Disclosed is a process for purifying 2,6-naphthalene dicarboxylic acid produced by disproportionation and more efficiently recycling byproduct dipotassium salts which includes the steps of:
a) Contacting an aqueous solution containing the disalt of 2,6-NDA(2,6-K2NDA) with carbon dioxide to form as a precipitate the monopotassium salt of 2,6-NDA (KHNDA) and an aqueous solution containing 2,3-KHNDA, K2NDA, and potassium bicarbonate;
b) Disproportionating said monopotassium salt (KHNDA) to form 2,6-NDA and an aqueous solution containing K2NDA, and potassium bicarbonate;
c) Separating said 2,6-NDA and concentrating said aqueous solution containing K2NDA and potassium bicarbonate by reverse osmosis.
本发明公开了一种用于纯化通过歧化反应生产的
2,6-萘二羧酸并更有效地回收副产物二
钾盐的工艺,该工艺包括以下步骤
a) 将含有 2,6-
萘二
甲酸二盐(2,6-K2N
DA)的
水溶液与
二氧化碳接触,形成 2,6-N
DA 的单
钾盐(KHN
DA)沉淀和含有 2,3-KHN
DA、K2N
DA 和
碳酸氢钾的
水溶液;
b) 将所述单
钾盐 (KHN
DA) 进行歧化,形成 2,6-N
DA 和含有 K2N
DA 和
碳酸氢钾的
水溶液;
c) 通过反渗透分离所述 2,6-N
DA 和浓缩所述含有 K2N
DA 和
碳酸氢钾的
水溶液。