A process for producing pyromellitic acid which comprises oxidizing 2,4,5-trimethylbenzealdehyde and/or its oxidized derivative in the presence of a catalyst containing iron, manganese and bromine, or additionally containing zirconium or cerium continuously or semi-continuously using aqueous acetic acid solvent and 0.05-2% by weight of bromide ion. The catalyst used in the present invention has high activity, and the catalyst solution has low corrosive because the reaction is performed at low bromide concentration by using a solvent of aqueous acetic acid. So pyromellitic acid is produced industrially advantageously in high yield continuously or semi-continuously which has been a major difficulty up to now.
一种生产焦苯四
甲酸的方法,包括在含有
铁、
锰和
溴的催化剂存在下氧化
2,4,5-三甲基苯甲醛和/或其氧化衍
生物,或者另外含有
锆或
铈,连续或半连续地使用
水合
乙酸溶剂和0.05-2%
溴离子重量。本发明中使用的催化剂具有高活性,由于在使用
水合
乙酸溶剂的情况下以低
溴浓度进行反应,催化剂溶液具有低腐蚀性。因此,通过连续或半连续地高产量生产焦苯四
甲酸,这是迄今为止的一大难题。