Development of molecular and solid catalysts for the direct low-temperature oxidation of methane to methanol.

The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active homogeneous molecular catalyst system and on heterogeneous molecular catalysts based on polymeric materials possessing ligand motifs within the material structure. The N-(2-methylpropyl)-4,5-diazacarbazolyl-dichloro-platinum(II) complex reaches significantly higher activity compared to the well-known Periana system and allows first conclusions on electronic and structural requirements for high catalytic activity in this reaction. Interestingly, comparable activities could be achieved utilizing a platinum modified poly(benzimidazole) material, which demonstrates for the first time a solid catalyst with superior activity compared to the Periana system. Although the material shows platinum leaching, improved activity and altered electronic properties, compared to the conventional Periana system, support the proposed conclusions on structure-activity relationships. In comparison, platinum modified triazine-based catalysts show lower catalytic activity, but rather stable platinum coordination even after several catalytic cycles. Based on these systems, further development of improved solid catalysts for the direct low-temperature oxidation of methane to methanol is feasible.

Parallelized N2O frontal chromatography for the fast determination of copper surface areas.

A parallel reactor setup in combination with a spatially resolving Fourier transform infrared focal plane array detector (FTIR-FPA) system in rapid scan mode has been developed which is capable of analyzing simultaneously the specific surface area of 15 copper catalysts. The system allows the reliable determination of copper surface areas with an error of about +/-1 m(2)/g. Problems are encountered with very fluffy catalyst powders, since this leads to excessive pressure drop over the catalyst bed. The error brought about by this effect can be eliminated by taking into account the flow deviations between channels in such cases.