Of Glycerol Patents (Class 568/869)
  • Patent number: 7098368
    Abstract: The invention discloses a hydrogenation process for removing impurities and controlling acid for use in downstream processing of biochemically-derived 1,3-propanediol. Preferably, the biochemically-derived 1,3-propanediol, before the contacting, has an initial color and, after the contracting, has a color that is lower than the initial color.
    Type: Grant
    Filed: May 5, 2004
    Date of Patent: August 29, 2006
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Mayis Seapan, George F. Diffendall, Robert E. Trotter, Tyler T. Ames, F. Glenn Gallagher
  • Patent number: 7084311
    Abstract: Disclosed is a process comprising contacting chemical 1,3-propanediol with hydrogen in the presence of a hydrogenation catalyst. Preferably, the chemical 1,3-propanediol, before the contacting has an initial color and, after the contacting, has a color that is lower than the initial color.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: August 1, 2006
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Hari Babu Sunkara, Mayis Seapan, George F. Diffendall, Tyler T. Ames
  • Patent number: 7038092
    Abstract: Disclosed is a process comprising contacting chemical 1,3-propanediol with hydrogen in the presence of a hydrogenation catalyst. Preferably, the chemical 1,3-propanediol, before the contacting has an initial color and, after the contacting, has a color that is lower than the initial color.
    Type: Grant
    Filed: August 12, 2005
    Date of Patent: May 2, 2006
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Hari Babu Sunkara, Mayis Seapan, George F. Diffendall, Tyler T. Ames
  • Patent number: 6909022
    Abstract: The present invention relates to a process of removing organic halogen-containing compounds from a liquid stream mainly containing one or more of the compounds selected from the group consisting of glycol, water and alcohol, which process involves contacting the stream with an ion-exchange material containing basic anions selected from the group of hydroxide, carbonate and bicarbonate.
    Type: Grant
    Filed: May 14, 2004
    Date of Patent: June 21, 2005
    Assignee: Shell Oil Company
    Inventors: Feike De Jong, Johannes Jacobus Maria Snel
  • Patent number: 6867337
    Abstract: A process for producing glycerin is comprised of the steps of: (1) contacting a fat with water at a temperature and pressure sufficient to produce hydrolyzed fat and a sweet water stream comprised of water, fat and glycerin; (2) introducing the sweet water stream into a vertical constant temperature zone and heating the sweet water stream to a temperature of at least 200° C.; (3) allowing sweet water stream of step (2) to separate into a top layer comprised of fat and a bottom layer comprised of glycerin and water while maintaining a temperature of the two layers of at least about 200° C. for a period of time sufficient to deactivate the prions; (4) separating the glycerin from the water.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: March 15, 2005
    Assignee: Cognis Corporation
    Inventors: Herbert C. Ahting, David A. Krabacher
  • Patent number: 6784326
    Abstract: A process for inhibiting the oxidative degradation of glycerin involving adjusting the pH of glycerin to a range of either: (a) from about 3.5 to about 5.0; or (b) to from about 10.0 to about 12.0.
    Type: Grant
    Filed: June 17, 1998
    Date of Patent: August 31, 2004
    Assignee: Cognis Corporation
    Inventor: Thomas Z. Li
  • Patent number: 6603048
    Abstract: A process is provided to separate 1,3-propanediol, glycerol, or a mixture of 1,3-propanediol and glycerol from a biological mixture using a molecular sieve.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: August 5, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: David Richard Corbin, Tucker Norton
  • Patent number: 6586642
    Abstract: A process for greatly improving the color index of polyhydric alcohols, especially trimethylolpropane, by hydrogenation comprises using, in the hydrogenation, an alcohol which has already been purified by distillation. The catalysts used are those conventionally employed in hydrogenations, preferably copper, nickel, palladium or ruthenium catalysts.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: July 1, 2003
    Assignee: BASF Aktiengesellschaft
    Inventors: Matthias Dernbach, Detlef Kratz, Achim Stammer, Mathias Haake, Michael Koch, Gerhard Schulz
  • Patent number: 6538164
    Abstract: Volatile compounds may be economically recovered from solids present in aqueous solution by subjecting the solution to rapid separation where the volatilization occurs in a flash, spray, or fluid bed, or mechanically agitated dryers. Rapidly separating the solids from the volatile compound greatly simplifies the isolation of the volatile compounds from water. The methods have utility for fermentation processes, solids management, and recycling processes.
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: March 25, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: F. Glenn Gallagher, George Schurr
  • Publication number: 20030040648
    Abstract: The present invention relates in general to triacylglycerol oil-based oligomers and oligomer complexes and methods of making and using same. In more particular, the present invention relates to soybean oil oligomers and oligomer complexes and the methods of making and using these soybean oil oligomers and oligomer complexes as well as the use of these soybean oil oligomers and oligomer complexes for the preparation and production of inks.
    Type: Application
    Filed: June 19, 2002
    Publication date: February 27, 2003
    Inventor: William A. Franks
  • Patent number: 6384243
    Abstract: An unsaturated fatty acid precursor of a natural 1,3-diol derivative, which precursor is the same as that which is naturally present in a cider apple, is enzymatically converted to the natural 1,3-diol derivative.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: May 7, 2002
    Inventor: Pascal Marc Brunerie
  • Publication number: 20020032355
    Abstract: The present invention relates generally to triacylglycerol oligomer products and methods of making, using and producing same.
    Type: Application
    Filed: December 7, 2000
    Publication date: March 14, 2002
    Inventor: William A. Franks
  • Patent number: 6344592
    Abstract: A method of producing a highly pure trimethylolpropane from a crude trimethylolpropane obtained by a reaction of n-butyl aldehyde and formaldehyde in the presence of a basic catalyst in a two-stage process of an aldol condensation and a crossed Cannizzaro reaction. Since a high-boiling component and an inorganic salt are removed in advance from the crude trimethylolpropane, hardly removable impurities such as condensation products in the crude trimethylolpropane are changed in the subsequent heat treatment under acidic conditions to components easily removable by distillation. By distilling the heat-treated crude trimethylolpropane, a highly pure trimethylolpropane with a low content of remaining formaldehyde and a low coloring degree is easily obtained.
    Type: Grant
    Filed: December 20, 1999
    Date of Patent: February 5, 2002
    Assignee: Mitsubishi Gas Chemical Company, Inc.
    Inventors: Atsushi Iwamoto, Teruyuki Ninomiya, Toshio Watanabe, Takaki Ikebe
  • Patent number: 6288287
    Abstract: A process for preparing a glycerol from a crude glycerol comprising a glycerol, a diol and water, comprising feeding the crude glycerol to a preparation apparatus comprising two or more, serially connected flash towers and a distillation tower connected to a final flash tower, wherein a bottom fraction of each flash tower is fed to a subsequent flash tower; and adjusting an internal pressure of each flash tower to from 0.13 to 40 kPa, an internal temperature of each flash tower to 140° C. or less, a water content of the bottom fraction of the final flash tower to 0.1% by weight or less, and a pressure at bottom of the distillation tower to from 0.13 to 0.90 kPa.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: September 11, 2001
    Assignee: Kao Corporation
    Inventors: Hideaki Ueoka, Takanobu Katayama
  • Publication number: 20010014763
    Abstract: A process for preparing a glycerol from a crude glycerol comprising a glycerol, a diol and water, comprising feeding the crude glycerol to a preparation apparatus comprising two or more, serially connected flash towers and a distillation tower connected to a final flash tower, wherein a bottom fraction of each flash tower is fed to a subsequent flash tower; and adjusting an internal pressure of each flash tower to from 0.13 to 40 kPa, an internal temperature of each flash tower to 140° C. or less, a water content of the bottom fraction of the final flash tower to 0.1% by weight or less, and a pressure at bottom of the distillation tower to from 0.13 to 0.90 kPa.
    Type: Application
    Filed: January 29, 2001
    Publication date: August 16, 2001
    Inventors: Hideaki Ueoka, Takanobu Katayama
  • Patent number: 6265625
    Abstract: This invention relates to a process for preparing and isolating glycols and to a thin-film evaporator which is used in carrying out the process.
    Type: Grant
    Filed: December 1, 1999
    Date of Patent: July 24, 2001
    Assignee: BASF Aktiengesellschaft
    Inventors: Frans Vansant, Jozef de Hert, Dieter Köffer, Gerhard Theis, Winfried Terjung
  • Patent number: 6060627
    Abstract: A water and allylic compound containing propoxylated glycerin stream is reduced in water content by evaporation and flashed at reduced pressure and elevated temperature to reduce the water content to 1000 ppm or less, and thereafter stripping allylic impurities from the propyxylated glycerin.
    Type: Grant
    Filed: May 8, 1997
    Date of Patent: May 9, 2000
    Assignee: Arco Chemical Technology, L.P.
    Inventor: Jon R. Valbert
  • Patent number: 5962749
    Abstract: This invention relates to a process for the purification of polyether polyols. This process enables the removal of residual alkaline metal catalyst from produced polyether polyol. It comprises a) adding glycerine to a polyether polyol that contains Group IA alkaline metal catalyst to form a precipitate, and b) separating the precipitate formed in a) to provide a purified polyether polyol. The present invention also relates to the purified polyether polyol produced by this process, the precipitate produced by this process, and the use of the precipitate as an alkaline metal catalyst in a process for the production of polyether polyols.
    Type: Grant
    Filed: December 24, 1997
    Date of Patent: October 5, 1999
    Assignee: Bayer Corporation
    Inventors: Harold R. Parsons, Donald C. Dunham, Steven L. Schilling, Keith J. Headley
  • Patent number: 5763692
    Abstract: A process for preparing a recyclate polyol obtained from glycolysis of polyurethanes and/or polyurea-polyurethanes comprises reacting scrap polyurethane and/or polyurea-polyurethane with a short-chain compound containing at least 2 OH groups in the presence of a catalyst and admixing a cyclic carbonate. The process results in a recyclate polyol having a low primary aromatic amine content which may be used to produce cellular or non-cellular polyurethanes, polyurea-polyurethanes, or polyisocyanurates.
    Type: Grant
    Filed: October 28, 1996
    Date of Patent: June 9, 1998
    Assignee: BASF Corporation
    Inventors: Paul C. Kierkus, Kimberly K. You
  • Patent number: 5723696
    Abstract: Glycerol, glycidol, glycerol carbonate or 2,2-dimethyl-1,3-dioxolane-4-methanol is polymerized into preponderantly linear oligomers at 150.degree. C. to 350.degree. C. in the presence of a catalyst, selected from RbF, CsF and/or KF impregnated on alumina and zirconium oxide. The alumina is preferably gamma-alumina.
    Type: Grant
    Filed: July 17, 1996
    Date of Patent: March 3, 1998
    Assignee: Unichema Chemie B.V.
    Inventors: Glyn Roberts, Alan Reginald Minihan, Johannes Arie M. Laan, Johan Jan W. Eshuis
  • Patent number: 5710350
    Abstract: A process for preparing diglycerol in high concentrations and high yields by partially reacting glycerol in the presence of an alkaline catalyst to form a reaction mixture containing from 10 to 15% by weight of diglycerol and separating the unreacted glycerol from the reaction mixture in a wiped film or short path first distillation zone at a reduced pressure of 0.5 to 5 mbar and distilling a bottoms product from the first distillation zone in a second distillation zone which is a short path distillation zone at a pressure of 0.05 to 0.3 mbar to obtain a second bottom product containing at least 90% by weight diglycerol. Diglycerol of higher purity can be obtained by recovering diglycerol as a distillate from a third distillation zone.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: January 20, 1998
    Assignee: Henkel Kommanditgesellschaft auf Aktien
    Inventors: Lutz Jeromin, Bernhard Gutsche, Reinhard Bunte, Volkmar Jordan
  • Patent number: 5679223
    Abstract: An extractive distillation process using a high boiling polyol such as glycerol is employed for separating high purity catechol, 3-methylcatechol and 4-methylcatechol from a high boiling, pitch-like dihydric phenol fraction. Fractional distillation first separates an impure overhead mixture of the catechol and 3-methylcatechol and an impure 4-methylcatechol bottoms. The impure overhead is extractively distilled to remove impurities and then extractively distilled again to separate the catechol and 3-methylcatechol. This produces a pure overhead of 3-methylcatechol and a bottoms of catechol and polyol which is distilled to recover the catechol and recycle the polyol. The impure 4-methylcatechol is distilled to remove residual material and then extractively distilled to remove impurities. The resulting mixture of 4-methylcatechol and polyol is distilled to recover the pure 4-methylcatechol and to recycle the polyol.
    Type: Grant
    Filed: June 15, 1995
    Date of Patent: October 21, 1997
    Assignee: Dakota Gasification Company
    Inventors: David H. Duncan, Gene G. Baker, Dana J. Maas, Kevin M. Mohl, Alfred K. Kuhn
  • Patent number: 5527974
    Abstract: The glycerol water (sweet water) accumulating in the high-pressure hydrolysis of natural fats and oils with steam into fatty acid and glycerol is continuously purified. Fats larger than 100 .mu.m in diameter are separated from the aqueous phase in a plate-type phase separator and are returned to the high-pressure hydrolysis process. The aqueous phase thus prepurified is passed through a cross-flow filtration membrane, more particularly a microfiltration membrane, and the concentrate is returned to the entrance of the plate-phase separator. Large product streams of glycerol water can be purified continuously, effectively and particularly economically despite frequent changes of provenance.
    Type: Grant
    Filed: September 29, 1994
    Date of Patent: June 18, 1996
    Assignee: Henkel Kommanditgesellschaft auf Aktien
    Inventors: Lutz Jeromin, Wilhelm Johannisbauer, Stefan Blum, Reinhold Sedelies, Heinrich Moormann, Bernd Holfoth, Juergen Plachenka
  • Patent number: 5421965
    Abstract: Glycerine is difficult to separate from bis(hydroxymethyl)tetrahydrofuran by conventional distillation or rectification because of the proximity of their boiling points. Glycerine can be readily separated from bis(hydroxymethyl)tetrahydrofuran by azeotropic distillation. Effective agents are m-xylene, beta-pinene and dicyclopentadiene.
    Type: Grant
    Filed: August 1, 1994
    Date of Patent: June 6, 1995
    Assignee: Lloyd Berg
    Inventor: Lloyd Berg
  • Patent number: 5198077
    Abstract: Glycerine cannot be easily separated from mannitol, lactose or lactitol by atmospheric or reduced pressure distillation because of their high boiling points. Glycerine can be readily separated from mannitol, lactose or lactitol by azeotropic distillation. Typical effective agents are biphenyl, benzyl benzoate and dimethyl phthalate.
    Type: Grant
    Filed: November 19, 1991
    Date of Patent: March 30, 1993
    Assignee: Lloyd Berg
    Inventor: Lloyd Berg
  • Patent number: 5190622
    Abstract: Glycerine cannot be easily separated from sorbitol by atmospheric or reduced pressure distillation because of their high boiling points. Glycerine can be readily separated from sorbitol by azeotropic distillation. Typical effective agents are biphenyl, benzyl benzoate and dimethyl phthalate.
    Type: Grant
    Filed: November 14, 1991
    Date of Patent: March 2, 1993
    Assignee: Lloyd Berg
    Inventor: Lloyd Berg
  • Patent number: 4990695
    Abstract: The invention provides a process for purifying crude glycerol such as splitters crude, soaplye crude and methanolysis crude which comprises a microfiltration step over a filter material on a ceramic support preferably comprising alumina. Preferably the filter material comprises zirconia and/or alumina. Preferably the process further comprises the step of distillation and/or treatment with ion exchange resins. Also the process may involve a combination of microfiltration and ultrafiltration.
    Type: Grant
    Filed: August 9, 1989
    Date of Patent: February 5, 1991
    Assignee: Unilever Patent Holdings B.V.
    Inventors: Thomas Buenemann, Johannes C. Oudejans, Pietro Gamba, Aldo Rampi
  • Patent number: 4980033
    Abstract: Triethylene glycol cannot be easily separated from glycerine or 1,2,4-butanetriol by atmospheric or reduced pressure distillation because of the closeness of their boiling points. Triethylene glycol can be readily separated from glycerine or 1,2,4-butanetriol by azeotropic distillation. Effective agents are p-xylene, alphapinene and diisobutyl ketone.
    Type: Grant
    Filed: September 4, 1990
    Date of Patent: December 25, 1990
    Assignee: Lloyd Berg
    Inventor: Lloyd Berg
  • Patent number: 4975158
    Abstract: Glycerine cannot be easily separated from triethylene glycol and 1,2,4-butanetriol by atmospheric or reduced pressure distillation because of the closeness of their boiling points. Glycerine can be readily separated from triethylene glycol and 1,2,4-butanetriol by azeotropic distillation. Typical effective agents are m-xylene, dipentene and 2-methoxyethyl ether.
    Type: Grant
    Filed: April 6, 1990
    Date of Patent: December 4, 1990
    Assignee: Lloyd Bert
    Inventor: Lloyd Berg
  • Patent number: 4919765
    Abstract: Tetrahydrofuran is recovered by a two stage distillation procedure from a crude hydrogenation product resulting from vapor phase hydrogenation of diethyl maleate and containing water, ethanol and a minor amount of n-butanol, and possibly also dissolved hydrogen, in addition to butane-1,4-diol, gamma-butyrolactone and "heavies" such as diethyl ethoxysuccinate. In the first distillation stage, conveniently operated substantially at atmospheric pressure, ethanol, water, and tetrahydrofuran are recovered as overhead product, are condensed to separate the condensible components from a hydrogen stream which can be vented, and then redistilled in the presence of a molar excess of a hydroxylic solvent containing at least two hydroxyl groups, such as butane-1,4-diol, in a second distillation zone.
    Type: Grant
    Filed: July 22, 1988
    Date of Patent: April 24, 1990
    Assignee: Davy McKee (London) Limited
    Inventors: Peter R. Wilkes, John Scarlett, George E. Harrison
  • Patent number: 4683347
    Abstract: The level of impurities such as glycerol-based acetals and/or ketals in glycerine, particularly glycerol-dimethylketal, is reduced by extraction of the glycerine with supercritical or near critical carbon dioxide.
    Type: Grant
    Filed: June 23, 1986
    Date of Patent: July 28, 1987
    Assignee: Shell Oil Company
    Inventors: Zaida Diaz, James H. Miller
  • Patent number: 4655879
    Abstract: An improved process for purification of glycerol obtained from natural sources comprising alkalizing a glycerol-containing crude mixture in the presence of air for oxidation, evaporating the mixture in a thin-layer evaporator with redistillation of the residue, rectification and reevaporation in a packed column characterized by low-pressure-loss plates with a falling-film evaporator designed for internal and external partial condensation and to separate off unwanted constituents of the mixture, bleaching the product with activated carbon and separating the bleach in known manner.
    Type: Grant
    Filed: October 26, 1984
    Date of Patent: April 7, 1987
    Assignee: Henkel Kommanditgesellschaft auf Aktien
    Inventors: Rolf Brockmann, Lutz Jeromin, Wilhelm Johannisbauer, Helmut Meyer, Otto Michel, Juergen Plachenka
  • Patent number: 4560812
    Abstract: Glycerine is recovered from an aqueous waste stream containing but minor amounts of glycerine by the requested steps of; (1) evaporating, (2) contacting with pentanol, (3) separating precipitated salt, (4) flashing to remove pentanol, and (5) vacuum distillation. This process is particularly useful treating saline waste water resulting from the manufacture of epoxy resins.
    Type: Grant
    Filed: December 10, 1984
    Date of Patent: December 24, 1985
    Assignee: Shell Oil Company
    Inventor: George C. Blytas
  • Patent number: 4554390
    Abstract: A method for harvesting algae of the genus Dunaliella from suspensions thereof in brines containing sodium chloride at a concentration of about 3M or above, wherein the algal suspension is contacted with an adsorbent having a hydrophobic surface so as to adsorb the algae thereon, and the adsorbent with the algae adsorbed thereon is separated from the brine..beta.-carotene and other useful cell components may be extracted from the adsorbed algae by treatment with a suitable solvent.
    Type: Grant
    Filed: June 7, 1983
    Date of Patent: November 19, 1985
    Assignees: Commonwealth Scientific and Industrial Research Organization, Betatene Limited
    Inventors: Cyril C. Curtain, Harvey Snook
  • Patent number: 4450294
    Abstract: An oxygenated organic compound, such as ethanol, is recovered from a dilute aqueous stream thereof by contacting said stream with crosslinked polyvinylpyridine resin or nuclear substituted derivative thereof to effect selective sorption of the compound by said resin. The sorbed compound is thereafter removed from the resin by stripping with an inert gas such as carbon dioxide.
    Type: Grant
    Filed: November 1, 1982
    Date of Patent: May 22, 1984
    Assignee: National Distillers and Chemical Corporation
    Inventor: Julian Feldman
  • Patent number: 4447643
    Abstract: A thermally efficient process for recovering an oxygenated organic material, such as ethanol, present in dilute aqueous solution is disclosed which comprises contacting said dilute aqueous solution with at least one inert extractant which is liquid at ambient temperature and pressure, said extractant being selected from the group consisting of unsubstituted and substituted cyclic secondary amines and unsubstituted and substituted aromatic cyclic amines having a distribution coefficient of at least about 0.70 or a separation factor of at least about 1.0.
    Type: Grant
    Filed: August 11, 1982
    Date of Patent: May 8, 1984
    Assignee: National Distillers and Chemical Corporation
    Inventor: Julian Feldman
  • Patent number: 4360407
    Abstract: The distillative separation of a mixture of glycerine and glycerine-based acetal or ketal transesterification products is aided by addition of a borate ester-forming compound to the mixture prior to distillation.
    Type: Grant
    Filed: March 22, 1982
    Date of Patent: November 23, 1982
    Assignee: The Dow Chemical Company
    Inventor: Robert L. Reierson
  • Patent number: 4349415
    Abstract: Process and apparatus for extracting an organic liquid from an organic liquid solute/solvent mixture. The mixture is contacted with a fluid extractant which is at a temperature and pressure to render the extractant a solvent for the solute but not for the solvent. The resulting fluid extract of the solute is then depressurized to give a still feed which is distilled to form still overhead vapors and liquid still bottoms. The enthalpy required to effect this distillation is provided by compressing the still overhead vapors to heat them and indirectly to heat the still feed. The process is particularly suitable for separating mixtures which form azeotropes, e.g., oxygenated hydrocarbon/water mixtures. The energy required in this process is much less than that required to separate such mixtures by conventional distillation techniques.
    Type: Grant
    Filed: September 28, 1979
    Date of Patent: September 14, 1982
    Assignee: Critical Fluid Systems, Inc.
    Inventors: Richard P. DeFilippi, J. Edward Vivian
  • Patent number: 4345976
    Abstract: The invention involves a process for substantially separating the components of mixtures of substances at least one of which is of low volatility while the other is of low or no volatility, the process using a compressed gas under supercritical conditions and an entrainer which increases the concentration of said mixture in the gaseous phase as well as the separation factor between the components to be separated. The process operates in two distillation zones the first of which substantially separates the components of low volatility in a process similar to a rectification process while the second distillation zone separates the top product of the first distillation zone from the gas with the aid of the entrainer which is condensed partially and in this state is passed in countercurrent to the gas carrying the separated component of low volatility.
    Type: Grant
    Filed: February 7, 1979
    Date of Patent: August 24, 1982
    Assignee: Siegfried Peter
    Inventors: Siegfried Peter, Gerd Brunner, Rolf Riha
  • Patent number: 4234509
    Abstract: Glycerol and aliphatic nitriles are simultaneously produced by treating liquid glycerides with gaseous ammonia at a rate of at least 200 liters of ammonia per kilogram of glyceride per hour at temperatures of from 220.degree. to 300.degree. C. in the presence of metal salts of carboxylic or sulfonic acids as catalysts and subjecting the product mixture to a phase separation into a nitrile phase and a glycerol/water phase. Preferred starting materials are vegetable and animal fats and oils.
    Type: Grant
    Filed: April 24, 1979
    Date of Patent: November 18, 1980
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Siegfried Billenstein, Bruno Kukla, Herbert Stuhler