A method for purifying an oxydiphthalic anhydride comprises diluting a first mixture comprising an oxydiphthalic anhydride, a solvent, a catalyst, and an inorganic salt with a solvent, to provide a second mixture having a solids content of 10 to 30 percent based on total weight of the second mixture; filtering and washing the solids of the second mixture at a temperature below the crystallization point temperature of the oxydiphthalic anhydride to provide a third mixture; hydrolyzing the third mixture by adding water and a water-soluble acid to form a fourth mixture; heating the fourth mixture; then cooling to provide a solid-liquid mixture, optionally decanting a portion of the liquid, re diluting the remaining solid-liquid mixture, then filtering to provide a solid component; washing the solid component with water to provide a fifth mixture of oxydiphthalic tetra acid and water; ring closing the oxydiphthalic tetra acid to provide oxydiphthalic anhydride, and filtering the oxydiphthalic anhydride.
一种用于纯化氧二苯二
甲酸酐的方法包括将含有氧二苯二
甲酸酐、溶剂、催化剂和
无机盐的第一混合物稀释至含固体物含量为总重量的10至30%的第二混合物;在低于氧二苯二
甲酸酐的结晶点温度的温度下过滤和洗涤第二混合物的固体以提供第三混合物;通过加入
水和
水溶性酸
水解第三混合物以形成第四混合物;加热第四混合物;然后冷却以提供固液混合物,可选择性地倾倒部分液体,重新稀释剩余的固液混合物,然后过滤以提供固体组分;用
水洗涤固体组分以提供氧二苯四
甲酸和
水的第五混合物;闭环氧二苯四
甲酸以提供氧二苯二
甲酸酐,并过滤氧二苯二
甲酸酐。