Oxygen → Dimethyl terephthalate

HRID 236045

Reaktionsgleichung

Reaktionsgleichung von HRID 236045
[C:1]([O:13][CH3:14])(=[O:12])[C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][CH:3]=1.O=O.C1(C)C=CC(C(OC)=O)=CC=1.CC1C=CC(C(O)=O)=CC=1.C(OC)(=O)C1C=CC(C([O-])=O)=CC=1>CO.CC1C=CC(C)=CC=1>[C:2]1([CH3:1])[CH:11]=[CH:10][C:5]([C:6]([O-:8])=[O:7])=[CH:4][CH:3]=1.[C:6]([O:8][CH3:9])(=[O:7])[C:5]1[CH:10]=[CH:11][C:2]([C:1]([O:13][CH3:14])=[O:12])=[CH:3][CH:4]=1

Komponenten

9

Edukt 5

HCID 977OxygenHCID 7455Methyl 4-methylbenzoateHCID 7470P-Toluic AcidHCID 8441Dimethyl terephthalateHCID 36144541,4-Benzenedicarboxylic acid, methyl ester

Produkt 2

HCID 8441Dimethyl terephthalateHCID 1543424-Methylbenzoate

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 887MethanolLösungsmittel2×HCID 7809P-XyleneLösungsmittel2×

Versuchsvorschrift

A process for the production of dimethyl terephthalate from p-xylene and methanol by oxidation in a reactor, in the liquid phase with atmospheric oxygen in the presence of dissolved heavy metal compounds as a catalyst, of a mixture of p-xylene and a fraction containing predominantly methyl p-toluate, which fraction is recycled into the oxidation, to obtain an oxidation product containing primarily p-toluic acid and monomethyl terephthalate, at a temperature of 140°-170° C. and under a pressure of 4-8 bar; by esterification of the oxidation product with liquid and subsequently vaporized methanol brought to an elevated pressure, at a temperature of 220°-280° C. and under a pressure of 20-25 bar in a reactor to obtain a raw ester containing primarily p-toluate and dimethyl terephthalate; by withdrawing the raw ester fraction and a methanol-containing vapor fraction from the esterification stage, by distillatory separation of the raw ester into a p-toluate fraction which is recycled into the oxidation, a raw dimethyl terephthalate fraction which is subjected to further processing by recrystallization in methanol, and a residual fraction which is optionally subjected to a thermal aftertreatment or a reactive treatment with methanol and is partially recycled into the process after a subsequent working-up step by distillation. In this process, the esterification of the oxidation product is conducted with a methanol-containing vapor, brought by compression to the elevated pressure and elevated temperature required for esterification, which methanol-containing vapor has been obtained from the filtrate of the recrystallization of the raw dimethyl terephthalate fraction by vaporization or also by rectification of the methanol-containing vapor fraction and optionally additional methanol-containing process streams, under a pressure lying below the pressure utilized in the esterification reactor.

Aufarbeitung

  1. customto obtain an oxidation product
  2. customat a temperature of 140°-170° C.

Quellen und Nachweise

ORD-Eintrag
ord-cf5467820f384d25a13ea7430581eafe
Quelldatensatz
uspto-grants-1987_02
Patentnummer
US04642369

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