| 摘要 |
Disclosed is an improvement in the cooxidation process for making dimethyl terphthalate (DMT). In the cooxidation process an oxidate comprising monomethyl terephthalate and p-toluic acid is esterified with methanol to form a reaction mixture comprising DMT and methyl p-toluate, methyl p-toluate is separated from the reaction mixture, and p-xylene and said methyl p-toluate are cooxidized in the liquid phase with molecular oxygen to form more oxidate, which is esterified, etc. The improvement comprises separating p-toluic acid from part of the oxidate prior to esterifying the oxidate, and cooxidizing separated p-toluic acid with said p-xylene and said methyl p-toluate. This improvement results in a lesser quantity of oxidate subjected to esterification, and a reduction in the quantity of methyl p-toluate cooxidized with p-xylene. |
