Standard Oil Company (indiana)

Amoco Corporation

Stephen J Pietsch

Jon J Harper

Hobe Schroeder

Juergen K Holzhauer

Houssam M Naim

Rusins Albertins

A method for purifying a naphthalene dicarboxylic acid produced by the liquid phase oxidation of a kialkylnaphthalene or partially oxidized derivative thereof in the presence of a catalyst comprising a bromine-containing component and at least one of a cobalt- or manganese-containing component.

Method for purifying a crude naphthalene dicarboxylic acid

A continuous process for the production of methacrylic acid ester of a C.sub.1 to C.sub.4 saturated aliphatic alcohol in the presence of a catalyst is disclosed. This process contemplates continuously introducing into a plug-flow reactor a feed stream containing methacrylic acid, a C.sub.1 to C.sub.4 saturated aliphatic alcohol in stoichiometric exesss relative to the methacrylic acid present, an esterification catalyst, and a liquid organic substance having a volatility no greater than that of methacrylic acid. The feed stream thus introduced into the plug-flow reactor is preferably maintained at substantially atmospheric pressure, while the contained methacrylic acid reactant is held at an esterification temperature and for a time period sufficient to esterify at least a portion of the introduced methacrylic acid. The admixture thus produced is continuously fractionated, preferably in a distillation zone or column, into a vaporized distillate stream and a liquid bottoms stream. The distillate stream has a relatively greater methacrylic acid ester content than the bottoms stream. A portion of the bottoms stream, constituted primarily by the liquid organic substance and the esterification catalyst, is recycled to the reactor while the remainder is purged.

Continuous process for production of methacrylic acid ester of C.sub.1

Precipitation-free recovery of catalyst metal content of residue from manufacture of trimellitic acid by oxidation with source of molecular oxygen of liquid pseudocumene in presence of cobalt and manganese, cobalt, manganese and cerium, followed by removal of trimellitic acid or its anhydride and, if used, reaction solvent and then separating manganese from the recovered metals. The foregoing is accomplished by extraction of such residue with water, contacting the resulting aqueous extract solution or suspension of insolubles in the aqueous solution with one side of a cation permeable fluoropolymer membrane whose other side is in contact with a hydrohalidic acid to permit metal ions to pass through the membrane, removing the hydrohalidic solution of the catalyst metals, and then after a pH adjustment adding metallic manganese to precipitate cobalt as metal.

Membrane separation of catalyst metals from trimellitic acid production

Recovery of cobalt and manganese metal oxidation catalysts from residue of trimellitic acid manufacture and separation of recovered cobalt from recovered manganese can be accomplished by a novel method involving dissolving the residue in water, displacing dissolved cobalt as cobalt metal by manganese metal added to the solution whose pH has been adjusted to pH of 6 and then using magnetic means for separating metallic cobalt from the cobalt-free solution.

Separation of cobalt and manganese from trimellitic acid process residue

Cobalt and manganese are recovered from incineration ash obtained by combustion of residue from the manufacture of trimellitic acid and its recovery as 4-carboxyphthalic anhydride and then the recovered cobalt is separated from the recovered manganese by magnetic separation. The foregoing is accomplished by extraction of the ash with an aqueous solution of hydrogen bromide or chloride, recovery of the extract solution, and the upward adjustment of its pH while adding powdered manganese to precipitate metallic cobalt for its separation by magnetic means.

Recovery of cobalt and manganese from ash of residue from manufacture of

Recovery of cobalt and manganese from residue of trimellitic acid manufacture and recovery as 4-carboxy-phthalic anhydride by extracting the residue with an aqueous alkaline solution containing carbonate ions which leaves a precipitate of metal carbonates, dissolving said precipitate as the metal chlorides, and at an upwardly adjusted pH adding powdered manganese to precipitate metallic cobalt and separating it by magnetic means.

A unique method of separating cobalt and manganese from residue obtained from the manufacture of trimellitic acid by the oxidation of pseudocumene in the presence of cobalt and manganese as metal oxidation catalysts and from each other without contributing to the problem of solids disposal. Said unique method comprises extracting the residues with water, removing cobalt and mangangese from the extract solution with a cation exchanger thereby producing a metal-free solution of trimellitic acid, regenerating the cation exchanger with a strong inorganic acid, adjusting the pH of the spent regenerating acid to pH of 3 to 4 if iron is present to precipitate it as its hydroxide but at least to pH of 6 while also adding powdered manganese to precipitate metallic cobalt.

Growing community of inventors

Oak Park, IL, United States of America

Stephen J Pietsch