Kinetic Study, Modeling and Simulation of Homogeneous Rhodium-Catalyzed Methanol arbonylation to Acetic Acid

Thermodynamic restrictions and simultaneous effects of operational conditions on the homogeneous rhodium-catalyzed carbonylation of methanol are studied in this line of research. It is shown that the general NRTL-Virial model can be appropriated to study thermodynamics of the carbonylation. It is obtained that the reaction is kinetically and thermodynamically reasonable at temperatures above 420K and below 520K, respectively. Moreover, at carbon monoxide partial pressures above 10 bar, the reaction rate is independent of the partial pressure. These results are in full accord with those reported in the literature. In addition, PCO > 2 bar is necessary for initializing the reaction. The parameters involved in the rate expression, equilibrium constants, CO solubility, and rate constant, are determined. The equilibrium constants are calculated with B3LYP/SDD ab initio method, and the value of Henry’s coefficient for CO (HCO) is determined as a function of temperature and methyl acetate conversion. The results predicted by this function agree well with those proposed by the general NRTL-Virial model with the errors below 11%. The Variation of CO solubility with acetic acid and methyl acetate concentrations is in good agreement with that obtained by others. It is found that the determined parameters give satisfactory predictions in modeling and simulation of the reaction.