Edward C Simpson

US Patent:

6153790, Nov 28, 2000

Filed:

Dec 1, 1998

Appl. No.:

9/201963

Inventors:

Raymond Lawrence June - Houston TX
Michael Wayne Potter - Sugar Land TX
Edward James Simpson - Houston TX
Charles Lee Edwards - Houston TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

C07C 51255

US Classification:

562414

Abstract:

A process to produce terephthalic acid is provided, the process including the steps of: providing a feed stream comprising a dialkyl substituted aromatic and in an organic acid solvent: contacting the feed stream with an oxidant, the oxidant containing at least 50% by volume oxygen and at an oxygen partial pressure of at least 1 psia, at a temperature between about 80. degree. C. and about 130. degree. C. , in the presence of a catalyst system comprising zirconium and cobalt, wherein the contacting is done in a stirred tank reactor; removing from the stirred tank reactor a vapor stream comprising the organic acid, water vapor and unreacted oxidant; condensing at least a portion of the organic acid and water from the vapor stream; separating at least a portion of the water from the organic acid back to the stirred tank reactor; returning at least a portion of the condensed organic acid back to the stirred tank reactor; continuously recovering from the stirred tank reactor a product comprising a diacid substituted aromatic; isolating solid crystals of diacid substituted aromatic from the reactor product; and recovering from the solid crystals a diacid substituted aromatic having a purity of preferably at least 97% by weight.