Abstract: Process for producing pure terephthalic acid having improved means for recovering and/or recycling terephthalic acid precursors, residual acetic acid and other reaction by-products, such as methyl acetate.

Abstract: A process for producing aromatic carboxylic acids efficiently by operating a distillation column for separating the vaporized reaction solvent and other useful ingredients from an oxidation reactor while permitting efficient energy recovery without causing any obstruction to turbine and without causing any clogging of the distillation column, said process comprising oxidizing an alkyl aromatic compound in a liquid reaction solvent comprising an aliphatic carboxylic acid with a molecular oxygen-containing gas in the presence of an oxidation catalyst in the said oxidation reactor to form an aromatic carboxylic acid, guiding the oxidation reactor exhaust gas into the distillation column to subject it to a distillation, passing the distilltion overhead gas to a condenser to form a condensate, which is returned to the distillation column, and to generate a steam on the shell side, which is guided to a steam turbine for energy recovery, and burning the condenser exit gas in order to drive a gas turbine for energy r

Abstract: A process for producing terephthalic acid and/or dimethyl terephthalate includes contacting a toluene-containing reaction stream with a first catalyst under toluene disproportionation conditions to produce an intermediate product stream of para-xylene with negligible ortho-xylene. The first catalyst includes a crystalline molecular sieve which has an ortho-xylene diffusion rate of at least 50 minutes. The first catalyst can be modified by selectivation with a silicon compound or carbon compound. The intermediate product stream, without need for para-xylene purification, is oxidized to terephthalic acid or dimethyl terephthalate.

Abstract: A process for producing pure carboxylic acids by catalytic liquid phase oxidation of a suitable precursor in a solvent in which the oxidation reaction is carried out in a plug flow reaction zone at a high solvent:precursor ratio and reaction conditions sufficient to maintain the pure acid in solution as it is formed, and product produced from such process.

Abstract: A methyl group-containing aromatic compound having a phenolic hydroxyl group protected by a protecting group, is oxidized with oxygen to provide an aromatic hydroxycarboxylic acid derivative. The protecting group includes, for example, an acyl group.

Abstract: A process for producing 2,6-naphthalenedicarboxylic acid comprising oxidizing 2,6-dimethylnaphthalene with a gas containing oxygen in a solvent comprising a lower aliphatic carboxylic acid in the presence of a catalyst comprising cobalt, manganese, and bromine, wherein the total amount of cobalt and manganese in the catalyst is 50 to 300 mg atom per 1 g mol of 2,6-dimethylnaphthalene, a ratio by g atom of manganese to cobalt in the catalyst is 20:1 to 4:1, and the oxidation is conducted at a temperature of 200 to 250.degree. C.; and a process as described above, wherein a mother liquor which is obtained from a slurry of a product of the oxidation via a step of solid-liquid separation is recyled to a step of oxidation after heat treatment at a temperature of 150.degree. C. or higher. In accordance with the processes, accumulation of substances which affect the oxidation adversely is prevented.

Abstract: Methods for oxidizing a hydrocarbon to an intermediate oxidation product by utilizing an activated initiator. The initiator is activated by partially oxidizing a first mixture of the initiator and a hydrocarbon, which mixture contains a rather large amount of initiator. The first mixture may even be just initiator. The first mixture, after the partial oxidation, is mixed with a second mixture containing hydrocarbon and a smaller amount of initiator. The second mixture may even contain no initiator at all. The oxidation is continued to a desired degree. Preferably, at least one of the two mixtures, and even more preferably both reaction mixtures contain an oxidation catalyst and an acidic solvent.

Abstract: A process for producing an aromatic dicarboxylic acid by simple operations using a simple apparatus is disclosed, which enables to effect separation and washing of the product crystals efficiently without suffering from clogging of the apparatus, while permitting recovery of the reaction solvent and catalyst with permission of an efficient replacement of the solvent.

Abstract: A process and an apparatus for producing an aromatic carboxylic acid by a liquid phase oxidation of an alkyl aromatic compound with a molecular oxygen-containing gas in the presence of an oxidation catalyst in a reaction solvent in an oxidation reactor, which process can afford to suppress the amount of non-condensing gas lost in accompaniment with the withdrawn slurry of the formed aromatic carboxylic acid crystals from the oxidation reactor to thereby increase the utilization efficiency of the molecular oxygen-containing gas, wherein a deflector 10 is arranged on the inner surface of the reactor wall at a portion downstream from the opening 9 for the slurry withdrawal line 8 in the flow path of the stirring stream 11 of the reaction liquor and the oxidation is conducted while stirring the reaction liquor by a stirrer 3 and while withdrawing the resulting slurry containing the formed aromatic carboxylic acid crystals from the reactor, by feeding the alkyl aromatic compound together with the reaction solvent

Abstract: Vanadium-containing catalysts are obtained by using polyvanadic acid as a source of vanadium. Vanadium-containing catalysts are obtained by mixing catalyst components other than vanadium, or their precursors, with a polyvanadic acid sol which is formed by ion-exchanging a metavanadic acid aqueous solution with a proton-type cation-exchange resin and performing polycondensation, and by drying and/or calcining the mixture.

Abstract: Purified terephthalic acid is prepared by a process of subjecting an aqueous solution of crude terephthalic acid to hydrogenation to reduce impurities, crystallizing this solution to produce a slurry of purified terephthalic acid in an aqueous liquor, and carrying out an integrated separation washing process.

Abstract: Methods for oxidizing a hydrocarbon to an intermediate oxidation product by utilizing an activated initiator. The initiator is activated by partially oxidizing a first mixture of the initiator and a hydrocarbon, which mixture contains a rather large amount of initiator. The first mixture may even be just initiator. The first mixture, after the partial oxidation, is mixed with a second mixture containing hydrocarbon and a smaller amount of initiator. The second mixture may even contain no initiator at all. The oxidation is continued to a desired degree. Preferably, at least one of the two mixtures, and even more preferably both reaction mixtures contain an oxidation catalyst and an acidic solvent.

Abstract: Process for the preparation of 3-phenylpropionic acid in which 3-phenylpropanal is subjected to an oxidation, at elevated temperature, in particular at a temperature of between 40.degree. and 80.degree. C., using a medium containing molecular oxygen. A high degree of conversion and a high selectivity are obtained. The starting material 3-phenylpropanal can be prepared in a suitable manner through the hydrogenation of cinnamaldehyde in the presence of a Pd-containing catalyst, after which the reaction mixture obtained can without intermediate further processing be used in the oxidation reaction. The combination of the two process steps constitutes a simple, commercially attractive process for the preparation of 3-phenylpropionic acid using cinnamaldehyde as a starting material. 3-phenylpropionic acid can be used in particular in the preparation of pharmaceuticals such as HIV protease inhibitors.

Abstract: Economical processes are disclosed for preparing relatively pure polycarboxylic acid from typical crude products of liquid phase oxidation, which do not involve intermediate steps of ester formation or require any alkanol containing solvent, for purification of "crude" polycarboxylic acid containing impurities which include one or more monofunctional aromatic compounds, trifunctional aromatic compounds, and/or color causing organic compounds formed by oxidation of a corresponding substituted aromatic compound in a liquid phase, e.g. 2,6-naphthalene dicarboxylic acid by liquid phase oxidation of 2,6-dimethyl naphthalene. The invention provides integrate processes which comprise reacting crude oxidation product with a polyalkyl amine amine, e.g. trialkylamine, forming an aqueous solution of the salts thus obtained, separating deleterious compounds from the solution, and recovering the polyalkyl amine and a relatively pure polycarboxylic acid product.

Abstract: Provided is a process for producing an aromatic carboxylic acid by oxidizing an aromatic compound having an alkyl group or a partially-oxidized alkyl group with a molecular-oxygen-containing gas in an aqueous medium, characterized in that a compound in which a transition metal is incorporated into a heteropoly-acid skeleton having a deficient structural moiety is used as a catalyst.In accordance with the present invention, the aromatic carboxylic acid can be produced efficiently at low costs.

Abstract: The invention relates to novel processes for the preparation of phenyl acetic acid derivatives of the formula (I) some of which are known ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 independently of each other each represent hydrogen, alkyl or alkoxy by ozonolysis of compounds of the formula (II) ##STR2## in which R.sup.4 represents hydrogen or methyl and oxidation of the reaction products obtained therefrom. The invention further relates to novel intermediates and a process for the preparation thereof.

Abstract: Processes using a titanium dioxide-supported purification catalyst are disclosed for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the rutile crystalline phase.

Abstract: A process for preparing aromatic carboxylic acids by the exothermic liquid-phase oxidation reaction of an aromatic feedstock compound, wherein energy is efficiently recovered from the exothermic oxidation reaction.

Abstract: There are disclosed a method for replacing a dispersion medium wherein an original slurry comprising solid particles and an original dispersion medium is introduced in a dispersion medium replacement column at the top thereof, a replacing dispersion medium is introduced in the column at the bottom thereof to replace the original dispersion medium with the replacing dispersion medium, the resultant replaced slurry comprising the solid particles and the replacing dispersion medium is taken out from the column at the bottom thereof, and the original dispersion medium is taken out from the column at the top thereof, which method comprises dividing the fluid in the intermediate portion into a plurality of parallel streams, stirring the slurry in the bottom of the column to uniformize the slurry, and controlling the feed rates of the replacing dispersion medium and the replaced slurry to maintain the slurry in the bottom portion of the column at a concentration higher than that of the slurry in the intermediate por

Abstract: Purified terephthalic acid is prepared by a process of subjecting an aqueous solution of crude terephthalic acid to hydrogenation to reduce impurities, crystallizing this solution to produce a slurry of purified terephthalic acid in an aqueous liquor, and carrying out an integrated separation washing process using a centrifuge having washing facilities.

Abstract: A process for preparing purified 2,6-naphthalenedicarboxylic acid which comprises hydrolyzing a dialkyl-2,6-naphthalenedicarboxylate with water at a reaction temperature of at least about 450.degree. F. under liquid phase condition, the amount of water present being sufficient to solubilize, at the reaction temperature, at least about 10 percent of the 2,6-naphthalenedicarboxylic acid formed; and a process for purifying 2,6-naphthalenedicarboxylic acid comprising combining impure 2,6-naphthalenedicarboxylic acid with a purification solvent, heating the resulting mixture under liquid phase conditions at a temperature of at least about 500.degree. F. to form a product mixture and thereafter recovering from the product mixture purified 2,6-naphthalenedicarboxylic acid.

Abstract: Processes using a titanium dioxide-supported purification catalyst are disclosed for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the ruffle crystalline phase.

Abstract: It is contemplated by the present invention to produce a high quality aromatic carboxylic acid by a liquid phase oxidation of an alkylbenzene by contacting it with a molecular oxygen-containing gas in a solvent containing a lower aliphatic carboxylic acid, under exclusion of any acceleration of decomposition of the solvent molecules and danger of explosion accident.

Abstract: A process for preparing o-nitroaromatic acids by direct oxidation of the corresponding o-nitroalkylaromatic compounds, utilizing salts of certain catalytic metals in the presence of an oxygen-containing gas and an aliphatic aldehyde or ketone at elevated temperature and pressure, is provided. The process allows catalyst recovery and reuse.

Abstract: A process for preparing an aqueous slurry of terephthalic acid, which comprises oxidizing p-xylene with molecular oxygen in a liquid phase in an acetic acid solvent in the presence of a catalyst, to obtain an acetic acid slurry of terephthalic acid, separating terephthalic acid crystals from the acetic acid slurry, washing the terephthalic acid crystals containing acetic acid, with p-xylene or an acetic acid ester, and then mixing water thereto.

Abstract: Alkoxynaphthalenecarboxylic acid is produced by a process comprising the addition of 1,3-butadiene to alkoxyalkylbenzene to yield an adduct. The adduct is cyclized in the presence of an acid catalyst to alkoxyalkyltetralin. The tetralin derivative is then dehydrogenated to produce aloxyalkylnaphthalene, which is oxidized to alkoxynaphthalenecarboxylic acid.

Abstract: Organic chemical oxidation reactions are carried out using pure or nearly pure oxygen and evaporative cooling. Advantageous operating results are achieved thereby, and the oxidation of organic chemicals resulting in the production of solid products or byproducts is facilitated by obviating the need for direct contact heat exchange surfaces that become coated with solid products or byproducts.

Abstract: A method for producing efficiently on a commercial scale pyromellitic anhydride having high purity and suffering only sparing coloration in a high yield from a raw material of high concentration is provided. By the use of a multilayer catalyst formed by packing on the reaction gas outlet side a first catalyst containing V and Mo and/or W and having an atomic ratio of Mo and/or W to V in the range of from 0.01 to 2, on the raw material mixed gas inlet side a second catalyst containing V, Mo and/or W and having an atomic ratio of Mo and/or W to V smaller than the atomic ratio of the first catalyst, and/or a third catalyst containing V and an alkali metal and having an atomic ratio of the alkali metal to V in the range of from 0.2 to 2.5, pyromellitic anhydride is produced by the vapor-phase oxidation of a tetraalkyl benzene with a molecular oxygen-containing gas.

Abstract: A process for producing 2,6-naphthalenedicarboxylic acid by oxidizing 2,6-dimethylnaphthalene by molecular oxygen in the presence of a catalyst including cobalt, manganese and bromine. The oxidation reaction is performed by using a 2,6-dialkylnaphthalene mixture of 2,6-dimethynaphthalene and a small amount of 2,6-diisopropylnaphthalene as a raw material. Thus, the desired 2,6-naphthalenedicarboxylic acid can be produced at a high yield.

Abstract: Process for improving a controlled oxidation reaction between at least one reactant and oxygen, in which at least one reactant is reacted with oxygen or an oxygen containing gas, constituting a reaction mixture, in the presence of at least one additional gas which is introduced into said reaction mixture and is selected from methane, ethane and helium, and the resulting reaction product from the oxidation reaction is possibly treated so as to give a final product.

Abstract: A process for preparing methylsulfonylbenzoic acids comprises oxidizing the corresponding methylsulfonyltoluenes with nitric acid and air in sulfuric acid in the presence of vanadium or cobalt compounds.

Abstract: A process for producing highly pure terephthalic acid, which comprises heating and dissolving crude terephthalic acid in water, and purifying it by contacting the aqueous solution with hydrogen at a temperature of from 260.degree. to 320.degree. C. in the presence of a platinum group metal catalyst, wherein the purification is initiated within three minutes after the aqueous solution under heating reaches a temperature of 250.degree. C.

Abstract: The invention relates to a process for preparing pyromellitic dianhydride (PMDA) by heterogeneously catalyzed oxidation in the gas phase by means of a gas containing molecular oxygen. The process involves oxidizing benzaldehydes which are 2,4,5-trialkylated by C.sub.1 - to C.sub.3 -alkyl groups or mixtures of benzaldehydes which are 2,4,5-trialkylated by C.sub.1 - to C.sub.3 -alkyl groups and benzenes which are 1,2,4,5-tetraalkylated by C.sub.1 - to C.sub.3 -alkyl groups in the presence of a catalyst. The catalyst contains as active components 5% to 95% by weight of one or more transition-metal oxides of sub-group IV of the Periodic Table of the Elements, from 1% to 50% by weight of one or more transition-metal oxides of sub-group V of the Periodic Table of the Elements.

Abstract: 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.

Abstract: A process for purifying a crude naphthalenedicarboxylic acid containing impurities and coloring substances obtained by the oxidation of a di-substituted naphthalene, dispense with the use of a large amount of alkali or acid, and producing a naphthalenedicarboxylic acid having a high purity and good color effectively and in a high recovery is disclosed, which comprises dissolving the crude naphthalenedicarboxylic acid in a mixed solvent comprising an amine compound and an alcohol and conducting crystallization.

Abstract: A process for making relatively high purity eulfonylbis(phthalic anhydride) is provided. 3,3',4,4'-tetramethyl diphenyl sulfone is catalytically oxidized in a solvent under liquid phase elevated temperature and pressure conditions. The catalyst is constituted by cobalt, manganese, zirconium, and bromine. Sulfonylbis(phthalic) acid is recovered by crystallization and is then heated to produce the anhydride. Preferably, the acid is purified prior to dehydration.

Abstract: A process for simultaneously producing a lactone and an aromatic carboxylic acid, which comprises oxidizing a cyclic ketone and an aromatic aldehyde wherein: the cyclic ketone/aromatic aldehyde molar ratio is set at 1.1:1 to 20:1 and the throughput of the aromatic aldehyde per a unit reaction solution volume and a unit time is set at 0.05 to 1.5 mol/1.hour.

Abstract: A compound of the formula ##STR1## and the dianhydride thereof are prepared by air oxidation in the presence of a catalyst mixture composed of at least 2 heavy metal salts and also bromine in an acid organic medium. The compounds can be employed for the preparation of partially fluorinated polycondensates, such as polyimides, polycarboxamides, esters of polyamidecarboxylic acids, polyamides and imide-oligomers.

Abstract: A process for preparing purified dimethyl-2,6-naphthalenedicarboxylate by the esterification of 2,6-naphthalenedicarboxylic acid is disclosed, and which process provides for the efficient removal of residual oxidation catalyst metals from the dimethyl-2,6-naphthalenedicarboxylate and efficient removal of particulate contaminants.

Abstract: A process for preparing a pyrazolecarboxylic acid compound of the formula (II): ##STR1## wherein Y and Z each represent a hydrogen, a halogen, a nitro, a cyano, COOR.sub.1, NR.sub.1 R.sub.2, CONR.sub.1 R.sub.2, SR.sub.1, SO.sub.2 NR.sub.1 R.sub.2, SO.sub.2 R.sub.3, R.sub.3 CO, OR.sub.4, CHX.sub.2 or CX.sub.3 ; A represents a hydrogen, an alkyl having 2 to 4 carbons, a phenyl, a pyridyl or OR.sub.5 ; where R.sub.1 and R.sub.2 each represent a hydrogen or an alkyl having 1 to 10 carbons; R.sub.3 represents an alkyl having 1 to 10 carbons; R.sub.4 represents a hydrogen, an alkyl having 1 to 10 carbons, a phenyl, CHF.sub.2, CF.sub.3 or CF.sub.3 CH.sub.2 ; R.sub.5 represents an alkyl having 1 to 10 carbons; and X represents a halogen, which comprises oxidizing a pyrazole compound of the formula (I): ##STR2## wherein Y, Z and A have the same meanings as above, by contacting the compound of formula (I) with an oxygen-containing gas in the presence of a metal catalyst at 20.degree. to 200.degree. C.

Abstract: Oxidation of alkylaromatics having a benzylic hydrogen atom is catalyzed by a catalyst comprising a palladium salt, a metal persulfate, a third metal salt, and a tin salt in a carboxylic acid for a period of time sufficient to convert the alkylaromatics to their corresponding oxidized derivatives. The catalyst is prepared by preheating the palladium salt and the metal persulfate at a temperature sufficient to provide the desired catalytic activity followed by additon of the third metal salt and the tin salt.

Abstract: A method to oxidize an oxidizable component in a liquid phase with an oxygen-containing gas is disclosed. The method comprises mixing the liquid phase and gas phase in a reactor with a rotating agitator element operated at constant power.

Abstract: Process for the preparation of compounds of the formula HO-Ar-COOH in which Ar is a substituted or unsubstituted aromatic ring system, by oxidizing, by means of oxygen or compounds which donate oxygen, compounds of the formula HO-Ar-R.sub.1 in which R.sub.1 is alkyl having 1 to 5 carbon atoms and Ar is as defined above, or the O-acyl derivatives of these compounds, in an organic solvent at 80.degree. to 130.degree. C. and in the presence of an acylating agent, a cobalt and/or manganese compound and a compound which donates bromide, ions, and subsequently hydrolysing the products in a conventional manner. In the presence of the acylating agent, a selective oxidation of the hydroxyl-substituted aromatic compounds to carboxylated hydroxy compounds, which are obtained in a good state of purity and yield, is obtained without the application of pressure.The compounds obtained in accordance with the process are, for example, valuable intermediates for the preparation of dyes, plastics and pharmaceuticals.

Abstract: An oxidation process is provided for converting dixylylpropane to isopropylidene bis(phthalic acid) in good yields with minimal by-product production, especially trimellitic acid production. The oxidation process employs an oxidation catalyst that includes zirconium as well as cobalt, manganese, and bromine.

Abstract: A process for the preparation of polyphenyl dicarboxylic acids is disclosed. The process comprises contacting para,para'-diisoalkyl or dialkyl-polyphenyl or an oxidation intermediate thereof with oxygen under reaction conditions sufficient to form para,para'-polyphenyldicarboxylic acid. The process is optionally carried out in the presence of cobalt, manganese, and bromine compounds.

Abstract: A method for making 2,6-naphthalene dicarboxylic acid by the oxidation of 2,6-diisopropylnaphthalene or its oxidation derivatives in the presence of a catalyst comprising cobalt, manganese, cerium and bromine components is disclosed.

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: Disclosed are a para- or meta-terphenyl-3,4,3",4"-tetracarboxylic acid or a dianhydride and a process for preparing the same. The para- or meta-terphenyl-3,4,3",4"-tetracarboxylic acid or a dianhydride thereof according to the present invention is a novel compound which is useful as a raw material for a polyimide having higher heat resistance and so on.

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: A method is disclosed for the liquid-phase oxidation of a di- (mono- or poly-)alkylaryl ether in the presence of a catalyst comprising cobalt, manganese and bromine components to a di- (mono- or poly-)carboxyaryl ether.