| 摘要 |
A process of the production of crude dimethyl terephthalate (DMT) incorporating recycling of high boiling residue. The process comprises: (A) oxidation of a mixture of p-xylene and p-toluic acid methyl ester (pT-ester) mixture in the liquid phase, with an oxygen containing gas in the presence of a catalyst. (B) esterification of the resulting acids with methanol. (C) distillation of the product mixture into (C1) a pT-ester rich fraction which is recycled to the oxidation step (A) (C2) a crude DMT fraction and (C3) a high boiling residue from which the catalyst is optionally recovered. The high boiling fraction (C3) is subjected to a methanolysis or a thermolysis followed by a methanolysis treatment. The catalyst is recovered. The residue is fed back, at least partially, to steps (A), (B) or (C) or to process streams that are intermediate to the process steps. |
