화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.37, No.5, 1917-1928, 1998
Measurement of residue curve maps and heterogeneous kinetics in methyl acetate synthesis
Kinetically controlled reactive distillation is a bridge between the two limiting cases of nonreactive and equilibrium reactive distillation. In this paper, we study the influence of heterogeneous catalysis on the transition from the nonreactive to the equilibrium reactive limits for the esterification of acetic acid with methanol. A Langmuir-Hinshelwood/Hougen-Watson rate model was developed to represent the reaction kinetics. Since reactive distillation is carried out at the boiling temperature of the liquid, the pressure of the system plays an important role in determining the product composition. Higher operating pressures imply higher temperatures and faster rates of reaction but could also lower equilibrium conversions (for exothermic systems) and trigger unwanted side reactions. To study the importance of side reactions and the effect of pressure on product selectivity, we also include the reaction kinetics for methanol dehydration. Isothermal batch kinetic experiments were performed using a heterogeneous (Amberlyst 15W) catalyst at various temperatures and catalyst concentrations. Independent binary adsorption experiments were also performed to estimate the adsorption equilibrium constants. As a test of the kinetic model, independent equilibrium reactive open-evaporation experiments were performed and the model prediction was found to be in good agreement with the experimental residue curve measurements. The model was also used to predict the behavior of the system in the kinetically controlled regime. Residue curves for the kinetically controlled cases are qualitatively similar to that of the equilibrium case, showing that the production of methyl acetate can be carried out using reactive distillation in both the equilibrium and the kinetically controlled regimes.