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    • 5. 发明公开
    • METHOD FOR PRODUCING AND PURIFYING MELAMINE
    • VERFAHREN ZUR HERSTELLUNG REINIGUNG VON MELAMIN
    • EP2457902A1
    • 2012-05-30
    • EP10802514.9
    • 2010-07-12
    • Otkrytoe Aktsionernoe Obschestvo Research & Design Institute Of Urea And Organic Synthesis Products (OAO NIIK)
    • NIKOLAEV, Evgeny YuryevichSKUDIN, Aleksei GeorgievichSOLDATOV, Aleksei VladimirovichPROKOPYEV, Aleksandr AlekseevichKUZNETSOV, Nikolai MikhailovichKostin, Oleg NikolaevichESIN, Igor Veniaminovich
    • C07D251/60C07D251/62
    • C07D251/60C07D251/62
    • The invention relates to the technique for producing melamine by converting urea into melamine using a non-catalytic method at high pressure, as a whole, as well as to a stage of removing dissolved gases from an aqueous solution of crude Melamine, and can be used in commercial production of melamine. The method for producing melamine comprises a stage of converting urea into melamine at increased temperature and pressure with the formation of a gas-liquid reaction mixture containing melamine, ammonia, carbon dioxide and impurities, and a melamine separation stage. In order to separate melamine, the gas-liquid reaction mixture is cooled with lowering pressure and contacting with an aqueous medium, resulting in the formation of an aqueous solution of crude melamine and the partial removal of dissolved gases. The melamine solution obtained is allowed to stand in order to decompose a part of impurities, the pressure and the temperature are lowered, and the dissolved gases are removed from the aqueous solution of crude melamine using the proposed method by means of blowing water vapour through this solution with simultaneous ammonia introduction. An alkali metal hydroxide solution is added to the resultant melamine solution and melamine is separated from the solution by crystallization. The technical result which can be produced when using this invention involves increase of melamine purity and ensuring independence of its purity from the process parameters fluctuations. Melamine-formaldehyde resins prepared on the base of melamine produced by the proposed method have a high degree of transparency.
    • 本发明涉及通过使用非催化方法在高压下整体将尿素转化为三聚氰胺以及从粗三聚氰胺的水溶液中除去溶解气体的阶段来生产三聚氰胺的技术,并且可以使用 在三聚氰胺的商业生产中。 生产三聚氰胺的方法包括在形成含有三聚氰胺,氨,二氧化碳和杂质的气液反应混合物和三聚氰胺分离阶段的过程中,在升高的温度和压力下将脲转化成三聚氰胺。 为了分离三聚氰胺,气 - 液反应混合物在降低压力下冷却并与水介质接触,导致形成粗三聚氰胺水溶液并部分除去溶解气体。 使所得的三聚氰胺溶液静置以分解杂质的一部分,降低压力和温度,并且使用所提出的方法通过吹入水蒸气从溶解的三聚氰胺水溶液中除去溶解的气体 溶液同时导入氨。 向所得三聚氰胺溶液中加入碱金属氢氧化物溶液,通过结晶将三聚氰胺与溶液分离。 当使用本发明时可以产生的技术结果涉及提高三聚氰胺纯度并确保其纯度与工艺参数波动的独立性。 通过所提出的方法制备的三聚氰胺基底上制备的三聚氰胺 - 甲醛树脂具有高度的透明度。