| 摘要 |
In dimethyl terephthalate production by Witten catalytic oxidation of p-xylene and methyl p-toluate and passing condensable vapor from oxidation, circulating products and excess starting materials as liquid into xylene tank, methyl formate and acetate formed in condensation system are hydrolyzed before organic phase enters xylene tank; organic and aqueous phases are separated in this tank; and dispersed water is separated before organic phase enters oxidation stage. Dimethyl terephthalate production by Witten process involves catalytic oxidation of p-xylene and methyl p-toluate with gas containing oxygen and passing condensable vapor from oxidation, circulating products and excess starting materials as liquid into xylene tank. The novel features are that methyl esters, formed by partial reaction of methanol with formic and acetic acid in the condensation system and present in an organic phase, are hydrolyzed before entering the xylene tank; an organic and an aqueous phase form and are separated in the xylene tank; and water present as disperse phase is separated from the organic phase in a phase separator before the organic phase enters an oxidation stage.
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