Patents Assigned to Degussa Aktiengesellschaft
  • Patent number: 5965760
    Abstract: This invention relates to a process for reducing the sulfane chain length of bis(silylorganyl)polysulfanes, in which these compounds are reacted with an anhydrous sulfide and a haloalkylsilane compound.
    Type: Grant
    Filed: November 13, 1998
    Date of Patent: October 12, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Rudolf Michel, Jorg Munzengerg
  • Patent number: 5962696
    Abstract: There is provided a process for the work-up of this material having the formula ##STR1## because of its poor crystallizability has heretofore been available only with large yield losses. The yield losses are due to the fact that the crystals of this compound are associated with large amounts of residual solvent material which gives rise to complex and expensive drying procedures. In accordance with the present invention the crude LPE is dried by means of fluid or supercritical carbon dioxide which maces it possible to reduce drying times from the previous range of about 124 hours to about 10 hours for the same amount of product and thus produce a dry LPE which has smaller amounts of residual solvent, as well as smaller by-products than that obtained by conventional drying.
    Type: Grant
    Filed: June 9, 1998
    Date of Patent: October 5, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Herbert Tanner, Karlheinz Drauz, Klaus Stingl, Gerhard Sator, Horst Bethge, Roland Moller, Thomas Tacke, Claus Rehren
  • Patent number: 5961945
    Abstract: An ammoxidizable compound is reacted with an ammonium salt, especially an inorganic ammonium salt, in the presence of a source of oxygen and an ammoxidation catalyst at 100 to 700.degree. C., preferably 200 to 700.degree. C., in order to produce cyano compounds of the formula R--CN, in which R is H or an organic group.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: October 5, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Lukas M. J. Von Hippel, Jorg Sauer, Rudiger Schutte, Manfred Sauer, Dietrich Arntz
  • Patent number: 5962131
    Abstract: Process for the production of preoriented filaments from polyester-based polymer mixtures by spinning the polymer mixtures with a draw-off speed v of at least 2500 m/min, a second amorphous, thermoplastically processable copolymer having a glass transition temperature of more than 100.degree. C. being added to the polyester, wherein the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyester is 1:1 to 10:1, in that the amount of copolymer added to the polyester is at least 0.05 wt.
    Type: Grant
    Filed: August 5, 1998
    Date of Patent: October 5, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Helmut Schwind, Wolfgang Janas, Klaus Dorn, Peter Kempf, Dietmar Wandel, Joachim Cziollek, Ulrich Thiele, Alexander Klein, Heinz-Dieter Schumann
  • Patent number: 5952399
    Abstract: A dental material based on an organic polymerisable binding agent has a content ofA) one or more mixed apatites of the typeA1) A.sub.10 (XO.sub.4).sub.6 Z.sub.2 +/B*.sub.10-u C*.sub.u (Y*).sub.6 Z'.sub.2 and/orA2) A'.sub.10-r (X'O.sub.4).sub.6-s Z".sub.2-t +/B'.sub.r (Y').sub.s Q.sub.t -B".sub.10-u' C'.sub.u' (Y").sub.6 Z'".sub.2 and/orA3) A".sub.10-r' (X"O.sub.4).sub.6-s' Z"".sub.2-t' +/A'".sub.r' (X'"O.sub.4).sub.s' +/B'".sub.10-u" C".sub.u" (Y'").sub.6 Z'"".sub.2in which the formulae assume the significance specified in the description, in a quantity that is effective for the absorption of ions from the biological application environment of the dental material. The polymerisable dental material has variably adjustable transparency, good polishability, high strength and the capacity to release and absorb ions into and from a biological environment. Also described is a process for using the mixed apatites A1), A2) and/or A3) in polymerisable dental materials.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: September 14, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventor: Harald Rentsch
  • Patent number: 5935708
    Abstract: In order to increase active oxygen stability, sodium percarbonate is coated with single or multiple layers of various substances. Sodium percarbonate particles consist of a core of sodium percarbonate fluidized bed spray granulate and sodium sulphate, which may be partially hydrated, as the sole constituent of a single coating layer. The particles exhibit both elevated active oxygen stability and very good ensilability. The coating layer is applied by spraying an aqueous Na.sub.2 SO.sub.4 solution onto the particles to be coated, which were themselves produced by fluidized bed spray granulation, in a fluidized bed and vaporizing water at a fluidized bed temperature of 35 to 100.degree. C.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: August 10, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Ruediger Schuette, Martin Bewersdorf, Claas-Juergen Klasen
  • Patent number: 5936112
    Abstract: Mixtures are disclosed of bis(silylorganyl)polysulfanes and silylorganylthiocyanates, which are produced by reacting polysulfanes with cyanides. The inorganic thiocyanate formed is subsequently allowed to react with a haloalkylalkoxysilane to form the silylorganylthiocyanate. These substances are used in plastic and rubber mixtures reinforced with silica and optionally carbon black.
    Type: Grant
    Filed: July 10, 1998
    Date of Patent: August 10, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Thomas Gobel, Ulrich Deschler, Jorg Munzenberg, Gerd Zezulka
  • Patent number: 5934073
    Abstract: An auxiliary heating system for a motor vehicle with an internal combustion engine. The auxiliary heating includes an emission control catalyst and a heat exchanger, integrated in the converter housing in front of and/or behind the catalyst, which provides the reaction heat released by the catalyst and the remaining heat of the exhaust gas to the heating of the passenger compartment. The heat generation may be increased by the injection of a fuel/air mixture before the catalyst and by using the catalyst as a catalytic burner and can be adapted to the heat requirements. The auxiliary heating of the invention prevents possible thermal damage of the catalyst during operation as a catalytic burner without many regulating elements by cooling the catalyst radiation. For this purpose, the heat exchanger is provided with an exchange surface which can freely exchange radiation with the radiant surface of the catalytic element.
    Type: Grant
    Filed: May 14, 1998
    Date of Patent: August 10, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Jurgen Gieshoff, Egbert Lox, Thomas Kreuzer
  • Patent number: 5932758
    Abstract: Disclosed is a process for producing .beta.-amino-.alpha.-hydroxycarboxylic acid derivatives of general formula (2R,3S)- or (2S,3E)-N-(X,Y)-3-amino-2-hydroxy-3-phenyl propionic acid-Z of Formula I, ##STR1## e.g. of (2E,3S)-3-amino-2-hydroxy-3-phenyl propionic acid or (2R,3S)-N-benzoyl-3-amino-2-hydroxy-3-phenyl propionic acid methylester. Compounds of type I are valuable intermediates in the total synthesis of Taxols which can be used in the treatment of various forms of cancer.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: August 3, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Klaus Stingl, Matthias Kottenhahn, Karlheinz Drauz
  • Patent number: 5928984
    Abstract: A process for preparing catalytically active coatings for the synthesis of hydrogen cyanide on moulded items substantially consisting of aluminum oxide. The catalytically active coating contain, as active components, at least one platinum group metal and a nitrate which are applied to the moulded item by means of a coating dispersion which contains the active components as finely divided solids. This means that the hitherto conventional production of aluminum nitride during the forming process is not required. The coatings therefore achieve their final activity level, which is well above that of conventional coatings, very rapidly. In addition, these catalysts can be started up under high load and have a lower operating temperature.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: July 27, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Lukas von Hippel, Christian Bussek, Joerg Sauer, Manfred Sauer, Dietrich Arntz
  • Patent number: 5928518
    Abstract: Process for separating and/or isolating organic compounds which are soluble in water, some of which are adsorbed on finely divided inorganic solids, by adsorption of this fraction and isolation of the loaded solid, which is characterised in thata) the solutions containing the organic compounds are placed in contact with a suitable solid, then cross-flow filtration is performed byb) allowing the suspensions produced to flow alongside a porous surface/membrane, whereinc) a pressure difference is set up between the side being flowed over and the opposite side of the surface/membrane,d) so that a fraction of the solution from which adsorbable compounds (a) have been partly or completely removed and is flowing over the surface/membrane passes through the surface/membrane in atransverse direction with respect to the direction of flow (filtrate flow),e) the non-adsorbed organic compounds (b) are isolated from this fraction,f) the fraction of solution or suspension which does not pass through the surface/membrane, op
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: July 27, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Wiltrud Schafer-Treffenfeldt, Stefan Stockhammer, Gerard Richet, Gunter Weissland
  • Patent number: 5925708
    Abstract: A precipitated silica with the following physicochemical properties:______________________________________ BET surface area 35 to 350 m.sup.2 /g BET/CTAB surface area ratio 0.8 to 1.1 Pore volume, PV 1.6 to 3.4 ml/g Silanol group density (V2 = 6 to 20 ml NaOH consumption) Average aggregate size 250 to 1500 nm CTAB surface area 30 to 350 m.sup.2 /g DBP value 150 to 300 ml/100 g V.sub.2 /V.sub.1 by Hg porosimetry 0.19 to 0.46 DBP/CTAB 1.2 to 2.4. ______________________________________is produced by reacting alkali silicate with mineral acids at temperatures of 60 to 95.degree. C. while maintaining a pH of 7.5 to 10.5 and continuously stirring, continuing the reaction to a solids concentration in the precipitation suspension of 90 to 120 g/l, adjusting the pH value to a value of less than or equal to 5, filtering out, washing, drying and optionally grinding or granulating the precipitated silica. The precipitated silica is used as a filler in vulcanizable rubber compounds and vulcanizates.
    Type: Grant
    Filed: July 15, 1997
    Date of Patent: July 20, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Heinz Esch, Udo Gorl, Robert Kuhlmann, Ralf Rausch
  • Patent number: 5922647
    Abstract: An anellated (oxa)hydantoin comprising the formula I ##STR1## wherein the (oxa)hydantoin of formula I possesses outstanding herbicidal properties.
    Type: Grant
    Filed: June 12, 1997
    Date of Patent: July 13, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Matthias Schafer, Karlheinz Drauz
  • Patent number: 5922900
    Abstract: A process for producing carboxylic acid esters by the following steps:a) preparation of a reaction mixture containing an alcohol and a carboxylic acid and/or a carboxylic anhydride and/or a carboxylic acid ester and or a partially esterified carboxylic acid,b) heating of this mixture to the suitable reaction temperature in the presence of a solid polysiloxane insoluble in the reaction medium and having sulphonic acid groups with intensive thorough mixing accompanied by continuous separation of the reaction water which forms, wherein the polysiloxane used as the catalyst in modified by treatment with a soluble aluminum, titanium or zirconium compound, and the spherical particles thereof have a diameter of 0.01 to 3 mm, a specific surface of 0.1 to 1200 m.sup.2 /g, a specific pore volume of 0.01 to 6.0 ml/g and a bulk density of 50 to 1000 g/l.
    Type: Grant
    Filed: September 3, 1997
    Date of Patent: July 13, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Stefan Wieland, Peter Panster
  • Patent number: 5919566
    Abstract: Inorganic support materials containing sulphonate and mercapto groups, and a process for the modification of these materials with the corresponding difunctional organosilicon compounds and use thereof as catalysts in acid-catalyzed reactions.
    Type: Grant
    Filed: October 21, 1996
    Date of Patent: July 6, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Hans Lansink-Rotgerink, Stefan Wieland, Emmanuel Auer
  • Patent number: 5919430
    Abstract: Microporous and mesoporous metal silicates are prepared by the hydrothermal reaction of a silicon and metal source in the presence of a template. The choice of raw materials influences the purity and hence the catalytic activity of the products. A pyrogenic mixed oxide is used as the silicon and metal source. Prepared products have the composition (SiO.sub.2).sub.1-x (A.sub.m O.sub.n).sub.x, where A is Ti, Al, B, V or Zr and x is 0.005 to 0.1. Shaped objects of the microporous and mesoporous metal silicates are obtained directly by using a shaped object of the pyrogenic mixed oxide. The products obtained are used as oxidation catalysts.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: July 6, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Steffen Hasenzahl, Helmut Mangold, Eckehart Roland, Mario Scholz, Georg Thiele
  • Patent number: 5914075
    Abstract: New alkali metal cyanide granulates based on sodium cyanide or potassium cyanide and a method for their preparation are disclosed. Commercially available alkali metal cyanide granulates consist of irregular particles; disadvantages are in particular the tendencies to form dust and to cake. The disclosed alkali metal cyanide granulates demonstrate a reduced tendency to cake and virtually no abrasion. The granulates are characterized by essentially spherical particles with particle diameters in the range 0.1 to 20 mm, a bulk density of more than 600 g/dm.sup.3, an abrasion of less than 1%, and a caking index of at most 4. The granulates can be prepared by fluidized bed spray granulation involving spraying an aqueous solution containing alkali metal cyanide onto alkali metal cyanide nuclei in a fluidized bed and evaporating the water.
    Type: Grant
    Filed: December 27, 1996
    Date of Patent: June 22, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Herbert Riemenschneider, Christian Alt, Martina Claus, Juergen Loroesch, Josef Leutner, Heinz Moench, Ruediger Schuette, Stefan Schulze
  • Patent number: 5907065
    Abstract: A method of producing 3,5,5-trimethylcyclohexa-3-ene-1-one (.beta.-isophorone) by isomerization of 3,5,5-trimethylcyclohexa-2-ene-1-one (.alpha.-isophorone) in a liquid phase in the presence of a homogeneous or heterogeneous catalyst in which a mixture with a relatively low concentration of .beta.-isophorone is drawn off from the reaction container and the .beta.-isophorone isolated by vacuum distillation. .beta.-isophorone is an important synthetic structural element for the production of carotinoids, vitamins and pharmaceutical products.
    Type: Grant
    Filed: September 26, 1997
    Date of Patent: May 25, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Steffen Krill, Gunes Giray, Frank Hubner, Rainer Hahn, Klaus Huthmacher, Herbert Tanner
  • Patent number: 5902682
    Abstract: Coated sodium percarbonate particles contain, in the coating, sodium carbonate and also one or more magnesium compounds, preferably magnesium sulfate, optionally in a partially hydrated form, in a single layer or in separate layers in the coating. Preferred coated sodium percarbonate particles contain two layers. Particles are prepared by spraying aqueous solutions containing the coating components onto sodium percarbonate in a fluidized bed with simultaneous evaporation of the water. The particles are suitable for use in detergents, bleaches and cleansing agents.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: May 11, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Birgit Bertsch-Frank, Martin Bewersdorf, Claas-Juergen Klasen, Thomas Lieser, Klaus Mueller, Juergen Rollmann
  • Patent number: 5900386
    Abstract: Disclosed are shell catalysts which contain, on powdered or shaped supports, one or more metals from groups VIII and IB of the Periodic Table of Elements. The catalysts are obtained by coating the support with the catalytically active metals in aqueous solutions of mono- or bimetallic colloids of these metals, wherein the colloids are stabilized by highly hydrophilic surfactants.
    Type: Grant
    Filed: July 14, 1997
    Date of Patent: May 4, 1999
    Assignee: Degussa Aktiengesellschaft
    Inventors: Andreas Freund, Peter Panster