Effects of reaction pressure on the activities and selectivities were investigated over Co/NaY-Zeolite and $Co/\gamma-Al_2O_3$ catalysts.
The fraction of higher hydrocarbons was significantly increased with reaction pressure for the Co/NaY-Zeolite(EW) and $Co/\gamma-Al_2O_3$ catalysts. Over the Co/NaY-Zeolite(IE) catalysts, Schulz-Flory type product distributions were observed at atmospheric pressure, but the preference for $C_4$ hydrocarbons was observed at 10 atm.
Over the Co/NaY-Zeolite(EW, IE) catalysts, the ratio of olefin to paraffin in $C_2$ and $C_3$ hydrocarbons was decreased with reaction pressure.