Purification Or Recovery Per Se Patents (Class 562/485)
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Publication number: 20030088121Abstract: A method for purifying crude 2,6-naphthalenedicarboxylic acid includes a reduction step of reducing crude 2,6-naphthalenedicarboxylic acid containing 6-formyl-2-naphthoic acid with hydrogen and a cleaning step of cleaning the reduction product with alcohol. Preferably, in the reduction step, the crude 2,6-naphthalenedicarboxylic acid and the hydrogen is brought into contact with a hydrogenation catalyst in a liquid phase, and particularly in water. The method makes the purification process less complex and makes it possible to produce high-purity 2,6-naphthalenedicarboxylic acid without damaging equipment or increasing cost.Type: ApplicationFiled: July 12, 2002Publication date: May 8, 2003Applicant: Kabushiki Kaisha Kobe Seiko Sho(Kobe Steel, Ltd.)Inventors: Yoshiyuki Nagase, Koji Yamamoto, Takeharu Tanaka, Maki Hamaguchi
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Patent number: 6515170Abstract: The present invention concerns an enzymatic oxidative deamination process of a dipeptide monomer to prepare an intermediate useful to prepare compounds having endopeptidase and angiotensin converting enzyme inhibition activity.Type: GrantFiled: April 26, 2001Date of Patent: February 4, 2003Assignee: Bristol-Myers Squibb Co.Inventors: Ramesh N. Patel, Amit Banerjee, Venkata B. Nanduri, Steven L. Goldberg, Robert M. Johnston, Thomas P. Tully, Laszlo J. Szarka, Shankar Swaminathan, John J. Venit, Jerome L. Moniot, William J. Winter, Neal G. Anderson, David A. Lust, Gerard Crispino, Sushil K. Srivastava
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Patent number: 6462230Abstract: A method of decomposing wastes containing target compounds having one or more of hydrolyzable bonds of ether bond, ester bond, amide bond and isocyanate bond wherein the method comprises continuously supplying the wastes in a molten state or liquid state to a reactor, continuously supplying super-critical water or high pressure/high temperature water to the reactor, bringing the water into contact with the wastes, thereby decomposing the target compounds and then recovering them as raw material compounds or derivatives thereof for the target compounds. Target compounds contained in wastes in chemical plants which could not be utilized but merely incinerated or discarded so far are continuously decomposed into raw material compounds or derivatives thereof for the aimed compound and can be reutilized effectively.Type: GrantFiled: August 4, 2000Date of Patent: October 8, 2002Assignees: Kabushiki Kaisha Kobe Seiko Sho, Takeda Chemical Industries, Ltd.Inventors: Yoshiyuki Nagase, Ryuichi Fukuzato
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Patent number: 6461700Abstract: Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications.Type: GrantFiled: August 23, 2001Date of Patent: October 8, 2002Assignee: BP Corporation North America Inc.Inventors: Edward E. Paschke, Bruce I. Rosen, David A. Peterson, David E. James, Melvin L. Luetkens, Jr., Charles W Bauer, Gary T. Brooks
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Patent number: 6455731Abstract: A process for producing a high purity aromatic polycarboxylic acid by purify a crude aromatic polycarboxylic acid in accordance with the steps of (I) forming an amine salt of an aromatic polycarboxylic acid from the crude polycarboxylic acid and an amine, (II) continuously decomposing the salt in a salt decomposition reactor in operations of (i) supplying an aqueous solution of the amine salt of an organic polycarboxylic acid formed in the step of forming a salt, (ii) removing the amine and water by distillation under heating and (iii) taking out a slurry containing crystallized aromatic polycarboxylic acid, and (III) separating and recovering crystals of the aromatic polycarboxylic acid from the slurry which is taken out in the step of decomposing the salt.Type: GrantFiled: May 17, 2001Date of Patent: September 24, 2002Assignee: Mitsubishi Gas Chemical Company, Inc.Inventors: Ryusuke Shigematsu, Masayoshi Hayashi, Shinichi Nagao, Jitsuo Oishi, Akio Hashimoto
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Publication number: 20020128508Abstract: The invention provides a process for producing lactic acid and products thereof from a medium containing an alkaline earth-metal salt of lactic acid, comprising (a) reacting a conjugated base of an alkali metal from a subsequent step with the medium to form a water soluble alkali metal lactate salt and a basic compound of the alkaline earth metal; (b) separating the water soluble alkali metal lactate salt and the basic compound of the alkaline earth metal; (c) splitting the water soluble alkali metal lactate to form a conjugated alkali metal base and a lactic acid product, which product is selected from the group consisting of lactic acid, a derivative thereof and combination thereof; (d) separating the conjugated alkali metal base and the lactic acid product; (e) reusing the separated conjugated alkali metal base or a product thereof in the step (a) and (f) reusing the basic compound of the alkaline earth metal separated in step (b), or a product thereof to form an alkaline earth-metal salt of lactic acidType: ApplicationFiled: November 19, 1999Publication date: September 12, 2002Inventors: AHARON MEIR EYAL, DAVID WITZKE, ROD FISHER
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Patent number: 6441225Abstract: A method is provided to produce dicarboxylic or tricarboxylic aromatic acid from salts of such acids, the method including the steps of providing an aqueous solution of a salt of a dicarboxylic or tricarboxylic aromatic acid, the aqueous solution having a pH of about 7 or greater; contacting the aqueous solution with sufficient carbon dioxide to lower the pH of the aqueous solution resulting in precipitation of at least a portion of the dicarboxylic or tricarboxylic aromatic acid; separating precipitated dicarboxylic or tricarboxylic aromatic acid from the solution; and recovering carbon dioxide from the solution.Type: GrantFiled: August 22, 2000Date of Patent: August 27, 2002Assignee: Mossi & Ghisolfi Overseas, S.A.Inventor: Thomas Fairchild Brownscombe
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Patent number: 6426431Abstract: Disclosed is a method of increasing the yield of 2,6-NDA which comprises: a) Dissolving a disproportionation reaction product containing a dialkali salt of 2,6-NDA in water and filtering off insoluble matter from the resulting solution; b) Precipitating the monoalkali salt of 2,6-NDA (KHNDA) with CO2; c) Suspending said monoalkali salt in water in a weight ratio higher than 8:1, water: monosalt; and d) Heating at a temperature above 100° C. and at a pressure above 100 psig. The improvements in yield are from about 20% to as high as 45%.Type: GrantFiled: August 22, 2000Date of Patent: July 30, 2002Assignee: Mossi & Ghisolfi Overseas S.A.Inventors: Zaida Diaz, Thomas F. Brownscombe
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Patent number: 6407286Abstract: A method for recovering and recycling excess hydrogen from process vent streams in the production of highly pure terephthalic acid where the production of the pure terephthalic acid comprises catalytically hydrogenating impure terephthalic acid, which typically contains 4-carboxybenzaldehyde (4-CBA), color bodies and other impurities, in aqueous liquid phase solution at elevated temperature and pressure.Type: GrantFiled: January 14, 2000Date of Patent: June 18, 2002Inventors: David Parker, Fiona Mary Campbell, Andrew Harrison
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Patent number: 6399790Abstract: Xylene derivatives, such as chloro-ortho-xylene, are oxidized in a solvent in the presence of at least one metal catalyst and optionally at least one promoter. The product comprises chlorophthalic acid or chlorophthalic anhydride.Type: GrantFiled: November 20, 2000Date of Patent: June 4, 2002Assignee: General Electric CompanyInventors: Sheree Lynell Schattenmann, Bahram Moasser, Joseph John Caringi
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Patent number: 6392091Abstract: The present invention provides a solvent extraction purification method for aromatic polycarboxylic acids that meet or exceed polymer-grade specification. The method includes dissolving a crude aromatic polycarboxylic acid in a base compound; removing impurities and excessive base compound; and removing residual base compound while making purified product. The purification method removes not only the impurities from the crude acid, but also the residual base compound from finished product that otherwise will contaminate the product. The salt in the cake is converted to product by acid-substitution, thermal decomposition, or electrolysis. The method uses base-extraction solvents to extract base compound and impurities from the salt. The residual base compound in the recovered product is then removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition.Type: GrantFiled: April 5, 1999Date of Patent: May 21, 2002Inventor: Tsong-Dar Vincent Lin
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Patent number: 6391823Abstract: A process for separating a compound from a mixture of different compounds is disclosed for compounds comprising at least two negatively charged groups connected by a linker group. The process comprises treating the mixture with a material comprising layers containing at least two different types of cation disposed in an ordered arrangement within each layer, such as layers of formula LiAl2(OH)6+, in order to separate the compound from the mixture by selective intercalation of the compound into the material.Type: GrantFiled: May 5, 2000Date of Patent: May 21, 2002Assignee: Isis Innovation LimitedInventors: Dermot Michael O'Hare, Andrew Michael Fogg
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Publication number: 20020002304Abstract: The present invention provides a solvent extraction purification method for aromatic polycarboxylic acids that meet or exceed polymer-grade specification. The method includes dissolving a crude aromatic polycarboxylic acid in a base compound; removing impurities and excessive base compound; and removing residual base compound while making purified product. The purification method removes not only the impurities from the crude acid, but also the residual base compound from finished product that otherwise will contaminate the product. The salt in the cake is converted to product by acid-substitution, thermal decomposition, or electrolysis. The method uses base-extraction solvents to extract base compound and impurities from the salt. The residual base compound in the recovered product is then removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition.Type: ApplicationFiled: April 5, 1999Publication date: January 3, 2002Inventor: TSONG-DAR VINCENT LIN
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Publication number: 20020002305Abstract: A process for producing a high purity aromatic polycarboxylic acid by purifying a crude aromatic polycarboxylic acid in accordance with the steps of (I) forming an amine salt of an aromatic polycarboxylic acid from the crude polycarboxylic acid and an amine, (II) continuously decomposing the salt in a salt decomposition reactor in operations of (i) supplying an aqueous solution of the amine salt of an organic polycarboxylic acid formed in the step of forming a salt, (ii) removing the amine and water by distillation under heating and (iii) taking out a slurry containing crystallized aromatic polycarboxylic acid, and (III) separating and recovering crystals of the aromatic polycarboxylic acid from the slurry which is taken out in the step of decomposing the salt.Type: ApplicationFiled: May 17, 2001Publication date: January 3, 2002Inventors: Ryusuke Shigematsu, Masayoshi Hayashi, Shinichi Nagao, Jitsuo Oishi, Akio Hashimoto
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Patent number: 6320073Abstract: In a process for producing aromatic dicarboxylic acids which incorporates the disproportionation of a salt of an aromatic mono- or dicarboxylic acid to produce the unreacted salt of an aromatic mono- or dicarboxylic acid and the salt of the desired aromatic dicarboxylic acid, a method is disclosed for separating the salt of the desired product from the unreacted salt which comprises passing both said unreacted salt and said salt of the desired product in an aqueous solution over an adsorbent comprising an activated carbon. The process is particularly suitable for separating potassium naphthoate from 2,6-K2NDA after potassium naphthoate is disproportionated to produce 2,6-K2NDA and 1- or 2-potassium naphthoate. The adsorbent can be regenerated by the use of a displacing agent and reused without off site regeneration.Type: GrantFiled: August 22, 2000Date of Patent: November 20, 2001Assignee: Shell Oil CompanyInventor: Raymond Lawrence June
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Patent number: 6310239Abstract: This invention relates to a process for manufacturing terephthalic acid and more particularly, to a process for manufacturing and recovering the highly purified terephthalic acid, in accordance with the practice of this invention comprising the following procedurses: alkali weight-reduction waste water discharged from weight-reduction process in a polyester textile dyeing complex is dissolved in water, adsorbed to remove impurities, and through acid-neutralization, terephthalic acid of this invention may be obtained.Type: GrantFiled: June 29, 1998Date of Patent: October 30, 2001Assignee: Sunkyong Industries Co., Ltd.Inventors: Hang-Duk Roh, Dongmok Bae
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Process of purifying and producing high purity aromatic polycarboxylic acids and derivatives thereof
Patent number: 6291707Abstract: The present invention provides a solvent extraction purification method for aromatic polycarboxylic acids or derivatives that meet or exceed polymer-grade specification. The method includes dissolving a crude aromatic polycarboxylic acid or derivative in a base compound; removing impurities and excessive base compound; and removing residual base compound while making purified product. The purification method removes not only the impurities from the crude acid or derivative, but also the residual base compound from finished product that otherwise will contaminate the product. The salt in the cake is converted to product by acid-substitution, thermal decomposition, or electrolysis. The method uses base-extraction solvents to extract base compound and impurities from the salt. The residual base compound in the recovered product is then removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition.Type: GrantFiled: July 2, 1999Date of Patent: September 18, 2001Inventor: Tsong-Dar Vincent Lin -
Patent number: 6284920Abstract: Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications. Aromatic monomer products and polymers produced therefrom having these advantages also are disclosed, as well as products such as pasteurizable bottles made from these polymers.Type: GrantFiled: October 4, 1999Date of Patent: September 4, 2001Assignee: BP Corporation North America Inc.Inventors: Edward E. Paschke, Bruce I. Rosen, David A. Peterson, David E. James, Melvin L. Luetkens, Jr., Charles W. Bauer, Gary T. Brooks
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Patent number: 6265608Abstract: An aromatic dicarboxylic acid is purified by oxidizing m-xylene or p-xylene to produce crude isophthalic acid or crude terephthalic acid, respectively. The products of the oxidizing step are hydrogenated in the presence of a palladium catalyst. Carbon monoxide is introduced during the hydrogenation step. The palladium catalyst is provided on a carbon substrate. The products of the oxidizing step are dissolved in a solvent, which may be water, prior to the hydrogenation step. The products of the oxidizing step may be dissolved at an elevated temperature, above the normal boiling point of the solvent. The oxidation step produces isophthalic acid, 3-carboxybenzaldehyde and fluorenones in the case of oxidizing m-xylene and produces terephthalic acid, 4-carboxybenzaldehyde and fluorenones in the case of oxidizing p-xylene.Type: GrantFiled: June 30, 1998Date of Patent: July 24, 2001Assignee: Eastman Chemical CompanyInventors: Charles E. Sumner, Jr., Brent A. Tennant
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Patent number: 6258980Abstract: There is described a process for the production of a substantially anhydrous salt of an organic acid which comprises reacting a basic compound of a metal with the appropriate organic acid, removing a substantial proportion of water present so as to produce the salt or its hydrate as a liquid phase and then dissolving the liquid phase in a non-aqueous solvent.Type: GrantFiled: June 27, 1994Date of Patent: July 10, 2001Assignee: Contracts Chemicals Ltd.Inventor: David Anthony Jones
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Patent number: 6255525Abstract: A process for preparing an aromatic carboxylic acid having improved purity comprising contacting at an elevated temperature and pressure a mixture comprising an impure aromatic carboxylic acid and a solvent in the presence of hydrogen gas with a carbon catalyst which is essentially free of a hydrogenation metal component.Type: GrantFiled: December 1, 1998Date of Patent: July 3, 2001Assignee: BP Amoco CorporationInventors: David Lee Sikkenga, M. Michelle Morie-Bebel, Stephen V. Hoover
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Patent number: 6255529Abstract: A method of decomposing wastes containing target compounds having one or more of hydrolyzable bonds of ether bond, ester bond, amide bond and isocyanate bond wherein the method comprises continuously supplying the wastes in a molten state or liquid state to a reactor, continuously supplying super-critical water or high pressure/high temperature water to the reactor, bringing the water into contact with the wastes, thereby decomposing the target compounds and then recovering them as raw material compounds or derivatives thereof for the target compounds. Target compounds contained in wastes in chemical plants which could not be utilized but merely incinerated or discarded so far are continuously decomposed into raw material compounds or derivatives thereof for the aimed compound and can be reutilized effectively.Type: GrantFiled: January 16, 1997Date of Patent: July 3, 2001Assignees: Kabushiki Kaisha Kobe Seiko Sho, Takeda Chemical Industries, Ltd.Inventors: Yoshiyuki Nagase, Ryuichi Fukuzato
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Patent number: 6248797Abstract: A method for extracting leachable contaminants from ion exchange resins comprises exposing the resin to supercritical carbon dioxide for a sufficient interval of time to allow at least a portion of the leachable contaminant to be solubilized by the supercritical carbon dioxide; followed by removal from the resin of the supercritical carbon dioxide having the leachable contaminant dissolved therein. The method is particularly useful for removing organic contaminants, which may or may not contain sodium or chlorine, from the resin, to thereby provide ion exchange resins which are suitable for critical use applications in the nuclear, electronics, pharmaceutical and food industries.Type: GrantFiled: May 17, 1999Date of Patent: June 19, 2001Inventors: Shelton A. Dias, Walter Shapka
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Patent number: 6245942Abstract: A method for reducing the carbonyl value of a composition containing carboxylic acid or carboxylic acid derivative includes contacting the composition containing carboxylic acid or carboxylic acid derivative with an amount of a catalyst and active methylene compound effective to lower the carboxyl value of the composition.Type: GrantFiled: February 26, 1999Date of Patent: June 12, 2001Assignee: Henkel CorporationInventor: Michael D. Staley
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Patent number: 6245939Abstract: An improved process for producing highly pure aromatic carboxylic acid from an impure solid acid product whereby the solid acid product is efficiently dissolved in a suitable solvent at relatively low temperatures despite the presence of solid lumps.Type: GrantFiled: November 30, 1998Date of Patent: June 12, 2001Assignee: E. I. du Pont de Nemours and CompanyInventors: Yu-Wei Hsu, Chen-Long Lin
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Patent number: 6239310Abstract: A subject of the invention is the method of recovery of terephthalic acid and ethylene glycol from poly/ethylene terephthalate/wastes. According to the invention poly/ethylene terephthalate/ is heated in an aqueous solution at the temperature from 150° C. to 280° C. with a reagent substance, chosen from the group, comprising bicarbonates of ammonia and alkali metals, ammonium carbamate and urea, which substances are used in amounts not less than a stoechiometric amount.Type: GrantFiled: August 2, 1999Date of Patent: May 29, 2001Inventor: Heinrich Smuda
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Patent number: 6140534Abstract: 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.Type: GrantFiled: January 13, 1999Date of Patent: October 31, 2000Assignee: HFM International, Inc.Inventors: Fu-Ming Lee, Wiston Lamshing, Randi Wright Wytcherley
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Patent number: 6087531Abstract: Disclosed is a process for the recovery of naphthalenedicarboxylic acid (NDA) from polyester materials prepared from and/or containing residues of NDA such as a poly(alkylene naphthalenedicarboxylate). In one embodiment, the process comprises contacting a polyester material prepared from and/or containing residues of NDA with water at a temperature of about 125 to 400.degree. C. in a pressured vessel to obtain an aqueous slurry of NDA and recovering the NDA. A second embodiment of the process comprises contacting such a polyester with an aqueous, alkali metal base solution to obtain an aqueous solution of a di-alkali metal naphthalenedicarboxylate salt, then neutralizing the aqueous solution with an acid to obtain an aqueous slurry or dispersion of NDA and recovering the NDA. The process is particularly useful for recovering 2,6-naphthalenedicarboxylic acid (2,6-NDA) from poly(ethylene naphthalenedicarboxylate) polyesters.Type: GrantFiled: June 19, 1998Date of Patent: July 11, 2000Assignee: Eastman Chemical CompanyInventors: Timothy Edward Long, Phillip Montgomery Hudnall, James Rodney Bradley
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Patent number: 6054610Abstract: 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.Type: GrantFiled: June 16, 1998Date of Patent: April 25, 2000Assignee: HFM International, Inc.Inventors: Fu-Ming Lee, Wiston Lamshing, Randi Wright Wytcherley
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Patent number: 6034269Abstract: 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.Type: GrantFiled: August 3, 1998Date of Patent: March 7, 2000Assignee: E. I. du Pont de Nemours and CompanyInventors: John Arthur Turner, Duncan Charles Woodcock
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Patent number: 6013835Abstract: 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.Type: GrantFiled: December 6, 1996Date of Patent: January 11, 2000Assignee: HFM International, Inc.Inventors: Fu-Ming Lee, Wiston Lamshing
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Patent number: 6005148Abstract: A supported catalyst comprising a support, an anchoring agent such as a heteropoly acid or anion, and a metal complex which is useful in a wide variety on organic reactions, especially the hydrogenation of substituted .alpha.,.beta. unsaturated acids and esters, is provided. Various methods of preparing the supported catalyst of the present invention is also disclosed.Type: GrantFiled: November 17, 1998Date of Patent: December 21, 1999Assignee: Seton Hall UniversityInventors: Setrak K. Tanielyan, Robert L. Augustine
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Patent number: 5973196Abstract: A process for producing purified terephthalic acid capable of controlling the transmittance of the purified terephthalic acid product promptly in a simple procedure without necessitating to alter the condition of the oxidation of paraxylene to thereby permit a minute control of the process and to allow to obtain a purified terephthalic acid product with a low and constant impurity level within a certain range, which process comprises hydrogenating a crude terephthalic acid resulting from a liquid phase oxidation of paraxylene in a hydrogenation reactor 6 in the presence of a hydrogenation catalyst, followed by precipitation of the crystals 8, a solid/liquid separation 11, re-slurrying 14 of the separated crystals in water and a further solid/liquid separation 16, to obtain a purified terephthalic acid; observing the transmittance of the resulting purified terephthalic acid; and controlling the temperature of the washing water so as to maintain the observed transmittance within a predetermined range.Type: GrantFiled: February 17, 1998Date of Patent: October 26, 1999Assignee: Mitsui Chemicals, Inc.Inventors: Toshinori Takano, Hiroshi Suzuki, Norio Taniguchi
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Patent number: 5777161Abstract: There is disclosed a process for producing highly pure terephthalic acid by the use of a dispersion medium replacement apparatus equipped with a stirring unit at the bottom portion for uniform dispersion, wherein an original slurry comprising a first dispersion medium and terephthalic acid crystals is introduced into a dispersion medium replacement apparatus at the top portion, a second dispersion medium is introduced into the apparatus at the bottom portion, a replaced slurry comprising principally the second dispersion medium and the terephthalic acid crystals is taken out from the apparatus at the bottom portion, and the first dispersion medium as a major component is taken out from the apparatus at the top portion, which process comprises maintaining a uniformly dispersed slurry at the bottom portion of the apparatus at a concentration higher than that of a slurry at the intermediate portion; maintaining the upper portion at a higher temperature in a vertical temperature distribution therein to form a temType: GrantFiled: July 7, 1997Date of Patent: July 7, 1998Assignees: Mitsubishi Gas Chemical Company, Inc., Toyo Boseki Kabushiki Kaisha, Mizushima Aroma Company, Ltd.Inventor: Masato Inary
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Patent number: 5767311Abstract: 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.Type: GrantFiled: June 7, 1995Date of Patent: June 16, 1998Assignee: Glitsch International, Inc.Inventors: Fu-Ming Lee, Wei-Teh Wade Shang
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Patent number: 5756833Abstract: 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.Type: GrantFiled: January 2, 1997Date of Patent: May 26, 1998Assignee: Amoco CorporationInventors: Bruce I. Rosen, Thomas M. Bartos
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Patent number: 5731459Abstract: The invention relates to a process for removing amino acids and/or aminosulphonic acids from preferably aqueous solutions which contain these as impurities by adsorbing the amino acids on zeolites. Solutions to which the process according to the invention can be applied are produced, for example, from the industrial synthesis of oligopeptides in which the amino acids serving as starting materials are always present in solution, sometimes to a not inconsiderable residual concentration, together with the desired end product.Type: GrantFiled: August 28, 1996Date of Patent: March 24, 1998Assignee: Degussa AktiengesellschaftInventors: Stefan Stockhammer, Wiltrud Schafer-Treffenfeldt, Gunter Knaup, Karlheinz Drauz, Elfriede Sextl
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Patent number: 5728870Abstract: 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.Type: GrantFiled: October 7, 1996Date of Patent: March 17, 1998Assignee: Amoco CorporationInventors: Juergen K. Holzhauer, Rusins Albertins, Stephen V. Hoover, David L. Sikkenga
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Patent number: 5723659Abstract: An improved process is disclosed for purifying impure aromatic polycarboxylic acids produced by the catalytic oxidation of polyalkylaromatic hydrocarbons which comprises contacting said impure acid with hydrogen and at least one hydrogenation catalyst, the improvement comprising said catalyst having a water insoluble and non-brittle coating of at least one polymeric material.Type: GrantFiled: February 3, 1997Date of Patent: March 3, 1998Assignee: Engelhard CorporationInventor: James F. White
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Patent number: 5712412Abstract: 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 porType: GrantFiled: November 27, 1995Date of Patent: January 27, 1998Assignees: Mitsubishi Gas Chemical Co., Inc., Toyo Boseki Kabushiki Kaisha, Mizushima Aroma Company, Ltd.Inventors: Masato Inary, Fumio Ohkoshi, Fumiya Zaima
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Patent number: 5684187Abstract: There is disclosed a process for producing highly pure terephthalic acid by converting a slurry of terephthalic acid crystals in acetic acid solvent which crystals are obtained by liquid-phase oxidation of p-alkylbenzene, into a slurry thereof in water solvent by mother liquor replacement and then subjecting the latter slurry to a catalytic hydrogenation treatment which process comprises the steps of introducing the slurry of terephthalic acid crystals in acetic acid into a mother liquor replacement column at the top portion; forming an accumulation layer of the terephthalic acid crystals at the bottom portion by the sedimentation of the crystals; feeding replacing water sufficient for the formation of upward rising stream of water to the inside of the column at the bottom portion; and withdrawing the accumulation layer of the crystals from the bottom portion of the column.Type: GrantFiled: April 29, 1996Date of Patent: November 4, 1997Assignees: Mitsubishi Gas Chemical Co., Inc., Toyo Boseki Kabushiki Kaisha, Mizushima Aroma Co., Ltd.Inventors: Fumio Ohkoshi, Masato Inary, Fumiya Zaima
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Patent number: 5654470Abstract: There is described a process for the depolymerization of polyethylene terephthalate into component monomers at ambient pressure. Monomer solids that deposit during cooling, as part of the recovery operation, are removed using a scraped wall heat exchanger.Type: GrantFiled: July 26, 1996Date of Patent: August 5, 1997Assignee: Eastman Kodak CompanyInventors: Andrius Algimantas Naujokas, William James Gamble
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Patent number: 5616792Abstract: 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.Type: GrantFiled: February 1, 1996Date of Patent: April 1, 1997Assignee: Amoco CorporationInventors: Thomas M. Bartos, Bruce I. Rosen
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Patent number: 5583254Abstract: Purified terephthalic acid is prepared by 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 and washing process. The integrated separation is performed by exchanging the acidic reaction medium with water to produce a water containing cake of terephthalic acid.Type: GrantFiled: January 13, 1995Date of Patent: December 10, 1996Inventors: John A. Turner, Eric Hindmarsh, David Parker, Ian P. Milne
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Patent number: 5576456Abstract: There is described a process for the depolymerization of polyethylene terephthalate into component monomers using a reactor in which the polyethylene terephthalate is a discontinuous phase which contacts a continuous phase of superheated methanol vapor.Type: GrantFiled: January 22, 1996Date of Patent: November 19, 1996Assignee: Eastman Kodak CompanyInventors: William J. Gamble, Andrius A. Naujokas
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Patent number: 5565609Abstract: There is provided a method of purifying a crude aromatic dicarboxylic acid which comprises purifying an aqueous solution of an organic amine salt of the crude aromatic dicarboxylic acid, and then thermally decomposing the organic amine salt whereby to recover the thus highly purified aromatic dicarboxylic acid.Type: GrantFiled: November 22, 1994Date of Patent: October 15, 1996Assignee: Mitsui Petrochemical Industries, Ltd.Inventors: Noriyuki Hirowatari, Hiroyasu Ohno, Kenji Shimamoto
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Patent number: 5563294Abstract: 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.Type: GrantFiled: March 4, 1994Date of Patent: October 8, 1996Assignee: Amoco CorporationInventors: Juergen K. Holzhauer, Rusins Albertins, Stephen V. Hoover, David L. Sikkenga
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Patent number: 5563293Abstract: A terephthalic acid slurry in acetic acid is produced by oxidizing p-xylene in acetic acid, removing water by evaporation of a stream of water and acetic acid, and returning acetic acid to the oxidation step. The terephthalic acid is separated from the reaction medium in a first zone to leave a deposit on a band, the deposit is washed with a first aqueous medium in a second zone, removed from the band in a third zone, and admixed with a second aqueous medium. Reaction medium is passed from the first zone to the oxidation step and terephthalic acid is recovered, preferably after further purification.Type: GrantFiled: June 6, 1995Date of Patent: October 8, 1996Assignee: Imperial Chemical Industries PLCInventors: Eric Hindmarsh, John A. Turner, Alan M. Ure
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Patent number: 5545746Abstract: An improved method for recovery of alkali metal or alkaline-earth metal terephthalate and of alkylene glycol, from polyalkylene terephthalate, in particular from polyethylene terephthalate (P.E.T.), alkylene glycol, in particular ethylene glycol produced in the form of vapor during the saponification reaction, initiated by the action of intensive kneading of polyalkylene terephthalate and the alkaline reagent at a temperature of 100.degree. to 200.degree. C. The alkylene glycol is recovered in gaseous form by entrainment by an inert gas or by extraction under low pressure. The alkaline terephthalate or alkaline-earth terephthalate is obtained in solid or powder form; it can easily be stored, transported and redissolved, in order to be purified and possibly transformed into terephthalic acid or ester.Type: GrantFiled: January 3, 1995Date of Patent: August 13, 1996Assignee: Institut Francais du PetroleInventors: Jacques Benzaria, Francois Dawans, Bruno Durif-Varambon, Jean-Bernard Gaillard
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Patent number: 5543564Abstract: This invention embodies a process for releasing acidic organic compounds in high yield and good purity from aqueous solutions of their salts which comprises converting the salts by carbon dioxide to their corresponding free acidic organic compounds and metal hydrogen carbonates, removing the acidic organic compounds from the mixture by extraction with an essentially water-insoluble organic solvent, and re-extracting the organic phase with carbon dioxide containing water. Using this process, the acidic organic compounds are completely released from their corresponding salts, i.e., the organic solution is free of salt. The acidic organic compounds released by the claimed process are organic compounds which contain acidic protons which can be replaced by metals. Some examples are carboxylic acids, sulfonic acids, phosphonic acids, phenols, naphthols, and aliphatic alcohols.Type: GrantFiled: January 11, 1995Date of Patent: August 6, 1996Assignee: Hoechst AktiengesellschaftInventors: J urgen Kulpe, Heinz Strutz, Hans-Martin R uffer, Siegbert Rittner