Isotope effect in Boudouard disproportionation reaction in optically pumped CO

Isotope composition of CO2 produced in CO-Ar mixtures optically pumped by a CO laser has been analyzed by Fourier transform infrared (FTIR) absorption spectroscopy. Carbon monoxide reactant is a higher-than-natural abundance mixture of 13CO and 12CO. Carbon monoxide in the reactor is vibrationally excited by resonance absorption of the laser radiation and is vibration-vibration (V-V) pumped up to high vibrational levels. 12CO vibrational level populations and temperature in the excited region are measured by FTIR emission spectroscopy. Highly vibrationally excited CO molecules chemically react to form CO2, which at these conditions is expected to be enriched in 13C isotope. Chemical reaction products are analyzed by FTIR absorption spectroscopy. The results show that CO2 in the products is enriched in 13C isotope, with enrichment coefficient varying from β = 1.25 to 1.9, and CO2 yield varying from 70 to 170 ppm. These results are in good agreement with the master equation kinetic model.