Patents by Inventor Philippe Fresnel

Philippe Fresnel 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: 4108866
    Abstract: An improved method of producing dialkyl-sulfoxides by oxidizing corresponding dialkyl-sulfides with hydrogen peroxide in aqueous acidic medium. It remedies the drawback of the similar prior art as concerns the separation of the sulfoxide formed from its reaction medium. The new method permits of easily recovering the sulfoxides in the state of good purity.The improvement consists in mixing the reaction medium with a large proportion of a solvent capable of yielding an azeotropic mixture with water. Then, after oxidization, the water is removed by distillation as azeotropic mixture. Preferably solvents are used which dissolve the dialkyl-sulfide but do not dissolve the sulfoxide formed; heptane is a particularly useful solvent. When an excess of the solvent is used, there is obtained, after distilling off the azeotropic mixture, a slurry of sulfoxide and solvent, easy to separate.
    Type: Grant
    Filed: June 8, 1977
    Date of Patent: August 22, 1978
    Assignee: Societe Nationale des Petroles d'Aquitaine
    Inventors: Bernard Tramier, Raymond Delourme, Philippe Fresnel