860296-11-3Relevant academic research and scientific papers
Solventless synthesis of propylene carbonate catalysed by chromium-salen complexes: Bridging homogeneous and heterogeneous catalysis
Ramin, Michael,Jutz, Fabian,Grunwaldt, Jan-Dierk,Baiker, Alfons
, p. 32 - 39 (2005)
Various homogeneous chromium-salen complexes were synthesised and tested concerning their catalytic performance in the synthesis of propylene carbonate from carbon dioxide and propylene oxide. The most active complexes were immobilised on a silica support and tested in the same reaction. Different immobilisation methods were applied including anchoring of the complex through coordination with the metal, and covalent bonding via the ligand. Rates up to 300 molproduct molCr-1 h-1 at 98% selectivity were achieved with the heterogeneous catalysts without the use of any additional solvent or co-catalyst. The coordinatively-bound complexes showed low stability and a very strong deactivation during reuse, whereas the corresponding covalently-bound complexes hardly showed any chromium leaching during catalyst recycling experiments. The catalysts were characterised by means of X-ray photoelectron spectroscopy (XPS), thermal analysis, inductively-coupled plasma optical emission spectrometry (ICP-OES) and diffuse reflectance IR spectroscopy (DRIFTS) in as-prepared state and after use.
