Abstract: A process for producing highly pure isophthalic acid which comprises (a) carrying out liquid phase oxidation of an m-dialkyl benzene with molecular oxygen in an acetic acid solvent in the presence of a heavy metal catalyst to form crude isophthalic acid, (b) contact-treating the resulting crude isophthalic acid with a noble metal catalyst belonging to the Group VIII of the Periodic Table supported by activated carbon in the presence of hydrogen, and then (c) separating the deposited isophthalic acid crystal and (d) filtration-treating the separated mother liquor and (e) recirculating the mother liquor thus treated into the liquid phase oxidation step (a) for reusing as a solvent in step (a) is disclosed.

Abstract: 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.

Abstract: In a process for producing purified terephthalic acid which comprises catalytically oxidizing p-xylene in liquid phase to produce crude terephthalic acid containing 4-carboxybenzaldehyde as a main impurity therein, and treating the crude terephthalic acid with hydrogen in the presence of hydrogenation catalyst in a reaction vessel, thereby to produce purified terephthalic acid containing 4-carboxybenzaldehyde in an amount of fixed range in a stationary manner, there is provided an improvement which makes it possible for the treatment to reach the stationary state promptly after partial exchange of deactivated catalyst for a new one. The improvement comprises feeding into the reactor crude terephthalic acid which contains 4-carboxybenzaldehyde in an amount larger than that in the stationary state of the treatment, and treating the terephthalic acid until the treatment reaches the stationay state.

Abstract: A process for the preparation of alkanesulfonylbenzoic acids from alkanesulfonylalkylbenzenes of the formula ##STR1## in which R.sup.1 and R.sup.2 are identical or different and are alkyl having 1 to 4 carbon atoms, but R.sup.2 has a meaning other than t-butyl, and X is H, F, Cl, Br or NO.sub.2, using molecular oxygen in acetic acid and/or propionic acid in the presence of a catalyst containing cobalt and bromine ions and, in particular when the meaning of R.sup.2 is other than methyl, also manganese ions, which is additionally carried out in the presence of metal ions of Main Group 2 and/or 3.

Abstract: Acetic acid is recovered from the mother liquor used to oxidize para-xylene to terephthalic acid by adding at least one organic compound having a melting point below 140.degree. C. and an atmospheric boiling point above 230.degree. C.

Abstract: A process for producing isophthalic acid by oxidation of m-xylene with an oxygen-containing gas in a hydrous acetic acid solvent in the presence of a cobalt/manganese/bromine system catalyst, the process being capable of industrially advantageously producing high-purity isophthalic acid having excellent whiteness, the process comprising (1) a step of carrying out an oxidation reaction in a main oxidation reactor under specified ranges of a catalyst concentration, a reaction temperature and an oxygen concentration in a discharge gas such that the concentration of 3-carboxybenzaldehyde becomes 500 to 10,000 ppm, (2) a step of further carrying out an oxidation reaction in a post oxidation reactor such that the concentration of 3-carboxybenzaldehyde becomes 100 to 800 ppm, separating crude isophthalic acid, evaporating remaining mother liquor and recovering acetic acid, and (3) mixing the crude isophthalic acid with purified acetic acid, stirring the resultant mixture at 100.degree. C.

Abstract: Substantial proportions of methyl acetate and unreacted polymethylbenzene are recovered from the waste gas produced during the oxidation of a polymethylbenzene to its corresponding polycarboxylic acid by passing the waste gas, after being cooled for removal of water vapor, through at least one bed of activated carbon and subsequently desorbing the methyl acetate and polymethylbenzene from the bed by passing a desorbing medium, such as steam, through the bed. Preferably, the cooled stream is heated to a temperature of at least 21.degree. C. (70.degree. F.) prior to being passed into the bed of activated carbon.There is also disclosed an improved process for the oxidation of a polymethylbenzene to its corresponding aromatic polycarboxylic acid, which process comprises producing the polycarboxylic acid and waste gas comprising methyl acetate, water vapor, and unreacted polymethylbenzene and treating the waste gas according to the above method.

Abstract: There is provided a process for recovering acetic acid from methyl acetate wherein the methyl acetate is hydrolyzed catalytically to methanol and acetic acid in the same tower or column that is used to separate the methanol from the acetic acid and the hydrolysis and separation are carried out coextensively in the vessel. The process is employed suitably in a process for the partial oxidation of a polymethylbenzene to a polycarboxylic acid in the presence of an oxidation catalyst and an acetic acid solvent.

Abstract: A process for producing 2,6-naphthalene dicarboxlic acid which comprises oxidizing a 2-alkyl-6-acyl naphthalene with molecular oxygen-containing gas in the presence of a catalyst containing cobalt, manganese and bromine in an acetic acid solvent, characterized in that the oxygen concentration in the exhaust gas is controlled so as to satisfy the following equation:15/(X+7.5)+0.1.ltoreq.Y.ltoreq.90/(X+8)+0.4 (1)wherein Y is oxygen concentration (volume %) in the exhaust gas and X (cm) is a distance between the inlet for an oxygen gas and the surface of the reaction solution in a static state, and the catalyst further contains an aromatic acid in which at least two carboxylic acid groups are in an orthposition or its precursor as a co-catalyst, and that part of all of the mother liquor from which the 2,6-naphthalene dicarboxylic acid crystal has been separated is cooled to remove the precipitated impurities, and thereafter is reused in the oxidation reaction, is disclosed.

Abstract: A method and system for increasing conversion efficiency of aromatic alkyl reactant to aromatic carboxylic acid product and for improving the quality of the product, are disclosed. The method and system provide for the continuous production of an aromatic carboxylic acid by the liquid phase, exothermic oxidation of an aromatic alkyl in a vaporizable solvent in an oxidation reactor. The reactor makes use of a vented, overhead condenser system and a separator system for condensation of vaporized reactor material, separation of the condensed solvent therefrom, and reflux of separated solvent back into the reactor. The improvement comprises combining the reactor liquid feedstream with the refluxed solvent upstream from the oxidation reactor.

Abstract: A process for oxidizing a dialkyl substituted benzene, such as meta-xylene, to an aromatic polycarboxylic acid, such as isophthalic acid, in the presence of a solvent, such as acetic acid, in an oxidation zone followed by an oxidation-crystallization zone, wherein a secondary dehydration tower is used to separate water from the solvent in the overhead stream from the oxidation-crystallization zone and provide a solvent-rich fluid for recycle to the oxidation zone, resulting in expanded capacity of the process coupled with a minimization of captial cost.

Abstract: A process is disclosed for oxidation of pseudocumene to trimellitic acid wherein process residue and bottoms from stripping procedures to recover process solvent are recycled and incorporated in filtrate mother liquor and reinjected into the oxidation reactor at a point in time at least after the first methyl group in the pseudocumene molecule has been oxidized to a carboxy group. Recovery of trimellitic acid is increased, catalyst recovery is increased in a form suitable for immediate recycle to the oxidation reaction, and waste products from the oxidation process are substantially reduced.

Abstract: A process for the preparation of naphthalenecarboxylic acid esters in which a substituted naphthalene is oxidized with molecular oxygen in the presence of a heavy metal-based catalyst in a solvent comprising a lower aliphatic monocarboxylic acid to form a naphthalenecarboxylic acid and the resulting acid is then esterified. The esterified product is purified by washing, recrystallization, and distillation in that order. Heavy metals are recovered as carbonates from filtrates and washings obtained by seeparation of crude acid and ester products and by washing thereof.

Abstract: Disclosed is an improved process for the continuous production of aromatic carboxylic acids such as terephthalic acid by the liquid-phase oxidation of an alkyl aromatic compound using an oxygen-containing gas. Operation of the process is improved by providing a spray of recycled reaction medium at or near the top of a columnar oxidation vessel to minimize entrainment of liquid and/or solid components of the reactor in the process off-gas.

Abstract: An apparatus and a method for continuously oxidizing an aromatic alkyl in the liquid phase and under oxidation reaction conditions, for the purpose of producing a desired aromatic carboxylic acid product, is disclosed. A seriatim arranged array of reactor compartments, each of which is adapted to accommodate a gaseous phase as well as a liquid phase is contemplated. Means for separately adjusting the reaction mixture composition of each reaction compartment is provided.

Abstract: A method is disclosed for producing purified trimesic acid prepared by a process involving the liquid-phase oxidation of mesitylene in a solvent consisting of an aliphatic C.sub.2 -C.sub.6 monocarboxylic acid, water or a mixture thereof in the presence of an oxidation catalyst comprising cobalt, manganese and bromine components, crystallizing crude trimesic acid by cooling to about 80.degree. C. to about 150.degree. C., separating crystallized trimesic acid from the mother liquor at a temperature in the range of 80.degree. C. to about 105.degree. C. and washing the separated crude trimesic acid crystals with water at a temperature of from about 10.degree. C. to about 100.degree. C.

Abstract: A process for exchanging a dispersing medium of a terephthalic acid slurry by introducing an aliphatic carboxylic acid slurry of terephthalic acid into a multi-stage column at the upper part thereof and introducing water at the lower part thereof to form an upflowing stream of water in the multi-stage column, while a sedimentation of terephthalic acid particles is effected, and withdrawing an aqueous aliphatic carboxylic acid solution from the upper part of the multi-stage column and an aqueous slurry of terephthalic acid from the lower part of the multi-stage column.

Abstract: A process for the manufacture of trimelitic acid from pseudocumene is disclosed. The pseudocumene is oxidized in the presence of a cerium, cobalt, manganese, and optionally zirconium, bromine catalyst wherein all of the cerium is added in the second stage of the oxidation, and wherein most of the bromine is also added during the second oxidation stage. Trimellitic acid is useful in the manufacture of polyester and polyamide-imides.

Abstract: A process for the manufacture of benzoic acid derivatives is described. The process is based on the reaction of a toluene derivative in a liquid phase oxidation with an oxygen containing gas in the presence of a phase-transfer catalyst (a), a transition metal salt (b) and traces of a polar solvent, such as water, the molar ratio between (a) and (b) being in the range of between 0.25:1 to 1.5:1. The phase-transfer catalyst is selected from quaternary ammonium and phosphonium salts having a total carbon atoms in the range of 17 to 58, the anion bound thereto being selected from Br.sup.-, F.sup.-, Cl.sup.-, OH.sup.-, CH.sub.3 COO.sup.- or HSO.sub.4.sup.31 . The benzoic acid derivatives produced are characterized by their very high purity and high conversion reaching generally values of above 95%.

Abstract: A process for the manufacture of benzoic acid is described. The process is based on the reaction of toluene in a liquid phase oxidation with an oxygen containing gas in the presence of a phase-transfer catalyst (a), a transition metal salt (b) and traces of a polar solvent, such as water, the molar ratio between (a) and (b) being in the range of between 0.25:1 to 1.5:1. The phase-transfer catalyst is selected from quaternary ammonium and phosphonium salts having a total carbon atoms in the range of 17 to 58, the anion bound thereto being selected from Br.sup.-, F.sup.-, Cl.sup.-, OH.sup.-, CH.sub.3 COO.sup.- or HSO.sub.4.sup.-. The benzoic acid produced is characterized by its very high purity and high conversion reaching generally values of above 95%.

Abstract: A process for the oxidation of pseudocumene to TMLA is disclosed which comprises catalytic oxidation of pseudocumene with air in the presence of acetic acid in an oxidation zone in the liquid phase wherein the weight ratio of acetic acid to pseudocumene is in the range of about 0.5-0:1.0 and the catalyst comprises one or more heavy metal oxidation catalysts comprising zirconium, cobalt, and manganese to provide about 0.1 to about 0.4 weight percent total metals based on pseudocumene and a source of bromine. The addition of the bromine component is controlled to provide a total of about 0.10 to about 0.30 weight percent total bromine based on pseudocumene. The total weight ratio of bromine ions to total metals ions is about 0.5 to about 2.0. The zirconium content is about 1 to about 5% and the manganese content is about 14 to about 60% each by weight of the total metals. The reaction temperature is about 300.degree. F. to about 420.degree. F.

Abstract: A method for removing impurities from an oxidative terephthalic acid synthesis mother liquor containing acetic acid, water, corrosion metals, a metal catalyst and organic impurities, comprising the steps of (a) removing from the mother liquor by evaporation from 50-95% of the acetic acid and water contained therein; (b) adding an amount of water to the concentrated mother liquor sufficient to dissolve the metal catalyst and form an aqueous mixture; (c) extracting the aqueous mixture by counter-current extraction with a substantially water-insoluble organic solvent, to produce a lighter phase containing the organic solvent, a minor amount of the water, acetic acid and the organic impurities and a heavier phase containing a major amount of the water, corrosion metals and the metal catalyst, and; (d) removing the corrosion metals from the heavier phase by heating and filtering, and; (e) removing the organic impurities from the lighter phase by distillation.

Abstract: A continuous stirred-tank reactor suitable for the liquid-phase oxidation of an aromatic alkyl to an aromatic carboxylic acid is provided with vertically disposed, relatively narrow baffles on the reactor wall and with oxidizing gas inlet means below the agitator in the reactor. The baffle width is about 0.02 to about 0.04 times the diameter of the reactor.

Abstract: An improved method for the preparation of a naphthalene dicarboxylic acid by liquid-phase catalytic oxidation of a diisopropylnaphthalene in a lower fatty acid-based solvent is disclosed wherein a catalyst system comprising bromine and the heavy metals cerium, cobalt, and manganese is used. The cerium compound used as a cerium source for the catalyst can be recovered from crystals of the naphthalene dicarboxylic acid product by dissolving the crystals in an alkali solution and separating the cerium compound as insolubles from the solution.

Abstract: A catalyst-recovery method for catalyst used in a continuous liquid phase oxidation process of an aromatic alkyl to an aromatic carboxylic acid product is disclosed. The aromatic carboxylic acid product is withdrawn from an oxidation reactor as an aqueous product and is thereafter subjected to crystallization to produce the aromatic carboxylic acid product and a product mother liquor stream. The product mother liquor stream is separated into a solvent-rich stream and a solids-containing catalyst-rich stream. The solids-containing catalyst-rich stream is separated into a by-product cake and a catalyst-bearing stream that is substantially free of solids. A portion of the catalyst-bearing stream is contacted with the vapor stream passing through the absorber system, and a catalyst-rich bottoms stream is thereafter withdrawn from the absorber system. A portion of the catalyst-rich bottoms stream is returned to the reactor.

Abstract: Recovery of cobalt and manganese catalyst from oxidation process, by precipitation with oxalic acid and alkali metal hydroxide, followed by oxidation of the precipitate in acetic acid to form cobalt and manganese acetate.

Abstract: Disclosed is a method for the production of benzene carboxylic acids and benzene carboxylic acid esters or their mixtures, while p-toloylic acid is made from p-xylene and terephthalic acid monomethyl ester is simultaneously prepared from p-toluylic acid ester. The oxidation is performed by the addition of oxidator liquid and gases containing oxygen in single orifice mixing nozzles with the formation of a highly disperse reaction phase and the single orifice mixing nozzles open into the oxidator liquid.

Abstract: A process is disclosed for the co-production of aliphatic monocarboxylic acids and polycarboxylic aromatic acids in high selectivity, conversion and yield. The aliphatic monocarboxylic acid can serve as a component of the solvent for the process.

Abstract: A process is disclosed for the oxidation of di- or trimethyl benzenes with molecular oxygen under liquid-phase conditions in the presence of a recovered cobalt and manganese catalyst, which has been recovered by heating oxidation incinerator ash in the presence of acetic acid and a reducing agent wherein the weight ratio of acetic acid to said oxidation incinerator ash is from about 1:1 to about 50:1, and the ratio of electrons which the reducing agent can deliver to atoms of the cobalt plus manganese in the oxidation incinerator ash is from about 0.1:1 to about 4:1 at about the boiling point of the acetic acid at atmospheric pressure and recovering the cobalt and manganese in liquid solution as the metal acetic acid salt, wherein the oxidation is carried out at a temperature of from about 100.degree. C. to about 250.degree. C.

Abstract: A method is disclosed for the liquid-phase oxidation of pseudocumene in the presence of an oxidation catalyst comprising cobalt, manganese, and bromine components wherein the metal catalyst are recycled to the oxidation reactor in the form of their oxalates.

Abstract: A method for the continuous, catalytic production of an aromatic carboxylic acid product by liquid-phase, exothermic oxidaion of an aromatic alkyl with an oxygen-containing gas and a solvent medium in an oxidation reactor and utilizing reverse osmosis is disclosed. In particular, a multiple ingredient or component-containing slurry product stream is withdrawn from the reactor, the slurry product stream is then separated to produce a product-containing stream and at least one mother liquor stream which contains, in addition to a number of desirable process stream components, such as oxidation reaction catalysts, a number of undesirable process stream impurities. The impurities are selectively removed from the mother liquor stream by passing at least a portion of the mother liquor stream through a reverse osmosis separation device to produce a catalyst-bearing stream having a relatively lesser impurities-to-catalyst weight ratio and a purge stream having a relatively greater impurities-to-catalyst weight ratio.

Abstract: A continuous process for producing a polycarboxylic acid product is disclosed. The process comprises combining a methyl substituted aromatic hydrocarbon, an oxidation catalyst, and an oxygen-containing gaseous stream in a reaction zone to produce a reaction mixture. The oxygen-containing gaseous stream includes non-condensible gases. The reaction mixture in the reaction zone is subjected to a predetermined temperature and pressure for a predetermined residence time to produce an admixture of reactants and reaction products. The reaction products include a vapor phase and a product-containing liquid phase. Heat is removed from the product-containing liquid phase by withdrawing a portion of such liquid stream from the reaction zone and passing such reaction zone-removed portion to a heat-removal/separation zone.

Abstract: The method and apparatus for manufacturing terephthalic acid (TA) are capable of producing TA having a closely controlled, desired amount of contaminant, 4-carboxy-benazldehyde (4-CBA), therein and/or a closely controlled optical density. In the method, a feed of para-xylene or similar feedstock mixed with catalyst components and solvent system is fed to a reactor stage comprising one or more reactors with oxygen for carrying out an exothermic oxidation reaction in the reactor stage, and an output slurry from the reactor stage is fed with oxygen to a first crystallizer of a crystallizing stage. The method comprises the steps of: determining empirical relationships between (1) the desired level of contaminant in the TA output product from the crystallizing stage and the oxygen uptake in the first crystallizer and (2) the oxygen uptake in the first crystallizer and the CO.sub.2 in the vent gas from the reactor stage; monitoring the CO.sub.

Abstract: A process is disclosed for purifying a crude terephthalic acid mother liquor stream comprising oxidation catalysts, terephthalic acid, color bodies and impurities by hydrogenation in the presence of a rhodium-on-carbon catalyst wherein color bodies and impurities are hydrogenated to saturated compounds for subsequent oxidation to carbon oxides. The terephthalic acid in said stream is thereupon recovered.

Abstract: A process for the production of aromatic carboxylic acid in a continuous manner by oxidizing an alkyl aromatic compound in the liquid phase with an oxygen-containing gas in the presence of heavy metal compound(s) and/or bromine-containing compound, which process is characterized by that a part of the reaction gas delivered from the reactor and freed from the condensing components is recirculated by returning it to the reactor at a portion within the gas region. Said process permits to produce aromatic carboxylic acids of high quality, while eliminating the troubles due to foaming occurring on the liquid surface in the reactor.

Abstract: The yield of dimethyl terephthalate obtained by the oxidation of a mixture of p-xylene and methyl p-toluate, preferably with air, and esterification of the thus-produced acids is increased by utilizing a mixture of cobalt and manganese compounds as the oxidation catalyst.

Abstract: Disclosed herein is a process for producing a highly pure produce of 2,6-naphthalenedicarboxylic acid in a large quantity at a moderate price by oxidizing 2,6-diisopropylnaphthalene while using a water-soluble salt of cobalt, a water-soluble salt of maganese or a mixture thereof, a water-soluble salt of cerium and a bromine compound as the catalyst of the oxidation.

Abstract: An improved method for continuously producing an aromatic carboxylic acid from an aromatic alkyl is disclosed. The reaction medium, contained within a pressurized reactor, includes an aqueous monocarboxylic acid solvent, the aromatic alkyl, and an oxygen-containing gas. Heat is generated in the reactor during the course of the oxidation reaction, and is removed from the reactor by vaporization of a portion of the reaction medium. The vaporized reaction medium that exits the pressurized reactor as a vapor is partitioned in a condenser system, which defines a reflux loop, into an aqueous partial condensate having a relatively lesser water-to-solvent weight ratio and a vapor phase having a relatively greater water-to-solvent weight ratio. At least a portion of the partial condensate is returned directly to the reactor as an aqueous direct reflux stream, while the vapor phase is withdrawn from the reflux as a vapor stream.

Abstract: A method is disclosed for recovery and recycle of metal catalyst components of a catalyst from the liquid-phase oxidation of pseudocumene in the presence of an oxidation catalyst comprising cobalt, manganese, and bromine components or cobalt, manganese, zirconium and bromine components wherein said catalyst components are recovered by oxalate precipitation from aqueous residue.

Abstract: A process is disclosed for recovery of cobalt and manganese, and other metals, in the form of their acetate salts, directly from mixed metal oxides present in oxidation residue incinerator ash comprising fly ash and clinkers from incineration of a residue from manufacture of benzene di- and tricarboxylic acids by catalytic means. These acetate salts are recycled directly for manufacture of benzene di- and tricarboxylic acids after recovery.

Abstract: A process for producing fiber grade terephthalic acid is disclosed. In this process impurities having high molecular weight are eliminated by hydrogenation comprising the following steps: (a) treating an aqueous solution containing at least about 1 percent of said impure terephthalic acid with hydrogen at a temperature in the range of about 300.degree. F. to about 450.degree. F. and at a pressure sufficient to maintain the solution in the liquid phase in the presence of a supported or unsupported metallic Group VIII noble metal catalyst wherein both the metal and support components are insoluble in the solution at the temperature and at a hydrogen partial pressure of from about 30 to about 300 pounds per square inch; (b) separating the treated solution from the catalyst; (c) crystallizing terephthalic acid from the separated solution while retaining impurities and the reduced aromatic compounds dissolved in the resulting mother liquor at a temperature in the range of about 100.degree. F. to about 450.degree.

Abstract: A method is disclosed for the continuous production of an aromatic carboxylic acid by the liquid phase, exothermic oxidation of an alkyl aromatic in a solvent in an oxidation reactor employing an overhead condenser system for condensation and recycle of vaporized solvent to the reactor, wherein the oxidation is performed at a relatively reduced temperature or pressure or at a relatively increased throughput of the alkyl aromatic without exceeding the elevation head between the condenser system and the reactor.

Abstract: A catalyst-recovery method for catalyst used in a continuous liquid-phase oxidation process of an aromatic alkyl to an aromatic carboxylic acid product is disclosed. The aromatic carboxylic acid product is withdrawn from an oxidation reactor as an aqueous product and is thereafter subjected to crystallization to produce the aromatic carboxylic acid product and a product mother liquor stream. The product mother liquor stream is separated into a solvent-rich stream and a solids-containing catalyst-rich stream. The solids-containing catalyst-rich stream is separated into a by-product cake and a catalyst-bearing stream that is substantially free from solids. A portion of the catalyst-bearing stream is contacted with the vapor stream passing through the absorber system, and a catalyst-rich bottoms stream is thereafter withdrawn from the absorber system. A portion of the catalyst-rich bottoms stream is returned to the reactor.

Abstract: A method is disclosed for the liquid-phase oxidation of pseudocumene in the presence of an oxidation catalyst comprising cobalt, manganese, and bromine components wherein the metal catalyst are recycled to the oxidation reactor in the form of their oxalates.

Abstract: A method for effecting the continuous, liquid phase oxidation of an alkyl aromatic with an oxygen-containing gas in the presence of an oxidation catalyst in stages in a single reactor is disclosed.

Abstract: This invention relates to the liquid-phase oxidation of pseudocumene and durene in the presence of multi-valent catalyst promoted by a source of bromine and to conducting the oxidation in two steps so that the amount of bromine added in the first stage is about 10 to about 35 percent of the total bromine added and the remainder is added in the second stage.

Abstract: Disclosed herein is a process for producing 2,6-naphthalenedicarboxylic acid together with trimellitic acid comprising oxidizing 2,6-diisopropylnaphthalene with molecular oxygen in the presence of a catalyst comprising a heavy metal(s) and bromine.

Abstract: A process for producing 2,6-naphthalenedicarboxylic acid which comprises oxidizing 2,6-diisopropylnaphthalene or its oxidation product as a starting material with molecular oxygen in a reaction medium containing at least 50% by weight of an aliphatic monocarboxylic acid having not more than 3 carbon atoms in the presence of an oxidation catalyst comprising (A) at least one heavy metal element selected from the group consisting of cobalt and manganese, and (B) bromine element, the 2,6-diisopropylnaphthalene and/or its oxidation product being used in a proportion of 0.1 to 5 moles per gram-atom of the heavy metal element of the oxidation catalyst.

Abstract: A method is disclosed for separating and measuring the fluorescence of 4-carboxy-p-terphenyl in crude terephthalic acid formed by the liquid-phase oxidation of p-xylene in a solvent.

Abstract: A process for the production of terephthalic acid from p-xylene and methanol by way of the dimethyl terephthalate obtained by oxidation, in the liquid phase with atmospheric oxygen in the presence of dissolved heavy metal compounds as the catalyst, of a mixture of p-xylene and a fraction containing predominantly methyl p-toluate, which fraction is recycled into the oxidation, to obtain an oxidation product containing primarily p-toluic acid and monomethyl terephthalate at a temperature of 140.degree.-170.degree. C. and under a pressure of 4-8 bar; by esterification of the oxidation product in a reactor with liquid and subsequently vaporized methanol brought to an elevated pressure, at a temperature of 220.degree.-280.degree. C.