Patents by Inventor Erhard Leistner

Erhard Leistner 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).

  • Process for the separation of dimethyl ether and chloromethane in mixtures
    Patent number: 5882485
    Abstract: A process for the separation of dimethyl ether and chloromethane in mixturesA process for the separation of dimethyl ether and chloromethane in mixtures by two distillation steps. In the first step, the mixture is subjected to an extractive distillation with water, aqueous salt solutions or organic liquids as extractant, the top product being chloromethane. In the second step, the dimethyl ether is separated from the extractant.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: March 16, 1999
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Peter Roth, Erhard Leistner, Hans Haverkamp, Wolfgang Wendel, Michael Kleiber
  • Process for the preparation and fractionation of a mixture of dimethyl ether and chloromethane with water as extractant
    Patent number: 5843286
    Abstract: A process for the preparation and fractionation of a mixture of dimethyl ether and chloromethane by extractive distillation with water as extractant. The mixture is prepared by reacting methanol with hydrogen chloride. It is then subjected to an extractive distillation with water as extractant, resulting in chloromethane as top product. In the next step, the dimethyl ether is removed by distillation and, in another step, the extraction water is separated from the methanol which is still present.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: December 1, 1998
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Peter Roth, Erhard Leistner, Hans Haverkamp
  • Process for the preparation and fractionation of a mixture of dimethyl ether and chloromethane with methanol as extractant
    Patent number: 5763712
    Abstract: This invention relates to a process for the preparation and fractionation of a mixture of dimethyl ether and chloromethane by extractive distillation with methanol as extractant. The mixture is prepared by reacting methanol with hydrogen chloride. The mixture is then distilled to remove water and is subsequently subjected to an extractive distillation with methanol as extractant, with chloromethane resulting as top product. In another distillation step, the remaining dimethyl ether is separated from the methanol.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: June 9, 1998
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Peter Roth, Erhard Leistner, Wolfgang Wendel