Method to produce aromatic carboxylic acids

摘要

A process to produce for example terephthalic acid is provided, the process including the steps of: providing a feed stream comprising a dialkyl substituted aromatic and an organic acid solvent: contacting the feed stream with a vapour stream, the vapour stream containing at least 50 % by volume oxygen and at an oxygen partial pressure of at least 1 psi, at a temperature between about 80 DEG C and about 130 DEG C, in the presence of a catalyst system comprising zirconium and cobalt, wherein the contacting is done in a stirred tank reactor; removing from the stirred tank reactor a vapour stream comprising the organic acid and water: condensing at least a portion of the organic acid and water from the vapour stream; separating at least a portion of the water from the organic acid separated from the vapour stream; returning at least a portion of the condensed organic acid back to the stirred tank reactor; continuously recovering from the stirred tank reactor a reactor product comprising a diacid substituted aromatic; isolating solid crystals of diacid substituted aromatic from the reactor product; and recovering from the solid crystals of diacid substituted aromatic a diacid substituted aromatic having a purity of at least 97 % by weight.