申请人:——
公开号:US20020002304A1
公开(公告)日:2002-01-03
The present invention provides a solvent extraction purification method for aromatic polycarboxylic acids that meet or exceed polymer-grade specification. The method includes dissolving a crude aromatic polycarboxylic acid in a base compound; removing impurities and excessive base compound; and removing residual base compound while making purified product. The purification method removes not only the impurities from the crude acid, but also the residual base compound from finished product that otherwise will contaminate the product. The salt in the cake is converted to product by acid-substitution, thermal decomposition, or electrolysis. The method uses base-extraction solvents to extract base compound and impurities from the salt. The residual base compound in the recovered product is then removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition. The purification method allows eliminating crystallizers for crystallization and equipment for drying and pneumatically carrying. Finally, the purification method is combined with the oxidation and solvent recovery in prior art to use only one set of process steps, instead of two, to produce aromatic polycarboxylic acids.
本发明提供了一种溶剂萃取提纯芳香族聚羧酸的方法,该方法可使芳香族聚羧酸达到或超过聚合物级规格。该方法包括将粗芳香族聚羧酸溶解在碱化合物中;除去杂质和过量的碱化合物;除去残留的碱化合物,同时制得纯化产品。这种提纯方法不仅能去除粗酸中的杂质,还能去除成品中残留的碱化合物,否则会污染产品。滤饼中的盐通过酸置换、热分解或电解转化为产品。该方法使用碱萃取溶剂萃取盐中的碱化合物和杂质。然后通过浸出、剥离、电磁波热搅拌或热分解蒸发等方法去除回收产品中残留的碱化合物。这种提纯方法可以省去结晶用的结晶器以及干燥和气动搬运设备。最后,纯化方法与现有技术中的氧化和溶剂回收相结合,只需一套工艺步骤,而不是两套,就能生产出芳香族聚羧酸。