The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 27, 2012
Filed:
Nov. 13, 2008
Gunnar Heydrich, Limburgerhof, DE;
Gabriele Gralla, Mannheim, DE;
Matthias Rauls, Blieskastel, DE;
Joachim Schmidt-leithoff, Mannheim, DE;
Klaus Ebel, Lampertheim, DE;
Wolfgang Krause, Brühl-Rohrhof, DE;
Steffen Oehlenschläger, Ludwigshafen, DE;
Christoph Jäkal, Limburgerhof, DE;
Marko Friedrich, Lorsch, DE;
Eike Johannes Bergner, Friesenheim-Heiligenzell, DE;
Nawid Kashani-shirazi, Ilvesheim, DE;
Rocco Paciello, Bad Dürkheim, DE;
Gunnar Heydrich, Limburgerhof, DE;
Gabriele Gralla, Mannheim, DE;
Matthias Rauls, Blieskastel, DE;
Joachim Schmidt-Leithoff, Mannheim, DE;
Klaus Ebel, Lampertheim, DE;
Wolfgang Krause, Brühl-Rohrhof, DE;
Steffen Oehlenschläger, Ludwigshafen, DE;
Christoph Jäkal, Limburgerhof, DE;
Marko Friedrich, Lorsch, DE;
Eike Johannes Bergner, Friesenheim-Heiligenzell, DE;
Nawid Kashani-Shirazi, Ilvesheim, DE;
Rocco Paciello, Bad Dürkheim, DE;
BASF SE, Ludwigshafen, DE;
Abstract
The present invention relates to a particularly economic overall method for producing menthol, specifically for producing optically active, essentially enantiomerically and diastereomerically pure L-menthol and racemic menthol, starting from the starting material citral which is available inexpensively on an industrial scale. The method comprises the following steps a) catalytic hydrogenation of neral and/or geranial to give citronellal, b) cyclization of citronellal to isopulegol in the presence of an acidic catalyst, c) purification of isopulegol by crystallization and d) catalytic hydrogenation of isopulegol to give menthol.