Alkali metal carbonate catalyzed carbon-carbon dioxide reaction. II. Reaction intermediates of potassium carbonate catalyzed C-CO2 reaction proved by the olefin isomerization.

Abstract

To confirm a redox mechanism proposed previously for the potassium carbonate catalyzed carbon-carbon dioxide reaction, isomerization of 1-butene was adopted as a test reaction for investigating the properties of the surface. The preferential formation of cis-2-butene was observed at room temperature on the evacuated carbon doped with K2CO3 in the presence of oxygen while no isomerization proceeded in the absence of oxygen. These facts were interpreted consistently in terms of the redox processes, K2O/C+C=2K/C+CO, 2K/C+CO2=K2O/C+CO, that is, isomerization of 1-butene proceeds on the K2O/C accumulated on the surface, which is reversibly recovered by addition of O2 at room temperature or by addition of CO2 at 650°C. On the carbon doped with K2CO3 used for C-CO2 reaction, however, the isomerization hardly proceeded because of the poisoning effect of CO2.