To determine suitable operating points for the PTK experiments, we first performed several steady-state experiments. We varied the pressure between 2 and 6 bar, the temperature between 220 and 280 °C and the H2:CO-ratio between 2 and 6. The respective conditions, as well as hydrocarbon selectivities are shown in table . GC measurements show absence of CO2 formation, therefore we assume only negligible water-gas shift activity. The hot and cold trap at the reactor outlet remained empty for all operating points, even after several days of operation. Therefore, we also assume that the formation of liquid hydrocarbons is negligible. As operating point 10 (see table 2) exhibits the lowest selectivity towards longer hydrocarbons, but still has a high enough selectivity for C2-4, this operating point was chosen for the PTK experiments. The respective volumetric flow rates through the reactor are shown in table . Since operating point 10 provides a CO conversion of 6.5 % we assumed differential conditions, where only negligible concentration gradients in the catalyst bed are present. Hence, a CSTR balance is appropriate for evaluation. Table