Recovery of acetic acid using esterification of acetic acid with n-octanol in a membrane reactor

Abstract

Down-cycle raw material utilization is a need when it comes to the step out of fossil fuel utilization. Carboxylic acid serve as bulk chemicals, and isolation from industrial aqueous process streams is an ongoing research. Therefore acetic acid esterification of an aqueous acid feed using n-octanol in combination with liquid/liquid-extraction with the solvent mixture n-octanol/n-undecane was investigated. Due to emulsion formation when 4-dodecylbenzenesulfonic acid was used as homogeneous catalyst, the reaction was transferred into a membrane reactor. The homogeneous esterification in the membrane reactor is described by phase transfer catalysis. The combination of acetic acid extraction from aqueous mixture combined with heterogeneous catalysis was investigated in the membrane reactor too. Physical extraction and heterogeneous catalysis lead to conversion of acetic acid, while the reactive solvent Tri-n-octylamine inhibited heterogeneous catalysis by Amberlyst®15. The work provides a novel approach for process intensification of liquid/liquid extraction in combination with an esterification reaction using a membrane reactor.