Patents Assigned to Degussa Aktiengesellschaft
  • Thermally split zirconium silicate, method of its production and use
    Patent number: 5614011
    Abstract: Thermally split zirconium silicate is produced such that the crystalline zirconium dioxide embedded in an amorphous silica phase exhibits an average grain or particle size (d.sub.50 value) in a range of 0.5 .mu.m to 3.0 .mu.m and a specific surface (BET) in a range of 3 to 15 m.sup.2 /g. The zirconium dioxide produced by this method is particularly suited for the production of zirconium silicate pigments with improved color characteristics. The thermally split zirconium silicate is also particularly well suited for processes used in the obtention of zirconium dioxide. The method of producing the thermally split zirconium silicate includes melting zirconium silicate in an induction melting furnace and cooling off a free falling stream of melt by blowing on it with a gas and/or spraying it with water.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: March 25, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventors: Dieter Binder, Peter Kleinschmit, Klaus Zetzmann, Hans Hoffmeister
  • Method of preparing amionoakylhydantoins and aminoalkyl-alpha-amino acids
    Patent number: 5608076
    Abstract: The invention relates to a method of preparing 5-(aminoalkyl)-hydantoins with basic side chain in which the protection of the amino function in the side chain is necessary during the formation of the hydantoin requires minimal expense.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: March 4, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventors: Matthias Kottenhahn, Karlheinz Drauz, Andreas Bommarius
  • Process for preparing potassium peroxomonosulfate triple salt
    Patent number: 5607656
    Abstract: A process for preparing the potassium peroxomonosulfate triple salt 2 KHSO.sub.5 .multidot.KHSO.sub.4 .multidot.K.sub.2 SO.sub.4 by partial neutralization of sulfuric acid-Caro's acid fed to a working solution containing KHSO.sub.5, KHSO.sub.4 and K.sub.2 SO.sub.4 with caustic potash solution and evaporation of water. The cold crystallization procedure (15.degree. C. or below) hitherto required is avoided and a high active oxygen yield is produced by using sulfuric acid-Caro's acid with 50 to 70 wt. % of H.sub.2 SO.sub.5 and 15 to 30 wt. % of H.sub.2 SO.sub.4 and a working solution with a concentration of 28 to 38 wt. % of KHSO.sub.5, 18 to 28 wt. % of KHSO.sub.4 and greater than 0 to 3 wt. % of K.sub.2 SO.sub.4 and supplying additional sulfuric acid, wherein the molar ratio of H.sub.2 SO.sub.5 to added H.sub.2 SO.sub.4 to KOH is 3 to 1:3 to 5:8.
    Type: Grant
    Filed: February 6, 1996
    Date of Patent: March 4, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventors: Hartwig Soicke, Georg Mannebach
  • Apparatus for producing sodium perborate monohydrate and product produced thereby
    Patent number: 5595001
    Abstract: Method and apparatus for producing sodium perborate monohydrate by dehydrating sodium perborate tetrahydrate in a fluid bed with heated air. Contact surfaces are arranged inside the fluid bed whose total area is the same as up to 500 times the area of the approach-flow bottom of the fluid bed. The contact surfaces are advantageously designed as heat exchangers whose surface temperature is adjusted to maintain 90.degree. to 110.degree. C. at the contact surfaces. The method results in a sodium perborate monohydrate with especially high abrasion resistance. In addition, the energy requirement is lower than that provided in the previously known method commonly used in the industry.
    Type: Grant
    Filed: May 25, 1995
    Date of Patent: January 21, 1997
    Assignee: DeGussa Aktiengesellschaft
    Inventors: Rudiger Schutte, Alexander Ruhs, Claas-Jurgen Klasen, Hans-Christian Alt
  • Formed copper catalyst for the selective hydrogenation of furfural to furfuryl alcohol
    Patent number: 5591873
    Abstract: A formed copper catalyst for the hydrogenation of organic compounds is disclosed, especially for the selective hydrogenation of furfural to furfuryl alcohol. The catalyst contains an intimate mixture of a pyrogenic silica, reduced copper and, optionally, a basic oxide as promotor. The catalyst is distinguished by a high specific catalytic activity, selectivities and yields.
    Type: Grant
    Filed: February 1, 1995
    Date of Patent: January 7, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventors: Martin Bankmann, Johannes Ohmer, Thomas Tacke
  • Method for the preparation of D-arginine and L-ornithine
    Patent number: 5591613
    Abstract: D-arginine and L-ornithine are prepared by means of the enzymatic conversion of DL-arginine in the presence of an L-arginase which selectively converts L-arginase to L-ornithine, permitting recovery of both D-arginine and L-ornithine.
    Type: Grant
    Filed: December 29, 1994
    Date of Patent: January 7, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventors: Kyriakos Makryaleas, Karlheinz Drauz, Andreas Bommarius
  • Paper containing a filler
    Patent number: 5591307
    Abstract: Paper containing a filler which is synthetic silica, which can be precipitated, spray-dried and ground. The synthetic silica reduces show through.
    Type: Grant
    Filed: May 31, 1995
    Date of Patent: January 7, 1997
    Assignee: Degussa Aktiengesellschaft
    Inventor: Arnold Storeck
  • Method of producing optically active pyrrolidines with high enantiomeric purity
    Patent number: 5585500
    Abstract: A method of producing optically active pyrrolidines of the general formula ##STR1## in which R.sup.1 is hydrogen or OH,R.sup.2 is a benzyl group which can have one or more alkyl-, alkoxy- and/or halogen substituents on the aromatic, and* is and/or can be an asymmetric center,by reducing the corresponding, enantiomerically pure pyrrolidinediones using activated alkali boron hydride.
    Type: Grant
    Filed: July 17, 1995
    Date of Patent: December 17, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Karlheinz Drauz, Matthias Kottenhahn, Michael Kraft, Michael Schwarm
  • Method of influencing the cis/trans isomer ratio of isophoronediamine in its preparation from isophoronenitrile
    Patent number: 5583260
    Abstract: A method of controlling the cis/trans isomer ratio in the preparation of isophoronediamine by the aminating hydrogenation of isophoronenitrile in the presence of ammonia, H.sub.2 and a catalyst. The reaction takes place in two temperature steps, initially at 10.degree. to 90.degree. C. and then at above 90.degree. to 150.degree. C. with a temperature difference of at least 30.degree. C. between the two steps, the contact time being shorter in the first step than in the second. The cis/trans ratio is increased by lowering the temperature of the first step.
    Type: Grant
    Filed: December 22, 1994
    Date of Patent: December 10, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Thomas Haas, Dietrich Arntz, Dieter Most
  • Process for the compression of powdered substances
    Patent number: 5580537
    Abstract: Powdered substances are compressed by a process wherein the powdered substances are enclosed in a flexible receptacle, the receptacle is enclosed in a pressure vessel and the space between the wall of the receptacle and the wall of the pressure vessel is pressurized with compressed gas.
    Type: Grant
    Filed: April 21, 1995
    Date of Patent: December 3, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Gerhard Sextl, Sabine Bartelt, Klaus Wilmes, Roland Reuter, Rudolf Schwarz, Friedel Worch
  • Precious-metal material for articles of jewelry and a method of manufacturing them
    Patent number: 5578383
    Abstract: A precious-metal material for articles of jewelry and having low specific weight, high resistance to corrosion, in spite of a low content of precious metals, and free from toxic constituents which consists of 33 to 99 wt. % precious metal powder, 1 to 67 wt. % of a thermosetting organic plastics and 0 to 10% filler.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: November 26, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Hans-Hermann Beyer, Karl-Anton Starz
  • Kerainase from fervidobacterium pennavorans DSM 7003
    Patent number: 5569599
    Abstract: An enzyme composition containing keratinase is obtained from Fervidobacterium pennavorans DSM 7003. The composition is capable of degradating keratin-containing substrates such as feathers, hair and horn within a few days at between 50.degree. and 105.degree. C. and at a pH of between 4 and 12 under anaerobic conditions. A pH of 10.5 and a temperature of 70.degree. C. or greater are preferred. Dissolving of the substrate can be at least 50% by weight after 24 hours, and in 1 to 4 days the entire substrate can be dissolved. Pretreatment of the substrate at a temperature of 120.degree. C. or greater is not required.
    Type: Grant
    Filed: November 2, 1994
    Date of Patent: October 29, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventor: Garabed Antranikian
  • System for accelerating the heating rate of a fixed bed catalyst by supplying supplemental energy
    Patent number: 5569441
    Abstract: A process and apparatus for accelerating the rate of heating of a fixed bed catalyst to a light-off temperature for a catalytic reaction is disclosed. Supplementary energy from an external energy source is provided to a predetermined area of the catalyst bed for a limited period of time. The fixed bed catalyst may be present as a solid body or in bulk form and has a gas inlet area defined by a cross-section of the flow through channels of the reaction media. The supplementary energy is supplied to one or more isolated sections of the gas inlet area of the catalyst. Such a system significantly reduces the energy required in order to effectuate at least partial conversion of harmful emissions during initial operation of the converter.
    Type: Grant
    Filed: December 5, 1994
    Date of Patent: October 29, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Bernd Engler, Egbert Lox, Andreas Niemann-Weber
  • Method for controlling the detoxification of cyanidic waste waters
    Patent number: 5569386
    Abstract: A method for controlling the detoxification of aqueous solutions containing cyanides and/or cyano complexes, in particular zinc cyano complexes, with the use of a source for formaldehyde for glycolnitrile formation and a source for hydrogen peroxide for perhydrolysis of the glycolnitrile is disclosed. During the addition of the source for formaldehyde at a pH value in the range from 8.5 to 12 the pH value is kept constant by addition of an acid. The addition of the source for formaldehyde is discontinued if the pH value no longer increases.
    Type: Grant
    Filed: December 5, 1994
    Date of Patent: October 29, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventor: Hubert Wolf
  • Process for using tantalum (V) nitride as a pigment and the colored products produced thereby
    Patent number: 5569322
    Abstract: An improved method for producing tantalum (V) nitride by means of nitriding an oxidic tantalum (V) compound is described. The Ta.sub.3 N.sub.5 product obtained in accordance with this method may be used as a red coloring pigment, particularly for coloring plastics and varnishes. An improved color intensity can be achieved and/or the reaction time can be shortened using the process in accordance with the invention. The process includes nitriding tantalum (V) hydrated oxide with the composition of the formula Ta.sub.2 O.sub.5. aq with a hydrate content (i.e., aq content) in a range of 14 to 17% by weight. The nitridation preferably takes place in the presence of a fluxing agent such as ammonium carbonate or boric acid.
    Type: Grant
    Filed: November 10, 1994
    Date of Patent: October 29, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Martin Jansen, Hans-Peter Letschert, Dietrich Speer
  • Method for producing granulated sodium percarbonate
    Patent number: 5560896
    Abstract: Sodium percarbonate is produced by means of fluidized bed granulation. The process includes spraying an aqueous sodium carbonate solution and a hydrogen peroxide solution onto nuclei in a fluidized bed and evaporating the water. In the process of the invention, it is not necessary to use a phosphorus-containing crystallization inhibitor in order to avoid cloggings and incrustations in and on the nozzle. This is accomplished by spraying the solutions through separate channels in a single ternary atomizer nozzle, to provide external mixing of the solutions with respect to the nozzle.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: October 1, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Martin Bewersdorf, Claas-Jurgen Klasen, Petra Look-Herber, Birgit Bertsch-Frank, Thomas Lieser, Klaus Muller
  • Method for treating water with acrolein and a device for the performance thereof
    Patent number: 5560833
    Abstract: Stretches of flowing water are doped with acrolein for the purpose of preventing excessive growth of plants and algae. In order to avoid transport of acrolein, acrolein is produced at the site where it is required by deacetalation of an acrolein acetal in the presence of an aqueous mineral acid. No electrical energy is necessary for this process. An acrolein acetal and an aqueous mineral acid solution are delivered from compression-proof storage tanks into a mixing chamber by the application of pressure from a pressure cylinder. The mixture is passed through a deacetalation reactor unit which includes a tubular reactor part and a container-shaped reactor part.
    Type: Grant
    Filed: July 27, 1994
    Date of Patent: October 1, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Peter Werle, Bernd Geissler, Martin Trageser
  • Flotation process for mechanical pulp using a surface active agent
    Patent number: 5554258
    Abstract: An improved process for bleaching pulps is disclosed in which the unbleached pulp is subject to flotation before bleaching and, if necessary, the circulating water is also purified of interfering compounds by flotation.
    Type: Grant
    Filed: May 5, 1994
    Date of Patent: September 10, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Hans U. Suess, Norbert Nimmerfroh, Ralf Grimmer
  • Aqueous solutions of organopolysiloxane-ammonium compounds, methods of their manufacture and use
    Patent number: 5552474
    Abstract: Disclosed are aqueous solutions of polymeric organosiloxane-ammonium compounds which possess ion exchange properties and a method for manufacture from solid organopolysiloxanes. The solutions are used in the hydrophobing treatment of inorganic materials and building materials.
    Type: Grant
    Filed: March 3, 1995
    Date of Patent: September 3, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Peter Panster, Stefan Wieland
  • Method of producing flexible plastic bands compounded with hard-material powders and/or soldering powders
    Patent number: 5547625
    Abstract: In order to manufacture flexible plastic bands of a thermoplastic synthetic resin containing 40% or more by volume hard materials and/or soldering powder, two grooved and heated shearing rollers arranged parallel to one another and running in opposite directions are used onto which components are applied. The front shearing roller must have a temperature of 25.degree. to 90.degree. C. on the application side and of 30.degree. to 80.degree. C. on the removal side, the rear shearing roller must have a temperature of 30.degree. to 130.degree. C. on the application side and on the removal side of 35.degree. to 100.degree. C., and the temperature of the rear shearing roller must be at least 5.degree. C. above the temperature of the front shearing roller. In addition, the front shearing roller must exhibit a speed of 5 to 25 rpms and the rear roller a speed which is 5 to 70% lower.
    Type: Grant
    Filed: January 7, 1994
    Date of Patent: August 20, 1996
    Assignee: Degussa Aktiengesellschaft
    Inventors: Karlheinz Gleissner, Hans-Martin Ringelstein, Ekkehard Lange