DE836354C - Process for the production of melamine from urea - Google Patents

Process for the production of melamine from urea

Info

Publication number
DE836354C
DE836354C DES3108A DES0003108A DE836354C DE 836354 C DE836354 C DE 836354C DE S3108 A DES3108 A DE S3108A DE S0003108 A DES0003108 A DE S0003108A DE 836354 C DE836354 C DE 836354C
Authority
DE
Germany
Prior art keywords
urea
melamine
ammonia
production
weight
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.)
Expired
Application number
DES3108A
Other languages
German (de)
Inventor
Dr Franz Kaess
Franz Maresch
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.)
SUEDDEUTSCHE KALKSTICKSTOFF-WERKE AG
Evonik Operations GmbH
Original Assignee
SUEDDEUTSCHE KALKSTICKSTOFF-WERKE AG
SKW Trostberg AG
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 SUEDDEUTSCHE KALKSTICKSTOFF-WERKE AG, SKW Trostberg AG filed Critical SUEDDEUTSCHE KALKSTICKSTOFF-WERKE AG
Priority to DES3108A priority Critical patent/DE836354C/en
Application granted granted Critical
Publication of DE836354C publication Critical patent/DE836354C/en
Expired 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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
    • C08K5/3477—Six-membered rings
    • C08K5/3492—Triazines
    • C08K5/34928—Salts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Description

Verfahren zur Herstellung von Melamin aus Harnstoff Die vorliegende Erfindung bezweckt die Herstellung von Melamin aus Harnstoff.Process for the production of melamine from urea The present The invention aims to produce melamine from urea.

Es ist bekannt, Harnstoff in Melamin überzuführen. Man verwendet hierbei als Zusatz Ammoniak in erheblichen Mengen, die einem Molverhältnis Harnstoff :Ammoniak von 1:8 bis 20 entsprechen. Hierbei sind Drucke von 4oo bis 5oo atü erforderlich. Erniedrigt man das Molverhältnis von 1:8 bis 2o auf i:4 und darunter, s() sind Drucke von 6oo bis iooo atü erforderlich.It is known to convert urea into melamine. One uses here as an additive, ammonia in considerable amounts, which has a urea: ammonia molar ratio correspond from 1: 8 to 20. This requires prints from 400 to 500 atmospheres. If the molar ratio is reduced from 1: 8 to 2o to i: 4 and below, s () are prints from 600 to 10000 atü required.

Die bei dieser Arbeitsweise erhaltenen Ausbeuten an Melamin betragen 18 bis 30°o.The melamine yields obtained in this procedure are 18 to 30 ° o.

Erfindungsgemäß vermeidet man die obengenannten Nachteile, nämlich Verwendung sehr großer Ammoniakmengen, hohe Druckbeanspruchung und geringe Ausbeuten durch Zusätze von wasserentziehenden Mitteln, insbesondere von Phosphorpentoxyd oder wasserfreier Phosphorsäure: Eine bevorzugte Arbeitsweise ist folgende: Harnstoff, wasserfrei, wird ein wasserentziehendes Mittel, z. B. Phosphorpentoxyd, zugesetzt; dieses kann auch mit Harnstoff zusammen verpreßt werden. Das Gemisch wird in einem geschlossenen Gefäß mit i bis .4 Vol Ammoniak, bezogen auf i Mol Harnstoff, bei einer Temperatur von mehr als ioo° und einem Druck von Zoo bis 4oo atü umgesetzt. Nach der Umsetzung kann das Reaktionsprodukt in der üblichen Weise gereinigt werden.According to the invention, the above-mentioned disadvantages are avoided, namely Use of very large amounts of ammonia, high pressure loads and low yields by adding dehydrating agents, especially phosphorus pentoxide or anhydrous phosphoric acid: A preferred procedure is as follows: urea, anhydrous, a dehydrating agent, e.g. B. phosphorus pentoxide added; this can also be pressed together with urea. The mixture is in one closed vessel with 1 to 4 vol ammonia, based on 1 mol urea a temperature of more than 100 ° and a pressure of zoo to 4oo atü. After the reaction, the reaction product can be purified in the usual way.

Beispiel i 9o Gewichtsteile Harnstoff, trocken, werden mit 8,5 Gewichtsteilen Phosphorpentoxyd gemischt und verprcßt, in einen Autoklaven gefüllt und 71,5 Gewichtsteile N H, eingeführt. Die Masse wird bis auf 4io@ C erhitzt, der Druck steigt bis auf 325 atii, die Reaktionsdauer beträgt 2'j,, Stunden. Die Ausbeute an Melamin beirägt 850;''o der Theori^.Example i 9o parts by weight of urea dry, may be mixed with 8.5 parts by weight of phosphorus pentoxide and verprcßt, charged into an autoclave and 71.5 parts by weight of NH introduced. The mass is heated up to 40 ° C., the pressure rises to 325 atii, the reaction time is 2 hours. The yield of melamine is 850; '' o der Theori ^.

Beispiel 2 9o Gewichtsteile Harnstoff, trocken, werden in einen Autoklaverr gegebe_r, c9,5 Gewichtsteile Phosphorpentoxyd werden zugesetzt und 6o G-wichtsteile Ammoniak eingeführt. Die Masse wird bis auf 46o° C erhitzt, der Druck beträgt 27o atii, die Reaktionsclauer 2 Stunden. Die Ausbeute an Melamin beträgt der Theorie.Example 2 90 parts by weight of urea, dry, are placed in an autoclave Given, c9.5 parts by weight of phosphorus pentoxide are added and 60 parts by weight Ammonia introduced. The mass is heated up to 46o ° C, the pressure is 27o atii, the reaction claws 2 hours. The yield of melamine is theoretical.

Claims (1)

PATE NTANSPEI;CH: Verfahren zur Herstellung von Melamin aus Harnstoff unter Zusatz von Ammoniak, dadurch gekennzeichnet, daß man Harnstoff mit Wasser entziehenden Mitteln, insbesondere mit Phosphorpentoxyd oder wasserfreier Phosphorsäure, in Gegenwart von Ammoniak im geschlossenen Gefäß erhitzt, wobei vorteilhaft das Phosphorpcntoxyd in einer Menge von maximal 20e0, auf Harnstoff bezogen, verwendet wird, maximal 4 Mol Ammoniak auf i Mol Harnstoff angewandt werden und bei Temperaturen über ioo° und Drucken von Zoo bis 4oo atü gearbeitet wird.PATE NTANSPEI; CH: Process for the production of melamine from urea with the addition of ammonia, characterized in that urea is mixed with water removing agents, especially with phosphorus pentoxide or anhydrous phosphoric acid, heated in the presence of ammonia in a closed vessel, which is advantageous Phosphorus oxide in an amount of a maximum of 20e0, based on urea, used is, a maximum of 4 moles of ammonia are applied to 1 mole of urea and at temperatures over ioo ° and printing from zoo to 4oo atü is being worked on.
DES3108A 1950-05-04 1950-05-04 Process for the production of melamine from urea Expired DE836354C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DES3108A DE836354C (en) 1950-05-04 1950-05-04 Process for the production of melamine from urea

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES3108A DE836354C (en) 1950-05-04 1950-05-04 Process for the production of melamine from urea

Publications (1)

Publication Number Publication Date
DE836354C true DE836354C (en) 1952-04-10

Family

ID=7469961

Family Applications (1)

Application Number Title Priority Date Filing Date
DES3108A Expired DE836354C (en) 1950-05-04 1950-05-04 Process for the production of melamine from urea

Country Status (1)

Country Link
DE (1) DE836354C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2902488A (en) * 1959-09-01 Process for the production of melamine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2902488A (en) * 1959-09-01 Process for the production of melamine

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