Patents by Inventor Othmar Stelzer

Othmar Stelzer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6300517
    Abstract: A description is given of new chiral phosphine ligands containing amino acid groups and having the formula I where R1 is hydrogen, a C1-C7-alkyl radical, a C6-C10-aryl radical or a monovalent metal, preferably sodium or potassium, R2 is hydrogen or a C1-C7-alkyl radical, R3 is hydrogen or an —NR5R6 radical, where R5 and R6 are identical or different and are hydrogen or C1-C7-alkyl or C6-C10-aryl radicals, m is 0 or 1, with the exception of the compounds in which R5 and R6 are hydrogen and at the same time R2 is hydrogen, R4 is phenyl and R1 is methyl or benzyl and a process for their preparation. These phosphine ligands are suitable as constituents of metal complexes which can be used as catalysts for reactions to form C—C, C—H, C—N, C—Si or C═O bonds.
    Type: Grant
    Filed: December 10, 1999
    Date of Patent: October 9, 2001
    Assignee: Celanese GmbH
    Inventors: Othmar Stelzer, Michael Tepper
  • Patent number: 6187953
    Abstract: Guanidinium phosphanes of Formula I wherein the substituents are defined as in the specification which are useful catalyst ligands for the carbon-carbon linkage reactions of the hect reaction.
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: February 13, 2001
    Assignee: Celanese GmbH
    Inventors: Othmar Stelzer, Franz Peter Schmidtchen, Antonella Hessler, Michael Tepper, Harald Dibowski, Michael Riedel, Helmut Bahrmann
  • Patent number: 6011172
    Abstract: The invention relates to a process for preparing alkali metal salts and/or alkaline earth metal salts of alkylphosphonous acids and dialkylphosphinic acids from elemental yellow phosphorus and alkyl halides, which comprises carrying out the reaction in the presence of aqueous alkali metal hydroxide or alkaline earth metal hydroxide or mixtures thereof. The invention likewise relates to the use of the compounds prepared by the process according to the invention for preparing flame retardants, extraction media and plant protection agents.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: January 4, 2000
    Assignee: Clariant GmbH
    Inventors: Norbert Weferling, Othmar Stelzer, Gunter Kolbe
  • Patent number: 5925785
    Abstract: The invention relates to secondary and tertiary phosphines of the formula ##STR1## in which R is hydrogen, an aryl or benzyl group or a straight-chain or branched alkyl group, n is 1 or 2 and M is potassium or sodium.These phosphines are prepared by reacting either alkali metal salts of fluorobenzene-2,4-disulfonic acid with phosphine or with primary or secondary phosphines, or secondary phosphines of the type HP?C.sub.6 H.sub.3 -2,4-(SO.sub.3 M).sub.2 !.sub.2 with a compound RX in which R is an alkyl, aryl or benzyl group and X is a halogen, in an aprotic solvent in the presence of at least stoichiometric quantities of a solid, powdered alkali metal hydroxide at temperatures of from 0 to 100.degree. C.
    Type: Grant
    Filed: March 20, 1997
    Date of Patent: July 20, 1999
    Assignee: Celanese GmbH
    Inventors: Othmar Stelzer, Oliver Herd, Norbert Weferling
  • Patent number: 5268479
    Abstract: A process is specified for the preparation of tertiary phosphines of the formulaR'PR.sub.2 or R.sub.2 P--[CH.sub.2 ].sub.3 --PR.sub.2in which R is an aryl, pyridyl or arylsulfonic acid group and R' is an aryl, pyridyl, arylsulfonic acid or n-butyl group, which comprises reacting phosphines of the formulaH.sub.n PR".sub.3-n or H.sub.2 P--[CH.sub.2 ].sub.3 --PH.sub.2in which R" is hydrogen or an n-butyl, aryl or pyridyl group and n is 1 or 2 with a halogen compound of the formulaX-R,in which R has the abovementioned meaning and X is fluorine, chlorine or bromine, in the presence of powdered potassium hydroxide and dimethyl sulfoxide and/or dimethoxyethane at temperatures between 0 and 100.degree. C., at least 1 mol of potassium hydroxide being used per mole of halogen compound.
    Type: Grant
    Filed: December 2, 1992
    Date of Patent: December 7, 1993
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Othmar Stelzer, Klaus-Peter Langhans, Norbert Weferling
  • Patent number: 5003108
    Abstract: For the preparation of phosphanes, phosphane and alkyl halides are reacted in the presence of alkali metal hydroxide solutions and tetraalkylammonium or tetraalkylphosphonium salts as the catalysts.
    Type: Grant
    Filed: December 11, 1989
    Date of Patent: March 26, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Othmar Stelzer, Klaus-Peter Langhans, Jurgen Svara, Norbert Weferling