A Systematic Method for the Development of Operating Policies for Two-Step Processes with Semibatch Reactive Distillation

Abstract

Semibatch reactive distillation (SBRD) is a variation on batch reactive distillation (BRD) in which one reactant or an entrainer is fed to the process continuously during the batch. Qi and Malone (Qi, W; Malone, M. F. Semibatch Reactive Distillation for Isopropyl Acetate Synthesis. Ind. Eng. Chem. Res. 2011Res. , 50, 1272Res. −1277 suggested SBRD for the synthesis of isopropyl acetate with acetic acid fed continuously at the top of the column to reduce the composition of the alcohol in the distillate product. The distillate product from the SBRD is a mixture of water and ester which can subsequently be separated by inverted batch distillation (IBD). The optimization of such a two-step batch process involves trade-offs between the two steps (SBRD and IBD). In this work, an algorithm for systematic design of such processes is developed and applied to processes for the synthesis of isopropyl acetate and ethyl acetate. The key variable connecting the two batch steps is the composition of alcohol in the SBRD distillate product. Allowing a higher alcohol composition makes SBRD operation easier but IBD operation more difficult. The algorithm identifies the alcohol concentration which minimizes total process time, which is closely related to energy consumption, as well as side feed flow rate and reflux ratio profiles during the batches.

Solubility and Liquid–Liquid Equilibria for the Isopropyl Acetate + Isopropanol + Acetic Acid + Water Quaternary System at 313.15 K and 101.3 kPa

“…For this quaternary mixture, separation and purification problems should be considered. With the continuous research and development of the isopropyl acetate synthesis method and new catalyst, the synthesis of isopropyl acetate has been transformed from the traditional multistage continuous production to the advanced reactive distillation process, and the method has been extensively studied. − Reactive distillation of the quaternary system isopropyl acetate + isopropanol + acetic acid + water and the related important vapor–liquid equilibrium data and thermodynamic and kinetic properties have been researched in recent years. − …”