Teijin Petrochemical Industries, Ltd.

Hercofina

Takao Fujii

Seiichi Yokoyama

Shinichi Takeda

Hideo Hasegawa

Kenji Nagura

Koshi Namie

Michio Yamamoto

A method of recovering useful components at least containing dimethyl terephthalate from high-boiling byproducts occurring in the production of dimethyl terephthalate, which comprises oxidizing p-xylene and/or methyl p-toluate with a molecular oxygen-containing gas in the presence of a heavy metal oxidation catalyst, subjecting the resulting oxidation product to esterification with methanol, separating dimethyl terephthalate and esters having lower boiling points than dimethyl terephthalate from the esterification reaction product by distillation, and thereafter treating the distillation residue containing byproducts having higher boiling points than dimethyl terephthalate with methanol to recover at least dimethyl terephthalate from the treated product; wherein the treatment of the distillation residue with methanol is carried out at a temperature of 110.degree. to 240.degree. C. under a pressure sufficient to maintain methanol in the liquid phase.

Recovering useful components at least containing dimethyl terephthalate

Disclosed is a process for the recovery of aromatic carboxylic acid or ester thereof from the residue fraction of the oxidation or esterification reaction mixture resulting from the oxidation or oxidation and esterification of an aromatic compound having at least one methyl or formyl group directly bonded to a ring carbon atom. The process comprises treating the residue fraction with hydrogen and a hydrogenation catalyst.

Recovery of aromatic carboxylic acid or ester thereof from residue

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Matsuyama, Japan

Takao Fujii