REACTION-KINETICS OF HYDROGEN AND AQUEOUS SODIUM AND POTASSIUM BICARBONATE CATALYZED BY PALLADIUM ON ACTIVATED CARBON

The intrinsic reaction kinetics of hydrogen and the aqueous bicarbonat e ion has been studied in the presence of a Pd/C catalyst up to satura tion of the salt solution. Experiments were carried out at temperature s of 20, 40 and 60 degrees C and at hydrogen pressures ranging from 1- 20 bar using a mechanically agitated slurry reactor. Based on the init ial rates, it is proposed that in the rate determining step a surface reaction between unadsorbed bicarbonate and associatively adsorbed hyd rogen is involved. A Langmuir-Hinshelwood type rate equation has been derived, which is based on the activities of the reacting species. Eva luation of the experimental data resulted in approximate values of the activation energy for the sodium and potassium salt. These were found to be about 23-25 kJ mol(-1). A good correlation (within 10% error) w as demonstrated between the predictions of the proposed rate equation and the experimental data at a constant carbon dioxide pressure of abo ut 1 bar.