Abstract: A process for oxidation with oxygen of at least one aromatic hydrocarbon having oxidizable, substituents that maximizes the utilization of oxygen without reduction in the quality of the carboxylic acid products produced by means of a stagewise countercurrent oxidation system is disclosed.

Abstract: Disclosed is a method and solvent composition capable of removing iron oxide deposits from the surface of titanium components without substantially damaging the underlying titanium component. Iron oxide deposits may be removed from the surface of a titanium component by contacting the titanium component with the solvent composition of the invention. The solvent composition may then be removed from contact with the titanium component to obtain a recyclable solvent composition which is recycled into repeated contact with the titanium component. The solvent composition comprises an aqueous mixture of an organic acid and a hydrohalide acid.

Abstract: Disclosed is a method and solvent composition capable of removing iron oxide deposits from the surface of titanium components without substantially damaging the underlying titanium component. Iron oxide deposits may be removed from the surface of a titanium component by contacting the titanium component with the solvent composition of the invention. The solvent composition may then be removed from contact with the titanium component to obtain a recyclable solvent composition which is recycled into repeated contact with the titanium component. The solvent composition comprises an aqueous mixture of an organic acid and a hydrohalide acid.

Abstract: Disclosed is a method and solvent composition capable of removing iron oxide deposits from the surface of titanium components without substantially damaging the underlying titanium component. Iron oxide deposits may be removed from the surface of a titanium component by contacting the titanium component with the solvent composition of the invention. The solvent composition may then be removed from contact with the titanium component to obtain a recyclable solvent composition which is recycled into repeated contact with the titanium component. The solvent composition comprises an aqueous mixture of an organic acid and a hydrohalide acid.

Abstract: Processes for the production of aromatic carboxylic acids is disclosed. The aromatic acids are produced by the liquid phase oxidation of a suitable acid precursor in a reaction medium comprising benzoic acid. According to one embodiment, the oxidation is carried out under plug-flow reaction conditions in a plug-flow reactor. The plug-flow conditions can be achieved by the use of a series of continuous stirred tank reactors. In another embodiment, the oxidation is carried out in two continuous stirred tank reactors fluidly connected in series. The preferred oxidation products are terephthalic acid, isophthalic acid, trimellitic acid, 2,6-naphthalene dicarboxylic acid, 1,5-napthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid and phthalic acid.

Abstract: Processes for the production of aromatic carboxylic acids is disclosed. The aromatic acids are produced by the liquid phase oxidation of a suitable acid precursor in a reaction medium comprising benzoic acid. According to one embodiment, the oxidation is carried out under plug-flow reaction conditions in a plug-flow reactor. The plug-flow conditions can be achieved by the use of a series of continuous stirred tank reactors. In another embodiment, the oxidation is carried out in two continuous stirred tank reactors fluidly connected in series. The preferred oxidation products are terephthalic acid, isophthalic acid, trimellitic acid, 2,6-naphthalene dicarboxylic acid, 1,5-napthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid and phthalic acid.

Abstract: An integrated process for vent gas treatment for the abatement of volatile emissions is disclosed. The vent gas comprises dioxygen, carbon monoxide, hydrocarbons and other organic compounds comprising one or more alkyl halide compound of 1 to 5 carbon atoms. In the preferred embodiment, the vent gas is heated and mixed with an amount of combustible fluid. Then the mixture is directed to a catalytic oxidation reactor having a suitable oxidation catalyst disposed therein, wherein the mixture is catalytically oxidized. The effluent from the catalytic oxidation reactor is directed to heat the incoming vent gas and subsequently to a scrubber wherein the effluent is scrubbed of soluble compounds and the resultant treated gas stream is vented. Importantly, the amount of combustible fluid supplied to the vent gas stream is controlled so at to provide sufficient reactants for the catalytic oxidation to maintain reaction temperatures from 200° C. and 600° C.

Abstract: Crystallization of a crystallizable material is achieved through heat exchange in a plate heat exchanger is disclosed. A mixture or solution comprising a crystallizable material is passed through a plate heat exchanger at an appropriate temperature and pressure such that the material is selectively crystallized. The processes are particularly useful in the production of para-xylene, dimethylnaphthalene, aromatic carboxylic acids, and aromatic anhydrides.

Abstract: Processes are disclosed for recovery of hydrogen bromide from one or more alkyl bromide compounds by hydrolyzing the alkyl bromide compounds to hydrogen bromide and corresponding alcohols, and simultaneously separating at least the alcoholic products of hydrolysis from aliphatic monocarboxylic acid solvent component. Also disclosed are process for preparing aromatic carboxylic acids by the exothermic, liquid-phase oxidation of an aromatic feedstock compound wherein the energy produced by the exothermic oxidation is efficiently recovered, and uses of water produced during the preparation of aromatic carboxylic acids are efficiently integrated into the process.

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: An apparatus useful for preparing aromatic carboxylic acids by the exothermic liquid-phase oxidation reaction of an aromatic feedstock compound is disclosed, wherein energy is efficiently recovered from the exothermic oxidation reaction.

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: 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: 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 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.