Abstract: A process for separating a feed mixture comprising at least one aromatic hydrocarbon and at least one non-aromatic hydrocarbon by extractive distillation (ED) utilizing a solvent mixture comprising sulfolane and at least one co-solvent. The co-solvent is an alkyl sulfolane having from 4 to 8 carbon atoms per molecule. The solvent mixture is added to the top of the ED column, and the feed mixture is added at a point on the ED column that is lower than the point where the solvent mixture is added. Extractive distillation is performed, and the aromatic and non-aromatic hydrocarbons are separated.

Abstract: An improved process for the recovery of aromatic compounds from a mixture containing aromatic and non-aromatic compounds and method for retrofitting existing equipment for the same is provided. The improved process comprises the steps of recovering aromatic compounds via parallel operation of a hybrid extractive distillation/liquid-liquid extractor operation and variations thereof. Methods of quickly and economically retrofitting existing recovery process equipment for use with the improved aromatics recovery process are also disclosed.

Abstract: Methods and apparatus for removing a catalyst from a reaction mixture formed by reacting a hydrocarbon or an oxygenated hydrocarbon with an oxidant in the presence of the catalyst in a reactor, in which the reaction mixture contains one or more dibasic acids. The catalyst is removed by adding water and/or cooling the reaction mixture to cause phase separation, recycling the polar phase to the reactor, and transferring the less-polar phase to an ion exchange unit to remove catalyst contained therein.

Abstract: An improved process for the recovery of aromatic compounds from a mixture containing aromatic and non-aromatic compounds and method for retrofitting existing equipment for the same is provided. The improved process comprises the steps of recovering aromatic compounds via parallel operation of a hybrid extractive distillation/liquid-liquid extractor operation and variations thereof. Methods of quickly and economically retrofitting existing recovery process equipment for use with the improved aromatic recovery process are also disclosed.

Abstract: A process for the removal of sulfur compounds from a hydrocarbon stream is disclosed. In a preferred embodiment, the process includes extractive distillation of a gasoline stream from a fluid catalytic cracker to reject olefins to a raffinate stream and simultaneously extract sulfur compounds to an extract stream.

Abstract: A process for separating a feed mixture comprising at least one aromatic hydrocarbon and at least one non-aromatic hydrocarbon by extractive distillation (ED) utilizing a solvent mixture comprising sulfolane and at least one co-solvent. The co-solvent is an alkyl sulfolane having from 4 to 8 carbon atoms per molecule. The solvent mixture is added to the top of the ED column, and the feed mixture is added at a point on the ED column that is lower than the point where the solvent mixture is added. Extractive distillation is performed, and the aromatic and non-aromatic hydrocarbons are separated.

Abstract: An improved process for the recovery of aromatic compounds from a mixture containing aromatic and non-aromatic compounds and method for retrofitting existing equipment for the same is provided. The improved process comprises the steps of recovering aromatic compounds via parallel operation of a hybrid extractive distillation/liquid-liquid extractor operation and variations thereof. Methods of quickly and economically retrofitting existing recovery process equipment for use with the improved aromatics recovery process are also disclosed.

Abstract: Methods and apparatus for removing a catalyst from a reaction mixture formed by reacting a hydrocarbon and an oxidant in the presence of the catalyst in a reactor, in which the reaction mixture contains one or more dibasic acids. The catalyst is removed by adding water and/or cooling the reaction mixture to cause phase separation, recycling the polar phase to the reactor, and transferring the non-polar phase to an ion exchange unit to remove catalyst contained therein.

Abstract: A process for separating a feed mixture comprising at least one aromatic hydrocarbon and at least one non-aromatic hydrocarbon by extractive distillation (ED) utilizing a solvent mixture comprising sulfolane and at least one co-solvent. The co-solvent is an alkyl sulfolane having from 4 to 8 carbon atoms per molecule. The solvent mixture is added to the top of the ED column, and the feed mixture is added at a point on the ED column that is lower than the point where the solvent mixture is added. Extractive distillation is performed, and the aromatic and non-aromatic hydrocarbons are separated.

Abstract: Disclosed is a method for recovering acrylic acid from process or waste water streams in which the stream is vaporized and contacted with a liquid high boiling solvent for acrylic acid, thereby absorbing acrylic acid into the solvent. Mixed trialkylphosphine oxides are a preferred solvent. Acrylic acid is stripped from the solvent with heat and, optionally, stripping gas. It may be separated from any accompanying materials to produce acrylic acid of high purity.

Abstract: Disclosed is a method for preparing isophthalic acid from metaxylene and especially for purifying crude isophthalic acid (IPA) produced in the course of such method, or otherwise, from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials. The purifying portion of the method comprises the step of: (1) filtering the dispersion to form a crude IPA filter cake; (2) dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution; (3) crystallizing purified IPA from the solution in the crystallization solvent by reducing the temperature, or pressure, or both of the solution; (4) separating the crystallized purified IPA from the solution; and (5) re-dissolving or soaking the washed purified IPA cake at elevated temperature, to remove the final traces of the crystallization solvent and obtain the desirable particle sizes and shape.

Abstract: A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.

Abstract: A method and apparatus for preparing purified terephthalic acid and, optionally, isophthalic acid from mixed xylenes. The method of the present invention purifies the oxidation reactor effluent containing a mixture of terephthalic acid and isophthalic acid as well as minor amounts of 4-carboxybenzaldehyde (4-CBA), 3-carboxybenzaldehyde (3-CBA), and toluic acid isomers, to produce purified terephthalic acid and, optionally, purified isophthalic acid in an integrated process.

Abstract: A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.

Abstract: Disclosed is a process for separating at least one cycloalkane containing 5-10 carbon atoms per molecule from at least one close-boiling alkane by extractive distillation of a feed consisting essentially of said at least one cycloalkane and said at least one alkane, the improvement comprising the use of certain pyrrolidones, certain morpholines, sulfoxides, sulfolanes, glycol compounds, or mixtures thereof, and optionally water; wherein said extractive distillation process produces (i) an overhead distillate product which contains a smaller volume percentage of said at least one cycloalkane and a larger volume percentage of said at least one alkane than said feed, and (ii) a bottoms product which contains said solvent and a larger volume percentage of said at least one cycloalkane and a smaller volume percentage of said at least one alkane than said feed; and wherein said at least one cycloalkane is separated from said solvent and recovered from said bottoms product.

Abstract: A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone.

Abstract: A method for reducing carboxybenzaldehyde isomers in crude terephthalic and/or isophthalic acids is described. Crude TPA or IPA is dissolved in N-methyl pyrrolidone and is subsequently contacted with an oxidant, such as substantially anhydrous hydrogen peroxide, to convert the carboxybenzaldehyde isomer (4-CBA or 3-CBA) to TPA or IPA under moderate temperature and pressure conditions.

Abstract: Disclosed is a process for recovering styrene from a feedstock containing at least styrene, ethylbenzene, and one or more aromatic or non-aromatic hydrocarbon compounds which includes separating said feedstock into a first stream relatively more concentrated in styrene than said feedstock and a second stream relatively more concentrated in ethylbenzene than said feedstock, recovering styrene from said first stream to produce a styrene product stream, dehydrogenating the ethylbenzene of said second stream to produce additional styrene, and recovering said additional styrene. The feedstock may be separated into said first and second streams by a process selected from the class consisting of extractive distillation, azeotropic distillation, distillation, liquid-liquid extraction, chemical complex formation, membrane separation, and combinations thereof, and the additional styrene may be recovered by recycling it into said feedstock.

Abstract: An extractive distillation process for separating at least one substituted unsaturated aromatic from a pyrolysis gasoline mixture, containing said aromatic and at least one close-boiling aromatic or non-aromatic hydrocarbon, employing a two part extractive solvent, the first part selected from propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone and mixtures thereof, and the second portion consisting of water.

Abstract: A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone or dimethyl acetamide.