For Inhibiting Or Preventing A Polymerization Reaction Patents (Class 203/8)
  • Patent number: 6695928
    Abstract: A method for the production of (meth)acrylic acid and/or a (meth)acrylic ester is provided. This method for the production of (meth)acrylic acid and/or a (meth)acrylic ester includes washing the device constructed for the production thereof with a basic solution and subsequently rinsing them with a solvent for the purpose of removing solid substances such as polymer and precipitate which occur during the production of (meth)acrylic acid and/or a (meth)acrylic ester.
    Type: Grant
    Filed: March 1, 2000
    Date of Patent: February 24, 2004
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Sei Nakahara, Takeshi Nishimura, Masatoshi Ueoka
  • Publication number: 20040031674
    Abstract: A process for working up mixtures containing (meth)acrylic acid and/or (meth)acrylic ester in a column for distilling, rectifying and/or fractionally condensing in the presence of at least one polymerization inhibitor and an oxygen-containing gas, wherein the partial oxygen pressure p(O2) in the gas phase of the entire column is from 2 to 5 hPa.
    Type: Application
    Filed: June 12, 2003
    Publication date: February 19, 2004
    Applicant: BASF Akiengesellschaft
    Inventor: Jurgen Schroder
  • Patent number: 6685823
    Abstract: Disclosed herein is a method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds. Also disclosed is a composition of matter comprising: A) an ethylenically unsaturated monomer and B) an effective inhibiting amount, sufficient to prevent premature polymerization during distillation or purification of said ethylenically unsaturated monomer, of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds used together with an effective amount of oxygen or air to enhance the inhibiting activity of said inhibitor.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: February 3, 2004
    Assignee: Uniroyal Chemical Company, Inc.
    Inventors: Brigitte Benage, Gerald J. Abruscato, Andrew J. Eisenstein
  • Patent number: 6676808
    Abstract: A method for starting up a distilling column destined to handle an easily polymerizing compound-containing solution characterized by supplying at the start of the operation of the distilling column a polymerization inhibitor to the bottom liquid of the distilling column having a temperature of not higher than 80° C. Further, by supplying a reflux liquid through the top of the distilling column or the middle stage of the column prior to the start of the temperature elevation of the distilling column, thereby preventing the polymerization of the easily polymerizing compound more effectively.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: January 13, 2004
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Kei Hamamoto, Yukihiro Matsumoto, Sei Nakahara, Misao Inada
  • Patent number: 6673212
    Abstract: Identified herein are inhibitors which may be added to the boiling pot portion of a distillation apparatus prior to or during the distillation of an alkylene carbonate. The inhibitors retard the occurrence of undesirable reactions of the alkylene carbonate with itself and impurities present in the pot, and hence greatly reduce or minimize the formation of undesirable by-products which otherwise tend to reduce overall yields of alkylene carbonate recovered by the distillation process. Higher distillation temperatures at higher pressures over the prior art are possible without attendant losses of significant amounts of recovered alkylene carbonate, which confers heretofore unseen flexibility in alkylene carbonate distillation.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: January 6, 2004
    Assignee: Huntsman Petrochemical Corporation
    Inventors: James R. Machac, Jr., Edward T. Marquis, Susan A. Woodrum, Ralph M. DiGuilio, Mike W. McKinney
  • Patent number: 6649028
    Abstract: The present invention provides a column treating method by use of a distillation column and so on, which method enables to effectively remove solid impurities such as precipitates and polymers contained or produced in a treating fluid, and to thereby stably operate the column treatment. Solid impurities in a treating fluid can be removed by carrying out: step (a) of drawing out the treating fluid from a drawing out outlet (16) at the column bottom of the treatment column (10) outside the treatment column (10), step (b) of removing solid impurities from the treating fluid, drawn out in step (a), by a strainer (40), and step (c) of returning the treating fluid, from which the solid impurities are removed in step (b), to a returning inlet (18) of the treatment column, with advancing physical and/or chemical treatment of the treating fluid in the treatment column (10).
    Type: Grant
    Filed: August 22, 2002
    Date of Patent: November 18, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Kazuhiko Sakamoto, Sei Nakahara, Masatoshi Ueoka, Naoto Kasaya
  • Publication number: 20030205451
    Abstract: A process is provided herein for the high yield production of high purity glacial methacrylic acid (“HPMAA”) that is substantially pure, specifically 99% pure or greater with a water content of 0.05% or less.
    Type: Application
    Filed: April 22, 2003
    Publication date: November 6, 2003
    Inventors: Keith Frederick Briegel, James Clarence Day, Michael Stanley DeCourcy, Donald Alan Ebert, Jamie Jerrick John Juliette
  • Publication number: 20030205503
    Abstract: A method for inhibiting and dissolving the deposits formed on caustic or alkaline scrubbers used in scrubbing acidic gases such as carbon dioxide, hydrogen sulfide, which are formed during the pyrolytic cracking of naphtha, ethane, and propane. The cracking operations produce certain oxygenated compounds such as vinyl acetate or acetaldehyde, which undergo polymerization under alkaline condition. The vinyl acetate on hydrolysis releases acetaldehyde under alkaline conditions. Amino acids such as 6 amino caproic acid and lactams such as epsilon caprolactam not only prevent but also dissolve the polymers formed by aldol condensation.
    Type: Application
    Filed: April 29, 2002
    Publication date: November 6, 2003
    Inventors: Mahesh Subramaniyam, Bankar Prashant
  • Patent number: 6641700
    Abstract: A purifying apparatus characterized by being equipped with a vapor dispersing device possessing in a vapor inlet part owned by the apparatus on the lateral inside thereof an opening part facing downward from the horizontal direction and a horizontal projected cross section area in the range of 10-40% of the cross section area of said apparatus. In consequence of the incorporation of the vapor dispersing device according to this invention, the drift of the gas is repressed, the efficiency of separation is improved, and the possible polymerization of a compound under treatment in the lower part of the column is prevented.
    Type: Grant
    Filed: March 3, 2000
    Date of Patent: November 4, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Hajime Matsumoto, Takeshi Nishimura, Yukihiro Matsumoto
  • Patent number: 6632329
    Abstract: A distillation apparatus is provided with a distillation tower, a reboiler, a bottom outflow pipe for drawing a liquid from the bottom of the distillation tower, and a pot provided between the bottom of the distillation tower and the bottom outflow pipe. A part of the drawn liquid is discharged to the outside of the distillation apparatus while the rest is flowed to the reboiler. The pot has a cross-sectional area smaller than a cross-sectional area of the distillation tower and larger than a cross-sectional area of the bottom outflow pipe.
    Type: Grant
    Filed: October 26, 2000
    Date of Patent: October 14, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Noriaki Mizutani, Yukihiro Matsumoto, Kazuhiko Sakamoto, Kenji Sanada
  • Patent number: 6627047
    Abstract: A method is provided for preventing an easily polymerizable substance from being polymerized in a thin-film type evaporating device by supplying a solution of the substance to the evaporating heating surface of the device by the centrifugal force of a stirring rotary shaft, characterized by mixing a distilled vapor of the substance with a molecular oxygen-containing gas and supplying the extracted liquid or a solution having lower viscosity than the extracted liquid to a feed raw material inlet thereby adjusting the quantity of a wetting liquid per unit length of the surface in the range of 0.02-2 m3/mHr. In the evaporation of the substance by the use of the device, a method for preventing the substance from polymerization is provided.
    Type: Grant
    Filed: April 21, 2000
    Date of Patent: September 30, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Yuichi Ijiri, Takeshi Nishimura, Yukihiro Matsumoto
  • Patent number: 6613196
    Abstract: A method for stopping a purifying column handling an easily polymerizing compound-containing solution is disclosed, which method is characterized by lowering the inner oxygen concentration of the column below the limit of oxygen concentration by supplying an inert gas to the column while the concentration of the gas of easily polymerizing compound is in the range of 100% to the lower limit of the flammable range in volume % of the purifying column or by further supplying a reflux liquid thereby cooling the interior of the column at a rate in the range of 0.01-10° C./min. This invention enjoys exceptionally high economic value in respect that it is capable of preventing the easily polymerizing compound from the occurrence of polymerization in the purifying column, precluding the interior of the purifying column from being clogged by adhesion of a polymer, and moreover avoiding the possibility of explosion.
    Type: Grant
    Filed: July 9, 2001
    Date of Patent: September 2, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Kei Hamamoto, Yukihiro Matsumoto, Sei Nakahara, Misao Inada
  • Publication number: 20030155227
    Abstract: Inhibitor blends comprising nitrosophenols and nitrosoanilines, optionally in combination with air or oxygen, reduce the premature polymerization of ethylenically unsaturated monomers.
    Type: Application
    Filed: January 29, 2003
    Publication date: August 21, 2003
    Applicant: CROMPTON CORPORATION
    Inventor: Brigitte Benage
  • Publication number: 20030150705
    Abstract: A method of recovering acrylic acid from a mixture comprising acrylic acid, water and acetic acid is disclosed, which includes:
    Type: Application
    Filed: December 30, 2002
    Publication date: August 14, 2003
    Inventors: Sanjeev D. Deshpande, Tao Wang, Olan Stanley Fruchey, Roger L. Roundy, Nathan K. Powell, Rafael G. Morales, Joseph E. Goins
  • Patent number: 6599397
    Abstract: This method of preventing polymerization of methacrylic acid inn the process of its production is characterized by comprising using, in a refining column, a combination of N-nitrosophenylhydroxylamine or salt thereof with an N-oxyl compound, an N-hydroxy-,2,2,6,6-tetramethylpiperidine compound and a 2,2,6,6-tetramethylpiperidine compound. In this method, N-nitrosophenylhydroxylamine or a salt thereof rises inside a refining column under splitting part thereof to effectively inhibit polymerization of (meth)acrylic acid or the like. The above polymerization in both vapor and liquid phases can be inhibited more effectively by the combined use of the compounds mentioned above.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: July 29, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Kazuhiko Sakamoto, Tomohiro Nakae, Kazuo Okochi, Masahiro Uemura, Sei Nakahara
  • Patent number: 6596129
    Abstract: The present invention provides: a process can be preventive of a polymerization in a distillation apparatus when distilling a solution containing easily polymerizable substances such as (meth)acrylic acid and (meth)acrylic acid ester. In the distillation process for an easily polymerizable substance-containing solution which includes the step of distilling an easily polymerizable substance-containing solution by a distillation column equipped with a condenser for condensation at a vapor outlet of the distillation column, at least one condenser for polymerization inhibition is further placed in series on a vapor outlet side of the condenser for condensation, and the easily polymerizable substance which is contained in vapor from an upstream condenser is condensed by a downstream condenser.
    Type: Grant
    Filed: October 31, 2000
    Date of Patent: July 22, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Yukihiro Yoneda, Takeshi Nishimura, Yasuhiro Shingai, Hajime Matsumoto
  • Patent number: 6592722
    Abstract: This invention relates to a process of inhibiting the polymerization of vinyl-containing materials through the use of an effective amount of a polymerization inhibitor comprising quinone diimide and a nitroxyl stable free radical under various conditions. This invention also relates to the polymerization inhibitor composition.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: July 15, 2003
    Assignee: GE Betz, Inc.
    Inventor: Grace B. Arhancet
  • Publication number: 20030127315
    Abstract: A tert-C4-C8-alkyl (meth)acrylate is prepared by reacting (meth)acrylic acid with an olefin of the formula 1
    Type: Application
    Filed: January 27, 2003
    Publication date: July 10, 2003
    Inventors: Ruprecht Kroker, Gerhard Nestler, Werner Schmitt, Winfried Schumm
  • Patent number: 6585862
    Abstract: The present invention provides an apparatus for handling an easily polymerizable compound such as (meth)acrylic acid which includes a tubular member that is furnished to a side wall of the apparatus and opened to the inside of the apparatus, specifically, for example, an apparatus and a method which effectively inhibit the polymerization of (meth)acrylic acid in a distillation column for (meth)acrylic acid wherein the distillation column has such as an inlet or outlet of gas or liquid, a manhole, or a tube into which an instrument is inserted. The tubular member (e.g. an inlet or outlet, a manhole, a tube into which an instrument is inserted) is set so as to have a downward gradient (&agr;) in the range of 3° to 70° toward the inside of the apparatus.
    Type: Grant
    Filed: August 19, 2000
    Date of Patent: July 1, 2003
    Assignee: Nippon Shokubai
    Inventors: Takeshi Nishimura, Yukihiro Matsumoto
  • Patent number: 6579442
    Abstract: Methods and compositions for inhibiting the polymerization of vinyl monomers are disclosed. Combinations of nitroxyl compounds and aliphatic amines are effective at inhibiting the polymerization of vinyl monomers under both processing and storage conditions.
    Type: Grant
    Filed: May 22, 2001
    Date of Patent: June 17, 2003
    Assignee: GE Betz, Inc.
    Inventor: Sherif Eldin
  • Publication number: 20030062253
    Abstract: The object of this invention to provide an improved arrangement that enables to prevent adhesion of polymer on or around the inner wall of a purification apparatus directly equipped on the outer wall thereof with an attachment such as a support by suppressing local temperature lowering inside the apparatus due to the existence of the attachment. The present invention provides a purification apparatus comprising an attachment directly mounted on an outer wall of the apparatus; and a covering material made of a low heat conductive material which partly or entirely covers the outer wall of the apparatus, and which partly or entirely covers the attachment.
    Type: Application
    Filed: September 26, 2002
    Publication date: April 3, 2003
    Inventors: Yukihiro Matsumoto, Takeshi Nishimura
  • Patent number: 6540881
    Abstract: This invention relates to a method for preventing (meth)acrylic acid from polymerizing during the course of distillation. The method provides for refining (meth)acrylic acid by a procedure including the steps of feeding a mixed gas obtained by catalytic gas phase oxidation of propylene and/or acrolein with a molecular oxygen-containing gas or a mixed gas obtained by catalytic gas phase oxidation of at least one compound of isobutylene, t-butyl alcohol, or methacrolein with a molecular oxygen-containing gas, to a (meth)acrylic acid collection column, collecting a (meth)acrylic acid-containing solution from the mixed gas, and feeding the (meth)acrylic acid-containing solution to a distillation column while maintaining the total concentration of aldehydes of 2-4 carbon atoms and acetone in the solution at a level of not more than 2000 ppm based on the amount of (meth)acrylic acid.
    Type: Grant
    Filed: March 22, 2000
    Date of Patent: April 1, 2003
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Kazuhiko Sakamoto, Kouji Ueno, Sei Nakahara, Masatoshi Ueoka
  • Publication number: 20030019737
    Abstract: A perforated tray without downcomer having only a small deviation between the opening ratio based on the diameter of a column and the actual opening ratio and a perforated tray column without downcomer formed by disposing such perforated trays without downcomer are provided. The perforated trays without downcomer are characterized by having a ratio of (A)/(B) in the range of 1.1-1.5, wherein A denotes the opening ratio found from the standard pitch between centers of holes and (B) denotes the opening ratio based on the diameter of a column.
    Type: Application
    Filed: July 17, 2002
    Publication date: January 30, 2003
    Inventors: Yukihiro Matsumoto, Kazuhiko Sakamoto, Kenji Sanada
  • Publication number: 20030010676
    Abstract: Methods and compositions for inhibiting the polymerization of vinyl monomers are disclosed. Combinations of nitroxyl compounds and aliphatic amines are effective at inhibiting the polymerization of vinyl monomers under both processing and storage conditions.
    Type: Application
    Filed: May 22, 2001
    Publication date: January 16, 2003
    Inventor: Sherif Eldin
  • Patent number: 6494996
    Abstract: A process for separating water from methanol in an aqueous methanol initial mixture, including subjecting said mixture to azeotropic distillation in the presence of sufficient added methyl acrylate to form an azeotrope with most of the methanol in said initial mixture such that a substantial proportion of methanol in the initial mixture is removed as an azeotrope of methanol and methyl acrylate in the overhead vapors resulting from said distillation and a major proportion of water in said initial mixture is removed in the liquid residue of said distillation.
    Type: Grant
    Filed: January 22, 2001
    Date of Patent: December 17, 2002
    Assignee: Celanese International Corporation
    Inventors: Benjamin A. Gilbert, Jeffrey R. Kirkpatrick, John C. McCall, Kenneth A. Windhorst
  • Publication number: 20020179426
    Abstract: Identified herein are inhibitors which may be added to the boiling pot portion of a distillation apparatus prior to or during the distillation of an alkylene carbonate. The inhibitors retard the occurrence of undesirable reactions of the alkylene carbonate with itself and impurities present in the pot, and hence greatly reduce or minimize the formation of undesirable by-products which otherwise tend to reduce overall yields of alkylene carbonate recovered by the distillation process. Higher distillation temperatures at higher pressures over the prior art are possible without attendant losses of significant amounts of recovered alkylene carbonate, which confers heretofore unseen flexibility in alkylene carbonate distillation.
    Type: Application
    Filed: April 22, 2002
    Publication date: December 5, 2002
    Applicant: Huntsman Petrochemical Corporation
    Inventors: James R. Machac, Edward T. Marquis, Susan A. Woodrum, Ralph M. DiGuilio, Mike W. McKinney
  • Publication number: 20020166758
    Abstract: The invention consists of a cost-effective process and facilities for obtaining high quality drinking water and high-grade brine as a chemical raw material from raw water regardless of how much salt it contains. When combined with a thermal power-generation process, the plant also produces electric power with a fuel utilization of over 85%.
    Type: Application
    Filed: July 3, 2002
    Publication date: November 14, 2002
    Inventor: Peter Vinz
  • Patent number: 6475348
    Abstract: A mixture contains one or more vinyl-containing compounds as component (A) and, as a further component, a stabilizer (B) which contains one or more readily volatile nitroxyl compounds as component (b1), one or more sparingly volatile nitroxyl compounds as component (b2), if required one or more aromatic nitro compounds as component (b3) and, if required, one or more iron compounds as component (b4). Stabilizers (B) contain the components (b1) and (b2), (b1) and (b2) and (b3), (b1) and (b2) and (b4), and (b1), (b2), (b3) and (b4), and the premature polymerization of vinyl-containing compounds during their purification or distillation is inhibited by a process in which a stabilizer (B) is added or the components of stabilizer (B) are added as individual substances or in at least two groups of the components.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: November 5, 2002
    Assignee: BASF Aktiengesellschaft
    Inventors: Heinz Friedrich Sutoris, Konrad Mitulla, Jacques Dupuis, Claus Kaliba
  • Publication number: 20020134661
    Abstract: A process for separating water from methanol in an aqueous methanol initial mixture, comprising subjecting said mixture to azeotropic distillation in the presence of sufficient added methyl acrylate to form an azeotrope with most of the methanol in said initial mixture such that a substantial proportion of methanol in the initial mixture is removed as an azeotrope of methanol and methyl acrylate in the overhead vapors resulting from said distillation and a major proportion of water in said initial mixture is removed in the liquid residue of said distillation.
    Type: Application
    Filed: January 22, 2001
    Publication date: September 26, 2002
    Inventors: Benjamin A. Gilbert, Jeffrey R. Kirkpatrick, John C. McCall, Kenneth A. Windhorst
  • Patent number: 6447649
    Abstract: This invention relates to a process of inhibiting the polymerization of vinyl-containing materials through the use of an effective amount of a polymerization inhibitor comprising quinone diimide and a nitroxyl stable free radical under various conditions. This invention also relates to the polymerization inhibitor composition.
    Type: Grant
    Filed: July 24, 2000
    Date of Patent: September 10, 2002
    Assignee: GE Betz, Inc.
    Inventor: Grace B. Arhancet
  • Publication number: 20020091283
    Abstract: The present invention provides a novel production process for a hydroxyalkyl (meth)acrylate in which, when the hydroxyalkyl (meth)acrylate is produced by carrying out a reaction between (meth)acrylic acid and an alkylene oxide, the unreacted (meth)acrylic acid can be effectively recovered and thereafter recycled as a raw reaction material. The production process for a hydroxyalkyl (meth)acrylate comprises the step of carrying out a reaction between (meth)acrylic acid and an alkylene oxide in order to produce the hydroxyalkyl (meth)acrylate, and further comprises the steps of: recovering the unreacted (meth)acrylic acid by distillation of the resultant reaction liquid; and thereafter recycling the recovered unreacted (meth)acrylic acid as a raw material for the reaction.
    Type: Application
    Filed: December 6, 2001
    Publication date: July 11, 2002
    Inventors: Hajime Matsumoto, Tetsuya Kajihara, Yukihiro Yoneda
  • Patent number: 6409886
    Abstract: In distillation of easily polymerizable compounds such as (meth)acrylic acid and (meth)acrylic esters using a distillation unit, a liquid having substantially the same composition with that of a liquid surrounding a constitutive member placed in the distillation unit is sprayed by a spraying and supplying device. The liquid supplied by the spraying and supplying device preferably has a wetting liquid rate (of the sprayed and supplied liquid, a flow rate of a liquid attaching to and wetting the constitutive member) of 0.5 m3/m2hr or more relative to the surface area of the constitutive member. The liquid supplied by the spraying and supplying device preferably contains a polymerization inhibitor. It is also preferred to supply a gas containing molecular oxygen to the distillation unit. This process can effectively inhibit the polymerization of the easily polymerizable compounds, which polymerization is liable to occur inside the distillation unit.
    Type: Grant
    Filed: April 14, 2000
    Date of Patent: June 25, 2002
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Yukihiro Matsumoto, Takeshi Nishimura
  • Patent number: 6409887
    Abstract: A monomer composition, stabilized against premature polymerization, comprising: a) an ethylenically unsaturated monomer or mixture of monomers polymerizable by free radical initiation, and b) an effective amount, sufficient to inhibit premature polymerization of component (a) of a mixture of: i) 1 to 99% by weight, based on the total weight of components (i) and (ii), of a mixture of at least one aromatic amine and at least one organic acid in a molar ratio of 10:1 to 1:10, and ii) 99 to 1% by weight, based on the total weight of components (i) and (ii), of at least one stable radical compound.
    Type: Grant
    Filed: April 13, 2001
    Date of Patent: June 25, 2002
    Assignee: AAH Marks and Company Limited
    Inventors: Anthony Pryce, Robert Charles Callin
  • Patent number: 6395140
    Abstract: In a process for the preparation of (meth)acrylic acid from a mixture which contains (meth)acrylic acid and a solvent having a boiling point above the boiling point of (meth)acrylic acid by distillation of the mixture in a column which is connected to an evaporator and has a stripping section and a rectifying section, between which the mixture is fed in, and a side take-off for the (meth)acrylic acid, a polymeization inhibitor is fed into the column in the region of the top of the column and in the region of the side take-off, that amount of polymerization inhibitor which is introduced in the region of the top of the column being smaller than the amount introduced in the region of the side take-off.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: May 28, 2002
    Assignee: BASF Aktiengesellschaft
    Inventors: Holger Herbst, Gerhard Nestler, Ulrich Hammon
  • Publication number: 20020027067
    Abstract: A method for stopping a purifying column handling an easily polymerizing compound-containing solution is disclosed, which method is characterized by lowering the inner oxygen concentration of the column below the limit of oxygen concentration by supplying an inert gas to the column while the concentration of the gas of easily polymerizing compound is in the range of 100% to the lower limit of the flammable range in volume % of the purifying column or by further supplying a reflux liquid thereby cooling the interior of the column at a rate in the range of 0.01-10° C./min. This invention enjoys exceptionally high economic value in respect that it is capable of preventing the easily polymerizing compound from the occurrence of polymerization in the purifying column, precluding the interior of the purifying column from being clogged by adhesion of a polymer, and moreover avoiding the possibility of explosion.
    Type: Application
    Filed: July 9, 2001
    Publication date: March 7, 2002
    Inventors: Kei Hamamoto, Yukihiro Matsumoto, Sei Nakahara, Misao Inada
  • Patent number: 6352619
    Abstract: Process for purifying acrylic acid in order to remove the polymer-type impurities in those places in the distillation columns in which they have a tendency to accumulate, and more particularly a process directed towards removing the polymeric impurities which are formed during a step for removing the aldehyde impurities from acrylic acid, according to which step the medium containing the acrylic acid to be purified is distilled by adding to this medium at least one amino compound of hydrazine type and by flushing away, at the foot of the distillation column, the heavy compounds formed by the said hydrazine-type amino compound(s) with the impurities. According to the invention, the acrylic acid to be purified is also distilled in the presence of at least one compound from the class of nonionic surface agents and of at least one polymerization inhibitor. Polysaccharide ethers and acetates, in particular ethers derived from cellulose or starch, may be mentioned as nonionic surface agents.
    Type: Grant
    Filed: April 14, 1999
    Date of Patent: March 5, 2002
    Assignee: Atofina
    Inventors: Michel Fauconet, Francis Augustin, Marc Esch
  • Patent number: 6350352
    Abstract: A process for distillative separation of pure (meth)acrylic acid from mixtures which include comprise (meth)acrylic acid and dimers and oligomers of (meth)acrylic acid and are essentially free from aldehydes and from components whose boiling point is lower than that of (meth)acrylic acid, using a distillation apparatus which has a thin-film evaporator, a condenser and a connection which contains a baffle device and links the thin-film evaporator and the condenser.
    Type: Grant
    Filed: February 22, 1999
    Date of Patent: February 26, 2002
    Assignee: BASF Aktiengesellschaft
    Inventors: Ruprecht Kroker, Manfred Wiedemann
  • Patent number: 6348135
    Abstract: In a process for the purification of (meth)acrylic acid and/or its ester using a distillation unit containing a distillation column, a multitubular reboiler and a pipe connecting these elements, an oxygen containing gas is supplied from a least one point in regions between the distillation column and an inlet of the multitubular reboiler and/or in regions between the inlet and an inlet side tube sheet of the multitubular reboiler. This process can effectively prevent the formation of polymerization products and can stably purify (meth)acrylic acid and/or its ester over a long time.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: February 19, 2002
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Sei Nakahara, Yukihiro Matsumoto, Masatoshi Ueoka
  • Patent number: 6348136
    Abstract: The present invention is directed to an apparatus and method for the distillation of a readily polymerizable vinyl aromatic compound employing a polymerization inhibitor. The vinyl aromatic compound is subjected to distillation in at least one fractionation column having at least one reboiler for maintaining the bottoms of said column at a proper temperature. The reboiler includes a heating section and a vapor phase section. The bottoms fraction from the fractionation column is cycled to the reboiler and subjected to heat to vaporize at least a portion of the bottoms fraction to form a vapor phase in the vapor section, A slip stream of the bottoms fraction is introduced to the vapor phase section of the reboiler. The slipstream contains polymerization inhibitor that had been added to the process at the fractionation column. The invention reduces fouling at the reboilers. The slipstream is optionally introduced to the reboiler using one or more spray nozzles.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: February 19, 2002
    Assignee: Fina Technology, Inc.
    Inventors: Marcus E. Ledoux, Kelli E. Prince, Adrian M. Jacobsen, Larry P. Braud, Jr.
  • Patent number: 6342647
    Abstract: It has been discovered that the polymerization of vinyl aromatic compounds, such as styrene, may be inhibited by the addition of a composition that contains a hindered hydroxylamine, and, optionally, a synergist together with the hindered hydroxylamine.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: January 29, 2002
    Assignee: Baker Hughes Incorporated
    Inventors: Glenn L. Roof, Muslim D. Shahid
  • Publication number: 20020008010
    Abstract: A method for starting up a distilling column destined to handle an easily polymerizing compound-containing solution characterized by supplying at the start of the operation of the distilling column a polymerization inhibitor to the bottom liquid of the distilling column having a temperature of not higher than 80° C. Further, by supplying a reflux liquid through the top of the distilling column or the middle stage of the column prior to the start of the temperature elevation of the distilling column, thereby preventing the polymerization of the easily polymerizing compound more effectively.
    Type: Application
    Filed: May 31, 2001
    Publication date: January 24, 2002
    Inventors: Kei Hamamoto, Yukihiro Matsumoto, Sei Nakahara, Misao Inada
  • Patent number: 6334935
    Abstract: A (meth)acryloxy-bearing alkoxysilane is isolated and purified to a high purity by distilling a reaction solution containing the (meth)acryloxy-bearing alkoxysilane in a thin-layer distillation device at a temperature of 90-160° C. and a vacuum of 1-15 mmHg. The resulting alkoxysilane product does not give rise to the quality problem that the product will gradually whiten during storage owing to contact with air. The occurrence of self-polymerization of the alkoxysilane is restrained.
    Type: Grant
    Filed: June 18, 1999
    Date of Patent: January 1, 2002
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Katsuhiro Uehara, Mikio Endo, Tohru Kubota, Satoshi Uchida, Kanji Murofushi
  • Publication number: 20010052481
    Abstract: Popcorn polymer growth is inhibited in unstabilized materials comprising olefinically unsaturated organic compounds by adding thereto an effective amount of an aliphatic alcohol of the formula I
    Type: Application
    Filed: March 2, 1999
    Publication date: December 20, 2001
    Inventors: MAIK ARON, MICHAEL BACHTLER, JURGEN KANAND
  • Publication number: 20010050216
    Abstract: A process for distillative separation of pure (meth)acrylic acid from mixtures which comprise (meth)acrylic acid and dimers and oligomers of (meth)acrylic acid and are essentially free from aldehydes and from components whose boiling point is lower than that of (meth)acrylic acid, using a distillation apparatus which has a thin-film evaporator, a condenser and a connection which contains a baffle device and links the thin-film evaporator and the condenser.
    Type: Application
    Filed: February 22, 1999
    Publication date: December 13, 2001
    Inventors: RUPRECHT KROKER, MANFRED WIEDEMANN
  • Publication number: 20010050217
    Abstract: A (meth)acryloxy-bearing alkoxysilane is isolated and purified to a high purity by distilling a reaction solution containing the (meth)acryloxy-bearing alkoxysilane in a thin-layer distillation device at a temperature of 90-160° C. and a vacuum of 1-15 mmHg. The resulting alkoxysilane product does not give rise to the quality problem that the product will gradually whiten during storage owing to contact with air. The occurrence of self-polymerization of the alkoxysilane is restrained.
    Type: Application
    Filed: June 18, 1999
    Publication date: December 13, 2001
    Inventors: KATSUHIRO UEHARA, MIKIO ENDO, TOHRU KUBOTA, SATOSHI UCHIDA, KANJI MUROFUSHI
  • Publication number: 20010009968
    Abstract: Methods and compositions for inhibiting the polymerization of ethylenically unsaturated hydrocarbons are disclosed. Combinations of aminophenol compound and either of phenylenediamine or hydroxylamine compounds are effective at inhibiting this polymerization under both processing and storage conditions.
    Type: Application
    Filed: January 24, 2001
    Publication date: July 26, 2001
    Applicant: BETZDEARBORN INC.
    Inventor: Sherif Eldin
  • Patent number: 6214174
    Abstract: A distillation column is arranged so that a liquid hole which allows liquid containing a polymerizable organic compound to flow from on a tray supporting member downward is formed in a part of the tray supporting member, for example, a support ring, so that substantial retention of the liquid on the tray supporting member is avoided. Therefore, the liquid, such as crude acrylic acid, is allowed to smoothly flow down from on surfaces of a tray and the tray supporting member, thereby causing no substantial retention of the liquid. As a result, polymerization which tends to occur when the liquid is retained on the surfaces of the tray and the tray supporting member thereby being heated is effectively prevented, and the polymerizable organic compound is efficiently purified.
    Type: Grant
    Filed: January 28, 1998
    Date of Patent: April 10, 2001
    Assignee: Nippon Shokubai Co., Ltd.
    Inventors: Hajime Matsumoto, Kazukiyo Arakawa
  • Patent number: 6210536
    Abstract: This invention is directed to certain N,N′-dinitroso phenylenediamines useful as polymerization inhibitors for acrylic acids and esters thereof. Also disclosed are compositions containing such compounds, and methods for inhibiting polymerization using such compounds and compositions.
    Type: Grant
    Filed: September 2, 1993
    Date of Patent: April 3, 2001
    Assignee: Uniroyal Chemical Company, Inc.
    Inventors: Anthony Vincent Grossi, Paul Edwin Stott
  • Patent number: 6200461
    Abstract: Methods and compositions for inhibiting the polymerization of ethylenically unsaturated hydrocarbons are disclosed. Combinations of aminophenol compound and either of phenylenediamine or hydroxylamine compounds are effective at inhibiting this polymerization under both processing and storage conditions.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: March 13, 2001
    Assignee: BetzDearborn Inc.
    Inventor: Sherif Eldin
  • Patent number: 6117276
    Abstract: When a nitroxyl compound is heated in an oxygen-free atmosphere with a vinyl aromatic monomer at 50-140.degree. C. for up to 60 days, it forms an activated inhibitor mixture which is superior to the nitroxyl compound itself in preventing the premature polymerization of a vinyl aromatic monomer during its processing and purification.
    Type: Grant
    Filed: March 26, 1998
    Date of Patent: September 12, 2000
    Assignee: Nalco/Exxon Energy Chemicals, L.P.
    Inventors: Glen T. Cunkle, Thomas F. Thompson, Volker H. von Ahn, Roland A. E. Winter