Jens Langanke

Substrate dependent synergetic and antagonistic interaction of ammonium halide and polyoxometalate catalysts in the synthesis of cyclic carbonates from oleochemical epoxides and CO2

Organic halides and polyoxometalates (POMs) were studied as catalyst systems for the insertion of carbon dioxide into epoxides originating from plant oils as biogenic feedstock. In the formation of methyl oleate carbonate, synergistic rate acceleration and increased cis-selectivity were observed using ammonium halide and transition metal substituted silicotungstate POMs catalysts in a combined system. Mechanistic insight into the cooperative action was gained by kinetic measurements and analysis of the stereochemical outcome of the reaction. For poly-epoxidised oleochemicals as substrates, the simple ammonium halide catalyst gave better performance as side reactions were encountered with the POM-containing system.

Regulated Systems for Catalyst Immobilisation Based on Supercritical Carbon Dioxide

Promising strategies to use supercritical CO2 (scCO2)for catalyst immobilisation can be developed on the basis of its unique and tunable solubility propertiesin the vicinity of, and especially just beyond, the critical data of pure carbon dioxide. The present chapterdescribes briefly the background and experimental details of four different methods. In the first case,scCO2 is used as a “switch” to precipitate homogeneous catalystsand extract the organic components. Biphasic systems, where an immiscible liquid provides a permanentstationary phase for the catalyst, are exemplified for polyethylene glycol (PEG) and ionic liquids as thecatalyst phase. Finally, so-called inverted biphasic systems, where scCO2 servesas the stationary phase for the catalyst, are presented with water as the mobile substrate/product phase.

Polymers from CO 2 —An Industrial Perspective

The chemical utilisation of carbon dioxide (CO2) as feedstock for the production of valuable polymers is a rewarding challenge. CO2 can either be used directly by copolymerization or indirectly by transformation of building blocks which were obtained from CO2 in a previous step. Both routes are discussed here. Moreover, the direct epoxide/CO2 copolymerization to yield polyether carbonates and the industrial efforts in the catalytic process development and scale-up at Bayer are highlighted and explained in detail.