Standard Oil Company (indiana)

Amoco Corporation

The Standard Oil Company

Jon J Harper

Stephen J Pietsch

Martin A Zeitlin

George E Kuhlmann

Rosemary F McMahon

Paul A Sanchez

Stephen P Brugge

Larry W Autry

Keith D Larson

Antonio E Navarrete

Richard J Thomas

Provided is a continuous process for producing 2,6-naphthalenedicarboxylic acid by the liquid phase oxidation of 2,6-dimethylnaphthalene comprising continuously adding to a reaction zone the oxidation reaction components comprising 2,6-dimethylnaphthalene, a source of molecular oxygen, a solvent comprising an aliphatic monocarboxylic acid, and a catalyst comprising cobalt, manganese and bromine components, wherein the atom ratio of manganese to cobalt is about 5:1 to about 0.3:1, the total of cobalt and manganese is at least about 0.40 weight percent based on the weight of solvent, and maintaining the contents of the reaction zone at a temperature of about 370.degree. F. to about 420.degree. F. and at a pressure sufficient to maintain at least a portion of the monocarboxylic acid in the liquid phase thereby oxidizing the 2,6-dimethylnaphthalene to 2,6-naphthalenedicarboxylic acid. By operating according to the process of this invention, 2,6-naphthalenedicarboxylic acid can be continuously produced in high yield and with low levels of impurities.

Process for preparing 2,6-naphthalene-dicarboxylic acid

A method is disclosed for producing purified 5-t-butylisophthalic acid by the liquid-phase oxidation of 5-t-butyl-m-xylene in a solvent and in the presence of a catalyst comprising cobalt, manganese and bromine components.

Method for producing 5-t-butylisophthalic acid

Acetic acid can be prepared in high conversions and selectively by the oxidation of liquid n-butane at temperatures of from 120.degree. C. up to 230.degree. C. in the presence of an acetic acid solution containing bromine ions in combination with ions of cobalt or cobalt and manganese. The debutanized effluent of such oxidation consists mainly of acetic acid and water but also contains esters and ketones boiling lower than acetic acid, some higher carbon content aliphatic acids and metal salts boiling higher than acetic acid and rather small amounts of 3-bromo-2-butanone which, although boiling higher than acetic acid, cannot be separated by simple distillation as can be the other non-acetic acid organic impurities. The present inventive technique for removal of said bromo-ketone has for its concept the use of a combination of cryogenic crystallization and removal of adhering mother liquor which can be practiced continuously in known apparatus devised for other fractional crystallizations.

Removal of bromobutanone from acetic acid

The oxidation of liquid n-butane with oxygen gas at a temperature of from 120.degree. C. up to 235.degree. C. in the presence of an acetic acid solution containing bromide ion in combination with ions of cobalt or cobalt and manganese produces a reaction effluent containing mainly acetic acid (65 to 72 weight percent) and water (23 to 27 weight percent) together with impurity concentrations of esters and ketones boiling lower than acetic acid, higher carbon (C.sub.3 and C.sub.4) aliphatic monocarboxylic acids boiling higher than acetic acid and the difficultly separable 3-bromo-2-butanone impurity. The concentration of said bromoketone can be decreased by maintaining said reaction effluent or its debutanized residue at a temperature of from 150.degree. C. up to 200.degree. C. for 15 to 150 minutes. Subsequent distillation even further decreases the concentration of the bromoketone in the acetic acid distillate fraction.

Decreasing 3-bromo-2-butanone content of acetic acid

Precipitation-free recovery of catalyst metal content of residue from manufacture of benzene carboxylic acid by oxidation with source of molecular oxygen of liquid methyl-substituted benzene in presence of cobalt, manganese, cerium, and mixtures of two or more thereof followed by removal of benzene carboxylic acid and, if used, reaction solvent. Such precipitation-free method comprises extracting such residue with water, contacting the resulting extract solution or suspension of insolubles in extract solution with one side of a cation permeable fluoropolymer membrane and contacting the opposite side of the membrane with a hydrohalidic acid.

Membrane separation of catalyst metals from aromatic acid production

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.

Excessive energy consumption of a combination of multi-fractionations and multi-distillations of concentrating aqueous acetic acid product of liquid phase oxidations, especially oxidation of liquid n-butane with oxygen gas while the butane is dissolved in liquid acetic acid containing a catalyst system comprising Co-Br or Co-Mn-Br, is avoided and an otherwise hard to remove bromo-ketone is readily removed by a combination of sequential steps of decompressing the oxidation reaction mixture to remove unreacted butane as well as gaseous products, heat treating the decompressed liquid at a temperature of from 150.degree. C. up to 200.degree. C. for from 15 up to 150 minutes, subjecting the heat treated liquid to fractionation while recycling to the rectification zone thereof an aqueous portion of low boiling impurities as a means for concentrating the acetic acid and thereafter further concentrating the acetic acid produced by continuous fractional crystallization.

Low bromine content glacial acetic acid

A process is disclosed for producing the dimethyl esters of aromatic dicarboxylic acids wherein the acid is esterified with a low molecular weight alcohol, the product is crystallized and separated to isolate a mass of the diester crystals and recover a mother liquor. An improvement in such process resides in the thermal oxidation with molecular oxygen of a mother liquor material to produce a mono methylphthalate from either p-methyl toluate or methyl-4-carboxybenzaldehyde. A portion of the oxidized mother liquor is recycled to the esterification zone wherein the mono methylphthalate can be esterified to the dimethyl ester while another portion of the oxidized mother liquor stream is passed to an evaporation treatment zone, preferably a wiped film evaporator, wherein overhead material is separated from a high boiling bottoms material and recycled to the esterification reaction zone. The high boiling bottoms stream from the evaporation treatment zone is purged from the system thereby removing from the overall process high boiling organics including ash.

Growing community of inventors

Naperville, IL, United States of America

Jon J Harper