Patents by Inventor Wolf-Dieter Pfeifer

Wolf-Dieter Pfeifer 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: 4961914
    Abstract: As a result of a special form of the surface coating of Al.sub.2 O.sub.3 catalysts using additional amounts of aluminum ions and very slight amounts of platinum ions, Al.sub.2 O.sub.3 was able to be used as catalyst for continuous operation (150 days and longer) in the preparation of hydrogen cyanide from hydrocarbons and ammonia, preferably in the BMA method.
    Type: Grant
    Filed: July 14, 1988
    Date of Patent: October 9, 1990
    Assignee: Degussa Aktiengesellschaft
    Inventors: Michael Witzel, Peter Kleinschmit, Wolf-Dieter Pfeifer, Carl Voigt, Peter Albers
  • Patent number: 4061674
    Abstract: Penicillamine or a homolog thereof is obtained by reacting a 2-disubstituted-5,5-alkyl-thiazolidine nitrile, alkyl having 1 to 6 carbon atoms, with a mineral acid in a two-stage proceeding wherein in the first stage relatively low temperatures and a relatively high concentration of the mineral acid are employed while in the second stage the concentration of the acid is relatively low and the temperatures are relatively high, the term "relatively" referring to the relationship of said two stages of the reaction with mineral acid.
    Type: Grant
    Filed: February 12, 1976
    Date of Patent: December 6, 1977
    Assignee: Deutsche Gold- und Silber-Scheideanstalt vormals Roessler
    Inventors: Friedrich Asinger, Wolf-Dieter Pfeifer, Heribert Offermanns, Paul Scherberich, Gerd Schreyer
  • Patent number: 4059589
    Abstract: Organic basic nitrogen compounds are formylated in the presence of acetic anhydride by adding the nitrogen compound as a salt and carrying out the formylation with an alkali or ammonium formate in an organic solvent having limited miscibility with water.
    Type: Grant
    Filed: July 12, 1974
    Date of Patent: November 22, 1977
    Assignee: Deutsche Gold- und Silber-Scheideanstalt vormals Roessler
    Inventors: Paul Scherberich, Wolf-Dieter Pfeifer
  • Patent number: 3946069
    Abstract: Penicillamine or a homolog thereof is obtained by reacting a 2-disubstituted-5,5-alkyl-thiazolidine nitrile, alkyl having 1 to 6 carbon atoms, with a mineral acid in a two-stage proceeding wherein in the first stage relatively low temperatures and a relatively high concentration of the mineral acid are employed while in the second stage the concentration of the acid is relatively low and the temperatures are relatively high, the term "relatively" referring to the relationship of said two stages of the reaction with mineral acid.
    Type: Grant
    Filed: December 20, 1972
    Date of Patent: March 23, 1976
    Assignee: Deutsche Gold-und Silber-Scheideanstalt vormals Roessler
    Inventors: Friedrich Asinger, Wolf Dieter Pfeifer, Heribert Offermanns, Paul Scherberich, Gerd Schreyer
  • Patent number: 3931208
    Abstract: 2 AND 5 SUBSTITUTED THIAZOLINE-(3) COMPOUNDS OF THE FORMULA: ##EQU1## in which R.sub.1, R.sub.2, and R.sub.3 and R.sub.4 are the same or different, R.sub.1 and R.sub.2 are straight or branched chain lower alkyl, alkenyl or aralkyl groups or together are a straight or branched chain alkylene or ethylenically unsaturated divalent aliphatic hydrocarbon group which joins with the adjacent carbon atom to form a ring and R.sub.3 and R.sub.4 are similarly defined except R.sub.3 can also be hydrogen by reaching a 2,2' dioxodisulfide of the formula ##EQU2## with an oxo compound of the formula ##EQU3## and with ammonia and hydrogen sulfide in the presence of an amine and an ammonium salt.
    Type: Grant
    Filed: November 5, 1973
    Date of Patent: January 6, 1976
    Assignee: Deutsche Gold- und Silber-Scheideanstalt vormals Roessler
    Inventors: Heribert Offermanns, Friedrich Asinger, Wolf-Dieter Pfeifer, Paul Scherberich, Gerd Schreyer