EP0807107A1 - Procede de purification de melanine - Google Patents

Procede de purification de melanine

Info

Publication number
EP0807107A1
EP0807107A1 EP96900304A EP96900304A EP0807107A1 EP 0807107 A1 EP0807107 A1 EP 0807107A1 EP 96900304 A EP96900304 A EP 96900304A EP 96900304 A EP96900304 A EP 96900304A EP 0807107 A1 EP0807107 A1 EP 0807107A1
Authority
EP
European Patent Office
Prior art keywords
melamine
pressure
bar
minutes
temperature
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Withdrawn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
EP96900304A
Other languages
German (de)
English (en)
Inventor
Martin Müllner
Helmut Fingrhut
Lorenzo Canzi
Gerhard Coufal
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.)
Agrolinz Melamin GmbH
Original Assignee
Agrolinz Melamin GmbH
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 Agrolinz Melamin GmbH filed Critical Agrolinz Melamin GmbH
Publication of EP0807107A1 publication Critical patent/EP0807107A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
    • C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
    • C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
    • C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
    • C07D251/40—Nitrogen atoms
    • C07D251/54—Three nitrogen atoms
    • C07D251/62—Purification of melamine
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
    • C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
    • C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
    • C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
    • C07D251/40—Nitrogen atoms
    • C07D251/54—Three nitrogen atoms
    • C07D251/56—Preparation of melamine
    • C07D251/60—Preparation of melamine from urea or from carbon dioxide and ammonia

Definitions

  • a large number of processes for the production of me laminate are already known from the literature.
  • a preferred starting material is urea, which is converted to melamine, ammonia and CO2 either at high pressure and non-catalytically or at low pressure and using a catalyst. It is also known that these by-products, in particular high-pressure processes, produce various by-products or impurities, such as, for example, Meiern, Melam, Ammeiin, Ammelid or Ureidomelamin, which impair the purity of the melamine.
  • the melamine produced by a high-pressure process is worked up, for example, in accordance with US Pat. No. 3,1 16,294 (Montecatini) by separating the CO2 and NH exhaust gases from the liquid melamine, which is then treated in countercurrent with NH3 in order to remove dissolved CO2 collected in another reactor and left for a certain time.
  • the separation column and the second reactor are kept under the same temperature and pressure conditions as the urea reactor, namely at 250 to 500 ° C and a pressure of about 40 to 150 bar.
  • the melamine thus obtained is removed from the second reactor and rapidly cooled by quenching with water or by mixing with cold gases.
  • the purity of melamine obtained by this process is not sufficient for many applications, for example in the production of melamine-formaldehyde resins for surface coatings, since the Meier content in particular is too high.
  • impurities such as Meier and melam are insoluble or sparingly soluble in water and aqueous alkali solutions, so that when melamine is recrystallized, for example following the Montecatini workup, these compounds are difficult and with melamine losses from the cleansing melamine can be removed.
  • the present invention therefore relates to a process for the purification of melamine, which is characterized in that contaminated melamine is left for 5 minutes to 20 hours at an ammonia partial pressure of 150 to 400 bar in a temperature range of 280 to 430 ° C. whereupon it is first rapidly cooled to room temperature and then relaxed or simultaneously cooled and relaxed and pure melamine is obtained in powder form.
  • the process according to the invention is suitable for the purification of melamine, which is obtained in any process known from the prior art and in particular contains impurities such as Meier and melam.
  • the melamine to be purified in the case that it is in crystalline form or as a powder, is first heated to a temperature within the temperature range from 280 to 430 ° C., preferably to or above the melting point of melamine to 400 ° C., and at an ammonia partial pressure of over 1 50 bar for a certain time in this area.
  • the melamine to be purified is already in the form of a melt or a liquid phase, such as, for example, following a high-pressure reactor for melamine synthesis by reacting with urea, this warm-up phase can be omitted and the temperature of the melt is brought to the desired value within the temperature range defined above.
  • the temperature of the melamine to be purified can be kept constant during the dwell time of the melamine, but it can also be changed within the temperature range defined above. For example, the temperature can be reduced or increased continuously or stepwise within the limits of the temperature range.
  • the residence time can vary within a wide range. It depends mainly on the desired final level of impurities, as well as on the ammonia partial pressure and on economic factors, and is between 5 minutes and 20 hours, preferably between 10 minutes and 10 hours, particularly preferably between 30 minutes and 4 Hours. Longer residence times are also possible if desired.
  • the ammonia partial pressure can also vary within a wide range and is between 150 and 400 bar. An ammonia partial pressure of up to 360 bar is preferably set, particularly preferably up to 300 bar.
  • Melamine is obtained by the process according to the invention in crystalline form or as a powder and in particular has a significantly reduced content of Meier and Melam.
  • the process according to the invention can be carried out batchwise or continuously.
  • the method according to the invention can be coupled to any melamine process known from the prior art.
  • Aus ⁇ method of the invention with one of the known from the prior art high-pressure processes, such as in Ullmann's Encyclopedia of Industrial Chemistry, 5 tn Edition, Vol. A-16, pp 174-179 beschrie ⁇ ben, combined.
  • the process according to the invention is particularly preferably carried out following known work-up steps for the high-pressure processes. These workup steps include a) separating the NH3 / CO 2 gas mixture obtained in the reaction of urea from the liquid melamine, and b) reducing the CO2 dissolved in the melamine by introducing NH3.
  • workup steps are described, for example, in US Pat. No. 3,116,294.
  • the process according to the invention can thus connect directly to the reactor for the urea conversion or can be carried out following the workup steps described above, the workup being able to comprise both steps a) in combination with b) and only one of these steps.
  • the autoclave was then quickly heated to a temperature T by immersion in a heat transfer medium and allowed to remain at this temperature for t minutes. Thereafter, the autoclave was quickly cooled by immersing it in cold water and then relaxed. The melamine cleaned in this way was examined for the final content of impurities, in particular Meier.
  • the process parameters such as weight of melamine (EW), pressure p, time t, temperature T, initial content of Meiern (MEo), Melam (MAo), Ammeiin (ANo), Ammelid (ADo), and ureidomelamine (UMo), as well as the The final content of Meiern (ME), Melam (MA), Ureidomelamin (UM) and partly Ammeiin (AN) and Ammelid (AD) are shown in Table 1.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé de purification de mélanine selon lequel on maintient de la mélanine non purifiée entre 5 et 20 heures à une pression ammoniacale partielle comprise entre 150 et 400 bar, dans une plage de température comprise entre 280 et 430 °C, avant de la refroidir ensuite rapidement jusqu'à la température ambiante puis de procéder à une détente, ou simultanément de la refroidir et de procéder à une détente. La mélanine pure est obtenue sous forme de poudre.
EP96900304A 1995-02-03 1996-01-08 Procede de purification de melanine Withdrawn EP0807107A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AT0018695A AT402296B (de) 1995-02-03 1995-02-03 Verfahren zur reinigung von melamin
AT1869/55 1995-02-03
PCT/EP1996/000045 WO1996023778A1 (fr) 1995-02-03 1996-01-08 Procede de purification de melanine

Publications (1)

Publication Number Publication Date
EP0807107A1 true EP0807107A1 (fr) 1997-11-19

Family

ID=3483772

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96900304A Withdrawn EP0807107A1 (fr) 1995-02-03 1996-01-08 Procede de purification de melanine

Country Status (12)

Country Link
EP (1) EP0807107A1 (fr)
JP (1) JPH11506415A (fr)
KR (1) KR19980701828A (fr)
CN (1) CN1172480A (fr)
AT (1) AT402296B (fr)
BR (1) BR9607332A (fr)
HR (1) HRP960044A2 (fr)
IL (1) IL117016A0 (fr)
NZ (1) NZ298425A (fr)
PL (1) PL321596A1 (fr)
TW (1) TW305838B (fr)
WO (1) WO1996023778A1 (fr)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT403579B (de) * 1995-12-07 1998-03-25 Agrolinz Melamin Gmbh Verfahren zur herstellung von hochreinem melamin
NL1003105C2 (nl) * 1996-05-14 1997-11-18 Dsm Nv Werkwijze voor de bereiding van melamine.
NL1003328C2 (nl) * 1996-06-13 1997-12-17 Dsm Nv Werkwijze voor het bereiden van melamine.
NL1003709C2 (nl) * 1996-07-30 1998-02-05 Dsm Nv Werkwijze voor het bereiden van melamine.
NL1006095C2 (nl) * 1997-05-21 1998-11-25 Dsm Nv Werkwijze voor het bereiden van melamine.
KR100495262B1 (ko) 1997-05-21 2005-06-14 코닌클리즈케 디에스엠 엔.브이. 멜라민의 제조방법
NL1006147C2 (nl) * 1997-05-28 1998-12-01 Dsm Nv Werkwijze voor het bereiden van melamine.
ES2195338T3 (es) 1997-05-28 2003-12-01 Dsm Ip Assets Bv Metodo para preparar melamina.
NL1006192C2 (nl) 1997-06-02 1998-12-03 Dsm Nv Werkwijze voor het bereiden van melamine.
KR100569572B1 (ko) 1997-06-02 2006-04-10 디에스엠 아이피 어셋츠 비.브이. 결정성 멜라민
JP2002502416A (ja) * 1997-06-02 2002-01-22 ディーエスエム エヌ．ブイ． メラミンの製造法
NL1008571C2 (nl) * 1998-03-12 1999-07-28 Dsm Nv Kristallijn melamine.
DE59906703D1 (de) 1998-11-13 2003-09-25 Agrolinz Melamin Gmbh Linz Verfahren zur herstellung von reinem melamin
CZ20012301A3 (cs) 1998-12-23 2002-03-13 Agrolinz Melamin Gmbh Způsob čiątění melaminu
NL1013217C2 (nl) * 1999-10-05 2001-04-06 Dsm Nv Werkwijze voor de bereiding van melamine.
NL1013456C2 (nl) * 1999-11-02 2001-05-03 Dsm Nv Kristallijn melamine en de toepassing in aminoformaldehydeharsen.
IT1315255B1 (it) * 1999-11-16 2003-02-03 Eurotecnica Dev And Licensing Procedimento di purificazione della melammina.
US20030028020A1 (en) * 2001-07-27 2003-02-06 Gupta Ram B. Process for the synthesis of high purity melamine
BR0214215A (pt) 2001-11-16 2004-12-21 Ami Agrolinz Melamine Int Gmbh Processo para a preparação de melamina isenta de melem e agentes de resfriamento brusco
DE102004018784A1 (de) 2004-04-14 2005-11-03 Ami-Agrolinz Melamine International Gmbh Verfahren zur Herstellung von reinem Melamin

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3116294A (en) * 1963-12-31 Process- for preparing high-purity melamine from urea
GB800722A (en) * 1955-03-12 1958-09-03 Montedison Spa Improvements in the production of melamine from urea
DE1217964B (de) * 1961-07-13 1966-06-02 Allied Chem Verfahren zur Gewinnung von reinem Melamin
DE1695564A1 (de) * 1966-07-22 1971-05-06 Nissan Chemical Ind Ltd Verfahren zur Herstellung von Melamin hoher Reinheit
US3637686A (en) * 1969-02-10 1972-01-25 Nissan Chemical Ind Ltd Process for recovering purified melamine
DE2522233A1 (de) * 1975-05-20 1976-12-02 Bollmann L Kg Maschine zum stapeln von flaechigen gegenstaenden, insbesondere brettern
IT1270577B (it) * 1993-02-22 1997-05-06 Wladimiro Bizzotto Reattore melamina ad alta pressione
FI96028C (fi) * 1993-07-01 1996-04-25 Kemira Oy Menetelmä melamiinin valmistamiseksi

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9623778A1 *

Also Published As

Publication number Publication date
KR19980701828A (ko) 1998-06-25
BR9607332A (pt) 1997-11-25
ATA18695A (de) 1996-08-15
TW305838B (fr) 1997-05-21
PL321596A1 (en) 1997-12-08
WO1996023778A1 (fr) 1996-08-08
CN1172480A (zh) 1998-02-04
HRP960044A2 (en) 1997-12-31
NZ298425A (en) 1999-04-29
JPH11506415A (ja) 1999-06-08
AT402296B (de) 1997-03-25
IL117016A0 (en) 1996-06-18

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