Eastman Chemical Company

Eastman-kodak Company

Grupo Petrotemex S.a. De C.v.

Thomas Earl Woodruff

Alan George Wonders

Ronald Buford Sheppard

Robert Lin

Brent Alan Tennant

Wayne Scott Strasser

Martin De Boer

Thomas Young Lightfoot

Charles Helton Hitchcock

Raymond Elbert Fogle, Iii

David Lee Denton

Carl Norman McCurry

Kenny Randolph Parker

Charles Edwan Sumner, Jr

Marcel De Vreede

Philip Edward Gibson

Ruairi Seosamh O'Meadhra

Eric Jackson Fugate

Johannes Wilhelmus Sluijmers

Judy E Kiefer

Ernest William Arnold, Iii

John David Aycock

William V Phillips

Disclosed is an optimized process and apparatus for more efficiently and economically carrying out the liquid-phase oxidation of an oxidizable compound. Such liquid-phase oxidation is carried out in a bubble column reactor that provides for a highly efficient reaction at relatively low temperatures. When the oxidized compound is para-xylene and the product from the oxidation reaction is crude terephthalic acid (CTA), such CTA product can be purified and separated by more economical techniques than could be employed if the CTA were formed by a conventional high-temperature oxidation process.

Oxidation system with sidedraw secondary reactor

Optimized liquid-phase oxidation

Disclosed is an optimized system for more efficiently and economically producing terephthalic acid. The system includes a multi-stage oxidative digestion system for processing an improved initial slurry from primary oxidation. The multi-stage digestion system is capable of adequately purifying the improved initial slurry without requiring significant liquor exchange between primary oxidation and oxidative digestion.

Polycarboxylic acid production system employing enhanced multistage oxidative digestion

Disclosed is an optimized system for more efficiently and economically producing terephthalic acid. The system employs an evaporative removal step downstream of oxidative digestion. The evaporative removal step removes a portion of the liquid phase and promotes precipitation of certain aromatic impurities. By promoting precipitation of certain aromatic impurities, the amount of the precipitated impurities in the recycled solvent is advantageously reduced.

Polycarboxylic acid production system employing enhanced evaporative concentration downstream of oxidative digestion

Oxidation system with internal secondary reactor

Oxidation system employing internal structure for enhanced hydrodynamics

Disclosed is a process to produce a purified carboxylic acid slurry. The process comprises removing impurities from a crystallized product in a solid liquid displacement zone to form the purified carboxylic acid slurry. The process produces purified carboxylic acid slurry having good color and low impurity levels without the use of purification steps like hydrogenation or an impurity removal process.

Process for the oxidative purification of terephthalic acid

The present invention relates to a process for oxidizing a slurry composition in a post oxidation zone in the presence of added steam. More specifically, the present invention relates to a process for oxidizing a crude terephthalic acid composition in a post oxidation zone in the presence of added steam in a process for the production of a crystallized post oxidation composition.

Method for oxidizing a slurry composition in a post oxidation zone in the presence of added steam

Disclosed is a process to produce a purified carboxylic acid slurry. The process comprises removing impurities from a crystallized product in a solid liquid displacement zone to form the purified carboxylic acid slurry. The purified carboxylic acid slurry is further cooled in a cooling zone and subsequently filtered and dried in a filtration and drying zone. The process produces purified carboxylic acid product having good color and low impurity levels without the use of purification steps like hydrogenation or filtrate purge.

The present invention provides an improved process for the purification of crude terephthalic acid which has been produced by the oxidation of para-xylene. The process comprises contacting the crude terephthalic acid with oxygen-containing gas at a temperature of about 190.degree. to 230.degree. C. and a pressure of about 1500 to 3600 kPa in the presence of a solvent comprising an alkanoic acid which is preferably acetic acid. The process further comprises the use of a novel and surprisingly effective catalyst system. The catalyst system comprises cobalt, a bromine source, and pyridine.

Process for the purification of terephthalic acid

Growing community of inventors

Kingsport, TN, United States of America

Thomas Earl Woodruff