Patents by Inventor Norbert Kohle

Norbert Kohle 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 and products of purification of anhydrosugar alcohols
    Patent number: 6670033
    Abstract: A process for the formation of a purified anhydrosugar alcohol is disclosed, whereby the resultant purified anhydrosugar alcohol has a purity of at least 99.8% and is substantially colorless. The anhydrosugar alcohol is purified by distillation, recrystallization from methanol, ethanol or ethylene glycol, melt recrystallization, or a combination thereof. Preferably, the purification is by distillation followed by recrystallization from methanol, ethanol or ethylene glycol. A test for determining the purity of the anhydrosugar alcohol is disclosed, wherein the color of the anhydrosugar alcohol after annealing at a temperature of at least 260° C. for at least four hours is examined. Alternatively, purity can be determined by examination of ultraviolet (UV) transmittance of the purified anhydrosugar alcohol at various wavelengths.
    Type: Grant
    Filed: November 27, 2001
    Date of Patent: December 30, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Michael A. Hubbard, Michael Wohlers, Helmut B. Witteler, Edward G. Zey, George Kvakovszky, Thomas H. Shockley, Larry F. Charbonneau, Norbert Kohle, Jochen Rieth