A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent and converting to the corresponding aromatic dianhydride. The extracting is carried out in an extraction column including a high specific surface area metal packing material and having an interface between the aqueous reaction mixture and the organic solvent that is at a level that is 14 to 85 % of the height of the extraction column.
一种制备芳香族二酐的方法包括在胺交换催化剂的存在下,在
水介质中将芳香族二
酰亚胺与取代或未取代的邻苯二酐反应,以提供包括N-取代邻苯
酰亚胺、芳香族
四酸盐和至少一种芳香族三酸盐或芳香族亚酰二酸盐的
水相反应混合物。该方法还包括通过用有机溶剂提取
水相反应混合物并转化为相应的芳香族二酐来从
水相反应混合物中去除邻苯
酰亚胺。提取是在提取柱中进行的,该提取柱包括高比表面积
金属填料,并且
水相反应混合物和有机溶剂之间的界面位于提取柱的高度的14%至85%的
水平处。