Basf Se Corporation

Basf Aktiengesellschaft

Marko Friedrich

Klaus Ebel

Rocco Paciello

Gunnar Heydrich

Wolfgang Krause

Gabriele Gralla

Norbert Götz

Matthias Rauls

Nawid Kashani-Shirazi

Steffen Oehlenschläger

Christoph Jäkel

Joachim Schmidt-Leithoff

Eike Johannes Bergner

Frank Hettche

Christoph Jäkal

Christian Zahm

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 has the following steps

Method for producing optically active, racemic menthol

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.

The present invention relates to a method of working up an aluminum-containing reaction product from the production of isopulegol by cyclization of citronellal in the presence of complex compounds, comprising at least one ligand of the formula (I),  Moreover, the invention relates to a method of producing isopulegol, and to a method of producing menthol.

Recovery of phenol ligands during the production of isopulegol

The present invention relates to diarylphenoxyaluminum compounds which are obtainable by reacting a bis(diarylphenol) ligand of the formula (I) with an alkylaluminum compound and/or a complex aluminum hydride. The invention moreover relates to the use of such diarylphenoxyaluminum compounds as catalysts. Moreover, the invention relates to a method of producing isopulegol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts. The invention also relates to a method of producing menthol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts and subsequent hydrogenation.

Diarylphenoxy aluminum compounds

The invention relates to a process for preparing optically active alkylsuccinic acid monoalkyl esters of the formula (I) where D and E are independently of one another H, C-Calkyl, R is C-Calkyl, aryl or alkylaryl.

Method for the production of optically active alkyl succinic acid monoalkyl esters

The present invention relates to a process for the preparation of isopulegol of formula (I): comprising the cyclization of citronellal of formula (II): in the presence of a tris(aryloxy)aluminum catalyst, wherein the cyclization is carried out in the presence of

Growing community of inventors

Lorsch, Germany

Marko Friedrich