Patents by Inventor Grace Tsien

Grace Tsien 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 recovering and purifying herbicidal phenoxybenzoic acid derivatives
    Patent number: 4594440
    Abstract: Crude phenoxybenzoic acid herbicide, e.g., acifluorfen, having one or more undesirable isomer/by-product impurities associated therewith is separated therefrom employing an inert solvent which is selective for the isomers/other by-products.
    Type: Grant
    Filed: July 25, 1983
    Date of Patent: June 10, 1986
    Assignee: Rhone:Pulenc, Inc.
    Inventors: Thomas J. Giacobbe, Grace Tsien
  • Process for recovering and purifying herbicidal phenoxybenzoic acid derivatives
    Patent number: 4405805
    Abstract: Crude phenoxybenzoic acid herbicide, e.g., acifluorfen, having one or more undesirable isomers/by-product impurities associated therewith is separated therefrom employing an inert solvent which is selective for the isomers/other by-products.
    Type: Grant
    Filed: July 27, 1981
    Date of Patent: September 20, 1983
    Assignee: Rhone-Poulenc, Inc.
    Inventors: Thomas J. Giacobbe, Grace Tsien
  • Use of calcium chloride to minimize hydrofluoric acid corrosion to glass during the chlorination of 4-chlorobenzotrifluoride
    Patent number: 4401623
    Abstract: There is provided a method for preventing corrosion in a glass-lined vessel due to HF liberated from an organic liquid medium. The method involves adding CaCl.sub.2 particles to this medium. This method is particularly useful in the chlorination of 4-chlorobenzotrifluoride to 3,4-dichlorobenzotrifluoride.
    Type: Grant
    Filed: July 17, 1981
    Date of Patent: August 30, 1983
    Assignee: Rhone-Poulenc Agrochimie
    Inventors: Thomas J. Giacobbe, Grace Tsien