = 1.51 moles of NaOH are added, the temperature increases to 100 to 110 ° C and 3 x 700 g of ammonia-water are removed by distillation with the addition of 2 x 700 g of water.

After the addition of 175.6 g of water, 3,000 g of a 31.9% by weight solution of the Na salt of polyaspartic acid are obtained. Distribution of the NACE assay assays molecular weights ZnO sepsis 3 ppm / 10 ppm according to GPCMW 10 - 300 mg [% of the teo- [g / mol] [% of theory] ria] 1,450 34 42/69 . It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (14)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1.- Procedure for performing polycondensation reactions, characterized in that the polycondensation of a monomer educt with external heat input is carried out in a a reactor combination consisting of at least two stages, formed by a pre-reactor and by a high-viscosity reactor, the low molecular weight dissociation products formed being evaporated off and a concentration of the product of the precursor reactor is carried out in the reactor. the reaction to a viscous prior product and the previous product is reacted completely to give the polycondensation product in the high viscosity reactor with thermal and mechanical energy input with a residence time of 20 seconds to 60 minutes.
2. 2. Method according to claim 1, characterized in that the educt is obtained by the reaction of 1,4-butanedicarboxylic acid or 1,4-bute-nodicarboxylic acid or a derivative thereof, with ammonia or with a compound that supplies ammonia.
3. 3. Process according to claim 1, characterized in that the educt is obtained by the reaction of maleic acid, fumaric acid, malic acid, asparaginic acid, maleic acid anhydride or mixtures thereof with ammonia or with a compound that supplies amoebic acid. Niaco
4. 4. Method according to claim 1, characterized in that an aqueous solution of ammonium salt of maleic acid is used as an educt, which is reacted in the combination of two-stage reactors to give polysuccinimide (PSI) during the reaction of polycondensation.
5. 5. Method according to claim 1, characterized in that the reaction is carried out in a previous reactor with a pressure of 0.01 bar to 100 bar, at temperatures above 100 ° C and with a residence time of 0. , 5 minutes up to 300 minutes and in the high pressure reactor at a temperature of 100 ° C up to 300 ° C and at a pressure of 0.01 bar up to 10 bar.
6. Method according to claim 5, characterized in that the reaction in the previous reactor is carried out at temperatures of 100 ° C to 250 ° C, preferably of 110 ° C to 200 ° C, at a pressure of 0.1 bar up to 25 bar, preferably from 1 bar to 10 bar, and with a residence time of 1 minute to 20 minutes, preferably from 2 to 10 minutes and in the high viscosity reactor at temperatures of 120 ° C to 250 ° C, preferably at 140 ° C up to 220 ° C, at a pressure of 0.1 bar up to 3 bar, preferably 0.5 bar up to 2 bar and with a residence time of 20 seconds up to 60 minutes, preferably 1 minute up to 30 minutes.
7. 7. Process according to claims 4 to 6, characterized in that an aqueous solution of ammonium salt of maleic acid with a molar ratio between the nitrogen in the ammonium salt and the maleic acid of 0.1 is used as starting material. up to 25, preferably from 0.5 to 8, and particularly preferably from 0.9 to 4, the proportion in water being from 20 to 90% by weight, preferably from 20 to 60% by weight, and particularly preferably from 25 to 40% by weight.
8. 8. Method according to claim 1, characterized in that all the types of apparatuses suitable for thermal exchange, which have a sufficient work volume for carrying out the chemical reaction, are used as a preliminary reactor.
9. 9. Process according to claim 1, characterized in that, as a high-viscosity reactor, apparatuses are used that are characterized by a sufficient thermal input and mechanical energy input for mixing and transport as well as for the renewal of the surface of the mixture. the reaction, by a volume of the reactor sufficient to guarantee the residence time (as well as by the capacity to be able to elaborate masses of high viscosity to dryness).
10. 10. Process according to claims 4 to 9, characterized in that the aqueous solution of the ammonium salt of maleic acid is fed to a pre-reactor configured as a coil and because the product of the polycondensation is recirculated and crumbled in the high-viscosity reactor by means of rotating kneading elements. and / or shear elements.
11. 11. Process according to claim 10, characterized in that the product of the polycondensation is concentrated in the high-viscosity reactor until it forms spreadable solid product particles.
12. 12. Process according to at least one of the preceding claims, characterized in that the polymers obtained in the second stage of the reaction are then subjected to a solvolysis, preferably to a hydrolysis.
13. 13. Process according to at least one of the preceding claims, characterized in that the polymers obtained have, if applicable after hydrolysis, basically recurring asparaginic acid units.
14. 14. Use of the polymers obtained according to at least one of the preceding claims in aqueous or non-aqueous systems for the dispersion of inorganic or organic particles, especially for the inhibition and dispersion of precipitates in the treatment of water.