Patents by Inventor David Y. Hsieh

David Y. Hsieh 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: 4306944
    Abstract: An improved process of distilling a cyclohexanone-rich overhead stream in a first still from a feed mixture comprising cyclohexanone, phenol and cyclohexanol of the type wherein a cyclohexanone-rich stream is withdrawn as a part of an overheads condensate from the first still and a phenol-rich stream is withdrawn as a part of a reboiled bottom stream from the first still. The improvement includes withdrawing a side stream substantially free of phenol from above the point where the feed mixture is fed to the first column and separating the side stream in a second still into a second cyclohexanone-rich overhead stream and a bottom stream containing cyclohexanone and cyclohexanol. The second cyclohexanone-rich stream may be returned to the first still.
    Type: Grant
    Filed: July 3, 1980
    Date of Patent: December 22, 1981
    Assignee: Allied Corporation
    Inventors: Andiappan K. Murthy, David Y. Hsieh