+

WO2003046035A1 - Method for the production of oxymethylene homo- or co-polymers - Google Patents

Method for the production of oxymethylene homo- or co-polymers Download PDF

Info

Publication number
WO2003046035A1
WO2003046035A1 PCT/EP2002/013451 EP0213451W WO03046035A1 WO 2003046035 A1 WO2003046035 A1 WO 2003046035A1 EP 0213451 W EP0213451 W EP 0213451W WO 03046035 A1 WO03046035 A1 WO 03046035A1
Authority
WO
WIPO (PCT)
Prior art keywords
formaldehyde
polyoxymethylene glycols
water
stage
aqueous solution
Prior art date
Application number
PCT/EP2002/013451
Other languages
German (de)
French (fr)
Inventor
Eckhard Ströfer
Harald Armbruster
Gitta Egbers
Reinhard Freyhof
Thorsten Friese
Ludwig E. Heck
Peter Hildenbrand
Hartmut Zeiner
Stephan Scholl
Hans-Helmut Görtz
Original Assignee
Basf Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Basf Aktiengesellschaft filed Critical Basf Aktiengesellschaft
Priority to AU2002356750A priority Critical patent/AU2002356750A1/en
Priority to DE10295499T priority patent/DE10295499B4/en
Publication of WO2003046035A1 publication Critical patent/WO2003046035A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
    • C08G2/08—Polymerisation of formaldehyde
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G4/00—Condensation polymers of aldehydes or ketones with polyalcohols; Addition polymers of heterocyclic oxygen compounds containing in the ring at least once the grouping —O—C—O—

Definitions

  • the invention relates to a process for the production of oxymethylene homo- or copolymers from an aqueous solution containing formaldehyde and polyoxymethylene glycols.
  • Polyoxymethylene homo- or copolymers are used as engineering plastics in a variety of applications.
  • polyoxymethylene homo- or copolymers are known. They can be produced, for example, by polymerizing trioxane or formaldehyde gas. The reaction is started by initiators such as BF 3 etherate and carried out with the addition of regulators such as methylal, butylal or dimethyl formal. The polymerization can be carried out in reaction extruders, shell belts, twin-screw mixers, kneaders or in suspension in an organic suspending agent.
  • Production usually starts from methanol as the starting product, which is converted into formaldehyde in large-scale industrial processes.
  • methanol is partially oxidized and dehydrated in a silver contact process.
  • an approximately 50% aqueous formaldehyde solution is obtained.
  • the formaldehyde solution is converted to trioxane after concentration in the presence of acidic catalysts.
  • the trioxane which is only about 2% in equilibrium with formaldehyde, is driven off by distillation together with water and formaldehyde and concentrated in a downstream column.
  • a water-immiscible solvent such as methylene Chloride or benzene is enriched in trioxane.
  • the trioxane must be purified further in order to be usable for the polymerization.
  • polyacetals For a general description of the production of polyacetals, reference can be made to engineering thermoplastics: polycarbonate, polyacetals, polyester, cellulose esters, publisher Ludwig Bottenbruch, ISBN 3-446-16368-9, in particular chapter 4, pages 300 to 331.
  • the known ner processes for the production of oxymethylene homo- and copolymers have a number of disadvantages.
  • numerous and complex separation steps are necessary to obtain high-purity formaldehyde or trioxane.
  • the separation is carried out using often chlorine-containing extracting agents, which have to be worked up or disposed of separately.
  • the object of the present invention is to provide a process for the preparation of oxymethylene homo- or copolymers which avoids the disadvantages of the known ner processes and in particular can be carried out more cheaply in terms of apparatus, the number of separation steps being able to be reduced.
  • the object is achieved according to the invention by a process for the production of oxymethylene homo- or copolymers from an aqueous solution containing formaldehyde and polyoxymethylene glycols
  • step (2) the polyoxymethylene glycols obtained in stage 1 are converted into oxymethylene homo- or copolymers in the presence of polycondensation catalysts with removal of water.
  • the aqueous solution used in step (1) and containing formaldehyde and polyoxymethylene glycols is preferably prepared by customary dehydrogenation of methanol. Reference can be made to the literature cited at the beginning.
  • oxymethylene homopolymers or copolymers can be prepared from polyoxymethylene glycols in an advantageous manner.
  • Formaldehyde is not only present in aqueous solutions in monomeric form, but also in the form of oligomers, so-called polyoxymethylene glycols. There is a thermodynamic equilibrium between the monomers and oligomers of different lengths.
  • the ner driving according to the invention now makes use of the fact that the oligomers present in equilibrium are themselves polyoxymethylene precursors which, according to the invention, are linked to the oxymethylene homo- or copolymers.
  • trioxane as an intermediate or a high purification, as is required in the known method, is not necessary. It has been found according to the invention that after at least partial separation of water and formaldehyde from an aqueous solution containing formaldehyde and polyoxymethylene glycols (in thermodynamic equilibrium), the phase obtained contains polyoxymethylene glycols, in which the molar ratio of polyoxymethylene glycols to formaldehyde is greater than 1: Is 0.6, can be converted directly into a polycondensation for the preparation of oxymethylene homo- or copolymers.
  • the molar ratio of polyoxymethylene glycols to monomeric formaldehyde and methylene glycol is preferably 1: 0.4 to 1: 0.
  • Polyoxymethylene glycols can have, for example, two to nine carbon atoms. In this case, mixtures of dioxymethylene glycol, trioxymethylene glycol, tetraoxymethylene glycol, pentaoxymethylene glycol, hexaoxymethylene glycol, heptaoxymethylene glycol, octaoxymethylene glycol and ⁇ onaoxymethylene glycol are used.
  • the mixture used in step (2) which contains the higher homologues of formaldehyde, can be prepared from a conventional formaldehyde solution by known methods for shifting the equilibrium to the side of the higher homologues.
  • formaldehyde and water are preferably at least partially evaporated from an aqueous solution containing formaldehyde and polyoxymethylene glycols. fung removed, and the remaining polyoxymethylene glycols are implemented in step (2) before establishing a thermodynamic equilibrium.
  • the evaporation can be carried out, for example, in a film evaporator or a distillation device.
  • Thin-film evaporators such as falling film evaporators or rotary film evaporators or reaction columns are preferably used.
  • a formaldehyde solution can be depressurized at a temperature of 50 to 150 ° C in a reaction column by greatly reducing the pressure under which the solution is, whereby the higher homologues of formaldehyde remain in the solution and monomeric formaldehyde formed from methylene glycol evaporated. Since the equilibrium between the higher homologues of formaldehyde and the monomeric formaldehyde in the solution is restored within 0.5 to 15 minutes at usual temperatures of 30 to 70 ° C, i.e.
  • the solution with the high proportion of higher homologues of formaldehyde according to the invention is preferably used within 10 minutes after its preparation in stage (1) in the process according to the invention in stage (2).
  • the further reaction is particularly preferably carried out within 5 minutes.
  • stage (1) Suitable processes for carrying out stage (1) are described, for example, in EP-A 0 934 922 and DE-A 199 25 870.
  • the polyoxymethylene glycols are used for the production of methylendi (phenylamine).
  • DE-A 199 25 870 does not contain any instructions for use.
  • a suitable device for carrying out stage (1) is described in this application, see also FIGS. 1 to 3.
  • the polyoxymethylene glycols obtained by the evaporation in stage (1) preferably have a water content of at most 35% by weight, particularly preferably at most 30% by weight, in particular at most 25% by weight, based on the mixture.
  • the reaction in step (2) can be carried out in any suitable device in which polyoxymethylene glycols can be converted to oxymethylene homo- or copolymers in the presence of polycondensation catalysts with the removal of water.
  • the reaction is preferably carried out in a list dryer, twin-shaft kneader or twin-shaft mixer with the possibility of degassing.
  • the reaction is particularly preferably carried out in a twin-screw extruder which has several degassing devices in the course of the screw.
  • a suitable twin-screw extruder is described, for example, in EP-A 0 080 656.
  • the twin-screw extruder described there (ZSK 30 from Werner and Pfleiderer) has an L: D ratio of 20.
  • the extruder has several sectors separated by baffle elements.
  • the polymerization or polycondensation is carried out in a first sector, while degassing and assembly are carried out in a second sector.
  • degassing and assembly are carried out in a second sector.
  • At least some of the water / formaldehyde mixture separated off in stage (1) can be removed, and the remaining formaldehyde can be returned to stage (1) after the thermodynamic equilibrium has been established.
  • stage (2) the polycondensation is carried out in the presence of catalysts customary for polycondensation.
  • catalysts customary for polycondensation Reference can be made to the literature cited at the beginning.
  • Typical polycondensation catalysts which can be used according to the invention are, for example, hydrochloric acid, phosphoric acid, methanesulfonic acid and their mixtures with phosphorus pentoxide, polyphosphoric acid esters, chlorine, sulfur and phosphorus-containing acids such as phosphorous acid, hypophosphorous acid and their alkali and alkaline earth metal salts, hypochlorous acid, perchloric acid and other such acids.
  • the polycondensation is carried out under conditions under which water can be continuously discharged from the reaction mixture. Pressure and temperature are set so that water can be drawn off from the reaction mixture. For example, atmospheric pressure or negative pressure can be used. The temperature is chosen to be as low as possible, for example in the range from 50 to 100.degree. In stages (1) and / or (2), customary comonomers, regulators, other auxiliaries or mixtures thereof can also be added.
  • Possible comonomers include oxocyclic compounds of small ring size with the structural features of an ether, acetal or lactone.
  • epoxides have become important, especially ethylene oxide.
  • Propylene oxide, styrene oxide, epichlorohydrin, 3,3-bis-chloromethyloxocyclobutane in addition to substituted glycidylphenyl ether or ethyl glycidate can be mentioned as further examples of polymerizable ethers.
  • Bifunctional comonomers with two polymerizable groups can also be used, so that weakly crosslinked terpolymers are obtained. These include, for example, diepoxides, diacetals or compounds each with an epoxy and cyclic acetal group.
  • Suitable cyclic acetals are dioxolane, 1,3-dioxane, 1,3-dioxepane (butanediol formal), 1,3,5-trioxepane, 1,3,6-trioxolane and substituted trioxolanes.
  • 1,3-dioxepane is used here.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)

Abstract

According to the invention, the production of oxymethylene homo- or co-polymers from an aqueous solution of formaldehyde and polyoxymethylene glycols is achieved, whereby 1) in a separation stage, water and formaldehyde are at least partly separated out from the aqueous solution, such that a phase containing polyoxymethylene glycols is obtained, in which the molar ratio of polyoxymethylene glycols to formaldehyde is greater than 1:0.6 and 2) the polyoxymethylene glycols obtained in stage 1) are reacted in the presence of polycondensation catalysts with abstraction of water to give oxymethylene homo- or co-polymers.

Description

Verfahren zur Herstellung von Oxymethylenhomo- oder -copolymeren Process for the preparation of oxymethylene homo- or copolymers
Die Erfindung betrifft ein Nerfahren zur Herstellung von Oxymethylenhomo- oder co- polymeren aus einer Formaldehyd und Polyoxymethylenglykole enthaltenden wässrigen Lösung.The invention relates to a process for the production of oxymethylene homo- or copolymers from an aqueous solution containing formaldehyde and polyoxymethylene glycols.
Polyoxymethylenhomo- oder copolymere werden als technische Kunststoffe in einer Vielzahl von Anwendungen eingesetzt.Polyoxymethylene homo- or copolymers are used as engineering plastics in a variety of applications.
Unterschiedliche Nerfahren zur Herstellung von Polyoxymethylenhomo- oder copolymeren sind bekannt. Sie können beispielsweise durch Polymerisation von Trioxan oder Formaldehyd-Gas hergestellt werden. Die Umsetzung wird dabei durch Initiatoren wie BF3- Etherat gestartet und unter Zusatz von Reglern wie Methylal, Butylal oder Dimethylformal durchgeführt. Die Polymerisation kann in Reaktionsextrudern, Schalenbändern, Zweiwellenmischern, Knetern oder in Suspension in einem organischen Suspensionsmittel durchgeführt werden.Different processes for the production of polyoxymethylene homo- or copolymers are known. They can be produced, for example, by polymerizing trioxane or formaldehyde gas. The reaction is started by initiators such as BF 3 etherate and carried out with the addition of regulators such as methylal, butylal or dimethyl formal. The polymerization can be carried out in reaction extruders, shell belts, twin-screw mixers, kneaders or in suspension in an organic suspending agent.
Die Herstellung geht in der Regel von Methanol als Ausgangsprodukt aus, das in groß- technischen Nerfahren zu Formaldehyd umgesetzt wird. Hierbei wird insbesondere Methanol im Silberkontakt-Nerfahren partiell oxidierend dehydriert. Als Nerfahrensprodukt wird in der Regel eine etwa 50%ige wässrige Formaldehydlösung erhalten.Production usually starts from methanol as the starting product, which is converted into formaldehyde in large-scale industrial processes. Here, in particular, methanol is partially oxidized and dehydrated in a silver contact process. As a rule, an approximately 50% aqueous formaldehyde solution is obtained.
Bei den üblichen Nerfahren wird die Formaldehyd-Lösung nach Aufkonzentrieren in Ge- genwart saurer Katalysatoren zu Trioxan umgesetzt. Das im Gleichgewicht mit Formaldehyd nur zu etwa 2% vorliegende Trioxan wird durch Destillation zusammen mit Wasser und Formaldehyd ausgetrieben und in einer nachgeschalteten Kolonne aufkonzentriert. Durch Extraktion mit einem mit Wasser nicht mischbaren Lösungsmittel wie Methylen- chlorid oder Benzol wird Trioxan angereichert. Nach Abtrennung des Lösungsmittels muß das Trioxan weiter aufgereinigt werden, um für die Polymerisation einsetzbar zu sein.In the usual ner processes, the formaldehyde solution is converted to trioxane after concentration in the presence of acidic catalysts. The trioxane, which is only about 2% in equilibrium with formaldehyde, is driven off by distillation together with water and formaldehyde and concentrated in a downstream column. By extraction with a water-immiscible solvent such as methylene Chloride or benzene is enriched in trioxane. After the solvent has been separated off, the trioxane must be purified further in order to be usable for the polymerization.
Für eine allgemeine Beschreibung der Herstellung von Polyacetalen kann auf Technische Thermoplaste: Polycarbonat, Polyacetale, Polyester, Celluloseester, Herausgeber Ludwig Bottenbruch, ISBN 3-446-16368-9, insbesondere Kapitel 4, Seiten 300 bis 331 verwiesen werden.For a general description of the production of polyacetals, reference can be made to engineering thermoplastics: polycarbonate, polyacetals, polyester, cellulose esters, publisher Ludwig Bottenbruch, ISBN 3-446-16368-9, in particular chapter 4, pages 300 to 331.
Ein kontinuierliches Nerfahren zur Herstellung von Oxymethylenpolymeren unter Einsatz von flüssigem Trioxan ist beispielsweise in EP-A 0 080 656 beschrieben.A continuous process for the production of oxymethylene polymers using liquid trioxane is described, for example, in EP-A 0 080 656.
Die bekannten Nerfahren zur Herstellung von Oxymethylenhomo- und copolymeren weisen eine Reihe von Nachteilen auf. Zum einen sind zahlreiche und aufwendige Auftrennungsschritte nötig, um zu hochreinem Formaldehyd oder Trioxan zu gelangen. Die Auftrennung erfolgt unter Einsatz von häufig chlorhaltigen Extraktionsmitteln, die gesondert aufgearbeitet bzw. entsorgt werden müssen.The known ner processes for the production of oxymethylene homo- and copolymers have a number of disadvantages. On the one hand, numerous and complex separation steps are necessary to obtain high-purity formaldehyde or trioxane. The separation is carried out using often chlorine-containing extracting agents, which have to be worked up or disposed of separately.
Aufgabe der vorliegenden Erfindung ist die Bereitstellung eines Verfahrens zur Herstellung von Oxymethylenhomo- oder copolymeren, das die Nachteile der bekannten Nerfah- ren vermeidet und insbesondere apparativ günstiger durchgeführt werden kann, wobei die Zahl der Auftrennungsschritte vermindert werden kann.The object of the present invention is to provide a process for the preparation of oxymethylene homo- or copolymers which avoids the disadvantages of the known ner processes and in particular can be carried out more cheaply in terms of apparatus, the number of separation steps being able to be reduced.
Die Aufgabe wird erfindungsgemäß gelöst durch ein Nerfahren zur Herstellung von Oxymethylenhomo- oder copolymeren aus einer Formaldehyd und Polyoxymethylenglykole enthaltenden wässrigen Lösung, wobei manThe object is achieved according to the invention by a process for the production of oxymethylene homo- or copolymers from an aqueous solution containing formaldehyde and polyoxymethylene glycols
(1) in einer Abtrennungsstufe aus der wässrigen Lösung Wasser und Formaldehyd zumindest teilweise abtrennt, so daß eine Polyoxymethylenglykole enthaltende Phase erhalten wird, in der das Molverhältnis von Polyoxy- methylenglykolen zu Formaldehyd größer als 1 :0,6 ist, und(1) at least partially separating water and formaldehyde from the aqueous solution in a separation stage, so that a phase containing polyoxymethylene glycols is obtained in which the molar ratio of polyoxymethylene glycols to formaldehyde is greater than 1: 0.6, and
(2) die in Stufe 1 erhaltenen Polyoxymethylenglykole in Gegenwart von Poly- kondensationskatalysatoren unter Abtrennung von Wasser zu Oxymethylenhomo- oder copolymeren umsetzt. Die in Stufe (1) eingesetzte, Formaldehyd und Polyoxymethylenglykole enthaltende wäss- rige Lösung wird vorzugsweise durch übliche Dehydrierung von Methanol hergestellt. Es kann auf die eingangs zitierte Literatur verwiesen werden.(2) the polyoxymethylene glycols obtained in stage 1 are converted into oxymethylene homo- or copolymers in the presence of polycondensation catalysts with removal of water. The aqueous solution used in step (1) and containing formaldehyde and polyoxymethylene glycols is preferably prepared by customary dehydrogenation of methanol. Reference can be made to the literature cited at the beginning.
Es wurde erfindungsgemäß gefunden, daß Oxymethylenhomo- oder copolymere aus Polyoxymethylenglykolen in vorteilhafter Weise hergestellt werden können.It has been found according to the invention that oxymethylene homopolymers or copolymers can be prepared from polyoxymethylene glycols in an advantageous manner.
Formaldehyd liegt in wässrigen Lösungen nicht nur in monomerer Form vor, sondern auch in Form von Oligomeren, sogenannten Polyoxymethylenglykolen. Zwischen den Monome- ren und Oligomeren unterschiedlicher Länge liegt ein thermodynamisches Gleichgewicht vor. Das erfindungsgemäße Nerfahren nutzt nun die Tatsache, daß die im Gleichgewicht vorliegenden Oligomere an sich schon Polyoxymethylenvorstufen sind, die erfindungsgemäß zu den Oxymethylenhomo- oder copolymeren verknüpft werden.Formaldehyde is not only present in aqueous solutions in monomeric form, but also in the form of oligomers, so-called polyoxymethylene glycols. There is a thermodynamic equilibrium between the monomers and oligomers of different lengths. The ner driving according to the invention now makes use of the fact that the oligomers present in equilibrium are themselves polyoxymethylene precursors which, according to the invention, are linked to the oxymethylene homo- or copolymers.
Hierbei ist eine Herstellung von Trioxan als Zwischenprodukt bzw. eine Hochreinigung, wie sie bei dem bekannten Verfahren erforderlich ist, nicht notwendig. Es wurde erfindungsgemäß gefunden, daß nach einer zumindest teilweisen Abtrennung von Wasser und Formaldehyd aus einer Formaldehyd und Polyoxymethylenglykole (im thermodyna- mischen Gleichgewicht) enthaltenden wässrigen Lösung die erhaltene Polyoxyme- thylenglykole enthaltende Phase, in der das Molverhältnis von Polyoxymethylenglykolen zu Formaldehyd größer als 1 :0,6 ist, direkt in eine Polykondensation zur Herstellung von Oxymethylenhomo- oder copolymeren überführt werden kann.Here, the production of trioxane as an intermediate or a high purification, as is required in the known method, is not necessary. It has been found according to the invention that after at least partial separation of water and formaldehyde from an aqueous solution containing formaldehyde and polyoxymethylene glycols (in thermodynamic equilibrium), the phase obtained contains polyoxymethylene glycols, in which the molar ratio of polyoxymethylene glycols to formaldehyde is greater than 1: Is 0.6, can be converted directly into a polycondensation for the preparation of oxymethylene homo- or copolymers.
Bevorzugt beträgt das Molverhältnis von Polyoxymethylenglykolen zu monomerem Form- aldehyd und Methylenglykol 1:0,4 bis 1:0. Polyoxymethylenglykole können dabei beispielsweise zwei bis neun Kohlenstoffatome aufweisen. In diesem Fall handelt es sich um Gemische aus Dioxymethylenglykol, Trioxymethylenglykol, Tetraoxymethylenglykol, Pentaoxymethylenglykol, Hexaoxymethylenglykol, Heptaoxy-methylenglykol, Octaoxy- methylenglykol und Νonaoxymethylenglykol.The molar ratio of polyoxymethylene glycols to monomeric formaldehyde and methylene glycol is preferably 1: 0.4 to 1: 0. Polyoxymethylene glycols can have, for example, two to nine carbon atoms. In this case, mixtures of dioxymethylene glycol, trioxymethylene glycol, tetraoxymethylene glycol, pentaoxymethylene glycol, hexaoxymethylene glycol, heptaoxymethylene glycol, octaoxymethylene glycol and Νonaoxymethylene glycol are used.
Das in Stufe (2) eingesetzte Gemisch, das die höheren Homologe des Formaldehyds enthält, kann aus einer üblichen Formaldehydlösung durch bekannte Verfahren zur Verschiebung des Gleichgewichts auf die Seite der höheren Homologen hergestellt werden. Vorzugsweise wird in Stufe (1) aus einer Formaldehyd und Polyoxymethylenglykole enthal- tenden wässrigen Lösung Formaldehyd und Wasser zumindest teilweise durch Verdamp- fung entfernt, und die zurückbleibenden Polyoxymethylenglykole werden vor Einstellung eines thermodynamischen Gleichgewichts in Stufe (2) umgesetzt.The mixture used in step (2), which contains the higher homologues of formaldehyde, can be prepared from a conventional formaldehyde solution by known methods for shifting the equilibrium to the side of the higher homologues. In stage (1), formaldehyde and water are preferably at least partially evaporated from an aqueous solution containing formaldehyde and polyoxymethylene glycols. fung removed, and the remaining polyoxymethylene glycols are implemented in step (2) before establishing a thermodynamic equilibrium.
Die Verdampfung kann beispielsweise in einem Filmverdampfer oder einer Destillations- einrichtung durchgeführt werden. Vorzugsweise werden Dünnschichtverdampfer wie Fall- filmverdampfer oder Rotationsfilmverdampfer oder Reaktionskolonnen eingesetzt.The evaporation can be carried out, for example, in a film evaporator or a distillation device. Thin-film evaporators such as falling film evaporators or rotary film evaporators or reaction columns are preferably used.
Beispielsweise kann eine Formaldehydlösung bei einer Temperatur von 50 bis 150°C in einer Reaktionskolonne entspannt werden, indem man den Druck, unter dem die Lösung steht, stark vermindert, wodurch die höheren Homologen des Formaldehyds in der Lösung verbleiben und monomeres, aus Methylenglykol gebildetes Formaldehyd verdampft. Da das Gleichgewicht zwischen den höheren Homologen des Formaldehyds und dem mono- meren Formaldehyd in der Lösung bei üblichen Temperaturen von 30 bis 70°C innerhalb von 0,5 bis 15 Minuten wieder eingestellt ist, d.h. die erfindungsgemäße Anreicherung an höheren Homologen in der Lösung nicht mehr vorliegt, setzt man die Lösung mit dem erfindungsgemäß hohen Anteil an höheren Homologen des Formaldehyds bevorzugt innerhalb von 10 Minuten nach deren Herstellung in Stufe (1) im erfindungsgemäßen Verfahren in Stufe (2) ein. Besonders bevorzugt erfolgt die weitere Umsetzung innerhalb von 5 Minuten.For example, a formaldehyde solution can be depressurized at a temperature of 50 to 150 ° C in a reaction column by greatly reducing the pressure under which the solution is, whereby the higher homologues of formaldehyde remain in the solution and monomeric formaldehyde formed from methylene glycol evaporated. Since the equilibrium between the higher homologues of formaldehyde and the monomeric formaldehyde in the solution is restored within 0.5 to 15 minutes at usual temperatures of 30 to 70 ° C, i.e. the enrichment of higher homologues according to the invention no longer exists in the solution, the solution with the high proportion of higher homologues of formaldehyde according to the invention is preferably used within 10 minutes after its preparation in stage (1) in the process according to the invention in stage (2). The further reaction is particularly preferably carried out within 5 minutes.
Es ist weiterhin möglich, bei der Herstellung und Reinigung von Formaldehyd aus einer entsprechenden Destillationskolonne Fraktionen zu entnehmen, die den erfindungsgemäßen Anteil an höheren Homologen des Formaldehyds aufweisen.It is also possible to remove fractions from a corresponding distillation column in the production and purification of formaldehyde which have the proportion of higher homologues of formaldehyde according to the invention.
Geeignete Verfahren zur Durchführung der Stufe (1) sind beispielsweise in EP-A 0 934 922 und DE-A 199 25 870 beschrieben.Suitable processes for carrying out stage (1) are described, for example, in EP-A 0 934 922 and DE-A 199 25 870.
Hier wird das Gleichgewicht zwischen Formaldehyd und höheren Homologen näher erläutert, so daß auf diese Schriften verwiesen werden kann.The balance between formaldehyde and higher homologues is explained in more detail here, so that reference can be made to these documents.
Gemäß EP-A 0 934 922 werden die Polyoxymethylenglykole zur Herstellung von Methyl- endi(phenylamin) eingesetzt. In der DE-A 199 25 870 sind keine Verwendungshinweise enthalten. Eine geeignete Vorrichtung zur Durchführung der Stufe (1) ist in dieser Anmeldung beschrieben, siehe auch die Figuren 1 bis 3. Die durch die Verdampfung in Stufe (1) gewonnenen Polyoxymethylenglykole weisen vorzugsweise einen Wassergehalt von maximal 35 Gew.-%, besonders bevorzugt von maximal 30 Gew.-%, insbesondere von maximal 25 Gew.-% auf, bezogen auf das Gemisch.According to EP-A 0 934 922, the polyoxymethylene glycols are used for the production of methylendi (phenylamine). DE-A 199 25 870 does not contain any instructions for use. A suitable device for carrying out stage (1) is described in this application, see also FIGS. 1 to 3. The polyoxymethylene glycols obtained by the evaporation in stage (1) preferably have a water content of at most 35% by weight, particularly preferably at most 30% by weight, in particular at most 25% by weight, based on the mixture.
Die Umsetzung in Stufe (2) kann in jeder geeigneten Vorrichtung durchgeführt werden, in der Polyoxymethylenglykole in Gegenwart von Polykondensationskatalysatoren unter Abtrennung von Wasser zu Oxymethylenhomo- oder copolymeren umgesetzt werden können. Vorzugsweise wird die Umsetzung in einem List-dryer, Zweiwellenkneter oder Zweiwellenmischer mit Entgasungsmöglichkeit durchgeführt. Besonders bevorzugt wird die Um- setzung in einem Doppelschneckenextruder durchgeführt, der im Schneckenverlauf mehrere Entgasungsvorrichtungen aufweist. Ein geeigneter Doppelschneckenextruder ist beispielsweise in der EP-A 0 080 656 beschrieben. Der dort beschriebene Doppelschneckenextruder (ZSK 30 von Werner und Pfleiderer) weist ein L:D-Verhältnis von 20 auf. Der Extruder weist mehrere durch Stauelemente getrennte Sektoren auf. In einem ersten Sektor wird die Polymerisation bzw. Polykondensation durchgeführt, während in einem zweiten Sektor entgast und konfektioniert wird. Für eine nähere Beschreibung des Extruders kann auf diese Schrift verwiesen werden.The reaction in step (2) can be carried out in any suitable device in which polyoxymethylene glycols can be converted to oxymethylene homo- or copolymers in the presence of polycondensation catalysts with the removal of water. The reaction is preferably carried out in a list dryer, twin-shaft kneader or twin-shaft mixer with the possibility of degassing. The reaction is particularly preferably carried out in a twin-screw extruder which has several degassing devices in the course of the screw. A suitable twin-screw extruder is described, for example, in EP-A 0 080 656. The twin-screw extruder described there (ZSK 30 from Werner and Pfleiderer) has an L: D ratio of 20. The extruder has several sectors separated by baffle elements. The polymerization or polycondensation is carried out in a first sector, while degassing and assembly are carried out in a second sector. For a more detailed description of the extruder, reference can be made to this document.
Aus dem in der Stufe (1) abgetrennten Wasser/Formaldehyd-Gemisch kann Wasser zu- mindest teilweise entfernt werden, und das verbleibende Formaldehyd kann nach Einstellung des thermodynamischen Gleichgewichts in Stufe (1) zurückgeführt werden.At least some of the water / formaldehyde mixture separated off in stage (1) can be removed, and the remaining formaldehyde can be returned to stage (1) after the thermodynamic equilibrium has been established.
In Stufe (2) wird die Polykondensation in Gegenwart von für Polykondensationen üblichen Katalysatoren durchgeführt. Es kann auf die eingangs zitierte Literatur verwiesen werden.In stage (2), the polycondensation is carried out in the presence of catalysts customary for polycondensation. Reference can be made to the literature cited at the beginning.
Übliche, erfindungsgemäß einsetzbare Polykondensationskatalysatoren sind beispielsweise Salzsäure, Phosphorsäure, Methansulfonsäure und deren Mischungen mit Phosphorpent- oxid, Polyphosphorsäureester, chlor-, schwefel- und phosphorhaltige Säuren wie phosphorige Säure, hypophosphorige Säure sowie deren Alkali- und Erdalkalimetallsalze, hypochlo- rige Säure, Perchlorsäure und andere derartige Säuren.Typical polycondensation catalysts which can be used according to the invention are, for example, hydrochloric acid, phosphoric acid, methanesulfonic acid and their mixtures with phosphorus pentoxide, polyphosphoric acid esters, chlorine, sulfur and phosphorus-containing acids such as phosphorous acid, hypophosphorous acid and their alkali and alkaline earth metal salts, hypochlorous acid, perchloric acid and other such acids.
Die Polykondensation wird unter Bedingungen durchgeführt, unter denen Wasser kontinuierlich aus dem Reaktionsgemisch ausgetragen werden kann. Druck und Temperatur werden so eingestellt, daß Wasser aus dem Reaktionsgemisch abgezogen werden kann. Es kann beispielsweise bei Atmosphärendruck oder Unterdruck gearbeitet werden. Die Temperatur wird möglichst niedrig gewählt, beispielsweise im Bereich von 50 bis 100°C. In den Stufen (1) und/oder (2) können zudem übliche Comonomere, Regler, weitere Hilfsstoffe oder Gemische davon zugesetzt werden.The polycondensation is carried out under conditions under which water can be continuously discharged from the reaction mixture. Pressure and temperature are set so that water can be drawn off from the reaction mixture. For example, atmospheric pressure or negative pressure can be used. The temperature is chosen to be as low as possible, for example in the range from 50 to 100.degree. In stages (1) and / or (2), customary comonomers, regulators, other auxiliaries or mixtures thereof can also be added.
Derartige Verbindungen sind in der eingangs zitierten Literatur, insbesondere in "Technische Thermoplaste", beschrieben. Mögliche Comonomere umfassen oxocyclische Verbindungen kleiner Ringgröße mit den Strukturmerkmalen eines Ethers, Acetals oder Lactons. Insbesondere haben Epoxide Bedeutung erlangt, besonders Ethylenoxid. Als weitere Beispiele polymerisierfähiger Ether können Propylenoxid, Styroloxid, Epichlorhydrin, 3,3- Bis-Chlormethyloxocyclobutan neben substituierten Glycidylphenylethem oder Glycidsäu- reethylestern genannt werden. Auch bifunktionelle Comonomere mit zwei polymerisierfä- higen Gruppen können eingesetzt werden, so daß schwachvernetzte Terpolymere erhalten werden. Hierzu zählen beispielsweise Diepoxide, Diacetale oder Verbindungen mit je einer Epoxid- und cyclischen Acetalgruppe.Such compounds are described in the literature cited at the beginning, in particular in "engineering thermoplastics". Possible comonomers include oxocyclic compounds of small ring size with the structural features of an ether, acetal or lactone. In particular, epoxides have become important, especially ethylene oxide. Propylene oxide, styrene oxide, epichlorohydrin, 3,3-bis-chloromethyloxocyclobutane in addition to substituted glycidylphenyl ether or ethyl glycidate can be mentioned as further examples of polymerizable ethers. Bifunctional comonomers with two polymerizable groups can also be used, so that weakly crosslinked terpolymers are obtained. These include, for example, diepoxides, diacetals or compounds each with an epoxy and cyclic acetal group.
Geeignete cyclische Acetale sind Dioxolan, 1,3-Dioxan, 1,3-Dioxepan (Butandiolformal), 1,3,5-Trioxepan, 1,3,6-Trioxolan sowie subsituierte Trioxolane. Insbesondere wird hier 1,3-Dioxepan eingesetzt.Suitable cyclic acetals are dioxolane, 1,3-dioxane, 1,3-dioxepane (butanediol formal), 1,3,5-trioxepane, 1,3,6-trioxolane and substituted trioxolanes. In particular, 1,3-dioxepane is used here.
Auch die Herstellung von Polymerblends durch Zusatz von Polymeren insbesondere in Stufe (2) ist möglich. Der Einsatz derartiger Comonomere, Blend-Komponenten usw. ist im Stand der Technik vielfältig beschrieben, beispielsweise kann auf DE-A 23 56 531 und DE-A 196 44 966 oder EP-A 0 678 535 verwiesen werden. Es kann ferner auf Prog. Po- lym. Sei., Vol. 18, 1993, Seiten 1 bis 84 verwiesen werden. It is also possible to produce polymer blends by adding polymers, in particular in stage (2). The use of such comonomers, blend components, etc. has been widely described in the prior art, for example, reference can be made to DE-A 23 56 531 and DE-A 196 44 966 or EP-A 0 678 535. It can also refer to Prog. Poly. Sci., Vol. 18, 1993, pages 1 to 84.

Claims

Patentansprüche claims
1. Verfahren zur Herstellung von Oxymethylenhomo- oder copolymeren aus einer Formaldehyd und Polyoxymethylenglykole enthaltenden wässrigen Lösung, dadurch gekennzeichnet, daß man1. A process for the preparation of oxymethylene homo- or copolymers from an aqueous solution containing formaldehyde and polyoxymethylene glycols, characterized in that
(1) in einer Abtrennungsstufe aus der wässrigen Lösung Wasser und Formaldehyd zumindest teilweise abtrennt, so daß eine Polyoxymethylenglykole enthaltende Phase erhalten wird, in der das Molverhältnis von Polyoxymethylenglykolen zu Formaldehyd größer als 1:0,6 ist, und(1) at least partially separating water and formaldehyde from the aqueous solution in a separation step, so that a phase containing polyoxymethylene glycols is obtained in which the molar ratio of polyoxymethylene glycols to formaldehyde is greater than 1: 0.6, and
(2) die in Stufe 1 erhaltenen Polyoxymethylenglykole in Gegenwart von Polykondensationskatalysatoren unter Abtrennung von Wasser zu Oxymethylenhomo- oder -copolymeren umsetzt.(2) the polyoxymethylene glycols obtained in stage 1 are converted to oxymethylene homo- or copolymers in the presence of polycondensation catalysts with removal of water.
2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß in Stufe (1) aus einer Formaldehyd und Polyoxymethylenglykole enthaltenden wässrigen Lösung Formaldehyd und Wasser durch Verdampfung zumindest teilweise entfernt werden und die zurückbleibenden Polyoxymethylenglykole vor Einstellung eines thermo- dynamischen Gleichgewichts in Stufe (2) umgesetzt werden.2. The method according to claim 1, characterized in that in stage (1) from an aqueous solution containing formaldehyde and polyoxymethylene glycols, formaldehyde and water are at least partially removed by evaporation and the remaining polyoxymethylene glycols are reacted in stage (2) before setting a thermodynamic equilibrium become.
3. Verfahren gemäß Anspruch 2, dadurch gekennzeichnet, daß die Verdampfung in einem Filmverdampfer oder einer Destillationseinrichtung durchgeführt wird.3. The method according to claim 2, characterized in that the evaporation is carried out in a film evaporator or a distillation device.
4. Verfahren nach einem der Ansprüche 2 oder 3, dadurch gekennzeichnet, daß die durch die Verdampfung gewonnenen Polyoxymethylenglykole einen Wassergehalt von maximal 35 Gew.-% aufweisen.4. The method according to any one of claims 2 or 3, characterized in that the polyoxymethylene glycols obtained by the evaporation have a water content of at most 35 wt .-%.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Umsetzung in Stufe (2) in einem List-dryer, Zweiwelle kneter oder Zweiwellenmischer mit Entgasungsmöglichkeit durchgeführt wird.5. The method according to any one of claims 1 to 4, characterized in that the implementation in stage (2) in a list dryer, twin-shaft kneader or twin-shaft mixer with the possibility of degassing is carried out.
6. Verfahren gemäß Anspruch 5, dadurch gekennzeichnet, daß die Umsetzung in Stufe (2) in einem Doppelschneckenextruder durchgeführt wird, der im Schneckenverlauf mehrere Entgasungsvorrichtungen aufweist. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß die Formaldehyd und Polyoxymethylenglykole enthaltende wässrige Lösung durch Dehydrierung von Methanol hergestellt wird.6. The method according to claim 5, characterized in that the reaction in stage (2) is carried out in a twin-screw extruder which has several degassing devices in the course of the screw. Method according to one of claims 1 to 6, characterized in that the aqueous solution containing formaldehyde and polyoxymethylene glycols is prepared by dehydrogenation of methanol.
Verfahren nach einem der Ansprüche 2 bis 7, dadurch gekennzeichnet, daß aus dem in der Stufe (1) abgetrennten Wasser/Formaldehyd-Gemisch Wasser zumindest teilweise entfernt wird und das verbleibende Formaldehyd nach Einstellung des thermodynamischen Gleichgewichts in Stufe (1) zurückgeführt wird.Method according to one of Claims 2 to 7, characterized in that water is at least partially removed from the water / formaldehyde mixture separated off in step (1) and the remaining formaldehyde is returned to step (1) after the thermodynamic equilibrium has been set.
Verfahren nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß in den Stufen (1) und/oder (2) übliche Comonomere, Regler, weitere Hilfsstoffe oder Gemische davon zugesetzt werden. Method according to one of claims 1 to 8, characterized in that in the stages (1) and / or (2) customary comonomers, regulators, further auxiliaries or mixtures thereof are added.
PCT/EP2002/013451 2001-11-30 2002-11-28 Method for the production of oxymethylene homo- or co-polymers WO2003046035A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2002356750A AU2002356750A1 (en) 2001-11-30 2002-11-28 Method for the production of oxymethylene homo- or co-polymers
DE10295499T DE10295499B4 (en) 2001-11-30 2002-11-28 Process for the preparation of oxymethylene homo- or copolymers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2001158813 DE10158813A1 (en) 2001-11-30 2001-11-30 Process for the preparation of oxymethylene homo- or copolymers
DE10158813.5 2001-11-30

Publications (1)

Publication Number Publication Date
WO2003046035A1 true WO2003046035A1 (en) 2003-06-05

Family

ID=7707544

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2002/013451 WO2003046035A1 (en) 2001-11-30 2002-11-28 Method for the production of oxymethylene homo- or co-polymers

Country Status (3)

Country Link
AU (1) AU2002356750A1 (en)
DE (2) DE10158813A1 (en)
WO (1) WO2003046035A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8354495B2 (en) 2008-04-16 2013-01-15 Ticona Gmbh Process for the preparation of oxymethylene polymers and apparatus suitable for this purpose
US8993709B2 (en) 2011-07-15 2015-03-31 Ticona Gmbh Process for producing oxymethylene polymers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10309286A1 (en) 2003-03-04 2004-09-16 Basf Ag Process for the thermal stabilization of highly concentrated formaldehyde solutions

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2369504A (en) * 1942-04-24 1945-02-13 Du Pont Formaldehyde polymers
DE1112505B (en) * 1958-09-27 1961-08-10 Degussa Process for the production of paraformaldehyde with medium reactivity and a water content of at most 0.2 percent by weight
GB1048191A (en) * 1963-04-10 1966-11-16 Skanska Attikfabriken Ab Process for producing formaldehyde polymers
EP0080656A1 (en) * 1981-11-28 1983-06-08 BASF Aktiengesellschaft Continuous process for producing oxymethylene polymers
EP1063221A1 (en) * 1999-06-07 2000-12-27 Basf Aktiengesellschaft Process for the reaction of a solution containing a mixture

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1045613B (en) * 1973-06-15 1980-06-10 Sir Soc Italiana Resine Spa PROCEDURE PERFECTED TO HANG ACETAL POLYMERS STABLE
HU213653B (en) * 1991-05-15 1997-09-29 Harsanyi Process for producing stable poly(oxymethylene)glycol solutions
JP2003147161A (en) * 2001-11-14 2003-05-21 Toray Ind Inc Polyoxymethylene resin composition

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2369504A (en) * 1942-04-24 1945-02-13 Du Pont Formaldehyde polymers
DE1112505B (en) * 1958-09-27 1961-08-10 Degussa Process for the production of paraformaldehyde with medium reactivity and a water content of at most 0.2 percent by weight
GB1048191A (en) * 1963-04-10 1966-11-16 Skanska Attikfabriken Ab Process for producing formaldehyde polymers
EP0080656A1 (en) * 1981-11-28 1983-06-08 BASF Aktiengesellschaft Continuous process for producing oxymethylene polymers
EP1063221A1 (en) * 1999-06-07 2000-12-27 Basf Aktiengesellschaft Process for the reaction of a solution containing a mixture

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8354495B2 (en) 2008-04-16 2013-01-15 Ticona Gmbh Process for the preparation of oxymethylene polymers and apparatus suitable for this purpose
US8993709B2 (en) 2011-07-15 2015-03-31 Ticona Gmbh Process for producing oxymethylene polymers

Also Published As

Publication number Publication date
AU2002356750A1 (en) 2003-06-10
DE10295499B4 (en) 2007-04-19
DE10295499D2 (en) 2004-10-28
DE10158813A1 (en) 2003-06-12

Similar Documents

Publication Publication Date Title
EP1913045B1 (en) Method for producing polyoxymethylenes
EP1922346A1 (en) Method for production of polyoxymethylene homo- or co-polymers
EP1861442B1 (en) Method for producing polyoxymethylenes
EP1861443B1 (en) Method for removing residual monomers from polyoxymethylenes
EP1699776B1 (en) Method for separating trioxane from a trioxane/formaldehyde/water mixture by means of pressure change rectification
WO2007051762A1 (en) Process for producing trioxane and at least one comonomer
EP1532126B1 (en) Method for producing tetrahydrofuran
EP2114544B1 (en) Method for separating trioxane from a trioxane/formaldehyde/water mixture by means of pressure change rectification
EP2225296A1 (en) Method for the production of polyoxymethylene homopolymers or copolymers by homopolymerizing or copolymerizing trioxane, starting from methanol
DE3330042C2 (en) Novolak-type substituted phenolic resins glycidyl ethers, processes for their preparation and their use as encapsulating compounds
DE10295499B4 (en) Process for the preparation of oxymethylene homo- or copolymers
DE68911211T2 (en) Process for the preparation of acetal polymers or copolymers.
DE4443150C2 (en) Acetal copolymers with improved mechanical properties
EP1753797B1 (en) Method for removing residual monomers from polyoxymethylenes
WO1999052959A1 (en) Polyoxymethylene moulding material with improved processing stability and a reduced emissions tendency
DE69902979T2 (en) Process for the production of heat-stable polyoxymethylene copolymers
EP1915358B1 (en) Integrated method for the production of trioxane from formaldehyde
DE2141327C3 (en) Thermoplastic molding compound based on poly (oxymethylene)
DE102004052380B4 (en) Process for the preparation of polyacetals
EP1915359A1 (en) Integrated method for producing trioxane from formaldehyde
DE60034115T2 (en) POLYACETALCOPOLYMER AND METHOD FOR THE PRODUCTION THEREOF
EP1912965A1 (en) Integrated process for preparing trioxane from formaldehyde
DE3207773A1 (en) Process for the continuous bulk polymerisation of trioxane
EP0573850B1 (en) Process for the preparation of pure trioxane
DE1570335A1 (en) Process for the preparation of oxymethylene polymers

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SC SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REF Corresponds to

Ref document number: 10295499

Country of ref document: DE

Date of ref document: 20041028

Kind code of ref document: P

WWE Wipo information: entry into national phase

Ref document number: 10295499

Country of ref document: DE

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Ref document number: JP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8607

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载