CATALYSIS BY IRON PENTACARBONYL OF THE POLYMERIZATION OF CARBON MONOSULFIDE IN A FLOW TUBE AT LOW-PRESSURES

The presence of very small pressures of iron carbonyl, Fe(CO)5, in a gas flow tube at ∼70 °C catalyzes the polymerization of carbon monosulfide (CS) on the walls of the reactor. Unusual kinetic behavior is observed in which the decay of CS is zero order under all conditions studied, even when the CS concentration is more than ten times greater than that of Fe(CO)5. The rate of CS decay was also independent of Fe(CO)5. concentrations at PFe(CO)5 ≥ 0.02 torr, and decreased markedly only at PFe(CO)5 < 0.001 torr. It is shown that a mechanism in which catalytic sites are created from Fe(CO)5 adsorbed via a Langmuir-type adsorption isotherm on the growing CS polymer can successfully rationalize all the experimental observations. © 1979 American Chemical Society.