Carbon-Hydrogen-Acetylene Equilibrium at High Temperatures

The concentration of acetylene in equilibrium with carbon and hydrogen at temperatures up to 3000°K has been measured experimentally using water-cooled quenching probes in a carbon tube furnace. Previous calculations of the thermodynamic properties of acetylene have been extended to cover this temperature range. Also, the effects of free radical species present at these temperatures were estimated. The only ones deemed important in the temperature range of this investigation were H and C2H; an estimate was made of the free energy of C2H to predict its effect on the composition of the quenched gas samples from the furnace. The predicted quenched gas compositions are in good agreement with the experimental measurements.