Jan Schütz

Methyltrioxorhenium-catalysed oxidation of pseudocumene in the presence of amphiphiles for the synthesis of vitamin E

Vitamin E is an essential food component and antioxidant of major economic relevance. 2,3,5-Trimethyl-1,4-benzoquinone is a key intermediate in the production of vitamin E, which can now be selectively achieved through MTO-catalysed oxidation of simple and inexpensive pseudocumene (1,2,4-trimethylbenzene), in the presence of hydrogen peroxide and an appropriate amphiphile.

Catalytic oxidation of aromatic hydrocarbons by a molecular iron–NHC complex

An iron–NHC complex bearing a tetradentate bis(N-heterocyclic carbene) ligand is applied as catalyst for the oxidation of methyl substituted arene substrates. Using hydrogen peroxide as the oxidant p-xylene and pseudocumene are converted to the corresponding phenols and benzoquinones. The influence of various reaction parameters like temperature, catalyst loading, and oxidant concentration is investigated and kinetic experiments reveal that a temperature reduction leads to an increased catalyst lifetime. Furthermore, an interesting selectivity towards unexpected phenolic products resulting from a methyl shift reaction is observed.

Aldol Condensations Catalyzed by Basic Anion‐Exchange Resins

The aldol condensations of various aldehydes with ketones in the presence of anionic (basic) ion‐exchange resins have been investigated. Both batch and continuous modes were studied and compared for the reaction of citral (a mixture of geranial and neral) with acetone to give ψ‐ionone. Different reaction conditions were investigated, and the performances of five different ion‐exchange resins were compared. The most stable resins could be used for 10 cycles in batch mode or 1000 min in continuous mode without a significant loss in activity or selectivity.

A novel approach to timberwood fragrances

Timberone (1-(2,2,6-trimethylcyclohexyl)hexan-3-one), a compound interesting the fragrance industry, was synthesized in three steps, starting from readily available citral. All reaction steps could be catalyzed by heterogeneous catalysts in good selectivity.