EP1756208A1 - Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides - Google Patents

Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides

Info

Publication number
EP1756208A1
EP1756208A1 EP05744786A EP05744786A EP1756208A1 EP 1756208 A1 EP1756208 A1 EP 1756208A1 EP 05744786 A EP05744786 A EP 05744786A EP 05744786 A EP05744786 A EP 05744786A EP 1756208 A1 EP1756208 A1 EP 1756208A1
Authority
EP
European Patent Office
Prior art keywords
water
ammonia
polyamides
cyclopentanone
sump
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP05744786A
Other languages
German (de)
English (en)
Inventor
Jens Assmann
Jürgen DEMETER
Jürgen Deininger
Oliver SÖTJE
Gad Kory
Jan-Martin LÖNING
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
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 SE filed Critical BASF SE
Publication of EP1756208A1 publication Critical patent/EP1756208A1/fr
Withdrawn legal-status Critical Current

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
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/04—Preparatory processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0033—Other features
    • B01D5/0036—Multiple-effect condensation; Fractional condensation
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/02—Preparation, purification or separation of ammonia
    • C01C1/10—Separation of ammonia from ammonia liquors, e.g. gas liquors
    • 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
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
    • C08G69/14—Lactams
    • C08G69/16—Preparatory processes
    • 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
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
    • C08G69/28—Preparatory processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the invention relates to a process for the distillative removal of ammonia and water from mixtures obtained in the production of polyamides, which, in addition to ammonia and water, contain a lactam and / or diamine and, if appropriate, an aminonitrile and / or dinitrile and, as an impurity, cyclopentanone that the separation takes place in at least two stages 1 and 2 by
  • the mixture is subjected to a distillation at an absolute pressure of 11 to 35 bar and a bottom temperature of 180 to 260 ° C., in which the top product K1 is an at least partially gaseous mixture containing water and ammonia, and the bottom S1 is a mixture containing water , the lactam and / or diamine and optionally the aminonitrile and / or dinitrile, and wherein the cyclopentanone is completely removed as the top product, and
  • the top product K1 obtained is subjected to further distillation at an absolute pressure of 11 to 35 bar and a bottom temperature of 180 to 260 ° C., the top product K2 being a mixture comprising ammonia and cyclopentanone, and the bottom product S2 being water.
  • the invention further relates to the use of this process in a process for the preparation of polyamides, and to a process for the production of polyamides, characterized in that ammonia and water are separated off from the resulting mixtures using the process mentioned at the beginning.
  • Aqueous solutions containing a lactam or other polyamide starting materials, ammonia and small amounts of cyclopentanone are obtained, for example, in the course of the production of polyamides.
  • 6-aminocapronitrile ACN
  • ACN 6-aminocapronitrile
  • PA 6 polyamide 6
  • polyamide 66 for example, adiponitrile (ADN) and hexamethylene diamine (HMD) can be reacted with water under catalysis or else without catalysis to give oligomers or prepolymers of PA66 and ammonia, the reaction mixture obtained contains as an undesirable by-product, inter alia, cyclopentanone and usually also unreacted nitrile, for example ADN, or unreacted diamine, for example HMD, and convert this reaction mixture further to polyamide 66 (PA 66).
  • ADN adiponitrile
  • HMD hexamethylene diamine
  • the processing of the aqueous reaction mixture containing ammonia is complex. Processes for the production of polyamides can be operated economically particularly if as many constituents of the reaction mixture as possible are recycled. However, the constituents to be recycled must be of particularly high purity, since otherwise the concentration of the contaminants at the target point of the recycling would be locally increased, in the sense of an undesired “enrichment” of the contaminants.
  • the end group concentration in the polymer or the polymer color number must meet high standards and remain very constant over time. This means that contamination in the feedstocks or material flows to be recycled must be minimized as far as possible.
  • WO 95/14665 and WO 95/14664 describe the reaction of ACN in the liquid phase with water in the presence of heterogeneous catalysts and a solvent to form a solution containing caprolactam and ammonia. Working up this solution is not described.
  • WO 00/20488 and WO 99/38908 teach the reaction of ACN in the liquid phase with water in the presence of heterogeneous catalysts to a liquid phase containing polyamide 6 or its prepolymers and water, and to a gas phase containing caprolactam or not converted aminonitrile, water and ammonia.
  • Working up of this gas phase is described in such a way that the separation into the constituents is generally carried out continuously using a distillation device, such as a distillation column.
  • the organic constituents separated off in the process, such as caprolactam or, to a large extent, unconverted aminonitrile can be completely or partially returned to the polymerization or hydrolysis process.
  • the handling of by-products or impurities is not mentioned.
  • WO 01/94308 describes the separation of a solution containing a lactam and ammonia in such a way that ammonia is completely distilled off from the solution at a pressure of less than 10 bar.
  • the aim is to obtain the ammonia as pure as possible - if necessary by using a second distillation column for the above-mentioned distillate.
  • the bottom product consisting essentially of lactam is available for further use, for example for the polymerization to PA 6.
  • by-products or impurities are not mentioned.
  • the by-products negatively affect the polymer properties, see e.g. DE-A 24 10863. In particular, they cause the color number (APHA or Hazen number or yellow number) to deteriorate.
  • the molded parts or fibers obtained from such polyamides have a disruptive inherent color, which is undesirable in many applications. In addition, the intrinsic color complicates the color-accurate coloring to colored polyamides.
  • the recycling of the sump containing by-product also has the disadvantage that later removal of the troublesome by-products such as cyclopentanone is no longer possible.
  • the sump In the ACN cyclization process, the sump must be cleaned in complex additional steps in order to To avoid disadvantages. In addition, undesirable locally higher concentrations of impurities occur.
  • the object of the present invention was to remedy the disadvantages described.
  • a method should be provided which enables the separation of ammonia and water from mixtures which contain ammonia, water, a lactam and / or diamine and optionally aminonitrile and / or dinitrile in a technically simple and economical manner.
  • the process should remove cyclopentanone and other by-products, which are otherwise either not at all or can only be removed by additional purification steps, from the bottom (product of value) of the separation stages.
  • the invention is based on a mixture such as is formed, for example, in the reaction of ACN or other nitriles with water to give lactams or in the reaction of dinitrile and diamine.
  • a mixture contains e.g. the lactam, also water as excess water, or - in the case of a reaction in the gas phase - as water used to quench the reaction product, ammonia (in an amount of 1 mol per mol of lactam) and usually also unreacted aminonitrile.
  • Cyclopentanone is also present as an impurity.
  • the mixture may also contain other impurities, such as may arise as by-products in the above-mentioned reaction, and also organic solvents.
  • Another such mixture contains e.g.
  • Adiponitrile and / or hexamethylenediamine also water as excess water.
  • Cyclopentanone is also present as an impurity.
  • the mixture may also contain other impurities, such as may arise as by-products in the above-mentioned reaction, and also organic solvents
  • lactams can be considered as lactam, in particular those which can be converted into polyamides.
  • Lactams of C 4 -C 20 omega-carboxylic acids for example 4-aminobutanoic acid lactam, 5-aminopentanoic acid lactam, 6-aminohexanoic acid lactam ("caprolactam”), 7-aminoheptanoic acid lactam or 8-aminooctanoic acid lactam, particularly preferably caprolactam, are preferred.
  • These lactams can be substituted, for example by C 1-4 alkyl groups, halogens such as fluorine, chlorine or bromine, C- alkoxy groups or C 1-4 carboxy groups. However, the lactams are preferably not substituted. Mixtures of such lactams can also be used. Lactams of this type are known to the person skilled in the art.
  • lactams can be prepared by reacting the corresponding aminonitriles with water, for example in the case of caprolactam by reacting 6-aminocapronitrile, as for example in EP-A-0 659 741, WO 95/14664, WO 95/14665, WO 96 / 22874, WO 96/22974, WO 97/23454, WO 99/28296 or WO 99/47500.
  • 6-aminocapronitrile as for example in EP-A-0 659 741, WO 95/14664, WO 95/14665, WO 96 / 22874, WO 96/22974, WO 97/23454, WO 99/28296 or WO 99/47500.
  • Suitable starting materials for polyamide production are described below.
  • aminonitriles that is to say compounds which have both at least one amino and at least one nitrile group
  • aminonitriles can be used as the aminonitrile.
  • ⁇ -amino nitriles are preferred, with the latter in particular ⁇ -aminoalkyl nitriles having 4 to 2 carbon atoms, more preferably 4 to 9 carbon atoms in the Alkylene radical, or an aminoalkylaryl nitrile with 8 to 13 carbon atoms are used, preference being given to those which have an alkyl spacer with at least one carbon atom between the aromatic unit and the amino and nitrile group.
  • Linear ⁇ -aminoalkyl nitriles are more preferably used as the ⁇ -aminoalkyl nitrile, the alkylene radical (-CH 2 -) preferably containing 4 to 12 carbon atoms, more preferably 4 to 9 carbon atoms, such as 6-amino-1-cyanopentane (6-aminocapronitrile), 7-amino-1-cyano-hexane, 8-amino-1-cyanoheptane, 9-amino-1-cyanooctane, 10-amino-1-cyanononane, particularly preferably 6-aminocapronitrile.
  • 6-amino-1-cyanopentane 6-aminocapronitrile
  • 7-amino-1-cyano-hexane 8-amino-1-cyanoheptane
  • 9-amino-1-cyanooctane 10-amino-1-cyanononane
  • 10-amino-1-cyanononane particularly
  • 6-aminocapronitrile is usually obtained by hydrogenating adiponitrile by known processes, for example described in DE-A 836938, DE-A 848654 or US Pat. No. 5,151,543.
  • dinitriles that is to say compounds which have at least two nitrile groups
  • ⁇ , ⁇ -dinitriles are preferred, with the latter in particular using ⁇ , ⁇ -dinitriles with 4 to 12 C atoms, more preferably 4 to 9 C atoms in the alkylene radical, or a cyanoalkylaryl nitrile with 7 to 12 C atoms , where preference is given to those which have an alkyl spacer with at least one carbon atom between the aromatic unit and the two nitrile groups.
  • the cyanoalkylaryl nitriles those are particularly preferred which have the two nitrile groups in the 1,4-position relative to one another.
  • the ⁇ , ⁇ -alkylenedinitrile used is more preferably linear ⁇ , ⁇ -alkylenedinitrile, the alkylene radical (-CH 2 -) preferably containing 3 to 11 carbon atoms, more preferably 3 to 8 carbon atoms, such as 1.4 -Dicyanbutane (adiponitrile), 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyaneheptane, 1,8-dicyanoooctane, 1,9-dicyannonane, 1,10-dicyandecane, particularly preferably adipodinitrile.
  • all diamines that is to say compounds which have at least two amino groups
  • ⁇ , ⁇ -diamines are preferred, with the latter in particular using ⁇ , ⁇ -diamines with 4 to 14 C atoms, more preferably 4 to 10 C atoms in the alkylene radical, or an aminoalkylarylamine with 7 to 12 C atoms , where preference is given to those which have an alkyl spacer with at least one aromatic spacer between the aromatic unit and the two have at least one carbon atom.
  • aminoalkylarylamines those which have the two amino groups in the 1,4-position relative to one another are particularly preferred.
  • Linear ⁇ , ⁇ -alkylenediamines are more preferably used as ⁇ , ⁇ -alkylenediamine, the alkylene radical (-CH 2 -) preferably containing 3 to 12 C atoms, more preferably 3 to 8 C atoms, such as 1 , 4-diaminobutane, 1, 5-diaminopentane, 1, 6-diaminohexane (hexamethylene diamine), 1, 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, particularly preferably hexamethylene diamine.
  • diamines, dinitriles and aminonitriles derived from branched alkylene or arylene or alkylarylenes such as 2-methylglutarodinitrile or 2-methyl-1,5-diaminopentane, can also be used.
  • the molar ratio of the nitrile groups present in the feedstocks capable of polyamide formation to the amino groups present in the feedstocks capable of polyamide formation has increased in the range from 0.9 to 1.1, preferably 0.95 to 1.05, in particular 0.99 to 1.01, particularly preferably 1, have been found to be advantageous.
  • polyamide-forming monomers that can be used are, for example, dicarboxylic acids, such as alkanedicarboxylic acids having 6 to 12 carbon atoms, in particular 6 to 10 carbon atoms, such as adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid, and terephthalic acid, isophthalic acid and cyclohexanedicarboxylic acid, or amino acids, such as alkane amino acids Use 5 to 12 carbon atoms, especially ⁇ , ⁇ -C 5 -C 12 amino acids.
  • dicarboxylic acids such as alkanedicarboxylic acids having 6 to 12 carbon atoms, in particular 6 to 10 carbon atoms, such as adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid, and terephthalic acid, isophthalic acid and cyclohexanedicarboxylic acid
  • amino acids such as alkane amino acids Use 5
  • ⁇ -C 5 -C 12 amino acid there can be 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, preferably 6-aminohexanoic acid , or their internal amides, so-called lactams, in particular caprolactam.
  • R 1 for -OH, -OC ⁇ -Alky! or -NR 2 R 3 and R 2 and R 3 independently of one another are hydrogen, C 1-12 alkyl and C 5 - 8 cycloalkyl, and m is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 stand.
  • Particularly preferred amino carboxylic acid compounds are those in which R 1 OH, such as -O-methyl, -O-ethyl, -On-propyl, -Oi-propyl, -On-butyl, -O-sec.-butyl, -O-ter.-butyl and -NR 2 R 3 such as -NH 2 , -NHMe, -NHEt, -NMe 2 and -NEt 2 mean, and m stands for 5.
  • R 1 OH such as -O-methyl, -O-ethyl, -On-propyl, -Oi-propyl, -On-butyl, -O-sec.-butyl, -O-ter.-butyl and -NR 2 R 3
  • -NH 2 , -NHMe, -NHEt, -NMe 2 and -NEt 2 mean, and m stands for 5.
  • 6-Aminocaproic acid, 6-aminocaproic acid methyl ester, 6-aminocaproic acid ethyl ester, 6-aminocaproic acid methyl amide, 6-amino caproic acid dimethyl amide, 6-aminocaproic acid ethyl amide, 6-aminocaproic acid diethyl amide and 6-aminocaproic acid amide are very particularly preferred.
  • X 1 and X 2 for -N.-OOH, -OOC ⁇ -alkyl or -ONR 2 R 3 , and R 2 and R 3 independently of one another are hydrogen, C 1-12 -alkyl and C 5-8 -cycloalkyl, and m is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.
  • Particularly preferred dicarboxylic acid compounds are those in which X 1 and X 2 are N, OOH, -00-C 1-4 alkyl such as -OO-methyl, -OO-ethyl, -OO-n-propyl, -OO-i-propyl, -OO-n-butyl, -OO-sec.-butyl, -OO-ter.-butyl and -ONR 2 R 3 as -ONH 2 , -ONHMe, -ONHEt, - ONMe 2 and -ONEt 2 , and m stands for 5.
  • Adiponitrile, adipomononitrilamide, adipic acid diamide, adipic acid monoamide, adipic acid, adipic acid mononitrile are very particularly preferred.
  • the starting compounds are commercially available or, for example, according to EP-A 234295 and Ind. Eng. Chem. Process Des. Dev. 17 (1978) 9-16.
  • Amino nitriles or dinitriles and diamines or mixtures containing aminonitrile, dinitrile and diamine are preferably used as polyamide-forming monomers together with water, particularly preferably in a molar ratio in the range from 1: 1 to 1:20, based on the overall process.
  • Amino capronitrile is particularly preferred, with a molar ACN: water ratio in the overall process of 1: 1 to 1:10.
  • a mixture of adiponitrile, hexamethylenediamine and aminocapronitrile is particularly preferred, with a molar ratio of the sum of adiponitrile, hexamethylenediamine and aminocapronitrile: water in the overall process of 1: 1 to 1 : 10.
  • caprolactam and / or hexamethylene diammonium adipate are preferably used as the polyamide-forming monomers.
  • caprolactam and / or hexamethylenediammonium adipate are preferably used as polyamide-forming monomers, if desired.
  • the mixture to be separated according to the invention may also contain oligomers, such as dimers, trimers, tetramers, pentamers, hexane amides or polymeric amides.
  • Oligomeric amides are understood to mean compounds or their mixtures which are obtained by linking a low number, for example 2 to 6, of monomers, such as amino nitriles, preferably 6-aminocapronitrile, or dinitriles, preferably adiponitrile, with diamines, preferably hexamethylene diamine, or mixtures thereof Monomers are available.
  • Polymeric amides are understood to mean homopolymers or copolymers, such as random or block copolymers, or mixtures thereof, which have recurring amide groups (-CONH-) in the main polymer chain.
  • Such amides can be obtained in a manner known per se from the monomers described above, e.g. Aminonitriles, preferably 6-aminocapronitrile, or dinitriles, preferably adiponitrile, with diamines, preferably hexamethylenediamine.
  • the mixture used according to the invention can be single-phase (for example gaseous or liquid), two-phase (for example gaseous / liquid or liquid / solid) or three-phase (gaseous / liquid / solid).
  • Lactam prepolymers for example PA6 prepolymers, are particularly suitable as solids.
  • prepolymers made of dinitrile and diamine are suitable, for example PA66 prepolymers.
  • the mixture is preferably fed to the distillation apparatus (see below) as a gaseous feed.
  • the distillative removal is carried out in at least two stages 1 and 2 (in contrast to the one-stage distillation described in WO 01/94308).
  • the process is preferably carried out continuously, ie the mixture to be separated is fed continuously to the distillation apparatus, from which a top product and a bottom are continuously withdrawn.
  • stage 1 the mixture is subjected to distillation at an absolute pressure of 11 to 35 bar and a bottom temperature of 180 to 260 ° C.
  • the pressure is preferably 13 to 32, particularly preferably 15 to 30 bar.
  • the bottom temperature is preferably 190 to 245 and particularly preferably 195 to 230 ° C.
  • the higher pressure of 1 to 35 bar differentiates the present invention from the process claimed in WO 01/94308, according to which the pressure is less than 10, preferably less than 8 bar.
  • the distillation separates the mixture into a top product K1 and a bottom S1.
  • the top product K1 contains a mixture containing water and ammonia.
  • it can contain small amounts of the lactam and / or diamine and / or dinitrile, usually at most 1000 ppm, preferably at most 500 ppm, in particular at most 100 ppm.
  • the top product K1 contains the cyclopentanone: according to the invention, the cyclopentanone is completely removed as the top product. This should not rule out that small amounts of cyclopentanone can remain in the sump S1.
  • the top product K1 is at least partially drawn off in gaseous form, gas being included in the gaseous form.
  • the ammonia drawn off is at least partially gaseous.
  • 60 to 100% by weight of the ammonia contained in the withdrawn top product K1 is present as a gas.
  • the sump S1 contains a mixture containing water, the lactam and / or diamine and possibly unreacted aminonitrile and / or dinitrile. It preferably contains no more than 500, in particular no more than 200 ppm ammonia.
  • the sump S1 preferably contains a maximum of 100 ppm, in particular not more than 10 ppm and very particularly preferably not more than 1 ppm of cyclopentanone.
  • the sump S1 can be used as a starting material, for example in the production of polyamides or their prepolymers (for example, the lactam is converted to PA 6). Consequently, in a preferred embodiment, the sump S1 is converted into a process for the production of polyamides. Due to its high purity, the sump S1 is particularly preferably transferred directly and without further purification to this process for the production of polyamide. This is economically very advantageous because there are no complex cleaning steps.
  • a suitable reactor for the production of PA 6 or PA66 or copolyamides is, for example, a two-phase reactor with a plurality of chambers arranged one above the other, which are connected to one another by liquid overflows and by gas distributors provided with baffles, the product PA 6 or PA66 from the sump this reactor is withdrawn.
  • a reactor is e.g. described in the application DE file number 10313681.9 dated March 26, 2003 or the PCT subsequent application file number PCT / EP / 04/002875 dated March 19, 2004.
  • the distillation pressure and distillation temperature in stage 1 of the separation process according to the invention should preferably be selected such that a stream essentially comprising ammonia, water and cyclopentanone can be drawn off in gaseous or at least partially gaseous form at the top, and the mixture comprising water, lactam and / or Diamine and possibly aminonitrile and / or di-nitrile remains.
  • At least part of the sump S2 is returned to stage 1 as a return, see below.
  • stage 2 the top product K1 obtained in the first distillation is subjected to a further distillation at an absolute pressure of 1 to 35 bar and a bottom temperature of 180 to 260 ° C.
  • the pressure is preferably 13 to 19, particularly preferably 15 to 18 bar.
  • the bottom temperature is preferably 190 to 211 and particularly preferably 195 to 207 ° C.
  • the further distillation separates the top product K1 into a top product K2 and a bottom S2.
  • the top product K2 contains a mixture containing ammonia and cyclopentanone, ie the impurities are drawn off overhead. Part of the head Product K2 can be condensed and returned to the second distillation device as reflux.
  • the ammonia can be separated off from the top product K2 in a customary manner, for example by distillation, and used further as a valuable product.
  • the sump S2 essentially contains water.
  • the sump S2 is preferably high-purity water. It can be used directly and without further purification operations, for example as hydrolysis water in the hydrolysis of the aminonitrile or dinitrile or a mixture thereof, or as extraction water in the extraction of polyamide 6, which usually follows the production of PA6.
  • the sump S2 (water) is partly or completely returned to stage 1 as reflux, i.e. the bottom S2 of the second distillation column is passed partially or completely as reflux to the first column.
  • This embodiment enables a particularly extensive separation of cyclopentanone with the top product K1.
  • the distillation pressure and distillation temperature in stage 2 of the process should preferably be chosen so that a stream essentially containing ammonia and cyclopentanone can be taken off at the top and water remains in the bottom.
  • the top product can be withdrawn in gaseous form, at least partially in gaseous form or, if appropriate after condensation, also in liquid form.
  • stage 2 The distillation devices for stage 2 are those mentioned in the first distillation (stage 1).
  • the feed from the second distillation namely the at least partially gaseous top product K1 from the first distillation
  • the second distillation apparatus is condensed before being fed to the second distillation apparatus. This can be done using conventional capacitors.
  • This condensed top product K1 is usually not returned to the first distillation stage in order to successfully separate the cyclopentanone via the top product K1.
  • stages 1 and 2 in terms of apparatus, for example in thermally coupled distillation columns or in dividing wall columns. These devices are described in Kaibel et al., Chemie Ingenieurtechnik 2004, 76, no. 3, pages 258-263.
  • the separation by distillation according to the invention can be accomplished with less expenditure on equipment and energy. It has been found that the separation according to the invention can be significantly improved again if a dividing wall column with an internal intermediate condensation stage above the dividing wall and a conventional top condenser is used compared to a conventional dividing wall column without an intermediate condenser.
  • Such a process, in which the separation is carried out in a dividing wall column with an internal intermediate condenser is particularly preferred.
  • stages 1 and 2 are carried out as described in a dividing wall column with an additional intermediate condenser, the aqueous solution to be separated, which contains lactam or diamine and / or dinitrile, ammonia and small amounts of cyclopentanone, is condensed or partially fed to the dividing wall column, and is thus obtained a mixture according to the composition of the bottom product S1 of stage 1 is usually used as the bottom product of the dividing wall column, a mixture according to the composition of the bottom product S2 of stage 2 as the side withdrawal stream, and a mixture according to the composition of the top product K2 of stage 2 as the top product ,
  • the method according to the invention can have, in addition to stages 1 and 2, further stages which are designed as explained above.
  • the top product K2 can be subjected to a further distillation in order to separate ammonia, cyclopentanone and other by-products.
  • the process according to the invention enables ammonia and water to be separated off from mixtures which contain ammonia, water, a lactam and / or diamine and optionally aminonitrile and / or dinitrile in a technically simple and economical manner.
  • the process provides a sump S1 , which does not contain cyclopentanone as a troublesome by-product, and can therefore be used in polyamide production without further purification.
  • the invention therefore also relates to the use of the separation process described in a process for the production of polyamides, and to a process for the production of polyamides, characterized in that ammonia and water are separated from the resulting mixtures with the described separation process.
  • Polyamides which are produced using the cyclopentanone-free bottoms S1 obtained by the process according to the invention are characterized by better properties, in particular by a significantly lower color number or a lower intrinsic color.
  • Such polyamides can be dyed with a precise shade and are particularly suitable as non-dyed natural goods for optically demanding molded parts.
  • a mixture A of 77.0% by weight of water, 13.9% by weight of ammonia, 9.1% by weight of caprolactam, 0.004% by weight of cyclopentanone and 0.045% by weight of CO 2 was added in an amount of 12.2 kg / h as a gaseous feed at a pressure of 21 bar absolute and a temperature of 235 ° C continuously fed to a first distillation column.
  • the diameter of the column was 50 mm, the total height of the separating part of the column was 6000 mm.
  • the rectifying section of the column was filled with ordered packings.
  • the stripping section was equipped with bell bottoms. The bottom temperature was 220 ° C.
  • the top product K1 of the first column was drawn off completely in gaseous form at 210 ° C. and 21 bar pressure at a rate of 18.3 kg / h and was composed as follows: 90.7% by weight of water, 9.2% by weight .-% ammonia, 6 ppm caprolactam, 275 ppm CO 2 and 33 ppm cyclopentanone.
  • the overhead product K1 was completely condensed and fed continuously to a second distillation column at an absolute pressure of 7 bar and a temperature of 170 ° C.
  • the diameter of the column was 80 mm, the total height of the separating part of the column was 7000 mm.
  • the stripping section of the stripping section of the column was fitted with bubble cap trays.
  • the bottom temperature was 205 C C.
  • the top product K2 of the second column was completely condensed at 44 ° C. and 17 bar pressure.
  • a partial amount of this condensate with an amount of 1.7 kg / h was drawn off and composed as follows: 2.5% by weight of water, 97.2% by weight Ammonia, 0.3 wt% CO and 230 ppm cyclopentanone.
  • the rest of the condensate flow was given as return to stage 2.
  • the bottom S2 of the second column was drawn off at 205 ° C. and 17 bar in an amount of 16.5 kg / h and was composed as follows: 99.9% by weight of water, 6 ppm of caprolactam, 50 ppm of ammonia, 10 ppm cyclopentanone and ⁇ 1 ppm CO 2 . Accordingly, the water obtained was of high purity.
  • the sump S1 of the first column was taken off kg h at 220 C C in an amount of 2,443 / and was composed as follows: 54.9 wt .-% water, 45.1 wt .-% of caprolactam, ⁇ 20 ppm ammonia, ⁇ 1 ppb CO 2 and ⁇ 35 ppb cyclopentanone.
  • the sump S1 was conveyed into a reactor R and polymerized there to PA 6.
  • the longitudinal axis of the reactor R was vertical and its reaction product was discharged from the reactor sump.
  • the ammonia formed and any other low molecular compounds and water formed were withdrawn from the reactor R overhead.
  • the reactor R had five chambers arranged one above the other in the longitudinal direction and separated from one another by liquid-tight trays. Each chamber was connected to the chamber immediately below by a liquid overflow. A liquid product stream was withdrawn via the liquid overflow of the lowest chamber.
  • the gas space above the liquid level in each chamber was connected to the chamber immediately above it by a guide tube, each of which led into a gas distributor with openings for the gas outlet below the liquid level.
  • a baffle was arranged vertically around each gas distributor, the upper end of which ended below the liquid level and the lower end above the liquid-tight floor of the chamber, and which separated each chamber into a fumigated and an ungased room.
  • a prepolymer was metered in, which resulted from the hydrolysis of 30 kg ACN with 30 kg water in a pressure reactor with an average residence time of 1.5 h at 80 bar after subsequent expansion to 230 ° C. and 25 bar and deposition of a gas phase G was obtained.
  • the gas phase withdrawn from the reactor R at the top was combined with the gas phase G, so that a total gas phase of 12.2 kg / h, comprising 77.0% by weight of water, 13.9% by weight of ammonia, 9.1% by weight of caprolactam, 0.004% by weight of cyclopentanone and 0.045% by weight of CO 2 .
  • This total gas phase is mixture A.
  • the reactor R was operated at 28 bar gauge pressure and a controlled bottom temperature of 275 ° C. The temperature profile in the reactor developed adiabatically.
  • the total residence time in reactor R was 1.65 hours, including a residence time in the bottom region of less than 10 minutes.
  • Example 2 The procedure was as in Example 1, but the mixture was separated according to the prior art WO 01/94308 at a pressure of 5 bar.
  • the top product was withdrawn in gaseous form at a rate of 1.79 kg / h and was composed of 5.5% by weight of water, 94.2% by weight of ammonia, ⁇ 1 ppm of caprolactam, 0.02% by weight Cyclopentanone and 0.3 wt .-% C0 2 .
  • a portion of the overhead was condensed and returned to the column at a temperature of 71 ° C.
  • the examples show that disruptive impurities could be completely removed from the sump S1 using the process according to the invention.
  • the sump S1 of the example according to the invention contained only 35 ppb cyclopentanone
  • the sump of the comparative example contained 10 ppm, ie about 300 times the amount of cyclopentanone.
  • the sump S1 could be used directly in the PA6 production without further purification.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Polymers & Plastics (AREA)
  • Inorganic Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Polyamides (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Other In-Based Heterocyclic Compounds (AREA)

Abstract

L'invention concerne un procédé de séparation distillative d'ammoniac et d'eau dans des mélanges produits lors de la fabrication de polyamides, contenant un lactame et/ou des diamines et éventuellement un aminonitrile et/ou dinitrile et cyclopentanone en tant qu'impureté. Ledit procédé comporte deux étapes: 1) distillation du mélange sous 11 à 35 bar de manière à obtenir de l'eau, de l'ammoniac et cyclopentanone en tant que produits de haut de colonne (K1), et de l'eau, le lactame et/ou les diamines et éventuellement l'aminonitrile et/ou le dinitrile en tant que produits de bas de colonne (S1); et 2) distillation de (K1) sous 11 à 35 bar de manière à obtenir de l'ammoniac et cyclopentanone en tant que produits de haut de colonne (K2), et de l'eau en tant que produit de bas de colonne (S2).
EP05744786A 2004-06-02 2005-05-31 Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides Withdrawn EP1756208A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200410027022 DE102004027022A1 (de) 2004-06-02 2004-06-02 Verfahren zur Abtrennung von Ammoniak und Wasser aus Lactam-haltigen Gemischen
PCT/EP2005/005833 WO2005118692A1 (fr) 2004-06-02 2005-05-31 Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides

Publications (1)

Publication Number Publication Date
EP1756208A1 true EP1756208A1 (fr) 2007-02-28

Family

ID=34968299

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05744786A Withdrawn EP1756208A1 (fr) 2004-06-02 2005-05-31 Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides

Country Status (10)

Country Link
US (1) US20070244272A1 (fr)
EP (1) EP1756208A1 (fr)
JP (1) JP2008501810A (fr)
CN (1) CN1961033A (fr)
AR (1) AR048981A1 (fr)
BR (1) BRPI0511648A (fr)
CA (1) CA2565503A1 (fr)
DE (1) DE102004027022A1 (fr)
TW (1) TW200613379A (fr)
WO (1) WO2005118692A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107089764B (zh) * 2017-04-25 2021-04-30 湖北绿色家园材料技术股份有限公司 一种聚酰胺生产中废水利用方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5151543A (en) * 1991-05-31 1992-09-29 E. I. Du Pont De Nemours And Company Selective low pressure hydrogenation of a dinitrile to an aminonitrile
DE4339648A1 (de) * 1993-11-20 1995-05-24 Basf Ag Verfahren zur Herstellung von Caprolactam
KR100539338B1 (ko) * 1996-08-30 2005-12-28 바스프 악티엔게젤샤프트 아미노니트릴로부터 폴리아미드의 제조방법
AT407050B (de) * 1997-12-29 2000-11-27 Chemie Linz Gmbh Verfahren zur herstellung von l-asparaginsäure
DE19804023A1 (de) * 1998-02-02 1999-08-05 Basf Ag Kontinuierliches Verfahren zur Herstellung von Polyamiden aus Aminonitrilen
DE19846014A1 (de) * 1998-10-06 2000-04-13 Basf Ag Beschleuniger für die Herstellung von Polyamiden aus Aminonitrilen
MY127068A (en) * 2000-06-05 2006-11-30 Basf Ag Removal of ammonia from solutions including caprolactam and ammonia
US6551465B1 (en) * 2001-04-23 2003-04-22 Uop Llc Dividing wall column control system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005118692A1 *

Also Published As

Publication number Publication date
BRPI0511648A (pt) 2008-01-02
JP2008501810A (ja) 2008-01-24
CN1961033A (zh) 2007-05-09
WO2005118692A1 (fr) 2005-12-15
CA2565503A1 (fr) 2005-12-15
TW200613379A (en) 2006-05-01
AR048981A1 (es) 2006-06-14
DE102004027022A1 (de) 2006-01-05
US20070244272A1 (en) 2007-10-18

Similar Documents

Publication Publication Date Title
EP0129196B1 (fr) Procédé pour la production continue de polyamides
EP0129195B1 (fr) Procédé pour la production continue de polyamides
EP0393546B1 (fr) Procédé de production continue de copolyamides à base de caprolactame et de sels de diamines et acides dicarboxyliques
EP0117495A2 (fr) Procédé pour la fabrication continue de polylactames
DE69925013T2 (de) Kontinuierliches polymerisationsverfahren zur herstellung von polyamiden aus omega-aminonitrilen
DE69819521T9 (de) Verfahren zur herstellung von polyamiden
EP1058704B1 (fr) Procede de production de polyamides par distillation reactive
DE102005040656A1 (de) Verfahren zur Herstellung von Polyamiden
EP1299450A1 (fr) Procede en continu de production de polyamides a partir d'aminonitriles
DE60209499T2 (de) Verfahren zur herstellung von nylon 6,6
EP1194473B1 (fr) Procede de production de polyamides a partir de lactames et d'extraits de polyamide
EP1165660B1 (fr) Procede de production de polyamide 6 a faible teneur en extrait, a haute stabilite de viscosite et a faible taux de remonomerisation
EP1242506B1 (fr) Procede de fabrication de polyamides
EP1756208A1 (fr) Procede de separation d'ammoniac et d'eau dans des melanges produits lors de la fabrication de polyamides
EP2964691A1 (fr) Production de polyamides par polymérisation hydrolytique et extractions multiples
EP1181324B1 (fr) Procede de production de polyamides
EP0393544B1 (fr) Procédé de préparation en continu de nylon 4,6
WO2014135627A1 (fr) Fabrication de polyamides par polymérisation hydrolytique suivie d'un dégazage
WO2004085513A1 (fr) Procede de production de polyamides
KR20070023784A (ko) 폴리아미드 제조 동안 발생하는 혼합물로부터 암모니아 및물의 분리 방법
EP1383822A1 (fr) Procede de production de polyamides

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20070102

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20070327

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20070918