Patents by Inventor James H. Dube

James H. Dube 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 purification of O,O-di(lower)alkyldithiophosphoric acids
    Patent number: 4209471
    Abstract: A liquid-liquid extraction method for recovering O,O-di(lower)alkyldithiophosphoric acid of increased purity from a crude mixture in which it is contained comprises intimately contacting said mixture with an acidic aqueous solution to form two liquid phases whereby the concentration of the thiophosphoric acid in the aqueous phase is increased; separating the two phases; contacting the aqueous phase with a stable, water-immiscible, volatile, organic solvent to form two liquid phases whereby the concentration of the thiophosphoric acid in the organic solvent is increased; separating the two phases; and vaporizing the organic solvent to recover high purity O,O-di(lower)alkyl dithiophosphoric acid.
    Type: Grant
    Filed: May 10, 1977
    Date of Patent: June 24, 1980
    Assignee: Ciba-Geigy Corporation
    Inventors: James H. Dube, Ralph Miller