EP0000158A1 - Process for the continuous production of aqueous solutions of salts of alkane dicarboxylic acids with alkane diamines - Google Patents

Process for the continuous production of aqueous solutions of salts of alkane dicarboxylic acids with alkane diamines Download PDF

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EP0000158A1
EP0000158A1 EP78100176A EP78100176A EP0000158A1 EP 0000158 A1 EP0000158 A1 EP 0000158A1 EP 78100176 A EP78100176 A EP 78100176A EP 78100176 A EP78100176 A EP 78100176A EP 0000158 A1 EP0000158 A1 EP 0000158A1
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mixing zone
aqueous
alkane
salts
zone
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German (de)
French (fr)
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EP0000158B1 (en
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Rudi-Heinz Dr. Rotzoll
Paul Dr. Duffner
Ernst Dr. Dietl
Georg Pilz
Gerhard Thiel
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BASF SE
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BASF SE
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/68—Preparation of compounds containing amino groups bound to a carbon skeleton from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/41—Preparation of salts of carboxylic acids
    • C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part

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  • the invention relates to a process for the continuous preparation of aqueous solutions of salts from alkanedicarboxylic acids with 6 to 12 carbon atoms and alkanediamines with 6 to 12 carbon atoms by reacting the corresponding alkanedicarboxylic acids with the respective alkanediamines in an aqueous solution of the salt to be prepared.
  • salts are produced from dicarboxylic acids and diamines, for example hexamethylene diammonium adipate, by reacting dicarboxylic acids and diamines in an alcoholic medium, for example methanol.
  • the corresponding salt precipitates out of the solution and is isolated by centrifugation. Since the operation with volatile flammable solvents is undesirable in technology, it has already started to produce such salts from aqueous solutions.
  • salts of dicarboxylic acids and diamines are obtained by starting from an aqueous solution of the salt to be prepared, which contains the excess dicarboxylic acid in solution and then neutralizing it with the diamine.
  • the technical task was therefore to produce aqueous solutions of salts from dicarboxylic acids and diamines in a continuous manner in such a way that equivalent ratios are maintained.
  • the new method has the advantage that there are no mother liquors that require treatment.
  • the new process is also very flexible and easy to control. It is therefore ideally suited for exercise on a technical scale.
  • the new process enables the continuous production of large quantities with little expenditure on equipment.
  • Alkane dicarboxylic acids with 6 to 12 carbon atoms are used as starting materials. It is preferable to start from straight-chain ⁇ , ⁇ -alkanedicarboxylic acids of the carbon number mentioned. Suitable dicarboxylic acids are, for example, adipic acid, azelaic acid, suberic acid, sebacic acid, decanedioic acid or dodecanedioic acid. Adipic acid and sebacic acid have gained particular technical importance.
  • alkane diamines with 6 to 12 carbon atoms are used as starting materials. It is preferred to start from straight-chain ⁇ , ⁇ -alkanediamines with the stated carbon number. Suitable alkane diamines are, for example, hexamethylene diamine, octamethylene diamine, decamethylene diamine or dodecane methylene diamine. Hexamethylenediamine has gained particular technical importance.
  • the preferred salts are hexamethylene diamonium adipate and hexamethylene diammonium sebacate.
  • concentration of the aqueous solution on the salts prepared is generally 45 to 65, in particular 55 to 65 percent by weight.
  • the alkane dicarboxylic acid to be used in each case is reacted with a corresponding alkane diamine in an aqueous solution of the salt to be prepared in each case. It is understood that the concentration of the aqueous solution of the salt used corresponds to that of the product.
  • the aqueous salt solution is returned from a first mixing zone via a conveying zone and a second mixing zone to the first mixing zone.
  • the amount of salt solution in the first mixing zone is advantageously 2 to 3 times the amount in all other zones and lines of salt solution.
  • the first mixing zone used is a stirred tank or an adequate device with mixing elements, e.g. Circulation pumps, it being important to ensure that the first mixing zone has sufficient buffer capacity compared to the other zones. Continuously pumping pumps such as e.g. Centrifugal pumps.
  • the second mixing zone is advantageously designed as a mixing section, i.e. deflections and / or internals ensure rapid, effective mixing of the medium flowing through. It is advantageous to circulate 40 to 80 times the amount of the content of the first mixing zone every hour.
  • alkanediamine in liquid form and alkanedicarboxylic acid are fed in as an aqueous solution.
  • the alkane diamines are advantageously used in molten form.
  • alkanediamines by adding small amounts of water, e.g. B. liquefy up to 20 percent by weight.
  • Alkane disarsonic acids are advantageously added in 48 to 55 weight percent aqueous solution. It goes without saying that the total amount of water supplied must be such that, after combination, a solution of salts of alkanedicarboxylic acids and alkanediamines corresponding to the desired concentration results.
  • the amount of the alkane diamines added is chosen so that it is below the necessary equivalent amount, based on the amount of dicarboxylic acid. It is advantageous to add 95 to 99 mole percent of the amount of diamine required for equivalence.
  • alkane diamines in particular on the suction side of the delivery zone and then the aqueous solution of alkane dicarboxylic acids, preferably on the pressure side of the delivery zone.
  • the reaction mixture which now contains a small amount of excess alkanedicarboxylic acid, is passed through a second mixing zone in order to ensure salt formation. Subsequent to the second mixing zone, the remaining amount of liquid alkane diamine is fed in, which is necessary to reach the equivalence point.
  • the equivalence point can easily be determined for the individual salts on the basis of the pH value. It is 7.65 for hexamethylene diammonium adipate (measured as a 10% aqueous solution at 25 ° C.) and 7.60 for hexamethylene diammonium sebacate. It is also possible to use a small excess of alkane diamine e.g.
  • alkanediamines add up to 0.5 mole percent and compensate for alkane diamine losses in the condensation.
  • the addition of the remaining amount of alkanediamine advantageously is followed by a further mixing zone, the structure of which corresponds to that of the second mixing zone. It has proven to be useful if the total amount of starting substances supplied per hour, i.e. Alkanediamines, alkanedicarboxylic acids and water correspond to 0.5 to 2 times the amount of aqueous salt solution in the entire circuit.
  • the aqueous solution of salts obtained from alkanedicarboxylic acids and alkanediamines is returned to the first mixing zone.
  • the aqueous solution is advantageously passed through a cooler beforehand. It has proven useful to maintain a temperature of 90 to 102 ° C during the reaction.
  • the addition of the remaining amount of alkane diamines is controlled on the basis of the pH of the aqueous salt solution which is circulated. This happens For example, in such a way that after the addition of the aforementioned starting materials, a small amount of saline solution is continuously taken, diluted to 10%, the pH is measured and, based on the measured pH, the amount of alkane diamine is controlled after the second mixing zone. It is advantageous to use a dilute alkane diamine solution, for example up to 25%, for control purposes.
  • the reaction is usually carried out at atmospheric pressure or slightly elevated pressure.
  • An inert gas atmosphere e.g. Nitrogen atmosphere, upright.
  • the aqueous salt solution is removed from the first mixing zone to the extent that it is formed, e.g. through an overflow.
  • FIG. 1 The method according to the invention is explained for example in FIG. 1.
  • a circulation system consisting of a stirred tank 1 with a stirrer 2, a circuit 3, a feed pump 4, a mixing section 7 and a cooler 11
  • liquid alkane diamine is fed on the suction side of the pump 4 via line 5, while on the pressure side of the pump feeds an aqueous solution of the alkanedicarboxylic acid via line 6.
  • the remaining amount of liquid alkanediamine is fed via line 8.
  • a small portion of the aqueous salt solution is continuously removed via line 9 and diluted to 10% and the pH is measured.
  • the values determined are transmitted as a pulse via the measuring line 10 to the feed line 8 and the feed quantity is thus regulated.
  • the resulting salt solution is removed from the system by the overflow line 12 to the extent that the solution forms.
  • Aqueous solutions of salts from alkanedicarboxylic acids and alkanediamines are used for the production of polyamides.
  • the method according to the invention is illustrated by the following example.
  • a circulation system consisting of a 5 m 3 stirred tank with stirrer, a circulation pump, a mixing section formed by deflection elements, a cooler and a pH control, 3.8 m 3 52.5% adipic acid solution and 1.65 t per hour molten hexamethylenediamine fed. Only so much heat of neutralization is dissipated to keep the system at 98 ° C.
  • a circulation pump 250 m 3 / h AH salt solution are pumped around in a circuit. 10 kg / h of AH salt solution are removed every hour and diluted to 10% AH salt content with water.

Abstract

Kontinuierliche Herstellung wäßriger Lösungen von Salzen aus Alkandicarbonsäuren von 6 bis 12 Kohlenstoffatomen und Alkandiaminen mit 6 bis 12 Kohlenstoffatomen durch Umsetzen der entsprechenden Alkandicarbonsäuren mit den jeweiligen Alkandiaminen in einer wä rigen Lösung des jeweils herzustellenden Salzes, wobei man die wäßrige Salzlösung aus einer ersten Mischzone über eine Förderzone und eine zweite Mischzone zurückleitet, zwischen der ersten und der zweiten Mishzone flüssiges Alkandiamin und eine wäßrige Lösung von Alkandicarbonsäure zuführt, mit der Maßgabe, daß man weniger als die äquivalente Menge an Alkandiamin zuführt, nach der zweiten Mischzone die restliche Menge an flüssigem Alkandiamin zugibt und aus der ersten Mischzone wäßrige Salzlösung in dem Maße entnimmt, wie sie gebildet wird. Die erfindungsgemäß hergestelten Salze werden für die Erzeugung von Polyamiden verwendet.Continuous production of aqueous solutions of salts from alkanedicarboxylic acids of 6 to 12 carbon atoms and alkanediamines with 6 to 12 carbon atoms by reacting the corresponding alkanedicarboxylic acids with the respective alkanediamines in an aqueous solution of the salt to be prepared, the aqueous salt solution being obtained from a first mixing zone via a Conveying zone and a second mixing zone returns, between the first and the second mixing zone liquid alkane diamine and an aqueous solution of alkane dicarboxylic acid, with the proviso that less than the equivalent amount of alkane diamine is added, after the second mixing zone the remaining amount of liquid alkane diamine is added and withdrawing aqueous salt solution from the first mixing zone to the extent that it is formed. The salts produced according to the invention are used for the production of polyamides.

Description

Gegenstand der Erfindung ist ein Verfahren zur kontinuierlichen Herstellung wäßriger Lösungen von Salzen aus Alkandicarbonsäuren mit 6 bis 12 Kohlenstoffatomen und Alkandiaminen mit 6 bis 12 Kohlenstoffatomen durch Umsetzen der entsprechenden Alkandicarbonsäuren mit den jeweiligen Alkandiaminen in einer wäßrigen Lösung des jeweils herzustellenden Salzes.The invention relates to a process for the continuous preparation of aqueous solutions of salts from alkanedicarboxylic acids with 6 to 12 carbon atoms and alkanediamines with 6 to 12 carbon atoms by reacting the corresponding alkanedicarboxylic acids with the respective alkanediamines in an aqueous solution of the salt to be prepared.

Wie aus den bekanntgemachten Unterlagen der NL-Patentanmeldung 65.07519 zu entnehmen ist, werden Salze aus Dicarbonsäuren und Diaminen, z.B. Hexamethylendiammoniumadipat, durch Umsetzen von Dicarbonsäuren und Diaminen im alkoholischen Medium, z.B. Methanol, erzeugt. Das entsprechende Salz fällt aus der Lösung aus und wird durch Zentrifugieren isoliert. Da die Arbeitsweise mit leicht flüchtigen brennbaren Lösungsmitteln in der Technik unerwünscht ist, ist man auch schon dazu übergegangen, solche Salze aus wäßrigen Lösungen zu erzeugen. Entsprechend der DT-OS 24 03 178 erhält man Salze aus Dicarbonsäuren und Diaminen, indem man von einer wäßrigen Lösung des herzustellenden Salzes ausgeht, die überschüssige Dicarbonsäure gelöst enthält und diese dann mit dem Diamin neutralisiert. Das entsprechende Salz fällt dann aus der wäßrigen Lösung aus wobei Schwankungen im pH-Wert der wäßrigen Lösung keinen negativen Effekt auf die Qualität des ausgefallenen Salzes haben. Bei der Herstellung wäßriger Lösungen solcher Salze ist jedoch streng darauf zu achten, daß Dicarbonsäure und Diamine in äquivalenten Mengen angewandt werden, um einen Überschuß der einen oder anderen Komponente zu vermeiden, da dies bei der Polykondensatiön störend wirkt. Feste Salze sind zudem in ihrer Handhabung sehr aufwendig. Deshalb ist man in der Technik dazu übergegangen, wäßrige Lösungen von Salzen aus Dicarbonsäuren und Diaminen für die Polykondensation zu verwenden.As can be seen from the published documents of NL patent application 65.07519, salts are produced from dicarboxylic acids and diamines, for example hexamethylene diammonium adipate, by reacting dicarboxylic acids and diamines in an alcoholic medium, for example methanol. The corresponding salt precipitates out of the solution and is isolated by centrifugation. Since the operation with volatile flammable solvents is undesirable in technology, it has already started to produce such salts from aqueous solutions. According to DT-OS 24 03 178, salts of dicarboxylic acids and diamines are obtained by starting from an aqueous solution of the salt to be prepared, which contains the excess dicarboxylic acid in solution and then neutralizing it with the diamine. The corresponding salt then precipitates out of the aqueous solution, with fluctuations in the pH of the aqueous solution having no negative effect on the quality of the precipitated salt. In the preparation of aqueous solutions of such salts, however, care must be taken to ensure that dicarboxylic acid and diamines are used in equivalent amounts in order to avoid an excess of one or the other component, since this has a disruptive effect on the polycondensation. Solid salts are also very complex to handle. Therefore, there has been a change in technology to use aqueous solutions of salts of dicarboxylic acids and diamines for the polycondensation.

Es war deshalb die technische Aufgabe gestellt, wäßrige Lösungen von Salzen aus Dicarbonsäuren und Diaminen in kontinuierlicher Arbeitsweise so herzustellen, daß äquivalente Verhältnisse eingehalten werden.The technical task was therefore to produce aqueous solutions of salts from dicarboxylic acids and diamines in a continuous manner in such a way that equivalent ratios are maintained.

Diese Aufgabe wird gelös.t in einem kontinuierlichen. Verfahren zur Herstellung wäßriger Lösungen von Salzen aus Alkandicarbonsäuren mit 6 bis 12 Kohlenstoffatomen und Alkandiaminen mit 6 bis 12 Kohlenstoffatomen durch Umsetzen der entsprechenden Alkandicarbonsäuren mit den jeweiligen Alkandiaminen in einer wäßrigen Lösung des jeweils herzustellenden Salzes, wobei man die wäßrige Salzlösung aus einer ersten Mischzone über eine Förderzone und eine zweite Mischzone in die erste Mischzone zurückleitet, zwischen der ersten und der zweiten Mischzone flüssiges Alkandiamin und Alkandicarbonsäure als wäßrige Lösung zuführt, mit der Maßgabe, daß man weniger als die äquivalente Menge an Alkandiamin zuführt, nach der zweiten Mischzone die restliche Menge flüssiges Alkandiamin zugibt und aus der ersten Mischzone wäßrige Salzlösung in dem Maße entnimmt, wie sie gebildet wird.This task is solved in a continuous. Process for the preparation of aqueous solutions of salts from alkanedicarboxylic acids with 6 to 12 carbon atoms and alkanediamines with 6 to 12 carbon atoms by reacting the corresponding alkanedicarboxylic acids with the respective alkanediamines in an aqueous solution of the salt to be prepared in each case, the aqueous salt solution being passed from a first mixing zone over a Conveying zone and a second mixing zone leads back into the first mixing zone, liquid alkane diamine and alkane dicarboxylic acid are fed as an aqueous solution between the first and second mixing zone, with the proviso that less than the equivalent amount of alkane diamine is fed, the remaining amount of liquid after the second mixing zone Alkanediamine is added and aqueous salt solution is removed from the first mixing zone to the extent that it is formed.

5as neue Verfahren hat den Vorteil, daß keine Mutterlaugen anfallen, die behandlungebedürftig sind. Ferner ist das neue Verfahren sehr flexibel und leicht regelbar. Es eignet sich deshalb in hervorragender Weise für die Ausübung im technischen Maßstab. Das neue Verfahren gestattet die kontinuierliche Herstellung großer Mengen mit kleinem apparativem Aufwand.The new method has the advantage that there are no mother liquors that require treatment. The new process is also very flexible and easy to control. It is therefore ideally suited for exercise on a technical scale. The new process enables the continuous production of large quantities with little expenditure on equipment.

Als Ausgangsstoffe verwendet man Alkandicarbonsäuren mit 6 bis 12 Kohlenstoffatomen. Bevorzugt geht man von gerad- kettigenα,ω-Alkandicarbonsäuren der genannten Kohlenstoffzahl aus. Geeignete Dicarbonsäuren sind beispielsweise Adipinsäure, Azelainsäure, Korksäure, Sebacinsäure, Decandisäure oder Dodecandisäure. Besonders technische Bedeutung haben Adipinsäure und Sebacinsäure erlangt.Alkane dicarboxylic acids with 6 to 12 carbon atoms are used as starting materials. It is preferable to start from straight-chain α, ω-alkanedicarboxylic acids of the carbon number mentioned. Suitable dicarboxylic acids are, for example, adipic acid, azelaic acid, suberic acid, sebacic acid, decanedioic acid or dodecanedioic acid. Adipic acid and sebacic acid have gained particular technical importance.

Ferner verwendet man als Ausgangsstoffe Alkandiamine mit 6 bis 12 Kohlenstkffatomen. Bevorzugt geht man von geradkettigen α,ω-Alkandiaminen mit der genannten Kohlenstoffzahl aus. Geeignete Alkandiamine sind beispielsweise Hexamethylendiamin, Octamethylendiamin, Decamethylendiamin oder Dodecanmethylendiamin. Besonders technische Bedeutung hat Hexamethylendiamin erlangt.Furthermore, alkane diamines with 6 to 12 carbon atoms are used as starting materials. It is preferred to start from straight-chain α, ω-alkanediamines with the stated carbon number. Suitable alkane diamines are, for example, hexamethylene diamine, octamethylene diamine, decamethylene diamine or dodecane methylene diamine. Hexamethylenediamine has gained particular technical importance.

Demzufolge sind die bevorzugten Salze Hexamethylendiamoniumadipat un4 Hexamethylendiammoniumsebacat. Die Konzentration der wäßrigen Lösung an den hergestellten Salzen beträgt in der Regel 45 bis 65, insbesondere 55 bis 65 Gewichtsprozent.Accordingly, the preferred salts are hexamethylene diamonium adipate and hexamethylene diammonium sebacate. The concentration of the aqueous solution on the salts prepared is generally 45 to 65, in particular 55 to 65 percent by weight.

Die jeweils zu verwendende Alkandicarbonsäure wird mit einem entsprechenden Alkandiamin in einer wäßrigen Lösung des jeweils herzustellenden Salzes umgesetzt. Es versteht sich, daß die Konzentration der verwendeten wäßrigen Lösung des Salzes derjenigen des Erzeugnisses entspricht.The alkane dicarboxylic acid to be used in each case is reacted with a corresponding alkane diamine in an aqueous solution of the salt to be prepared in each case. It is understood that the concentration of the aqueous solution of the salt used corresponds to that of the product.

Die wäßrige Salzlösung wird aus einer ersten Mischzone über' eine Förderzone und eine zweite Mischzone in die erste Mischzone zurückgeleitet. Vorteilhaft beträgt die in der ersten Mischzone befindliche Menge an Salzlösung das 2- bis 3-fache gegenüber der in sämtlichen übrigen Zonen und Leitungen befindlichen Menge an Salzlösung. In der Regel verwendet man als erste Mischzone einen Rührkessel oder eine adäquate Vorrichtung mit Mischorganen, z.B. Kreislaufpumpen, wobei darauf zu achten ist, daß die erste Mischzone eine ausreichende Pufferkapazität gegenüber den übrigen Zonen aufweist. Als Förderzone verwendet man kontinuierlich fördernde Pumpen, wie z.B. Kreiselpumpen. Die zweite Mischzone ist vorteilhaft als Mischstrecke ausgebildet, d.h. man sorgt durch Umlenkungen und/oder Einbauten für eine rasche wirkungsvolle Durchmischung des durchströmenden Mediums. Vorteilhaft wird Stündlich die 40- bis 80-fache Menge des Inhalts der ersten Mischzone im Kreis geführt.The aqueous salt solution is returned from a first mixing zone via a conveying zone and a second mixing zone to the first mixing zone. The amount of salt solution in the first mixing zone is advantageously 2 to 3 times the amount in all other zones and lines of salt solution. As a rule, the first mixing zone used is a stirred tank or an adequate device with mixing elements, e.g. Circulation pumps, it being important to ensure that the first mixing zone has sufficient buffer capacity compared to the other zones. Continuously pumping pumps such as e.g. Centrifugal pumps. The second mixing zone is advantageously designed as a mixing section, i.e. deflections and / or internals ensure rapid, effective mixing of the medium flowing through. It is advantageous to circulate 40 to 80 times the amount of the content of the first mixing zone every hour.

Zwischen der ersten Mischzone und der zweiten Mischzone wird Alkandiamin in flüssiger Form und Alkandicarbonsäure als wäßrige Lösung zugeführt. Die Alkandiamine werden vorteilhaft in geschmolzener Form angewandt. Es ist jedoch auch möglich, Alkandiamine durch Zugabe von geringen Mengen an Wasser, z. B. bis zu 20 Gewichtsprozent zu verflüssigen. Alkandisarsonsäuren werden vorteilhaft in 48 bis 55 gewichtsprezentiger wäßriger Lösung zugeführt. Es versteht sich, daß die insgesamt zugeführte Menge an Wasser so bemessen sein muß, daß nach Vereinigung eine der gewünschten Konsentration entsprechende Lösung von Salzen aus Alkandicarbensäuren und Alkandiaminen resultiert. Die Menge der zugelünrzen Alkandiamine wird so gewählt, daß sie unterhalb der nötigen äquivalenten Menge, bezogen auf die Menge an Dicar- bensäure, liegt. Vorteilhaft führt man 95 bis 99 Molprozent der zu Äquivalenz nötigen Diaminmenge zu.Between the first mixing zone and the second mixing zone, alkanediamine in liquid form and alkanedicarboxylic acid are fed in as an aqueous solution. The alkane diamines are advantageously used in molten form. However, it is also possible to add alkanediamines by adding small amounts of water, e.g. B. liquefy up to 20 percent by weight. Alkane disarsonic acids are advantageously added in 48 to 55 weight percent aqueous solution. It goes without saying that the total amount of water supplied must be such that, after combination, a solution of salts of alkanedicarboxylic acids and alkanediamines corresponding to the desired concentration results. The amount of the alkane diamines added is chosen so that it is below the necessary equivalent amount, based on the amount of dicarboxylic acid. It is advantageous to add 95 to 99 mole percent of the amount of diamine required for equivalence.

Vorteilhaft führt man zunächst Alkandiamine zu insbesondere' auf der Saugseite der Förderzone und dann die wäßrige Lösung an Alkandicarbonsäuren, vorzugsweise auf der Druckseite der Förderzone.It is advantageous first to carry out alkane diamines in particular on the suction side of the delivery zone and then the aqueous solution of alkane dicarboxylic acids, preferably on the pressure side of the delivery zone.

Das Reaktionsgemisch, das nun eine geringe Menge an überschüssiger Alkandicarbonsäure enthält, wird durch eine zweite Mischzone geleitet, um eine Salzbildung zu gewährleisten. Anschließend an die zweite Mischzone wird die restliche Menge an flüssigem Alkandiamin zugeführt, die zur Erreichung des Äquivalenzpunktes erforderlich ist. Der Äquivalenzpunkt läßt sich für die einzelnen Salze leicht anhand des pH-Wertes bestimmen. Er beträgt für Hexamethylendiammoniumadipat 7,65 (gemessen als 10 %-ige wäßrige Lösung bei 25°C) und für Hexamethylendiammoniumsebacat 7,60. Es ist auch möglich Alkandiamin in geringem Überschuß z.B. bis zu 0,5 Molprozent zuzusetzen und Verluste an Alkandiamin bei der Kondensation auszugleichen. Vorteilhaft folgt auf die Zugabe der restlichen Menge an Alkandiamin eine weitere Mischzone, die in ihrem Aufbau der zweiten Mischzone entspricht. Es hat sich bewährt, wenn die stündlich insgesamte zugeführte Menge an Ausgangsatoffen, d.h. Alkandiaminen, Alkandicarbonsäuren und Wasser dem 0,5 bis 2-fachen der im gesamten Kreislauf befindlichen Menge an wäßriger Salzlösung entspricht.The reaction mixture, which now contains a small amount of excess alkanedicarboxylic acid, is passed through a second mixing zone in order to ensure salt formation. Subsequent to the second mixing zone, the remaining amount of liquid alkane diamine is fed in, which is necessary to reach the equivalence point. The equivalence point can easily be determined for the individual salts on the basis of the pH value. It is 7.65 for hexamethylene diammonium adipate (measured as a 10% aqueous solution at 25 ° C.) and 7.60 for hexamethylene diammonium sebacate. It is also possible to use a small excess of alkane diamine e.g. add up to 0.5 mole percent and compensate for alkane diamine losses in the condensation. The addition of the remaining amount of alkanediamine advantageously is followed by a further mixing zone, the structure of which corresponds to that of the second mixing zone. It has proven to be useful if the total amount of starting substances supplied per hour, i.e. Alkanediamines, alkanedicarboxylic acids and water correspond to 0.5 to 2 times the amount of aqueous salt solution in the entire circuit.

Die erhaltene wäßrige Lösung von Salzen aus Alkandicarbonsäuren und Alkandiaminen wird wieder in die erste Mischzone zurückgeführt. Vorteilhaft wird die wäßrige Lösung vorher durch einen Kühler geleitet. Es hat sich bewährt, wenn man bei der Umsetzung eine Temperatur von 90 bis 102°C aufrecht erhält.The aqueous solution of salts obtained from alkanedicarboxylic acids and alkanediamines is returned to the first mixing zone. The aqueous solution is advantageously passed through a cooler beforehand. It has proven useful to maintain a temperature of 90 to 102 ° C during the reaction.

Besonders vorteilhaft ist es, wenn man die Zugabe der restlichen Menge an Alkandiaminen aufgrund des pH-Wertes der im Kreis geführten wäßrigen Salzlösung steuert. Dies erfolgt z.B. so, daß man nach der Zugabe der vorgenannten Äusgangsstoffe fortlaufend eine kleine Menge an Salzlösung entnimmt, diese auf 10 % verdünnt, den pH-Wert mißt und aufgrund des .gemessenen pH-Werts die Zugabemenge an Alkandiamin nach der zweiten Mischzone steuert. Vorteilhaft ist es wenn man zur Steuerung eine verdünnte Alkandiaminlösung, z.B. bis zu 25 %-ig anwendet.It is particularly advantageous if the addition of the remaining amount of alkane diamines is controlled on the basis of the pH of the aqueous salt solution which is circulated. this happens For example, in such a way that after the addition of the aforementioned starting materials, a small amount of saline solution is continuously taken, diluted to 10%, the pH is measured and, based on the measured pH, the amount of alkane diamine is controlled after the second mixing zone. It is advantageous to use a dilute alkane diamine solution, for example up to 25%, for control purposes.

Die Umsetzung wird in der Regel bei Atmosphärendruck oder schwach erhöhtem Druck zugeführt. In der ersten Mischzone hält man vorteilhaft eine Inertgasatmosphäre, z.B. Stickstoffatmosphäre, aufrecht. Aus der ersten Mischzone wird die wäßrige Salzlösung in dem Maße entnommen, wie sie entsteht, z.B. durch einen Überlauf.The reaction is usually carried out at atmospheric pressure or slightly elevated pressure. An inert gas atmosphere, e.g. Nitrogen atmosphere, upright. The aqueous salt solution is removed from the first mixing zone to the extent that it is formed, e.g. through an overflow.

Das Verfahren nach der Erfindung wird beispielsweise an Figur 1 erläutert. In ein Kreislaufsystem, bestehend aus einem Rührkessel 1 mit einem Rührer 2, einem Kreislauf 3, einer Förderpumpe 4, einer Mischstrecke 7 und einem Kühler 11 wird auf der Saugseite der Pumpe 4 über Leitung 5 flüssiges Alkandiamin zugeführt, während man auf der Druckseite der Pumpe über die Leitung 6 eine wäßrige Lösung der Alkandicarbonsäure zuführt. Über die Leitung 8 wird die restliche Menge an flüssigem Alkandiamin zugeführt. Mittels Leitung 9 .entnimmt man fortlaufend einen kleinen Teil der wäßrigen Salzlösung und verdünnt sie auf 10 % und mißt den pH-Wert. Die ermittelten Werte werden als Impuls über die Meßleitung 10 auf die Zuführungsleitung 8 übertragen und so die Zulaufmenge geregelt. Die entstehende Salzlösung wird mittels der Überlaufleitung 12 dem System in dem Maße entnommen, wie sich die Lösung bildet.The method according to the invention is explained for example in FIG. 1. In a circulation system, consisting of a stirred tank 1 with a stirrer 2, a circuit 3, a feed pump 4, a mixing section 7 and a cooler 11, liquid alkane diamine is fed on the suction side of the pump 4 via line 5, while on the pressure side of the pump feeds an aqueous solution of the alkanedicarboxylic acid via line 6. The remaining amount of liquid alkanediamine is fed via line 8. A small portion of the aqueous salt solution is continuously removed via line 9 and diluted to 10% and the pH is measured. The values determined are transmitted as a pulse via the measuring line 10 to the feed line 8 and the feed quantity is thus regulated. The resulting salt solution is removed from the system by the overflow line 12 to the extent that the solution forms.

Wäßrige Lösungen von Salzen aus Alkandicarbonsäuren und Alkandiaminen werden zur Herstellung von Polyamiden verwendet. Das Verfahren nach der Erfindung sei an folgendem Beispiel veranschaulicht.Aqueous solutions of salts from alkanedicarboxylic acids and alkanediamines are used for the production of polyamides. The method according to the invention is illustrated by the following example.

Beispielexample

Einem Kreislaufsystem, bestehend aus einem 5 m3 Rührkessel mit Rührer, einer Kreislaufpumpe, einer durch Umlenkorgane gebildeten Mischstrecke, einem Kühler und einer pH-Regelung werden stündlich 3,8 m3 52,5 %-ige Adipinsäure-Lösung und 1,65 t geschmolzenes Hexamethylendiamin zugeführt. Es wird nur soviel Neutralisationswärme abgeführt, um das System auf 980C zu halten. Mit einer Kreislaufpumpe werden 250 m3/h AH-Salz-Lösung im Kreis umgepumpt. Stündlich werden 10 kg/h AH-Salz-Lösung entnommen und mit Wasser auf 10 % AH-Salz-Gehalt verdünnt. Ober den pH-Wert dieser Lösung erfolgt die Steuerung der Zugabe von 10 %-igem Hexamethylendiamin, welches zum Erreichen der Äquivalenz von pH 7,65 noch nötig ist. über einen standhaltenden Syphon fließen stündlich 5,95 m3 63 %-ige AH-Salz-Lösung aus dem Kreislaufsystem ab.A circulation system consisting of a 5 m 3 stirred tank with stirrer, a circulation pump, a mixing section formed by deflection elements, a cooler and a pH control, 3.8 m 3 52.5% adipic acid solution and 1.65 t per hour molten hexamethylenediamine fed. Only so much heat of neutralization is dissipated to keep the system at 98 ° C. With a circulation pump, 250 m 3 / h AH salt solution are pumped around in a circuit. 10 kg / h of AH salt solution are removed every hour and diluted to 10% AH salt content with water. The pH of this solution is used to control the addition of 10% hexamethylenediamine, which is still necessary to achieve the equivalence of pH 7.65. 5.95 m 3 63% AH salt solution flows out of the circulatory system every hour via a siphon.

Claims (6)

1. Verfahren zur kontinuierlichen Herstellung wäßriger Lösungen von Salzen aus Alkandicarbonsäuren von 6 bis 12 Kohlenstoffatomen und Alkandiaminen mit 6 bis 12 Kohlenstoffatomen durch Umsetzen der entsprechenden Alkandicarbonsäuren mit den jeweiligen Alkandiaminen in einer wäßrigen Lösung des jeweils herzustellenden Salzes, dadurch kennzeichnet, daß man die wäßrige Salzlösung aus einer ersten Mischzone über eine Förderzone und eine zweite Mischzone in die erste Mischzone zurückleitet, zwischen der ersten und der zweiten Mischzone flüssiges Alkandiamin und eine wäßrige Lösung von Alkandicarbonsäure zuführt, mit der Maßgabe, daß man weniger als die äquivalente Menge an Alkandiamin zuführt, nach der zweiten Mischzone die restliche Menge an flüssigem Alkandiamin zugibt und aus der ersten Mischzone wäßrige Salzlösung in dem Maße entnimmt, wie sie gebildet wird.1. A process for the continuous preparation of aqueous solutions of salts from alkanedicarboxylic acids of 6 to 12 carbon atoms and alkanediamines with 6 to 12 carbon atoms by reacting the corresponding alkanedicarboxylic acids with the respective alkanediamines in an aqueous solution of the salt to be prepared, characterized in that the aqueous salt solution returns from a first mixing zone via a conveying zone and a second mixing zone into the first mixing zone, supplies liquid alkanediamine and an aqueous solution of alkanedicarboxylic acid between the first and second mixing zones, with the proviso that less than the equivalent amount of alkanediamine is added the remaining amount of liquid alkane diamine is added to the second mixing zone and aqueous salt solution is removed from the first mixing zone to the extent that it is formed. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man auf der Saugseite der Förderzone flüssiges Alkandiamin zuführt.2. The method according to claim 1, characterized in that liquid alkane diamine is supplied on the suction side of the conveying zone. 3. Verfahren nach Ansprüchen 1 und 2, dadurch gekennzeichnet, daß man auf der Druckseite der Förderzone die wäßrige Lösung an Alkandicarbonsäure zuführt.3. Process according to Claims 1 and 2, characterized in that the aqueous solution of alkanedicarboxylic acid is supplied on the pressure side of the conveying zone. 4. Verfahren nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß die Zugabe der restlichen Menge an flüssigem Alkandiamin durch den pH-Wert der wäßrigen Salzlösung vor dem Wiedereintritt in die erste Mischzene gesteuert wird.4. The method according to claims 1 to 3, characterized in that the addition of the remaining amount of liquid alkane diamine is controlled by the pH of the aqueous salt solution before re-entry into the first mixing scene. 5. Verfahren nach den Ansprüchen 1 bis 4, dadurch gekennzeichnet, daß man die 40- bis 80-fache Menge an der in der ersten Mischzone befindlichen Salzlösung stündlich umwälzt.5. Process according to claims 1 to 4, characterized in that the 40- to 80-fold amount of the salt solution in the first mixing zone is circulated every hour. 6. Verfahren nach den Ansprüchen 1 bis 5, dadurch gekennzeichnet, daß man eine Temperatur von 90 bis 102°C einhält.6. Process according to claims 1 to 5, characterized in that a temperature of 90 to 102 ° C is maintained.
EP78100176A 1977-06-27 1978-06-16 Process for the continuous production of aqueous solutions of salts of alkane dicarboxylic acids with alkane diamines Expired EP0000158B1 (en)

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WO1998054119A1 (en) * 1997-05-30 1998-12-03 Sigma-Tau Healthscience S.P.A. Water-soluble salts of dodecandioic acid and pharmaceutical and nutritional compositions containing same
EP2546227A1 (en) * 2011-07-11 2013-01-16 Uhde Inventa-Fischer GmbH Method for producing an aqueous solution of salts

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US4442260A (en) * 1983-03-14 1984-04-10 E. I. Du Pont De Nemours & Company Preparation of salt solution useful for making nylon
FR2916756B1 (en) * 2007-06-04 2009-07-17 Rhodia Recherches & Tech METHOD FOR MANUFACTURING A SOLUTION OF DIACID / DIAMINE SALTS
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CN104130133B (en) * 2013-05-01 2018-01-19 英威达纺织（英国）有限公司 Feedforward process control in nylon salt solution preparation method
TW201446729A (en) * 2013-05-01 2014-12-16 Invista Tech Sarl Nylon salt solution preparation processes with trim diamine
TW201529640A (en) 2013-12-17 2015-08-01 Invista Tech Sarl Process for producing partially balanced acid solution with vessel having a disperser head for nylon salt production
CN104555163B (en) * 2014-12-26 2017-08-15 河南神马尼龙化工有限责任公司 A kind of nylon salt aqueous solution storage device and storage method
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US6255503B1 (en) 1997-05-30 2001-07-03 Sigma-Tau Healthscience S.P.A. Water-soluble salts of dodecandioic acid and pharmaceutical and nutritional compositions containing same
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WO2013007451A1 (en) * 2011-07-11 2013-01-17 Uhde Inventa-Fischer Gmbh Method for producing an aqueous solution of salts
RU2602817C2 (en) * 2011-07-11 2016-11-20 Уде Инвента-Фишер ГмбХ Method of producing aqueous salt solution
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DE2861152D1 (en) 1981-12-24
DE2728818A1 (en) 1979-01-04
US4233234A (en) 1980-11-11
JPS6223736B2 (en) 1987-05-25
EP0000158B1 (en) 1981-10-14
DE2728818B2 (en) 1979-08-30
IT7824770A0 (en) 1978-06-20
IT1096589B (en) 1985-08-26
JPS5412317A (en) 1979-01-30
DE2728818C3 (en) 1980-05-08

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