Amoco Corporation

Bp Corporation North America Inc.

Standard Oil Company (indiana)

Ricky L Wittman

Hobe Schroeder

Philip Nubel

Muin S Haddad

George E Kuhlmann

Philip O Nubel

Timothy H Keyes

Joseph D Fox

Jeffrey J Foster, Sr

Impure aromatic carboxylic acids such as are obtained by liquid phase oxidation of feed materials comprising aromatic compounds with substituent groups oxidizable to carboxylic acid groups, or comprising aromatic carboxylic acid and one or more aromatic carbonyl impurities that form hydrogenated species more soluble in aqueous solvents or with less color or color-forming tendencies than the aromatic carbonyl impurity, are purified to an aromatic carboxylic acid product with lower levels of impurities by a process comprising contacting an aqueous solution comprising the impure aromatic carboxylic acid with hydrogen at elevated temperature and pressure with an attrition-resistance, acid stable catalyst composition comprising at least one hydrogenation catalyst metal and a support comprising relatively high surface area silicon carbide.

Process for purification of aromatic carboxylic acids

This invention relates to control or removal of amounts of dissolved iron that may be present in liquid process streams in the manufacture of aromatic acids. The present invention further relates to the control or removal of dissolved iron contaminants present in liquid streams during the manufacture of a crude aromatic acid. The present invention also further relates to the control or removal of dissolved iron contaminants present in liquid streams during the purification of a crude aromatic acid. The present invention also further relates to controlling of decreasing the formation of iron oxides on the surfaces of equipment used during the manufacture of crude aromatic acid and/or purification of crude aromatic acid.

Method of removing iron contaminants from liquid streams during the manufacture and/or purification of aromatic acids

A method is disclosed for the purification of crude terephthalic acid, crude isophthalic acid or a crude naphthalene dicarboxylic acid that employs a titanium dioxide-supported purification catalyst.

Catalyst and method for purifying crude terephthalic acid, isophthalic

Solutions of crude isophthalic acid are purified by hydrogenation in the presence of a catalyst comprising two Group VIII noble metal-containing components.

Purification of crude isophthalic acid

A method is disclosed for reactivating a Group VIII noble metal catalyst employed in the purification of crude terephthalic acid formed by the liquid-phase oxidation of p-xylene in the presence of a catalyst comprising cobalt, manganese and bromine components.

Method for reactivating a group VIII noble metal catalyst for use in the

Metallic catalysts are improved in performance and life when extended as a thin surface layer upon a porous, sintered metal substrate, particularly when employed in hydrogenation or decarbonylation reactions.

Catalyst composition

A particulate catalyst composition suitable for purification of terephthalic acid under reducing conditions and a method of preparation of such catalyst are disclosed. The catalyst composition includes catalytically active rhodium on a porous, granular, carbonaceous support material having a surface area of at least about 600 m.sup.2 /gram. Rhodium is present in an amount of about 0.01 to about 2 weight percent, based on the total weight of dry catalyst composition and calculated as elemental metal. In the presence of hydrogen, this catalyst exhibits a reduced terephthalic acid decomposition rate that is comparable to that for a palladium-on-carbon catalyst having the same catalyst metal loading. The catalyst is prepared by contacting a carbonaceous support material having a surface area of at least 600 m.sup.2 /gm and a pH value in its aqueous suspension of 9-11 with an aqueous rhodium salt solution having a pH of 1-4.

Rhodium on carbon catalyst

This invention relates to the preparation of the subject aqueous solution from a non-bromine manganous salt. More specifically this invention pertains to a critical order of dissolving such salt and elemental bromine and to the use of an anti-oxidant for the manganous ion to prevent its conversion to hydrated manganous dioxide: MnO(OH).sub.2. According to 'A Comprehensive Treatise On Inorganic And Theoretical Chemistry', J. W. Mellor, Vol. XII at pages 189 and 259 (published by Longmans, Green and Co., 1947) hydrated manganous dioxide results from the oxidation of a solution of manganous salt with chlorine, bromine, hypochlorous acid, hydrogen peroxide, etc. Such oxidation of a solution of manganous acetate was specifically mentioned. Such hydrated manganous dioxide is described as a white solid product which upon standing in contact with air becomes a dark brown to black product identified as MnO.sub.2. The same reference at page 381 reports the preparation of manganous bromide by reaction of bromine with a solution of manganous oxide. We have found that the addition of bromine gas or liquid to a stirred aqueous solution containing manganous ions from a source other than manganous bromide caused the formation of a precipitate which contains the previously dissolved manganese component. The same precipitate formed upon addition of manganous acetate tetrahydrate to a stirred aqueous solution of elemental bromine.

Growing community of inventors

Aurora, IL, United States of America

Ricky L Wittman