Kinetic Research On Synthesis Tert-Butyl Acetate With Acetic Acid And Isobutylene

With the rapid development of the petrochemical industry, light olefins resources become more and more rich. The development and utilization of the olefins in liquefied petroleum gas (LPG) olefins to produce high-added value products become a new topic. The influence of within diffusion and outside diffusion on esterfication of isobutylene and acetic acid in tubular reactor. The experimental results show that different particle size of catalyst (20 to 60 mesh) and inside diffusion have little influence on the conversion of isobutylene When space velocity is more than 25 h-1, effect of the outside diffusion is negligible. Based on this, the influence of the technological conditions on the esterfication reaction were investigated and the optimum technological conditions for dynamics experiments were determined as follows:below 35℃of temperature,1.0 to1.2 Mpa pressure,4.0～5.0 of acetic acid, to tert-Butyl acetate mole ratio,25 h-1 of space velocity.Because of the strong non-ideal nature of the reaction system, the dynamic model equations were established by using activities of the components instead of mole fraction. Three kinds of activity calculation models (UNIFAC. Gmeling-UNIFAC, Larsen-UNIFAC) were used to calculated activity of the component in the reaction system. it was found that the calculation values of Gmeling-UNIFAC model and Larsen-UNIFAC model were close. Considering the associating property of acetic acid, Larsen-UNIFAC model was choosen to calculate the activities of the components in the reaction system. Furthermore chemical equilibrium constants Kep for esterfication reactions were obtained. The results show that Kep from experiment method is more credible than that from the theory calculation method.Based on three mechanism principles for homogeneous phase model P-H, heterogeneous phase model E-R, L-H, four kinds of dynamic model equations were set up. Fitting calculation with experimental data by Runge-Kutta method and least squares method. furthermore kinetic parameters for each model were obtained by using component activity instead of mole fraction. The results show that E-R (HAc adsorption) model and P-H model have better fitting results than the E-R (IB adsorption) model and L-H model. According to analysis from the identification index parameters and fitting effect for models, E-R (HAc model) is better than P-H model.