Entrainer effect of n-hexanol reactant on coproducing n-butyl and n-hexyl acetate in energy-efficient reactive distillation

Abstract

This study demonstrates the entrainer effect of a co-reactant alcohol on the feasibility of complete conversion and product recovery in reactive distillation (RD) for concurrently producing n-butyl acetate (BuAc) and n-hexyl acetate (HexAc). Introducing n-hexanol widens heterogeneous liquid regions and more purified common byproduct of water can be removed by liquid-liquid decantation. Thus, the participation of n-hexanol is essential for offering higher purity to water and esters with higher reaction extents achieved. To verify the feasibility of the binary-esterification system, the liquid-liquid equilibrium (LLE) region and liquid composition trajectory are visualized in the quaternary space and it is found that the water purity in the direct sequence of RD is 99.41 mol %, which is higher than that of RD with the BuOH single esterification (99.16 mol%). In terms of energy savings for the binary ester production, the upper reactive dividing wall column is the most effective among the design alternatives and reduces the reboiler duty by 13.35 % compared with the total reboiler duty of two conventional single esterification RD systems.