Patents by Inventor Rudolf Helm

Rudolf Helm 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: 5502256
    Abstract: 2,2'-Dinitrodiphenyl disulphide is obtained in particularly good yields and purities in a simple manner by reacting 2-chloronitrobenzene with an aqueous alkali metal disulphide solution in the presence of phase transfer catalysts and an organic solvent.
    Type: Grant
    Filed: December 7, 1994
    Date of Patent: March 26, 1996
    Assignee: Bayer Aktiengesellschaft
    Inventors: Ferdinand Hagedorn, Helmut Fiege, Robert So/ llner, Rudolf Helm
  • Patent number: 4400560
    Abstract: A process for preparing a mixture of polyhydroxyl compounds having low molecular weight by catalytically hydrogenating a formose mixture with hydrogen on a metal catalyst. The hydrogenation is carried out at a pH of 7.5 to 12.5 and at elevated temperature and pressure. The formose mixture comprises (i) up to 70 wt. % formose, (ii) up to 1.6 wt. % lead ions and (iii) up to 5 wt. % calcium ions with at least one of (ii) or (iii) being present. The catalyst which is present in an amount of 4-240 wt. % (based on formose solution) is a compound taken from the group consisting of nickel, cobalt and compounds thereof. The mixture of polyhydroxyl compounds made in accordance with the present invention is useful as a starting material in the production of polyether polyols, polyester polyols and polyurethane plastics.
    Type: Grant
    Filed: March 9, 1981
    Date of Patent: August 23, 1983
    Assignee: Bayer Aktiengesellschaft
    Inventors: Roland Richter, Hanns P. Muller, Kuno Wagner, Rudolf Helm, Jurgen Zander
  • Patent number: 4034042
    Abstract: Object of the invention is a process for the production of 4-nitroso diphenylamine wherein N-nitroso diphenylamine is rearranged in the presence of an alcoholic hydrogen chloride solution by selecting the reaction conditions in such a way that the hydrochloride of 4-nitroso diphenylamine remains dissolved in the reaction medium. In this way spontaneous, uncontrollable decompositions do not occur.
    Type: Grant
    Filed: March 5, 1973
    Date of Patent: July 5, 1977
    Assignee: Bayer Aktiengesellschaft
    Inventors: Karlfried Wedemeyer, Rudolf Helm