Separation of ethyl acetate–isooctane mixture by heteroazeotropic batch distillation

Abstract

This paper studies the separation of an ethyl acetate-isooctane mixture by heterogeneous azeotropic distillation in a batch rectifying column. An initial list of 60 candidates was studied but only methanol and acetonitrile were obtained as potential heterogeneous entrainers. These entrainers form a low boiling heterogeneous azeotrope with isooctane. Experimental verification of the miscibility gap with isooctane was performed at 25 • C for each entrainer giving a smaller region for methanol than for acetonitrile. Feasibility of the heterogeneous azeotropic batch distillation was carried out experimentally in a laboratory batch distillation column having 44 theoretical equilibrium stages and using a high reflux ratio. Several distillate fractions were taken as a function of the temperature at the top of the column. For both methanol and acetonitrile, the main fraction was defined by the condensed vapor providing a liquid-liquid split of the isooctane/entrainer heteroazeotrope into the decanter. Ethyl acetate impurity was detected in both decanted phases, but in much lower amount when using acetonitrile as entrainer. The process with acetonitrile also resulted in a shorter operating time and higher purity and recovery yield of isooctane as the main distillate product. Pure ethyl acetate remained into the boiler at the end of each process.

Azeotropes as Powerful Tool for Waste Minimization in Industry and Chemical Processes

“…This mixture features a low boiling point azeotrope (76.3 °C). In 2014, Gerbaud and coworkers screened 13 entrainers, among 60 candidates, for the recovery of high purity compounds through heterogeneous azeotropic distillation [ 23 ]. Among these, only acetonitrile and methanol were selected as effective entrainers for heterogeneous azeotropic distillation in a rectifying column configuration.…”

A Convenient Hybrid Method for Obtaining Liquid–Liquid Equilibrium Data in Ternary Systems

“…Phase equilibrium measurements are required in many fields and a wide range of applications, from food, materials, metallurgy, geological, oil, polymers, and pharmaceutical industries to energy, including carbon capture and storage (CCS) and carbon capture and utilization (CCU) as well as in scientific fundamental research. Generally, ternary liquid–liquid phase equilibrium data are scarce in the literature. − Among the difficulties related to investigating phase equilibria in ternary systems are the very expensive equipment and the analysis of the phases at equilibrium. One of the most common methods to analyze the phase compositions is gas chromatography (GC).…”

“…Ternary systems including acetonitrile may serve as more selective alternatives to pure acetonitrile in Quick-Easy-Cheap-Effective-Rugged-Safe (QuEChERS) protocols of extraction of pesticide residues, veterinary drugs, mycotoxins, or polycyclic aromatic hydrocarbons in various food matrices . Our literature search revealed that for the first two systems the measurements are available at other temperatures − than in our work herein.…”

Optimization of decanter temperature in separating partially miscible homoazeotrope to reduce cost and energy consumption

“…For the separation of the former, pressure‐swing distillation, azeotropic distillation, and extractive distillation are studied to perform efficiently. Principally, many homoazeotropes are separated by adding an entrainer which could form heteroazeotropes with at least one component of the original mixtures in the continuous distillation and batch distillation . Chien et al applied cyclohexane which could form heteroazeotrope with water to separate isopropyl alcohol/water homoazeotropic system and they used bifurcation analysis and dynamic simulation to implement robust control.…”

“…Principally, many homoazeotropes are separated by adding an entrainer which could form heteroazeotropes with at least one component of the original mixtures in the continuous distillation [20][21][22][23][24] and batch distillation. [25][26][27][28] Chien et al 29 applied cyclohexane which could form heteroazeotrope with water to separate isopropyl alcohol/water homoazeotropic system and they used bifurcation analysis and dynamic simulation to implement robust control. Then Chien et al 30 optimized the two-column approach to separate the mixture based on total annual cost (TAC) and found that it is more economical compared with the three-column approach.…”