Patents by Inventor Ruldolf Hopp

Ruldolf Hopp 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).

  • Separating optically pure d-l-isomers of menthol, neomenthol and isomenthol
    Patent number: 3943181
    Abstract: A process for the separation of optically active d- and l-isomers of a compound selected from the group consisting of menthol, neomenthol and isomenthol, which comprises esterifying a d,l-isomeric mixture of the compound with an acid selected from the group consisting of benzoic acid optionally carrying at least one substituent on the benzene ring and hexahydrobenzoic acid; forming a supersaturated solution or a supercooled melt of the d,l-ester; inoculating the solution or melt with crystals of the d- or l-form of the ester to effect selective crystllization of one of the two optical isomers; separating the crystals and subjecting them to hydrolysis to yield the corresponding enantiomorph of the starting compound.
    Type: Grant
    Filed: September 3, 1974
    Date of Patent: March 9, 1976
    Assignee: Haarmann & Reimer Gesellschaft mit beschrankter Haftung
    Inventors: Jurgen Fleischer, Kurt Bauer, Ruldolf Hopp