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1. (WO2001036397) MELAMINE PURIFICATION PROCESS

Pub. No.:    WO/2001/036397    International Application No.:    PCT/IT2000/000443
Publication Date: Sat May 26 01:59:59 CEST 2001 International Filing Date: Sat Nov 04 00:59:59 CET 2000
IPC: C07D 251/60
C07D 251/62
Applicants: EUROTECNICA GROUP S.A. (Swiss Branch)
NOE', Sergio
Inventors: NOE', Sergio
Title: MELAMINE PURIFICATION PROCESS
Abstract:
A process for the purification of melamine, deriving from urea, according to a high pressure non catalytic process, by means of polycondensates and other by-products transformation, which by-products derive from the melamine synthesis comprising the following steps: dissolving in water the raw liquid melamine containing polycondensates and other melamine synthesis by-products, subjecting such solution to a treatment capable to remove dissolved CO2, limiting its concentration to a value lower than 0.5 wt.%, submitting raw melamine solution, to the action of ammonia, in an amount of 5 to 25 wt.%, at a temperature of 100 to 250 °C and leaving the mixture to react for some minutes, recovering a solution having polycondensates concentration lower than 1000 ppm, typically less than 100 ppm.